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Proceedings of the Chemical Society. March 1959 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue March,
1959,
Page 73-108
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PROCEEDINGS OF THE CHEMICAL SOCIETY MARCH 1959 THE BEGINNINGS OF CO-ORDINATION CHEMISTRY By H. M. POWELL (THEUNIVERSITY, OXFORD) EARTH,stones that fall from the Heavens and a combination of telescope and spectrograph pro- vide evidence that chemistry has been going on in many regions for a very long time and no one would presume to identify the beginning of any branch of it in an absolute way. Co-ordination compounds even the Werner-type existed before Werner and before man. Ligands more complex than ammonia ethylenediamine or water but recognisably related to them are co-ordinated to transition-metal atoms in some natural com- pounds of the vegetable and animal kingdoms and Na,Co(CSN),,8H20 is known as a rare mineral julienite.Man’s first synthesis of co- ordination compounds may have occurred in re- mote times since it seems very probable that suitable materials containing iron potash and nitrogenous matter such as blood or animal hooves may have been heated together to give ferrocyanides. In 1704 Diesbach a chemist of Berlin partly by accident found how to prepare Prussian blue but apparently in the hopes of gain concealed the technological know-how for some time. Instructions for the preparation given in the Philosophical Transactions of the Royal The Original Prescription Praeparatio Caerulei Prussiaci ex Germania Missa ad Johannem Woodward M.D. Prof. Med. Gresh. R.S.S. Tartari crudi & Nitri crudi Siccati ad 3 iiii. Pulverisentur minutissime & commisceantur deinde admoto igneo carbone detonentur & habebis Salis Tartari extemporanei 3 iiii.Dum Woodward Phil. Dam 1724,33 15. 73 Society in 1724 may be taken to mark an im- portant stage in the development of modem co-ordination chemistry. This paper1 is reproduced below. The preparation published by John Woodward is described as being from Germany but how it was obtained is not clear. Dr. John Woodward Professor of Medicine at Gresham College is distinguished beyond most co-ordination chemists in that he was not only elected a Fellow of the Royal Society but was also expelled. He insuked Sir Hans Sloane and refused to withdraw. As a result of well-planned experiments in which the preparation was re- peated and modified John Browne F.R.S.showed2 that the alum is not necessary and that the blue colour cannot be obtained with silver or several other metals. He concluded that its origin lies in the iron and thus he made the first step in building up the chemical constitutional formula of this substance. The road has led to the Con- ference to be held in London in a few days’ time where among the 140 contributed papers on a variety of newer types of co-ordination com-pound there is still something new to be learnt about ferrocyanides. The Prescription Translated Preparation of Prussian Blue sent from Germany to John Woodward M.D. Prof. Med. Gresh. F.R.S. Take 4 02. of crude tartar and 4 oz. of dried crude nitre; powder them minutely and mix.Detonate them with charcoal and you then have 4 oz. of extemporaneous alkali. While this salt is a Browne ibid. p. 17 adhuc calidum est hoc Sal pulverisetur subtilis- sime & addantur sanguinis Bovini probe exsic- cati & subtiliss. pulv. 3 iiii. Haec bene mixta indantur crucibulo ut tertia pars vacua sit; imposito dein operculo igni committatur & circumdetur crucibulum carbonibus ut sensim ardescat & materia sine praepropera accensione flammam concipiat & ignescat. In hoc ignis gradu teneatur materia donec flamma & accensio remittat; augeatur demum ignis ut valde candeat materia & parum flammae e crucibulo amplius emineat. Remove demum ab igne crucibulum & materiam mortario ingestam leviter contere & ad manus habeto aquae ferventissimae pluvialis libras 4 ponderis civilis cui materiam adhuc ferventem immittas & per semihorae spatium coque; decoctum per linteum coletur & materia remanens nigra aquae portioni denuo affusa igni iterum apponatur coquatur & percoletur ; id quod eousque continuandum donec salsedo & acrimonia omnis e materia sit elixiviata & aqua redeat insipida.Humores omnes in linteo & materia residuos fortiter exprime & ubi singula in unum colligeris igni iterum committe & ad remanentiam 7 librarum evapora & ulteriori usui serva sub. No. 1. Porro Vitrioli Anglici ad albedinem leviter calcinati 3 i. solvatur in Aquae pluvial 5 vi. filtretur per chartam & signetur No.2. Denique aluminis crudi 3 viii. Solvatur in libris 4 aquae ferventissimae ad omnimodam Aluminis consumptionem hoc rite peracto, adjunge solutionem Vitrioli sub. No. 2. asserva-tam quae ex igne fervens ingeratur ollae satis magnae & amplae & cum lixivio No. 1. seorsim bene fervefacto combinetur. Fiet ex continenti magna ebullitio & apparebit color viridis montani seu chrysocollae; effundatur alternis vicibus durante ebullitione ex uno vase in aliud qua cessante quieti committe. Tum linteo insinuetur ut aquositas transeat color vero in linteo remaneat ; si igitur nihil humiditatis amplius distillet cum spathula lignea e linteo in ollam novam minorem remove; superfunde postea spiritus salis comm. 3 ii. vel3 iii. & statim apparebit color caeruleus pulcherrimus ; quae probe mixta per noctem quiescant quo facto aquae pluvialis magna quantitas addatur in gyrum moveatur spathula & posteaquam resedit materia aqua decantetur & recens aqua super- fundatur & eousque labor reiteretur donec omnis acrimonia sit desumpta & aqua insipida defluat ; hoc pacto praecipitatum tuum summe caeruleum linteo expanso ingere ut aqua distil- let sensimq; color calore leni exsiccetur usui.PROCEEDINGS still hot it is finely powdered and 4 oz. of well- dried and finely powdered ox blood is added. These well-mixed components are placed in a crucible so that it is two-thirds filled. After it has been covered with a lid it is put on a fire and the crucible is piled round with coals so that it gradually begins to glow and the material takes fire and begins to burn without any violent out- burst.The material is kept in this degree of fire until the flame and eruption slacken. The fire is then increased until the substance glows intensely and little further flame emanates from the cruc- ible. Then remove the crucible from the fire and grind the material gently in a mortar; have ready 2 pints of boiling fresh water into which the material is thrown while still glowing and boil for the space of half an hour. The decoction is passed through a piece of linen and the remaining black material on to which a further portion of water is poured is once more placed on the fire boiled and filtered. This procedure should be continued until the saltiness and all bitterness have been washed out and the water remains in- sipid.Well press out all the liquors remaining in the linen and the material and when you have collected them all together place again on the fire and evaporate down to 3Q pints and keep for later use. (No. 1). Then take 1 oz. of green vitriol calcined gently to whiteness and dissolve it in 6 oz. of fresh water; filter through paper and call this No. 2. Then take 8 oz. of crude alum. Treat it with 2 pints of boiling water until com- plete dissolution of the alum and when this has been done add it to the solution of vitriol No. 2 which is taken boiling from the fire put into a pot of sufficient capacity and combined with the well boiling lixivium Nu.1 previously set apart. There is a great effervescence of the contents and a green or greenish-blue colour appears. The liquid is poured alternately from one vessel to another during the effervescence until it stops; then let it stand. It is then transferred to a piece of linen so that the liquors may flow through and the coloured substance remain on the linen. When no further water drips through it is re-moved from the linen with the aid of a wooden spatula into a fresh smaller pot. Pour on to it 2 or 3 oz. of spirit of common salt and at once there appears a most beautiful blue colour. All is well stirred and allowed to settle overnight. Then a large quantity of fresh water is added and stirred with a spatula. After the material has settled the water is decanted and a fresh lot of water is poured over it and this operation is repeated until all bitterness has been washed away and the water which flows out is insipid.When this has been completed transfer the in- MARCH1959 N.B.-Calcinatio magni momenti est in hoc opere nam color cyaneus & caeruleus obscurus ortum sum trahit a calcinatione levi mediocri & forti sanguinis arefacti cum sale Tartari & inde diversitas coloris. Lifivia ferventissima uno eodemque festina- tissimo actu sunt confundenda. sensely blue precipitate to a taut piece of linen to that the water may gradually drain away. The pigment is dried in a gentle heat and is then ready for use. N.B.-In this procedure the calcination is of great importance because the sea-blue colour and the hidden sky-blue arise according as the cal- cination of the dried blood with the alkali is light medium or strong and hence there is a diversity of colour.The well-boiling lixivia are to be mixed one with the other in the most rapid manner. Structural Representation of Aromatic Compounds By WILSONBAKER (THEUNIVERSITY, BRISTOL) THEPublication Committee of the Chemical Society discussed at recent meetings how in view of modern developments aromatic and certain other unsaturated compounds should be represented in structural formulae in the Society’s publications. The Committee resolved that (1) KekulC-type structures should in general continue to be used. (2) Large circles representing six delocalised m-electrons in cyclic systems (with or without positive or negative signs as appropriate) should be permitted for certain types of compounds and in certain circumstances.(3) Cyclic systems having more or fewer than six delocalised n-electrons may be represented by formulae containing dotted lines. (4) No new symbols need be introduced. The Committee authorised publication of the following article prepared by Professor Wilson Baker as presenting its general views. Summary of Reasons for the General Preference for Kekule‘ Structures rather than for Formule with Circles.-(a) KekulC structures* have been almost universally used for at least 90 years and have not been found wanting. The symbolism should not be changed unless some very real advantages accrue e.g.more accurate representation more ready repre- sentation of chemical reactions less liability to mis- use and misunderstandings greater ease in reckoning the number of m-electrons etc. No such advantages appear to be associated with the circle symbol. (6) Unlike KekulC structures circles cannot be used in conjunction with arrows representing electro- meric changes (see para. 5). (c) Except in very simple usually monocyclic cases the circle as such does not readily give the number of m-electrons. The circle has however some advantage in this respect in the representation of simple heterocyclic substances including meso- ionic compounds. (d) Formula= with circles unlike the corresponding KekulC formula are misleading in certain cases (see para.14 structures 46 and 50). (e) KekulC structures unlike those with circles allow limited representation of uneven m-electron distribution e.g. in naphthalene indane pyrrole etc. by writing the most important canonical form. 1. The Circle Symbol.-The symbol should be a large continuous circle as in (3) not a dotted circle. 2. Meaning of the Circle Symbol.-Many difficulties arise if the circle is used vaguely e.g. to represent “aromatic” character. It is essential that the meaning of the circle should be quite definite and it is recom- mended that it must in all cases represent six de-localised m-electrons (a n-electron sextet) which may in part be shared with an adjacent sextet or sextets.l m-Electron sextets can be so represented in five- six- or seven-membered cyclic compounds in which all the annular atoms take part in a single conjugated system.2 The cyclic compounds may be neutral or they may be cations (e.g.4) or anions (e.g. 5) or they may be radicals (e.g. 47). Thus if benzene is represented by (3),naphthalene is (1) and anthracene is (2).It has been objected that * In this paper the phrase “Kekulk structures” means ring systems drawn so as to contain the maximum number of non-cumulative double bonds. Baker “Development of the Concept of Aromaticity” in “Perspectives in Organic Chemistry,” Ed. Sir Alexander Todd Interscience Publ. Inc. New York 1956 pp. 34-67. See Dewar “The Electronic Theory of Organic Chemistry,” Oxford Univ.Press 1949 p. 160. (1) might be thought to represent a molecule with 12 r-electrons whereas there are in fact only 10. How- ever when two n-electrons are shared by two fused Mgs as in (l) the total number of n-electrons is 2 less than the number of rings x 6. Hence in naphthalene the number of n-electrons is 2 x 6 -2 = 10. Similarly in anthracene (2) the number of n-electrons is 3 x 6 -4 = 14.(For the calculations in more complicated cases s8e Appendix.) More simply in all such cases the number of n-electrons is equal to the number of carbon atoms taking part in the conjugated system but this calculation does not of course involve the circle symbol. 0) (2) It must be emphasised that it is nut recommended that benzene naphthalene and anthracene should normally be represented by formula (3) (I) and (2); the Kekuld structures are preferable.3. Use of Kekule' Structures.-It is recommended that KekulC structures should continue to be general- ly used but that in certain types of compounds and in certain circumstances the circle symbol may be preferable (see paras. 7,8,9 and 10). The circle might be used if for example it were desired to emphasise the close similarity which exists as the result of delocalisation of n-electrons between benzene (3) the tropylium cation (4),and the cyclo- pentadienyl anion (5). This similarity is not so ap-parent if the KekulC type structures (6) (7) and (8) are used for these compounds. 0+a-0 (6) (7) (8) 4.Formula! containing both Kekule' and Circle Symbols.-Formulae such as (9) (lo) and (11) con- taining both circles and double bonds have been used but are not generally acceptable. They possess no advantage over the Kekul6 structures which should be used except perhaps in a very few special cases (see para. 10). (9) 00) (I I) 5. Representation of Electromeric Chnges.-An * Baker and Ollis Qwt.Rev. 1957 11 15. PROCEEDINCH important objection to the general use of the circle is that it is not possible to represent electromeric changes satisfactorily or logically as is possible with Kekulk structures 6. Heterocyclic Compoundr.-There seems to be little if any advantage in representing e.g. thiophen oxazole indole and pyridine by (1 2) (1 3) (14) and (15) with circles rather than by the KekulC structures (16) (17) (18) and (19).The formula with circles might however be used if the general aromatic character of these compounds were being discussed in terms of their possession of sextets of delocalised nelectrons (see para. 3). H (17) (18) One disadvantage of such formula with circles is that they appear to represent uniform delocalisation of the six n-electrons which is certainly not achieved. On the other hand the KekulC structures with their conventional implication of delocalisation represent the actual state of the molecule at least as well as the formula= with circles. 7. Tropylium and Cyclupentadienylium Ions.-The tropylium cation and the cyclopentadienylium anion may be represented equally acceptably either by the formulae with circles (4) and (5) or by the Kekuld formula (7) and (8).In formula (4) and (5) the charges associated with the ions are appropriately placed within the circle according to the usual practice. The use of circles in these and related cases should certainly be permissive. Note that the number of r-electrons in these cases is equal to the number of carbon atoms taking part in the conjugated system plus one if the formula is that of an anion and minus one if the formula is that of a cation. 8. Meso-ionic Compounk-There is much to be said for using a circle in the representation of such compounds as N-phenylsydn~ne~ (20) rather than by representing them by an almost arbitrarily chosen MARCH1959 canonical form e.g.(21). All the canonical forms which might be used to represent meso-ionic com-pounds are dipolar or tetrapolar. Formula (20) at CH-C-0-+,CH;pLC-O-Ph-N' @ I Ph-N 1 'N-0 -0 (20) (2 0 once conveys the information that there are 6 z-electrons associated with the heterocyclic ring and that the system is aromatic; formula (21) must be studied closely before it is evident that 6 n-electrons are present. Nevertheless formulae of both types (20) and (21) are acceptable. Difficulties arise in fused-ring meso-ionic com- pounds. Thus (22) represents such a compound* as a dipolar canonical Kekulk form; (23) represents the R-'pi" P JOP ,I@? 02) 03) (24) same compound with the circle symbol and positive charge in the meso-ionic ring but KekulC bonds in part of the pyridine ring; (24) uses circles in both rings.Formula such as (22) and (24) are acceptable but only one of these types should be used normally in a single publication or series of papers. The mixed formula (23) cannot be regarded as acceptable. Fortunately these are rare compounds. 9. Azu1enes.-The azulenes present a more difficult problem. For the hydrocarbons the KekulC formula (25) and the formula with circles and electric charges (26) have been used. It is obvious that (25) represents (25) (26) (27) a molecule having 10 rr-electrons and in view of the substance of paragraph 2 formula (26) also clearly has 10 .rr-electrons.That there is transfer of electronic charge from the seven- to the five-membered ring is not obvious from the KekulC formula (25) but the complete charge transfer indicated in (26) goes too far because the dipole moment of azulene is only 1.0 D. In view of the facts that a seven-membered carbon ring is associated with a positive charge in the aromatic state and that a five-membered carbon ring is associated with a negative charge perhaps (26) is preferable to (25). The use of circles without charge signs in such cases is incorrect. It is suggested that formulae of both types (25) and (26) be accepted. If it is thought that (26) indicates a Lawson and Miles Chem. and Id. 1958,461. degree of doublebond character in the central bond which is probably not justified then (27) might be used where the dotted line represents a peripheral conjugated system (for other uses of the dotted line see paras.11 and 13). However the KekulC structure (25) indicates the single bond character of the central bond quite satisfactorily because the formula cannot be drawn with a double bond common to the two rings. 10. Azuleniurn Cations.-Formula (28) and (29) have been used to represent the azulenium cation; it is known that the proton becomes attached to the carbon in position 1. Formula (28) is certainly ac- ceptable but (29) may be thought preferable because it gives a probably more accurate representation of the n-electron distribution. It is perhaps only in such a case or in e.g. (30) that it is permissible to use both a circle and a double bond or KekulC structure within the same formula.11. Phenalene Derivatives.-There seems little ad- vantage in using other than KekulC-type formulae for the cation (32) anion (33) and free radical (34) related to phenalene (31). The positions of the plus minus and radical signs shown in (32) (33) and (34) are not intended to imply that these formulae are correct; they are simply canonical structures which can be drawn. A dotted line round the periphery of the molecule has also been used as in (33 and is acceptable without prejudice to the question of whether or not this representation is correct (see paras. 13 14). (34) (35) 12. Representation of Compounds having One or More Fixed Double Bondi in All the Kekule' Struc- tures.-The simplest compound of this type is ace naphthylene (36) all three KekulC structures of which have a double bond between carbon atoms 1 and 2.This feature is emphasised if circles are used in the two six-membered rings (37) but the presence of circles and double bonds in the same formula is con- sidered unacceptable (para. 4). Any one of the Kekulk structures preferably (36) with its conven- tional implication of the others is undoubtedly a satisfactory representation of acenaphthylene. The case of zethrene5 is similar. It might be sug-gested that it should be given formula (38) so as to emphasise the fact that in allthe Kekulk structures the central hrbon system is butadienoid whereas the four outer Mgs form two naphthalenic systems.Formula (38) however may be criticised for the same reason as formula (37) and the molecule is undoubtedly adequately represented by a purely KekulC structure. 13. Use of the Dotted Line extending over the Con- jugated System-It was suggested in paragraph 9 that formula (27) may be acceptable for azulene and in paragraph 11 that (35) may represent the phen- alenylium ion. The benzotropylium cation may be represented similarly by (39) though this formula may suggest that the positive charge is evenly dis- tributed over the molecule; the alternative formula (40) appears to locate the positive charge too definite-ly in the seven-membered ring. It is recommended that in spite of their shortcomings formulae of (4 11 (42) (43) either type (39) or (40) be accepted.KekulC structures for the benzotropylium cation are not entirely satisfactory. Dotted lines seem to be appropriate for cyclic PROCEEDINGS conjugated systems with more or fewer n-electrons than six for example Boekelheide’s cyclodecapenta- ene derivative (41) (10 n-electrons in the periphery) and Breslow’s triphenylcyclopropenyl cation (43) with only 2 such n-electrons.’ Circles could not be used in place of the dotted lines in formulz (41) and (43) but Kekulk structures (42) and (44)are accept- able alternatives. The idea has been extended to com- pounds of the porphyrin and the phthalocyanine class where there are much larger conjugated cyclic systems. It may be pointed out that cyclo-octatetra- ene having 8 T-electrons would not be properly represented by an octagon with an inscribed dotted line because strictly speaking,* it is not a conjugated hydrocarbon;it is non-planar and contains alternate double and single bonds and is therefore correctly represented by a KekulC structure.Dotted lines have been used for a very long time to represent mesomeric structures e.g. the ally1 anion enolate ions transition states etc. -8 [CH~-CH-CH,] -o -CH -CH -14. The Phenalenyl Radical and Triangu1ene.-Difficulties arise in a few cases if circles are used instead of Kekulk structures. Suppose the following question is asked. Can the substance depicted in the incomplete formula (45) represent an ordinary aromatic hydrocarbon ? CH HC”CH (45) (47) (48) If the three circles are put in giving (46) (C and H atoms are omitted) the result appears to be an ordinary tricyclic aromatic hydrocarbon until it is realised that the formula is CI3H9,and that it has odd numbers of hydrogen atoms (nine) and of n-electrons (thirteen) so that the substance must be Clar Lang and Schulz-Kiesow Chern.Ber. 1955 88 1520; see also Coulson and Moser J. 1953 1341. Boekelheide and Windgassen J. Amer. Chem. SOC.,1958 80 2020. Breslow J. Arner. Chem. Soc. 1957 79 5318; Breslow and Yuan ibid. 1958 80 5991. Baker and McOmie “Non-benzenoid Aromatic Compounds” in “Progress in Organic Chemistry,” Ed. J. W. Cook, Butterworths Scientific Publications 1955 Vol.111 pp. 48 49. MARCH1959 a free radical. The free radical nature may best be represented by (47) in the same way that CH3-is used to represent the methyl radical. It must be realised that the dot in (47) does not represent an actual n-electron because the three circles already indicate the 13 n-electrons (see appendix). Any one of the Kekulk-type structures e.g. (48) shows immediately both the radical nature of the molecule and that it possesses 6 x 2 + 1 = 13 n-electrons. Note that the dot in (48) Iike the dot used in the methyl radical does represent an actual n-electron. A similar case is afforded by triangulene (un- kn~wn).~ If one were given the carbon and hydrogen structure (49) and attempted to depict the derived aromatic structure by putting in circles the result would be (50),an apparently normal aromatic hydro- carbon C22H12, with 22 n-electrons (see appendix).This is an erroneous conclusion because (49) must in fact be a diradical having two unpaired n-electrons. (49) If triangulene is represented by any of the Kekulb structures e.g. (51) it is at once apparent that it must be a diradical of which (51) is one of the canonical forms. Formula (50) is therefore quite un- satisfactory but it might be rationalised by placing it in brackets with two dots outside (these must not be counted as n-electrons in addition to those designated by the six circles) (cf. formula 47). 15. If finer points of bond distribution require dis-cussion any special symbolism should be explained in each paper where it is used; such special symbolism should whenever possible not be liable to confusion with the more general representations discussed above.1° Appendix.-Use of circIes in caIcuIating the number of n-electrons in polycyclic systems.As an example the total number of welectrons in pyrene (52) may be calculated as follows :4 x 6 (four sextets) -4 x 1 (four n-electrons shared between two sextets) -2 x 2 (two n-electrons shared between three sextets) = 16. The four separate sextets are set out in diagram (53) to show why these 4 x 1 and 2 x 2 subtractions of n-electrons have to be made. Thus in any neutral polycyclic system the total number of 77-electrons is equal to the number of circles x 6 less the number of carbon atoms com- mon to two rings x 1 less the number of carbon atoms common to three rings x 2.By applying this calculation to the case of coronene (54) the total number of n-electrons is found to be 24(7 x 6 -6 x 1 -6 x 2 = 24). Theultimate case of a fused polycyclic aromatic compound is graphite having n six-membered rings and n circles; there would be 2n carbon atoms and 2n n-electrons (n x 6 -2n x 2 = 212). In comparison with these calculations the number of n-electrons may be more easily calculated from any Kekul6 formula (2 x number of double bonds) and in purely aromatic hydrocarbons the number of rr-electronsis more simply still equal to the number of carbon atoms. This article has benefited greatly from the helpful advice received from Drs.J. F. W. McOmie and W. D. Ollis and from their willingness to be drawn into many fruitful discussions. I thank also the members of the Council and the Publication Com- mittee of the Chemical Society who have given me the benefit of their advice and comments. (Janwy 16th 1958.) Clar and Stewart. J. Amer. Chem. SOC.,1953 75,2661; Clar Kemp and Stewart Tetrahedron 1958 3 325. lo Cf. Clar Ironside and Zander J. 1959 142. PROCFJED~NGS LANGMUIR MEMORIAL LECTURE* Irving-& By Sir ERICRIDEAL IRVING was born in Brooklyn New York LANGMUIR on January 31st 1881 the son of Charles and Sadie Comings Langmuir the latter a descendant of the Lunt family which went to America in the May-flower.He obtained his primary education in the public schools in Brooklyn afterwards travelling With his parents to Paris where his father had large Insurance interests. Here he studied for three years. On his return to the United States he worked at the Chesnut Hill Academy Philadelphia the Pratt Insti- tute in Brooklyn and at the School of Mines in Columbia where he graduated in metallurgical en- gineering in 1903. He took a Ph.D. degree in Gottingen in 1906 where Nernst does not appear to have been particularly impressed by him.From 1906 to 1909 he taught chemistry at the Stevens Institute of Technology at Hoboken in New Jersey. In the summer of 1909 he was invited by Dr. Whitney Director of the Research Laboratory of the General Electric Company to visit the laboratory at Schenectady and he joined the staff there.Dr. Whitney suggested that he should spend some time in the laboratory to see which of the current investi- gations was of most interest to him. At that time Coolidge in developing the X-ray tube had succeed- ed in drawing tungsten wire. From time to time the drawn wire proved to be brittle and it was suspected that occluded gas was responsible. Dr. Whitney sug- gested that Langmuir should examine this in more detail and thus was started a series of monumental investigations which will always be associated with the name of Irving Langmuir. One general characteristic of Langmuir‘s work was the directness and simplicity of his approach. He once said “Perhaps my most deeply rooted hobby is to understand the mechanism of simple and familiar phenomena”.Langmuir noted that the heat loss from tungsten wires heated in hydrogen increased at an abnormally high rate when the temperature was raised; thus up to about 2,300”~the heat loss was what could be expected but at 3,300”~ it was over four times the calculated value. He was led to the view that the extra heat was absorbed in dissociating molecular hydrogen into the atomic form. He then considered in detail the exact molecular mechanism for this process of dissociation. Again he observed that when a tungsten filament was heated to high temperatures in hydrogen at a few bars pressure there was a gradual diminution in the gas pressure-in other words a clean-up of the gas.He concluded that the molecular hydrogen dissociated by impact on the * Delivered before the Society at Burlington House on hot wire and that the atoms were adsorbed by the glass walls of the vessel. These observations were rapidly extended in several directions. They led to establishing rigorous equations for computing the heat loss from elec- trically heated wires of different shapes and sizes and to the determination of the equilibrium constant for the dissociation of hydrogen over an extended range of temperatures an investigation which culminated in the practical result of the atomic-hydrogen blow- pipe or arc. Perhaps the most important of these developments was the extension of the work to the study of clean-up of various gases with filaments of different materials which in turn may be said to have been the basis of those remarkable experiments on chemical reactions at low pressures.Incidentally the practical by-products of these investigations were many. The Langmuir vacuum- pump and the nitrogen-filled electric lamp may be mentioned as especially important. Indeed Lang- muir’s vacuum-pump was instrumental in developing one of the most interesting of legal controversies “when is a vacuum not a vacuum.” Fleming the original discoverer of the thermionic valve of a simple type claimed in his patent that he exhausted the bulb containing the two wires by means of an oil-pump. Langmuir utilising his vapour-condensa-tion pump naturally obtained a more effective vacuum and with it the secondary ionisation by electron collision with the residual gas was greatly diminished.He found that when a filament was heated in a gas at a few bars pressure the subsequent reaction was one of four different types. First the filament might be attacked directly by the gas. Thus when a tungsten filament is heated in oxygen at 100 bars pressure the oxide formed W03 distils off continuously its rate of formation being proportional to the pressure of the oxygen. Langmuir showed that the fraction of molecules striking the wire calculated by the Herz-Knudsen equation which underwent reaction was independent of the pressure but varied with the temperature E being 0.00033 at 1070”~ and 0.12 at 2520”~.On the other hand in some reactions the gas reacts only with the vaporising atoms of the filament. He found for example that the clean-up of nitrogen by hot tungsten proceeded by this method. The rate of clean-up is equal to the rate of vaporisation of the tungsten until the pressure falls so that metallic atoms can get to the walls without collision. Such adsorbed atoms donot react with nitrogen but if the bulb is cooled in liquid air atoms impinging on March 12th 1959. Irving Langmuir MARCH1959 adsorbed nitrogen do react. He could even estimate the extent of coverage of the glass by adsorbed nitrogen by this method. Carbon monoxide behaved in a similar manner. It is of interest that in examining the oxidation of carbon monoxide at the surface of a platinum wire he found that this gas could be adsorbed in two different ways-an unreactive low-temperature form and a reactive form into which the former was slowly converted at higher temperatures-the first recorded case of what are now termed activated adsorptions.A third type of reaction consisted in the filament’s acting catalytically on the gas remaining unchanged itself. A good example of this is the dissociation of hydrogen. Fourthly the hot filament emits electrons and these in their turn may alter the composition of the gas. The last two observations led Langmuir to an extended series of investigations into the phenomena accompanying thermionic emission from clean and partly covered surfaces into the effects of the emitted electrons and of positive ions on the gas and the development of spacecharge equations for currents flowing between concentric spheres and coaxial cylinders.Hiscontributions to physics are considered by many to be as important as his work on chemistry (and its oscillations) especially with respect to the study of the plasma i-e. that region of ionised gas in which both the positive-ion and electron concentration are approximately equal. This represented a major ad- vance in physics. Starting from the Richardson equa- tion for the thermionic emission from a clean surface I = AT2exp (-b/T) he examined the effects of partial coverage of a tungsten emitter with adsorbed ions such as thorium and caesium.He showed that the fraction of the surface covered could be derived from the work hnctions of the emitter when clean +” when corn- pletely covered +’ and when partly covered + by the simple relation -8 = (4”-+>/<p$7 Again he showed that the thermionic electrons emitted were in Maxwellian distribution since the number which were capable of moving against a retarding field of Vvolts were given by the Boltz- mann equation nf8 = exp (-Ve/kT) In further investigations of the plasma he made great use of what we now term “the Langmuir probe.” This consisted of an electrode inserted in the gas the electrode potential being adjusted so that no current would flow into or out of it. With Kingdon he investigated the thermal ionisa-tion of gases and studied equilibria of the type which may be represented by the equation Mt,M++e He developed equations more general than those of Saha and applicable to systems which were con- tained in walls of fhite dimensions.Langmuir’s equation in general use at the present time is as follows where n, n, n are the number of electrons positive ions and atoms per ml. V is the ionising potential of the gas in volts and T the temperature. He made a number of interesting observations on thermionic emission from partly covered surfaces which still merit detailed investigation. From a clean metal the simple image force holding the electron back i.e. e2/4x must fail in close proximity to the surface. He found that the relationship 4 = e/2x‘ was applicable where x’ was of the order of the atomic radius of the metal.One very interesting experiment which he carried out with a thorium-covered tungsten surface showed that the electron emission was 126,OOO times greater than for a bare surface. If the surface were half covered the emission was 63,000 times as great. However if the thorium were uniformly distributed and the work function 4 were a linear function of the surface covered the electron emission would only be (126,000)0.6or 356 times greater. He showed that there was a departure from the Schottky emission and that if surface impurities were removed and sharp points eliminated he could attain 100,OOO volts without any appreciable cold-cathode effect. These investigations culminated in the development of the ‘Kenetron’.Two other important discoveries were made in this field. He established the existence of surface migra- tion of ad-atoms and ad-ions and proposed a two- dimensional diffusion equation of the form D = & and further showed that the polarisation or the di-pole moment of the ad-atom or ad-ion varied with the surface coverage. Langmuir next considered in detail the nature of the adsorbed phase. He regarded it as an extension of the Bragg lattice of the substrate and that only short-range forces were involved; that in fact each atom of the substrate involved a valency linkage with the adsorbate which was but a monolayer thick. This concept led to the important hypothesis that con- densation and evaporation from the surface were mutually independent processes and that no lateral interaction took place.This is the basis of his famous PROCEEDINGS isotherm which we now know has very extended but not universal application. He considered the conditions obtaining at the equilibrium state when a fraction 8 of the surface is covered and a fraction 1 -8 is bare. The rate of evaporation of a gas held on to a single elementary square will be r8 a process independent of the condensation reaction which is given by the expression ap(1 -8) where v is the specific rate of evaporation from that surface at the working temperature the number of molecules of gas striking one sq. cm. per second and a the condensation coefficient.Equating these rates we obtain (1 V8= p~~a-8) or 8/(i -8) = ap/v The reciprocal of v is evidently the lifetime of the adsorbed species on the surface and Langmuir ob- tained values for various gases on metallic and glass surfaces over a wide range of temperature from which he was able to compute the latent heats of evaporation. Langmuir advanced cogent reasons for assuming that the condensation coefficient on clean surfaces was unity and that the hitherto accepted concept of a = (1 -r) where r is now the reflexion coefficient was in fact erroneous. At the same time he remarked that when hydrogen molecules strike a hydrogen-covered surface at high temperatures it is possible that as many as 81 % of the molecules are reflected.Since condensation and evaporation are independent processes it had to be assumed that the condensed molecules were in equilibrium on the wire. Later measurements on this point indicate that such may be the case for metal atoms striking different metal substrates but is not generally true for gases hitting metal surfaces. By application of the principle of detailed balancing he developed those equations for the rate of catalytic reactions taking place at surfaces such as surface de- compositions the simplest of which is the dissocia- tion of hydrogen and he indicated various mechan- isms for interactions at surfaces in gaseous reactions. These can all be formulated by using the simple kinetic concepts which Langmuir expressed so clearly.He showed inter atia that an interaction could take place between juxtaposing adsorbed fked neighbours between two surface-adsorbed mobile species or by collision from the gas phase of some species with the other chemisorbed reactant. These two methods of surface reaction are sometimes termed the Langmuir Hinshelwood Bonhoffer and Farkas and the Rideal mechanism respectively. The assignment of any particular surface reaction to the correct mechanism has not proved to be as simple as was once thought but no one can deny that the ad- vances made by Langmuir over the “diffusive” views of Faraday and Bodenstein opened up a completely new era both in thought and in experiment. Langmuir in his second monumental paper examines the properties of surface films on liquids.Benjamin Franklin Miss Pockels and Lord Ray- leigh had already established that fatty-acid films thrown on the surface of water were but unimolecular in thickness. Langmuir performed the simple but most revealing experiment of measuring the areas of equal numbers of molecules of long-chain fatty acids compressed upon the surface of water. The areas of all straight-chain acids when so compressed were found to be identical regardless of the chain length. This basic experiment led Langmuir to the concept of the oriented monolayer an idea which both Sir William Hardy and Professor Devaux had arrived at several years before Langmuir who however had not noted their papers. His simple compressional apparatus was rapidly developed to become an in- strument of precision and now there are many mechanical devices based upon the original Lang- muir trough.Langmuir proceeded to study the com- pressional behaviour of these monolayers and showed that separate phases could exist analogous to matter in three dimensions. Of particular interest was his discovery of the so-called liquid expanded films in which the hydrocarbon tails form a continuous “oily” phase whilst the polar heads spread in the underlying substrate. These he termed duplex films and showed that the compressional curve fitted the equation of state (T -go)(A -A,) = kT.I need not refer to the vast amount of interest which these monolayers on liquid substrates have raised. The work of Professor N.K. Adam alone is sufficient to emphasise their importance. These and similar ex- periments led Langmuir to the view that since short- range forces alone were involved it was practicable to regard complex molecules as having separate sur- face energies for each different part of their structure and he then considered the properties of pure liquids from this point of view. He noted that the free surface of a liquid would consist of the least active portions of the molecules the view that Sir William Hardy had advanced. He developed simple equations based upon the Boltzmann equation for the heats of evaporation of liquids and the reasons for the depar- ture of unsymmetrical liquids from Stefan’s relation between the surface tension and the latent heats of evaporation.The principle of independent surface action was extended to consider the free energies of molecules in binary liquid mixtures. The forms of vapour-pressure curves as well as Raoult’s law for such systems were found to be a natural consequence of this principle. The implications of this work in considering the MARCH1959 structure of complex molecules of proteins of re- actions in surfaces and their biological implications are indeed far-reaching and profound. Just as Langmuir investigated the formation of multilayers of the alkali metals on a tungsten sub- substrate so likewise with Miss Blodgett he examined the formation of multilayers on chromium strips inserted and withdrawn through monolayers on water kept at constant compression by means of a piston oil.Thus out of the original observation of gas liberation from a tungsten filament three vast fields of new territory were explored by this remark- able man namely surface layers on solids electrical discharges in gases and surfaces of liquids. In each field he can be regarded as an original pioneer and the majority of his concepts have stood the test of time. He was interested in quite a number of topics other than these during the progress of this work. I shall mention but two of them. He helped to clarify the concept of covalency and electron-pairing which had been introduced in 1916 by G. N. Lewis. Eddington had been advancing the concept of ulti-mate rational units in the universe an idea which was likewise developed by Tolman and G.N. Lewis and Adams. Langmuir showed that values of Planck’s constant and the charge on an electron could be ob-tained from this theory and from Sommerfeld‘s rela- tion between h and e in terms of the Rydberg con- stant obtained with hydrogen and helium. From the equation e2 32n2 h = -.-c 15 he obtained h = 6.481 x ergs and e = 4.745 x lW1* e.s.u. During the Second World War Langmuir was engaged in such problems as submarine detection smoke formation and the de-icing of aeroplanes. Langmuir’s smoke-generator in a slightly modified form is now recognised as the standard apparatus whilst from this work and that with Dr. Schaefer on deicing the modem method of cloud “seeding” with solid carbon dioxide or silver iodide for the purpose of producing precipitation “Project Cirrus” has arisen.It is very natural that in this cascade of new concepts and new ideas some were afterwards found to be fallacious. When convinced however of his errors as in the induced evaporation of thorium or the cyclol structure of protein monolayers he was always ready to accept the facts and incorporate the new information in developing his theories. In 1912 Langmuir married the former Marian Mersereau of South Orange N.J. A son Kenneth and a daughter Barbara Mrs. H. R. Summerhayes jun. survive him. Langmuir’s outside interests were many. He loved sailing especially with his family whether on Lake George where he had a summer cottage or on the sea where he was an excellent navigator.He made many extensive and some very difficult climbs in the Canadian Rocky Mountains as well as in the Swiss Alps. He also indulged in skiing as well as flying his own and the Company’s plane. Indeed he flew rather embryonic planes-I once had a flight with him at Schenectady to test some new altimeters and the plane had nothing but air between the seats and the earth the seats being slung across the fuselage. He worked a good deal at home and he had the most attractive manner towards children who were al-ways ready to listen to him explaining some natural or scientific event. In spite of his many honours he remained a generous and unselfish seeker after truth. He was twice awarded the Nichols Medal of the New York section of the American Chemical Society of which he later became President once in 1915 for his work on chemical reactions at low pres- sures and again in 1920 for his work on atomic structures.In 1918 he received the Hughes Medal of the Royal Society of which he was made a foreign member for his researches on molecular physics. In 1920 he received from the American Academy of Arts and Sciences the Rumford Medal for his work on thermionic emission and for his development of the gas-filled electric lamp. He also was recipient of the Cannizzaro prize from the Royal Academy at Rome and the Perkin Chandler and Willard Gibbs medals from his own country. In 1932 Langmuir became the first American industrial chemist to be awarded the Nobel Prize granted him for researches in his new-found surface chemistry.He was elected an Honorary Fellow of the Chemical Society in 1929. In 1934 he received the Franklin and Holley medals and in 1937 the Johns Scott award from the city of Philadelphia. In 1944 he became the fourth American to receive the Faraday Medal from the British Institute of Electrical Engineers and his last award in 1950 was the Mascart Medal of the SocietC Franqaise des fjlectriciens. He had numerous honorary degrees from Universities including Edin-burgh Oxford Harvard Princeton Johns Hopkins and Queens in Canada. He had a heart attack whilst on his vacation at Woods Hole on Cape Cod and died in the home of his nephew Dr.David Langmuir in Falmouth on August 17th 1957 at the age of 76. I have attempted to give a brief sketch of the life work of this remarkable man. Probably no scientist not even excepting Lord Kelvin has left us with such a wealth of scientific achievement combined with practical instrumentation. PROCEEDINGS COMMUNICATIONS Cyclisation during the Phosphorylation of Uridine and Cytidine by Polyphosphoric Acid A New Route to the 02,2’-Cyclonucleosides By E. R. WALWICK and C. A. DEKKER W. K. ROBERTS (BIOCHEMISTRY DEPARTMENT, UNIVERSITY OF CALIFORNIA BERKELEY) THEphosphorylation of pyrimidine ri bonucleosides with polyphosphoric acid was first investigated by Hall and Khoranal who reported the isolation of the 2’(3’),5’-diphosphates of uridine and cytidine.It has now been found that in applying this procedure to uridine and cytidine [or their 2’(3’)-phosphates] one obtains in addition to the ribonucleoside diphos- phates the 3’,5’-diphosphates of 3-/%~-arabofuran- osyluracil and 3-/3-~-arabofuranosylcytosine(IIT) respectively. The new diphosphates were isolated as crystalline cyclohexylammonium salts after fractionation by gradient elution chromatography. Partial identifica- tion was accomplished by analysis titration and ultraviolet spectra. Enzymic dephosphorylation gave the corresponding arabofuranosides of which the former was identified by comparison with an authen- tic sample of 3-/3-~-arabofuranosyluracil(spongouri-dine)2 and the latter by conversion into spongouri- dine on treatment with nitrous acid.The 3-/3-~- arabofuranosylcytosine(IV) gave white prisms (from 50% ethanol) m.p. 212-213*5” [aJDZ3 + 158” (c 0.5 in water) at pH 2 hma,. 279,212 mp (E 13,400 9800) and Amin 240 mp (E 1200) and at pH 12 Amax. 272 and shoulder 225 mp (E 9500 8400) and Amin. 248 mp (E 5400) pKu 4-1. That the 3-~-~-arabofuranosylpyrimidine diphos-phates had arisen by hydrolysis of phosphorylated derivatives of 02,2’-cyclonucleosides could be shown by direct isolation of the intermediates. To prevent destruction of the oxazolidine ring of the 02,2’- cyclouridine derivative excess of either aqueous acid or base had to be avoided. After the reaction of uridine and polyphosphoric acid at 85-90’ for 5 hours the inorganic phosphoric acids were removed by ether-extraction and the remaining materials neutralised and dephosphorylated with prostatic phosphatase.The major product which was isolated by chromatography on cellulose was 02,2’-cyclo-uridine identical with an authentic ample.^ The en- hanced stability to acid of the 02,2’-cyclocytidine intermediate permitted hydrolysis of pyrophosphate bonds and removal of inorganic phosphate in the usual fashi0n.l After ion-exchange fractionation the 3’,5’-diphosphate of 02,2’-cyclocytidine (I) was isolated as the free acid m.p. 192-193’ [a]k3 -337.8’ (c 1.0 in water) at pH 1-7 Amax 262 232 mp (E 10,400 9100) and Amin. 243 mp (e 6700). Hall and Khorana J. Arner. Chem. SOC.,1955 77 1871. Brown Todd and Varadarajan J.1956 2388. Titration showed p&’s at < 2.5 and 6.6 (2) with degradation occurring above pH 10 resulting in the uptake of one additional equivalent. Hydrolysis in warm neutral or alkaline solution gave compound (III),thus establishing the positions of the phosphate groups as 3’ and 5’. Dephosphorylation of compound (I) using prostatic phosphatase gave 02,2’-cyclo- cytidine (as the chloride) (11) m.p. 248-250” (de-camp.) [MI,= -21.8” (c 2.0 in water) at pH 1-7 Amax. 262,231 mp (E 10,600,9400) and Amin. 243 mp (E 6500). The compound was stable to periodate. On titration it showed no alkali uptake below pH 10 at which point hydrolysis ensued giving compound (IV). R = PO,H ; R‘= PO~H-It seems likely that the mechanism for the cyclisa- tion involves the displacement of a pyro(or po1y)- phosphate group from the 2’-position of a ribonu- cleoside derivative with C-0 bond fission.Although this is similar in some respects to the tosyl displace- ment employed in the initial synthetic route to the cyclonucleosides,2 the driving force in the present case must be the partial dissociation of the C,,,-O bond of the derivative in the polyphosphoric acid solvent at the moderately high temperatures (60-90”) used. We thank Dr. H. G. Khorana and Dr. D. M. Brown for reference compounds and helpful discus- sions and acknowledge support by the American Cancer Society and the National Science Foundation. (Received February 4th 1959.) MARCH1959 The Highest Fluoride of Osmium By G.B. HARGREAVES and R. D. PEACOCK (THEUNIWRSITY, BIRMINGHAM) WEINSTOCK recently showed by analysis and MALM~ vapour-density measurements and X-ray photo- graphy that the highest fluoride of osmium pre- viously thought to be octafluoride is actually a hexafluoride. In view of the photosensitivity of the compound2 and the difficulty of analysing it inde- pendent evidence of its formula has been sought. Variationsof magnetic susceptibility (dc,) with temperature Temp. 1O6XA 1O/X* Peff (K) (c.g.s. units) (c.g.s. units) (B.M.) Authors' results 297.0" 943 106.0 1.50 273.0 996 100-4 1 -48 252.0 1062 94.2 1 -47 235.0 1118 89.5 1.46 220.0 1172 85.3 1.44 202.0 1255 79.7 1 -43 184-0 1332 75.1 1 -42 164.0 1564 67.0 1-41 138.0 1675 59.7 1.37 117-0 1886 53.0 1.33 Results of Dr.J. Lewis 267.8 995.4 100-5 1 -47 246.0 1024 97.7 1 *43 222-7 1107 90.4 1.41 198.6 1174 85-2 1.37 175.5 1279 78-2 1.35 152.0 1504 66.5 1.36 129.6 1652 60.5 1-31 120.8 1759 56.9 1.31 105.9 1890 52.9 1-27 98.5 1958 51.1 1-25 81-5 2333 42.9 1 -24 The magnetic behaviour of the higher fluoride of osmium measured over the temperature range 80-297"~ varies in a way (Fig. 1) to be expected for a compound of sexivalent osmium with two un- paired spins [cf. the quinquevalent fluororhen-ate~(v)~]. The plot l/xAagainst T (where T is the absolute temperature) shows that the moment follows the Curie-Weiss relationship xAcc 1/(T + 8) with a Curie constant 8 -66' (Fig.2 and Table). These results rule out octavalent osmium conclusively. One of the samples was analysed and gave an osmium to fluorine ration of I :6+1 confirming osmium hexa- fluoride. Osmium hexafluoride is a volatile compound with the physical properties reported by Weinstock and Malm. Our preparation which was made by reaction between osmium sponge (from Messrs. Johnson Matthey & Co.) and elementary fluorine at about 30O0c,could be handled and stored under rigorously dry conditions in a Pyrex apparatus. The tubes for the magnetic measurements were filled under a vacuum. 100 G *50 0 I I 0 /ooo 20Oo 300" Temp.(c) FIG.1. 0 Authors'. Dr. J. Lewis. 1-00 10oo 200° 300° Temp.(K FIG.2.0 Authors'. Dr. J. Lewis. In view of these results it is clear that the other fluorides of osmium reported by Ruff and Tschirch4 will have to be reinvestigated. We are indebted to Professor G. Wilkhon for permission to use laboratory facilities at Imperial College and to Dr. J. Lewis for a duplicate set of magnetic measurements made at University College. (Received December 17th 1958.) Weinstock and Malm J. Amer. Chem. SOC.,1958 SO 4466. * Dr. A. M.Hepworth personal communication. Hargreaves and Peacock J. 1958 3776. Ruff and Tschirch Ber. 1913 46 929. PROCEEDINGS The Absolute Stereochemistry of Emetine:Optical Correlation with the Indole Alkaloids By A. R. BATTERSBY and S. GARRATT (THEUNIVERSITY, BRISTOL) THEbiogenetic interest of structural relationships can be heightened by taking relative and absolute stereochemical correlations into consideration.Thus it is established1 that all the indole alkaloids of known stereochemistry that are thought to be biosynthesised from tryptophan and phenylalanine or their equi- valents2 have the same absolute configuration at one asymmetric centre. Moreover this centre is invari- ably derived in current biogenetic schemes from the same carbon atom in the postulated precursor; the importance of this has been emphasised recent1y.l If as Robinson ~uggests,~ emetine (V) is formed in the plant by the type of synthesis which operates in the indole series then the corresponding asymmetric centre C(lo) in emetine would be expected to have this same absolute configuration.The following experiments show this to be so. Corynantheine (I) was converted by the method of Janot and Goutarel? and by a variation using di- hydrocorynantheine into dihydrocorynantheal per- chlorate (11) and further into dihydrocorynanthean perchlorate (111) of known absolute stereochemistry.6 The last base was dehydrogenated by mercuric acetate to yield 3-dehydrodihydrocoryanthean per-chlorate (IV). In this laboratory we had previously6 carried out the same steps on protoemetine per- chlorate (VI) which has the same stereochemistry as emetine and is that shown or the mirror image6; the diethyl base perchlorate (VII) and the corres- ponding 3-dehydro-derivative (VIII) were obtained.Salt [MI" AIM1 I1 +63" 111 -69 111-11 -132" IV f318 IV-111 f387" VI -43 VII -165 VII-VI -122" VIII f317 VIII-VII f482" *Determined for the sodium-D line at 20-25" in aqueous ethanol made from 70 ml. of ethanol and 5 ml. of water. The molecular-rotation data for these salts given in the Table show that protoemetine and therefore emetine has the same absolute configuration as di- hydrocorynantheal so that the formula (VI) (VII) and 07111) show the correct enantiomers. When this information is combined with that from our earlier l Bose Chatterjee and Iyer Indian J. Phrm. 1956 18 185; Wenkert and Bring J. Amer. Chem. Soc. 1958 80, 3484; 6.Bose Chem. and Ind. 1958 1690. * Woodward Nature 1948 162 155; Saxton Quart. Rev. 1956 10 108.a Robinson Nature 1948 162 524. Janot and Goutarel Bull. SOC.chim. 1951 18 588. van Tamelen Aldrich and Katz J. Amer. Gem. SOC.,1957 79 6426; Wenkert and Bhgi ref. 1. Battersby Davidson and Harper Chem. and Id. 1957 983; Battersby and Cox ibid. p. 983. MARCH1959 studies6*' it is possible to represent the complete absolute stereochemistry of emetine by structure 0. Grateful acknowledgment is made to Professor Battersby ibid. 1958 1324 and refs. therein. M.-M. Janot for a generous gift of corynantheine and to the Department of Scientific and Industrial Research for a Maintenance Award to S.G. (Received January 19th 1959.) 6a-Huoro-16a-Methylhydrocort.isoneand Related Steroids By J. A. EDWARDS H. J. RINGOLD, A. ZAFFARONI and CARLDJERASSI (RESEARCH SYNTEX,S.A.APT.POSTAL LABORATORIES 2679 MEXICO,D.F.) As cortical hormone activity is increased by intro- duction of a 6a-fluorine atom1 or a 16(a or p)-methyl group2 we have studied the cumulative effect of these two groups and now report the synthesis of the 6a-fluoro- 16 cc-methyl derivatives (111) and (IV) of "Substance S" and of hydrocortisone. 1 6 a-Methyl-20-oxopregn-5-en-3~-yl acetate (I) was converted by monoperphthalic acid oxidation into the 5a:6cc-oxide which was cleaved with boron trifluoride3 in ether-benzene solution to the 5:6-fluorohydrin (Ira). Successive treatment4 with acetyl chloride-acetic anhydride perbenzoic acid and alkali provided 6p-fluoro- 16 x-methyl-20-oxopreg- nane-3P :5a:17 a-trio1 5-acetate (I1 b) transformed into the21 acetoxy-compound (IIc) by bromination at C(zl followed by displacement with sodium iodide and finally acetolysis with potassium acetate in boil- ing acetone.Oxidation of the diacetate (IIc) with chromium trioxide in acetone-sulphuric acid led to the corresponding 3-ketone which when treated with hydrogen chloride in acetic acid lost acetic acid and suffered inversion at C,, to yield the 6a-fluoro-16~- methyl derivative of "Substance S" acetate (IIla) m.p. 196-198" [a] + 76" (in CHCI,). Hydrolysis to the free alcohol and incubation5 with bovine-adrenal glands gave 6 a-fluoro-16 a-methyl- hydrocortisone (IVa) (30 % yield) which was purified as the acetate (IVb) m.p. 225-228" and 245-248" [x] + 115" (in CHCI,).Apart from its intrinsic interest this substance represents a suitable starting material for the introduction of a 9 a-fluorine atom and for the synthesis of the various dl-and 1 l-oxo- analogues. The 6 a-fluoro-l6 a-methyl derivative of "Sub-stance s'' is an important substrate for microbio- logical reactions. We have also synthesised the 16a- methyl derivative of "Substance S" (Le. I11 without 6a-fluorine) since this would open an alternative synthetical route to 16-methyl-corticoids2 lacking a 6-substituent. 5 a :6p-Dichloro-16 a-methyl-20-0~0- pregnan-3P-yl acetate was converted into the 3p:17a diol by Gallagher's meth~d.~ The 21-acetoxyl group was introduced as described above AC (1' (El:a ;R-Ac.R'-R$ RLH b ;R-RX H,d=Ac &OH c ;R-H ,R'=A~.R& OH.R3=OAC F F @I>: a ;R-Ac b; R=H (I V) a; R=H b;R=Ac then chromium trioxide oxidation followed by de- chlorination with zinc in acetic acid gave directly 16a-methyl-3:2O-dioxopregn-4-ene-17a: 21-diol 21- acetate m.p. 98-103" [a] + 91" (in CHCI,). Incubation of the free alcohol m.p. 187-191" [a],+ 90" (in CHCI,) with bovine-adrenal homo- genates5 led to the previously reported2 16a-methyl- hydrocortisone. (Received December 23rd 1958.) Bowers and Ringold J. Amer. Chem. SOC.,1958 80,4423; Hogg et al. Chem. and Ind. 1958 1002. Arth et ai.,J. Amer. Chem. SOC.,1958 80 3160 3161 ; Oliveto et a/. ibid. 1958 80 4428 4431 ;Taub et al. ibid. 1958 80,4435. Henbest and Wrigley J. Chem. SOC.,1957 4765; Bowers and Ringold Tetrahedron 1958 3 14.Kritchevsky and Gallagher J. Amer. Chem. SOC.,1951 73 184. Zaffaroni US. P. 2,671,752; see also J. Amer. Chem. SOC.,1958 80 6110. PROCEEDINGS The Biosynthesis of Alternariol By R. THOMAS (LONDON SCHOOL OF HYGIENE MEDICINE, AND TROPICAL w.c.1) THE hypothesis that certain naturally occurring Aghoramurthy and Seshadri4 postulated a bio- phenols arise by condensation of acetate units has synthesis of alternariol involving oxidative coupling been proved for a number of cases.l However all of orsellinic (2:4-dihydroxy-6-methylbenzoic)and these have required additional stages involving 3 5-dihydroxyphthalic acid accompanied by decar- oxidation reduction decarboxylation etc. For alter- boxylation.While the observed labelling sequence is nario120it is possible to arrive at the final structure not at variance with this mechanism there is no solely by the head-to-tail linkage of seven acetate obvious reason for preferring it to the simpler non- units. The biosynthesis of alternariol is of particular oxidative pathway. Furthermore the orientation of interest as it is a probable precursor of several other the hydroxyl groups in alternariol is not such as products of Alternaria tenuis? which appear to be would arise from the usual type of phenol c0upling.j derived from alternariol monoethyl ether. If the direct condensation pathway is valid then the F0 c-CO c c,o OC c c-co c 70 c-co 7CH,!4C0 i; C 1- Kuhn-Roth Me?02H -CHI c H OH O Me OH ........................................W 4-to2 -HO *\ 0,N MeOH \NO OH - CBr;NG Sodium [l -14C]acetate when added to the two carbon atoms (1 and 1’) linking the benzene Czapek-Dox growth medium was incorporated into rings would arise from a single acetate unit thus alternariol to the extent of -7%. Subsequent de- necessitating prior formation of one of the two rings. gradation as in the formula conclusively showed the If mediation of orsellinic acid is assumed one in- incorporation of acetate in the predicted manner. teresting possible precursor of alternariol would be The distribution of 14Cis expressed in the Table on compound (II) since it can in theory give rise to a number of other natural products as will be outlined Posn. Activy. Posp Activy. in a subsequent communication.1 0 1 0.90 2 1.05 2’ 0 CO2H 3 0 3‘ (0.95) OH ncr I nu 4 (1-11) 4’ 0 5 0 5’ (0.95) 6 0.90 6’ 0 Me 0 co 1.14 (fl> the basis of an overall activity of seven units; the This work was carried out during the tenure of an values in parentheses were obtained by difference Imperial Chemical Industries Research Fellowship. and those of carbon atoms 3’ and 5‘ are the mean of their combined activities. (Received,January 12th 1959.) Birch Fortschr. Chem. org. Naturstofle 1957 16 186; Birch Fitton Pride Ryan Herchel Smith and Whalley, J. 1958 4576. Raistrick Stickings and Thomas Biochem. J. 1953 55 421. Rosett Sankhala Stickings Taylor and Thomas ibid. 1957 67 390. a Aghoramurthy and Seshadri J. Sci. Ind. Res. India 1954 13 A 114.Barton and Cohen “Festschrift Arthur Stoll,” Birkhauser Basle 1957 p. 117. MARCH1959 Relative Signs of Proton Spin-Spin Coupling Constants in a Conjugated Diene System By J. A. ELVIDGE and L. M. JACKMAN (CHEMISTRY DEPARTMENT IMPERIAL COLLEGE OF SCIENCE AND TECHNOLOGY LONDON) THE relative signs of proton spin-spin coupling constants and their importance in the theory of the coupling mechanism have been discussed by Bak Shoolery and Wi1liams.l McConnel12 finds that a molecular-orbital treatment predicts a positive sign for all long-range H-H coupling constants whereas the Dirac vector model leads3,l to an alternation in the sign along a chain or ring. Valence-bond theory predicts that spin couplings through nelectron systems in even alternate hydrocarbons are positive for protons separated by an odd number of C-C bonds but negative for even numbers.* Experi- mentally determined H-H coupling constants in fluorobenzenel and naphthalene5 are of the same The spectrum of the cis-cis-isomer can be analysed as an A2X2nuclear spin and the calculated band positions and intensities all correspond to the observed values within experimental error.J values are given in the Table the large coupling constants Jasand JBy are taken as po~itive.~ This makes the relative sign for Jaynegative and leaves undeter- mined that for Jaa .(Absolute signs cannot of course be given.) The interpretation of the spectrum of the trans- trans-isomer is based on an A2B2model.5 Because of solubility and resonance-saturation difficulties the experimental spectrum is less well resolved so that the coupling constants cannot be cakulated with the Coupling constants (J) and chemical shifts (T)*for the olefinic protons of the muconic esters cis-cis" 11.8 -1.3 trans-trans 11.2 -0.7 cis(xfi)-trans(y8)c 10.7 0 h1.3 11.3 f0.6 16.5 0 10.7 10% in CC14.Jols 4.12 2.13 2.13 4.12 JaP 3.79 2.66 2.66 3.79 14-8 4~2~ 3.5 1.8 4.1 The 7-values for the cis-trans-muconate a 20 % in CCI,. 10% in hot Et,COs. have been taken as the mid-points of the appropriate multiplets and small errors (0.07 p.p.m.) will have been introduced. Exact calculations are in progress. * Tiers J. Phys. Chem. 1958 62 1151. sign for each pair of positions round these rings i.e.in fluorobenzene the ortho- and rneta-couplings have the same sign and the same is true for the 1 :2- 2 3- and 1 :3-couplings in naphthalene. In contrast it has been claimed6 that the complex spectrum of but-1 -ene is best interpreted by assuming a negative coupling constant between protons on the 1- and the 3-carbon atoms. However the calculated spectrum is not in complete agreement with the experimental. We now provide unequivocal examples of a change in the sign of H-H coupling constants along a con- jugated diene The compounds examined were the three isomeric &methyl muconates (I) whose stereo- chemistry is established.' 8 rP Q CO,Me-CH=CHCH=CH-CO,Me (I) same precision as previously. Even so there is no doubt that again Jay has a sign opposite to that of J,p (see Table).The cis-trans-isomer gives an eleven-line spectrum which indicates considerable degeneracy. This is best explained by assuming that Jay and JO,S vanish and that Jas = JflY. It is interesting that JBy in the trans-trans-isomer is much greater than in the other two isomers. This appears to Occur partly at the expense Of Ja@ which is abnormally low for a trans-double bond. It might k significant that this 's the only One Of the isomers for which indicate a comP1etelY CO-planar arrangement of the molecule. This isomer is likely to have the highest bond order for the central &bond and a fully trans-relationg between the @-and the y-hydrogen atom. The observed band Bak Shoolery and Williams J.Mul. Spectroscopy 1958 2 525. McConnell J. Chem. Phys. 1956,24 460. Idem. ibid. 1955 23 2454. 'Idem ibid. 1959 30 126. Pople Schneider and Bernstein Cunud. J. Chem. 1957 35 1060. Alexander J. Chem. Phys. 1958,u) 358. Elvidge Linstead Sims and Orkin J. 1950 2235; Evans Smith Linstead and Elvidge Nature 1951 168 772; Elvidge Linstead and Sims J. 1953 1793. McConnell McLean and Reilly J. Chem. Phys. 1955 23 1152. Pople Chem. Suc. Special Publ. No. 12 1958 p. 21 1. PROCEEDINGS ~~ origins are in agreement with the assigned stereo- The relevant spectra of the esters will be submitted chemistry and with the spectra already reported for in the later full publication. We thank the referee two isomers of the /?-methylmuconic ester.1° for helpful comment.loElvidge J. 1959 474. (Received,January 27th 1959.) Cyclo-octatetraene-Iron Complexes By T. A. MANUEL and F. G. A. STONE CHEMICAL HARVARD (MALLINCKRODT LABORATORY UNIVERSITY CAMBRIDGE U.S.A.) MASSACHUSETTS THE existence of compounds (C,H,),M(CO), where tense carbonyl stretching modes in the infrared GH,is a cyclopentadienyl group1 or aromatic hydro- spectrum (2058 and 1992 cm.-l). High-resolution carbonsv3 and M is a transition metal as well as bi-nuclear magnetic resonance measurements on the nuclear metal-azulene complexes,* led us to attempt latter complex confirm its diamagnetism and show a the synthesis of a binuclear transition-metal com- single proton resonance at 152 C.P.S. on the low-field pound having two metal atoms symmetrically side.Cyclo-octatetraene itself shows a single proton separated by a C,H conjugated ring system. A recent resonance (1 7 1 c.P.s. low-field side) the proton theoretical justification5 of this idea has prompted us resonances of both compounds being referred to that to communicate some of our results. of cyclohexane. The single proton resonance ex- Since cyclo-octatetraene has eight potential 7-hibited by the monoiron complex implies that no electrons and since it has been suggested that in four carbon atoms in the C,H moiety are preferenti- butadieneiron tricarbony16 the iron is bonded to a ally bonded to the metal atom but that all eight molecular orbital involving all four atoms of the carbon atoms are equivalently bonded.This view is butadiene moiety it seemed reasonable to expect qualitatively supported by the observation that this that treatment of cyclo-octatetraene with iron penta- compound does not decolorise solutions of bromine carbonyl might afford (CO),FeC,H,Fe(CO),. While in carbon tetrachloride although a reaction occurs it is true7 that the normal state of the cyclo-octa- with liberation of carbon monoxide. Professor W. N. tetraene ring appears to be the tub form (D2,J,in-Lipscomb has kindly consented to investigate this dicating that there is little delocalisation of electrons structure by X-ray diffraction to determine whether in the ring it is conceivable that the bonding of a in crystalline C,H,-Fe(CO) the carbon atoms of the metal atom to the hydrocarbon would change the C,H ring are coplanar.It is just possible however geometry of the ring so as to permit more complete that a nearly planar arrangement of the ring carbon r-electron delocalisation. atoms would meet the requirement of proton equi- From the reaction between iron pentacarbonyl and valence especially if slight puckering was based on cyclo-octatetraene we have isolated a compound a D or. "crown" structure for the eight-membered GH,Fe2(CO)6 which could be an example of a sym- ring. metrical binuclear complex. This compound is a Small amounts of a black air stable compound yellow air-stable solid which decomposes near 185". C,H,Fe,(CO) were also isolated from the cyclo- It is slightly soluble in organic solvents sublimes in octatetraene-iron pentacarbonyl reaction.This com- vacuo,and shows just two intense carbonyl stretching pound decomp. 220° has four carbonyl stretching modes at 2041 and 1984 cm.-l. Rather surprisingly modes (2026 1992,1953 and 1783 cm.-l). The band it is formed only in very low yield from the cyclo- at 1783 cm.-l is in the bridging carbonyl region and octatetraene-iron pentacarbonyl reaction. The prin- so this product is undoubtedly a derivative of Fe cipal product obtained in 60-70% yield is a com- (CO) in which two carbon monoxide groups have pound C,H,Fe(CO), m.p. 92" decomp. -155" been replaced by a cyclo-octatetraene group. (Found C 54.3; H 3.3; Fe 22.9. Cl1H,O,Fe re-quires C 54-1; H 3.3; Fe 22.9 %) stable to air and We thank the National Science Foundation for the moisture.The complex C,H,Fe(CO) forms deep red award of a predoctoral fellowship (to T.A.M.) and crystals sublimes easily in a high vacuum and is the Research Corporation for the award of a very soluble in organic solvents. Like the di-iron Frederick Gardner Cottrell grant for the support of compound the mononuclear complex has two in- this work. (Received February 6th 1959.) 1 Piper Cotton and Wilkinson J. Inorg. Nuclear Chem. 1955 1 165; and earlier work there cited. a Nichols and Whiting Proc. Chem. Sac. 1958 152. 8 Fischer and Ofele Z. Naturforsch. 1958 13b 458; Fischer Ofele Essler Frohlich Mortensen and Semmlinger Ber. 1958 91 2763. Burton and Wilkinson Chem. and Znd. 1958 1205; Burton Green Abel and Wilkinson ibid. 1958 1592. Brown ibid.,1959 126. Hallam and Pauson J..1958 642. ' Person Pimentel and Pitzer J. Amer. Chem. SOC.,1952 74 3437. MARCH1959 Biflavonyls A New Class of Natural Product. The Structures of Ginkgetin Isoginkgetin and Sciadopitysin By w. BAKER, A. C. M. FINCH W. D. OLLIS,and K. W. ROBINSON (THEUNIVERSITY BRISTOL) GINKGETIN, a yellow pigment obtained in 1932l from the autumn leaves of the maidenhair tree (Ginkgo biloba) was shown by Nakazawa2 to have a formula C32H22010 and to possess flavonoid properties but the structure suggested by him is unacceptable. We find that ginkgo leaves yield two isomeric pigments C,2H220,, ginkgetin m.p. 342-344” and isogink- getin (hydrated) final m.p. 355”. Both ginkgetins yield the same tetramethyl ether and on demethyla- tion the same hexahydric phenol characterised as its hexa-acetate but they yield different tetra-acetates thus showing that they have the same C30 skeleton and oxygenation pattern.The following evidence now determines unequivocally their complete struc- tures and has led to the recognition of a new class of natural product. M -* V” eow *Meo 0 (n) The ultraviolet absorption spectra of the two ginkgetins and of apigenin and acacetin are strikingly similar and are compatible with the presence of two non-interacting flavonoid groupings in the gink- getins. Oxidation of ginkgetin tetramethyl ether with alkaline hydrogen peroxide gives p-anisic acid 2-hydroxy-4,6-dimethoxybenzoicacid and a di-carboxylic acid C,2H,(OMe),(OH)(C02H)2 which was necessarily a derivative of diphenyl.This sug- gested that during the biosynthesis of the ginkgetins a dehydrogenative coupling of two phenolic pre- cursors was probable. Numerous examples of this type of reaction are known,3 and if a 5,7,4’-oxygena- tion pattern (I) is accepted for the precursor as indicated by the ultraviolet spectra of the ginkgetins a C-C coupling might involve any of the positions 3’ 6 and 8. However the formulse of the three acids obtained from ginkgetin tetramethyl ether restricts the interflavonoid linkage either to 3‘-6” or 3’-8” and for reasons given below the latter is very strongly favoured and the discussion is therefore restricted to this possibility. These reasons led to an examination of structure (II) for ginkgetin tetramethyl ether; the proof of the positions of the methoxyl groups marked * is given below.While our work was in progress Kariyone and Kawano4 described a yellow pigment sciadopitysin C30H1204(OH)3(OMe)3, from Sciadopitys verticillata (umbrella pine) whose trimethyl ether was identical with ginkgetin tetramethyl ether. They proposed for sciadopitysin trimethyl ether a formula different from (11) but their extensive degradation studies are com- pletely compatible with (II) except for the formation of a stable acid C,,H,,O by degradation of sciado- pitysin; this we believe to be C24Hla08 and of accept- able genesis. Kariyone and Kawano’s studies do not permit the location of the methoxyl groups marked * in (10.Through the kindness of Mr. C. Puddle of Bodnant Gardens Denbighshire who has supplied us with plant material we have found that degrada- tion of sciadopitysin with alkaline hydrogen peroxide gives 4-methoxyisophthalic and p-anisic acid. The position of the third methoxyl group follows from the alkaline hydrolysis of sciadopitysin which yields a compound C23H140,(OMe)2 and 2,6-dihydroxy-4- methoxyacetophenone. These facts coupled with the information derived by oxidative degradation of compound (11) require sciadopitysin to be repre- sented by the formula (111; R = R = Me) though the positions of the two hydroxyl groups marked * are not thus established. One of these hydroxyl groups must occupy position 5” because there is only one carbonyl band in the infrared spectrum of sciadopitysin.The other Furukawa Sci.Papers Inst. Phys. Chem. Res. Tokyo 1932 19 27; 1933 21 278. a Nakazawa J. Pharm. SOC.Japan 1941 61 174 228. Barton and Cohen “Festschrift Arthur Stoll,” Birkhauser Basel 1957 p. 117; Erdtman and Wachtmeister ibid. p. 144. ‘Kariyone and Kawano J. Pharm. SOC.Japan 1956,76,448,451,453,457. PROCEEDINGS unplaced hydroxyl group has been shown to be in position 7” as the result of a close interpretation of the effect of base upon the ultraviolet spectrum of sciadopitysin; the detailed reasoning will be given in the full publication. It follows that sciadopitysin must.have structure (III;R = R’ = Me) and that in consequence ginkgetin tetramethyl ether is (11) thus locating the three methoxyl groups marked *.Isoginkgetin when degraded with alkaline hydro- gen peroxide gives 4-methoxyisophthalic acid and p-anisic acid so that its structure is established as (111; R = Me R’ = H). Ginkgetin similarly yields 4-methoxyisophthalic acid and p-hydroxybenzoic acid and since it shows only one band in the carbonyl region of its infrared spectrum it follows that both the 5-and the 5”-hydroxyl group are unmethylated. The effect of base upon the ultraviolet spectrum of ginkgetin proves that it contains a hydroxyl group para to a carbonyl group from which it is abnormally difficult to remove a proton; this can only be inter- preted if this group is in position 7” so that there must be a methoxyl group in position 7.Ginkgetin is therefore (III;R = H R’ = Me). Thus the structures of ginkgetin isoginkgetin and sciadopitysin are determined but as mentioned earlier this evidence is also compatible with a 3’,6”-biflavonoid structure. However the 3’,8“-structure is preferred from a consideration of the mechanism of biosynthesis and because these bi- flavonyls may be fully methylated without difficulty. A 5”-hydroxyl group in a biflavonyl containing a 3’,6”-linkage would be severely sterically hindered. It might be expected that these biflavonyls should be optically active because of restricted rotation about the interflavonoid linkage but optical activity could not be detected. It may be mentioned that the structures can be deduced without making biogenetic assumptions but that the arguments are complicated.These biflavonyls belong to a new class of natural product and their biosynthesis doubtless involves flavonoid precursors. Other members of this class are apparently known including kayaflavone sotet- suflavone and hinokiflavone but we have not yet been able to consult the original literat~re.~ The isolation of the two ginkgetins from the sole representative of the Ginkgoales order and of a third biflavonyl from another gymnosperm belonging to the Coniferales is of considerable taxonomic interest. It is a pleasure to thank Professor D. H. R. Barton for interesting discussions on this and other bio- synthetic aspects of phenol-dehydrogenation reac- tions. (Received February 9th 1959.) Kariyone and Sawada “Complete publication in memory of Professor T.Kariyone,” 1956 p. 16; quoted by Chen and Chang J. 1958 146. Direct Detection of TrimethylcarboniumIons By J. ROSENBAUM and M. C. R. SYMONS (DEPARTMENT OF CHEMISTRY THE UNIVERSITY SOUTHAMPTON) A FUNDAMENTAL part1 of the SJ process for nucleophilic substitution is that carbonium ions are postulated as transient intermediates but we know of no direct physical evidence for the presence of aliphatic carbonium ions. In view of the surprising stability of dilute solutions (ca. 10-4~) of monoaryl- carbonium ions in sulphuric acid,2 we have applied the same experimental procedure2 to the preparation of CMe,+ ions from t-butyl alcohol and 2-methyl- propene. Both compounds give clear colourless solu- tions which have a single measurable ultraviolet band having Amax.292 f2 mp (E 7 x lo3) with a half- height width of 4900 cm.-l. This band appears slowly according to a first-order rate law for t-butyl alcohol but very rapidly for the olefin. The solutions are stable and the spectra reproducible. If this intense band is due to CMe,+ ions the )electronic transition almost certainly involves C-H bonding electrons of the methyl groups which are already delocalised by hyperconjugation. We suggest that the transition involves charge-transfer from methyl towards the central carbon atom. Trimethylborine and CMe,+ are isoelectronic. If our interpretation is correct then BMe should have a similar spectrum but with a maximum at somewhat shorter wavelengths.Indeed we find that dilute solu- tions of trimethylborine in hexane have an intense band with Amax. 260 mp (E-6000; half-height width AH 4500 cm.-l); in general the spectrum resembles that of t-butyl alcohol in sulphuric acid. We conclude that our assignment is reasonable and that conversion of the alcohol and olefin into carbonium ions is essentially complete. Also since trimethylborine is planar it seems probable that CMe,+ is also planar and has the classical structure assumed here rather than being a v-complex of the type annexed. H [.e*C+HJ+ We thank Professor R. C. Cookson for his interest and D.S.I.R. for a maintenance grant to J.R. (Received February loth 1959.) Cf. Ingold “Structure and Mechanism in Organic Chemistry,” Bell and Sons Ltd.London 1953 p. 310. Grace and Symons J. 1959 958. MARCH1959 4l’-Indenylideneflav-%ene An Oxygen Analogue of Cyclopentadienylidenecycloheptatriene By G. V. BOYD (WESTHAMCOLLEGE LONDON, OF TECHNOLOGY E.15) AROMATIC stability has been predicted1 for the “mixed fulvalene,” cyclopentadienylidenecyclo-heptatriene (I), for which a dipolar canonical form (Ib) can be written in which each ring has attained a sextet of w-electrons. This compound is not yet known but a tetrabenzo-derivative 1-9’-fluorenyl-idene-2,3 6,7-dibenzocyclohepta-2,4,6-triene has been prepared by Pullman and his colleagues.2 The striking stability of some oxygen analogues of azulene3 stimulated our interest in 4cyclopentadi- enylidenepyran @I) which is isoconjugate with the hydrocarbon (I) and a representative of this ring system is now reported.Schonberg and his co-workers recently prepared another namely 4-9’- flu orenylidene-2,6-dip hen~lpyran.~ Additions of indene to salicylideneacetophenone catalysed by sodium hydroxide and pyridine gave the colourless adduct (III) m.p. 149.5”(decomp.) (C=O band at 1670 cm.-l in Nujol) which was con- verted by perchloric acid in ether-acetic anhydride6 into a yellow pyrylium perchlorate. Sodium hydroxide or water readily hydrolysed this salt to the stable bright red 4-1 ’4ndenylideneflav-2-ene (IV) m.p. 157.5”,Amax. (in cyclohexane) 234 (log c 4-45) 268 (4-23) 296 (4-56) 345 (3-97) 360 (3-81),442 mp (3-89) whose structure follows from the method of preparation analysis and behaviour as an anhydro- base treatment with perchloric acid regenerates the pyrylium salt.The flavene probably has the strainless planar trans-configura t ion (IV) but geometrical isomer ism about the central “double bond” may not arise in compounds of this type since molecular-orbital calculations2 indicate a very low bond order for the central linkage of the mixed fulvalene (I). (Received,February 16th 1959.) lTinker J. Chem. Phys. 1951 19 981. a Pullman Pullman Bergman Berthod Fischer Hirshberg Lavie and Mayot Bull. SOC.chim. France 1952 19 73. Boyd J. 1958 1978. Schonberg Elkaschef Nosseir and Sidky J. Amer. Chem. Soc. 1958 80 6312. Pinck and Hilbert ibid.1946 68 2014. Allen and Sallans Canad. J. Res. 1933 9 578. The Electric Dipole Moments of Some Aromatic Chromium Tricarbonyl Complexes By E. W. RANDALL and L. E. SUTTON (PHYSICAL LABORATORY, CHEMISTRY OXFORD) THEelectric dipole moments of a number of aromatic chromium tricarbonyl complexes,l measured in benzene solution are given in Table 1. The results for the methyl-substituted benzene complexes of chromium fit the relation pn = px + 0.23n (where is the moment of the parent benzene complex and n is the number of methyl groups) within 0.05 D. This may be explained on the basis of structures of the type shown in Fig. 1. All the methyl- substituted benzene complexes except that of toluene were chosen so as to retain an axis of sym- metry perpendicular to the aromatic plane since the dipole moments must then all lie along the axis AB.Even for the toluene complex (no axis of symmetry in the above sense) the component of the dipole moment at right angles to this axis AB is small. The differences in the measured moments may be attri- buted to an electronic effect of 0.23 D per methyl 6+ 6- group in the direction A+B which is rather large when compared with the methyl-to-ring group moment of 0.4 D especially since it is generated at right angles to the latter. There does not appear to be any unique behaviour associated with a C,,symmetry in the aromatic com- ponent as one might expect from Fischer Bottcher and Ruch’s view2. Analysis3 of the moments of the monosubstituted Nicholls and Whiting Proc.Chem. SOC.,1958 152 and references therein. Fischer and Bottcher Chem. Ber. 1956 89 2397 and references therein. PROCEEDMGS TABLE1 Aromatic Dipole momenta component (D) Chromium complexes PhF 4.91 PhCl 5-08 p-C,H,MeCl 5.19 C6H6 5-08 PhMe 5.26 p-C6H4Me2 5.52 1,3,5-C,H,Me 5.81 1,2,4,5-C&,Me 6.04 C6Me6 6.48 Ph2 5.35 PhOMe 5-43 Ph-NMe 6.30 C yclo hepta triene 4-52 Molybdenum complex Mesitylene-Mo(CO) 6.36 Errors < f0.05 D benzene derivatives gives the axial electronic effects Apx (taken as zero in the benzene complex) which are shown in Table 2. There is some uncertainty in Ap when the substituent groups Y are unsym-metrical about the C6H,-Y bond because all con- figurations of such groups about this bond are not A I I I Cr oc/ip 1 O ‘CO I I B FIG.1 equally probable.There is uncertainty even for sym- metrical groups because the relation between dp and the change in the substitution moment dpy(see Fig. 2) can only be guessed. We have calculated dpx for the limits Apy = 0,Apy = dpx. The magnitude and the direction of Apx are TABLE 2 Substituent Y Apx (D) Me 0.23 per Me OMe 0-25-0.20 NMe 1-21-1 -01 Ph 0.25 H 0-0(by definition) c1 -0.264.42 F -0.39-0.66 moments3 or by the Taft factors 0; and uR,4 but appear to be related to the total electronic effect of Y since a plot of dp against the sum of the Taft factors (oI+ oR)is linear save for the points for Y = F and Y = Ph.The basic strengths of aromatic com-pounds measured in hydrogen fl~oride,~ so far as they are known are also related to dpx. The dipole moments for the benzene and cyclo- heptatriene complexes are respectively 5.08 f0.02 and 4.52 k 0.02 D. If (1) the double bonds of the ring of the latter were in a plane,6 (2) the methylene group were on the side of this plane remote from the FIG.2 metal atom,’ and (3) the donor powers of the two trienes were the same then the moment of the latter should be greater than that of the former. If the methylene group were syn to the metal atom the moment would be reduced to ca. 4-8 D. Both stereo- chemical possibilities lead to the tentative conclusion that the donor power of cycloheptatriene is less than that of benzene.A comparison of the chromium- and the molyb- denum-mesitylene analogues shows that there is a larger electronic effect with molybdenum. We are grateful to Drs. B. Nicholls M. C. Whiting and W. R. Jackson who gave us the samples and to Imperial Chemical Industries Limited for a relatedineither to the inductive effect nor to the meso- maintenance grant (to E.W.R.). meric effect alone of Y,as measured either by dipole (Received January 28th 1959.) Vector moments as in Katritzky Randall and Sutton J. 1957 1769. Taft “Steric Effects in Organic Chemistry,” Wiley New York 1956 p. 558. Mackor et al. Internat. Conf. Co-ordination Chemistry Amsterdam 1955. For refs. see ref. 7. Abel Bennett Burton and Wilkinson J.1958 4559. MARCH1959 The Oosporein-Tomichaedin Degradation Novel Conversion of a Dibenzoquinone into a Naphthaquinone By J. SMITHand R. H. THOMSON (UNIVERSITY OF AJ~ERDEEN) IT has been shown1,2 that the naturally occurring standard procedures starting from 2,6-dimethyl- dibenzoquinone oosporein (= chaetomidin,l = iso-naphthalene and the product is identical with oosporein2)(I) undergoes a remarkable degradation tomichaedin. on fusion with potassium hydroxide to form a com- Two other products isolated from the potash pound (tomichaedin) regarded as a hydroxymethyl-fusion were oxalic acid1 and n-butyric acid.2 The naphthaquinonecarboxylic acid. As tomichaedin former would arise by hydrolysis of the form (Ia) affords trimellitic acid when oxidised with alkaline at a and b.Alternatively fission of structure (Ia) at Me OH--HO permanganatel or hydrogen peroxide,2 it must be bonds a and c could yield a-oxobutyric acid which 3-hydroxy-2-methylnaphthaquinone-6- or -7-carbox- would not be expected to survive but is conceivably ylic acid. The annexed mechanism would account the source of the n-butyric acid. We have confirmed for the formation of one of these the reaction pro- by paper chromatography that the latter is present mding by fission of the bonds a and b in the in small amount and a search for its origin is in tautomeric structure (Ia). progress. We have now synthesised the quinone-acid (11) by (Received January 28th 1959.) I Nishikawa J. Fac. Agric. Tottori Univ. 1952 1 71; Itahashi Murakami and Nishikawa Tdhoku J.Agric. Res. 1955 5 281. a Shigematsu,J. Inst. Polytechnics Osaka City Univ. Ser. C. 1956 5 100. The Photo-induced Oxidation of Propan-2-01by Acid Chromate By U. K. KLANINGand M. C. R. SYMONS (DEPARTMENT UNIVERSITY OF CHEMISTRY OF SOUTHAMPTON) IT is generally agreed that the first step in the oxidation of alcohols by acid chromate led to the oxidation of alcohols by Crm in acidic media results concl~sion~~~ that the first step involved the decom- in the formation of Crw. Watanabel and Westheimer position of the monoester to give Crw (reaction 1) have discussed alternative mechanisms and arrived R,CH.OCrO,-+ hv -+R2C0 + Crw ... . . . .(1) at this conclusion mainly because of the effect of R,CH-OCrO,-+ hv+ adding Mnn salts.Possible further evidence for the formation of Crw is given by Pungor and Trompler.2 R2CH.0. (or CR,-OH) + Crv.. . .(2) A kinetic study of the photochemically induced However the alternative reaction (2) could not be Watanabe and Westheimer J. Chem. Phys. 1949 17 61; cf. Waters Quart. Rev. 1958,12 277. Pungor and Trompler J. Inorg. Nuclear Chem. 1957,5 123; 1958 7 412. Klanhg Acta Chem. Scand. 1958,12 576. Ihm. ibid. p. 807. eliminated; and since it should be possible to dis- tinguish between reactions (1) and (2) by magnetic and stoicheiometric measurements of the reaction products if the reaction could be stopped at this stage we have studied the photolysis of glasses con- taining isopropanol Crw and phosphoric acid at 90"~. Under those conditions highly reactive primary or secondary products are often permanently trapped in the glass and free radicals even in very low concentration can be detected by electron-spin re~onance.~ We conclude that if step (2) were im- portant the alcohol radicals should be very readily detected and that on warming disproportionation of CrV should yield 67 % of the original Crw.In con- trast no electron-spin resonance absorption would be expected if step (1) predominated and the mini- mum yield of CrVI on softening would be 33 % of the original. In fact no electron-spin resonance absorp- tion could be detected after irradiation for 12 hr. with light of wavelength 3650 A and the yield of CrvI on warming was 33 % (12 hr.) and 37 % (6 hr.).We conclude that only reaction (1) is significant. The quantum efficiency for the photo-induced oxidation at room temperature varies with acidity and light intensity and it was found that a reaction sequence which included the formation of CrIl satis- factorily expIained the result^.^ However it is now PROCEEDINGS found that quantum efficiencies at low acidities are not compatible with this mechanism since they fall below 50% of the maximum measured quantum efficiency and the published mechanism4 requires that the quantum efficiency should never fall below 50 %. A mechanism which fits all results so far obtained including the effect of oxygen and Mnn salts on the quantum efficiency is (l) followed by Crw + CrvI -+ 2CrV .. . . . . . . . .. . . . . . . . . . . . . .(3) CrIV + R,CH.OCrO- -+ CrV+ Crm + R,CO. .(4) CrV + R,CH*OH + H+-+ CrIII + R,CO. .. .. .(5) CrV + Crm -+ Crv + Cr"' . . . . . . .. .. . . . . .. .(6) Watanabe and Westheimer discussing the cor- responding thermal reaction,l included steps (3) (5) and (6) but were unable to reject a variety of other reactions which included those previously proposed for the phot~lysis.~ Step (6) which involves inter- action between two unstable intermediates is the key reaction since it provides a quantitative ex- planation for the variation in quantum efficiency with conditions. Such direct evidence has not been obtained for this step in the dark reaction. (Received January 19th 1959.) 5 Symons and Townsend J.1959 263; Gibson Symons and Townsend J. 1959 269. The Structures of Spirilloxanthin and Related Carotenoids By M. S. BARBER and B. C. L. WEEDON L. M. JACKMAN (IMPERIAL COLLEGE AND TECHNOLOGY, OF SCIENCE SOUTH LONDON, KENSINGTON S.W.7) SPIRILLOXANTHIN (rhodoviolascin) is a dimethoxy- carotenoid C42H6002 found in species of both Thio-and Athio-rh0daceae.l Structure (I; R = R' = a) was proposed by Karrer et aZ.,2but this vinyl ether d-e-f= HO formulation is inconsistent with the visible and infra- red light absorption spectra and with the resistance to acid hydrolysis. Permanganate oxidation to bixindial (I; R = R' = CHO) and a higher &aldehyde (probably I; R = R' = CH:CMeCHO) established the polyene chromophore,2 and an unambiguous assignment of structure (I; R = R' = b) can now be made from a study of the nuclear magnetic resonance spectrum in the 9.5-6-5 p.p.m.region.* This shows bands at 6-78 (OMe) 7.70 (doublet J = 6.8 cps) 8-02 and 8-83. The doublet at 7-70can be assigned to a methylene group with one neighbouring proton; the shift from the normal position (8.3-8.7) being attributable to the adjacent double bond and oxygen-bearing carbon atom. The band at 8.02 is typical of methyl groups of the type CH:CHCMe:CH in polyene system^.^ That there is no methyl group at the end of the con- jugated system follows3 from the absence of absorp- tion between 8.1 and 8-5. The band at 8.83 is * The spectrum of a chloroform solution was determined at 40 Mc and calibrated against tetramethylsilane as an internal standard.Band positions are given as walues defined by Tiers (J. Phys. Chern. 1958,62 1151). Karrer and Solmssen Helv.Chim. Ada 1935,18,1306; Polgar van Nie1,and Zechmeister Arch.Biochem.,1944,5,243. Karrer and Koenig Helv. Chim. Acta 1940 23 460. Barber Jackman and Weedon unpublished work. MARCH1959 ~~~ ~~ exceptionally sharp and must therefore be assigned to methyl groups on a fully substituted carbon atom. Methyl groups in saturated aliphatic systems occur at 9.10-9.15. The present shift to 8-83 is similar to that in e.g. t-butyl alcohol and is due to the proximity of the oxygen atom. The relative in- tensities of the bands are in agreement with the structure (I; R = R’ = b).Biosynthetical studies4 show that spirilloxanthin is derived from lycopene (I; R = R’ = c) and indicate that lycoxanthin (I; R = c R’ = d) lycophyll (I; R = R’ = d) “P481” “OH-P481” and “OH- spirilloxanthin” are involved probably as inter-mediates in this conversion. The transformation of the end groups can now be visualised as involving (i) oxidation to the hydroxy-derivative (d) (ii) anionotropic rearrangement to a CMe,.O-com-pound (e.g. e) (iii) prototropic rearrangement of the resulting 1 :4-diene to give the fully conjugated isomer (e.g. f) and (iv) methylation though the order of some of these stages is doubtful. From these considerations and the properties so far reported we suggest that “P481” is (I; R = b R‘ = c) “OH-P481” is (I; R = b R’ = d) and “OH-spirilloxan- thin is (I;R = b R“= f).It is hoped to examine the validity of these proposals and those for spheroid- enone and “pigment Y”,5 by further studies of nuclear magnetic resonance. Spirilloxanthin was isolated both from Chromatium (supplied by Dr. J. R. Postgate) and from Rrp. rubrum (from Dr. T. W. Goodwin). It has m.p. 218” (in benzene) 546 509 and 481 mp (lo-% 122 144 and 103 respectively) vmax 2817 1078 (OMe) and 967 cm.-l (conjug. trans-CH:CH). The authors thank the Medical Research Council Antibiotics Research Station (Clevedon) for growing the bacteria and the D.S.I.R. for a maintenance grant (to M.S.B.). (Received February loth 1959.) Goodwin and Land Arch. Mikrobiol. 1956 24 305; Goodwin ibid.p. 313; van Niel Goodwin and Skins, Biochem. J. 1956,63,408; Braithwaite and Goodwin Nature 1958,182 1304; Jensen Cohen-Bazire Nakayama and Stanier Biochim. Biophys. Acta 1958 29 477; Jensen Acta Chem. Scand. 1958 12 1698. Goodwin Land and Sissins Biochem. J. 1956,64,486; Nakayama Arch. Biochem. Biophys. 1958,75 356. NEWS AND ANNOUNCEMENTS Russian “Journal of Inorganic Chemistry.”-Starting with the January 1959 issue The Chemical Society is to publish with the support of the Depart- ment of Scientific and Industrial Research a cover- to-cover translation of the monthly journal Zhurnal neorganicheskoi Khimii a publication of the Academy of Sciences of the U.S.S.R. The translation will be undertaken for the Society by Infosearch Ltd. and the Society has appointed Professor P.L. Robinson as Executive Editor of the publication. Professor Robinson will be assisted by an advisory panel of distinguished inorganic chemists. The sale and distribution of the journal will be undertaken by Cleaver-Hume Press Ltd. 3 1 Wright’s Lane London W.8 from whom a detailed prospec- tus giving the scope of this journal may be obtained. Translations will be issued in monthly parts as soon as possible after the Russian original is avail- able. The subscription rate will be f30 per annum but Universities and Technical Colleges may sub- scribe at a discount of 25 % if orders are placed directly with Cleaver-Hume Press. Single issues can be purchased at 24 per copy to all purchasers. The Society also hopes to start the publication within the next year of translations of the Russian “Journal of Physical Chemistry” (ZhurnaEfizicheskoi Khimii) and “Progress in Chemistry” (Uspekhi Khimii).Nominations to Honorary Fellowship.-The Council has nominated Professor K. Freudenberg (Heidelberg) Professor W. Hieber (Munich) Profes-sor G. T. Seaborg (Berkeley California) and Professor A. St022 (Bade) to Honorary Fellowship of the Society. Subject to Bye-law 13 these elections will take place on May 7th. Professor K. Freudenberg is distinguished by reason of his pioneering work in organic chemistry particularly in two fields namely (1) the relation of optical rotation to configuration which led to the earliest consistently correct identifications of re-actions with inversion an understanding of the useful scope of the principle of optical superposition and latterly the determination of absolute con- figurations of a wide range of substances including terpenes by reference back to tartaric acid; (2) deter- mination of the basic structures of naturally oc-curring carbohydrate high-polymers particularly starch cellulose and their components.Professor W. Hieber has built up over a period of years the only school of research devoted to the study of metallic carbonyls and their derivatives. A large proportion of what we know of these com- pounds is derived from his work and some of the more recent developments in organic synthesis based on the use of carbonyls are likewise directly related to it.Professor G. T. Seaborg is one of the leading radio- chemists who with his collaborators at Berkeley has discovered most of the new artificial elements. He is equally skilled as an experimenter and in the theoretical aspects of the subject. Professor A. Stoll who has recently retired from his position as Research Director of “Sandoz,” Bade is world-renowned for his contributions to organic chemistry in general and to the chemistry of natural products in particular. Local Representatives-Council has approved the following changes of Local Representatives Glasgow . . Dr. G. €3. Nancollas in place of Dr. G. L. Buchanan. Liverpool . . Mr. R. Towers in place of Dr. D. W. Broad. North Wales .. Dr. J. R. Turvey in place of Dr.J. E. McKail. Sheffield . . . . Dr. J. McKenna in place of Mr. H. J. V. Tyrrell. Election of New Fellows.-1 16 Candidates whose names were published in Proceedings for January were elected to the Fellowship on February 12th 1959. The 1959 Waverley Gold Medal Competition.-Research is sponsoring the Waverley Gold Medal Essay Competition for the seventh year in succession. The competition is designed to encourage and pro- mote improved and more effective reports of scientific and technical work. It was felt that the scientist in his laboratory and the engineer in the production plant must learn to express his views and translate his work into terms that are readily under- stood by other scientists directors of industrial firms and others interested in the advance of science and technology.The Waverley Gold Medal named after and bearing the coat of arms of the late Lord Waverley together with E100 will be awarded for the best essay of about 3,000 words describing a new PROCEEDINGS scientific project or practical development giving an outline of the scientific background the experi- mental results and the potential application of the project or process in industry. The essays will be judged for technical content by specialists in the subject for clarity of presentation and for style. A second prize of E50 will be awarded and also a special prize of E50 for the best entry from a com- petitor under the age of thirty on July 31st 1959. If the first prize is awarded to a competitor under the age of thirty the special prize will go to the next best entry.The competition is open only to persons engaged in scientific work from January 1st to July 31st 1959. Further particulars are available from the Editor of Research 4/5 Bell Yard London W.C.2 and final entries must be received not later than July 31st 1959. Exhibition of Laboratory Apparatus.-An exhibi-tion of instruments and general laboratory apparatus will be held at the College of Technology Ashley Down Road Bristol on April lst 2nd and 3rd 1959. Among those exhibiting will be Messrs. Baird & Tatlock Controlled Heating Doran Instrument Co. Edwards High Vacuum Electronic Instruments Ltd. H. J. Elliot Evershed & Vignoles Gas Chromatography Engelhard Industries Hilger & Watts Sir Howard Grubb Parsons & Co.Isopad Jencons Scientific J. A. Joblings Johnson-Matthey Loughborough Glass Co. L. Oertling R. E. Pickstone W. G. Pye Quickfit & Quartz Shandon Scientific Stanton Instruments Thermal Syndicate J. W. Towers Townson & Mercer Unicam Ltd. Tickets are being sent to members in the Bristol Cardiff Mid-Southern Counties South Wales and South-Western Counties Sections of the Royal Insti- tute of Chemistry; any others requiring tickets may obtain them from the Exhibition Secretary E. John Skerrett Research Station Long Ashton Bristol. Symposium Cancellation.-The Symposium on Therapeutics that was to have been held in Gardone Italy on August 20-27th 1959 (announced in Proceedings for February p.64) has now been cancelled. Deaths of Fellows.-We regret to announce the death (22.2.59) of Dr. William Hobson Mills President of the Society 1941/4 and formerly Fellow and President of Jesus College Cambridge. A full obituary notice will be published. The deaths of the following are also announced Dr. George MacDonaZd Bennett C.B. (9.2.59) Vice-president of the Society 1948/51 and formerly Government Chemist; Mr. Herbert John Evans (1 8.12.58) Public Analyst of Carmarthen ;Dr. Robert Benjamin Forster MARCH1959 (10.2.59) formerly of Leeds and Bombay Univer- sities; Mr. William Charles Slater (1 3.2.59) of London S.E.1; Mr. Harold Taylor (27.12.58) of Blackburn; and Dr.Henry Edgar Watt (8.2.59) formerly of T. and H. Smith Limited Edinburgh. Personal.-Mr. J. Bodton Research Manager of Droylsden Research Laboratory Courtaulds Ltd. has been elected President of the International Federation of Associations of Textile Chemists. Mr. R. C. Chirnside,Chief Chemist of the Research Laboratories of The General Electric Company Ltd. Wembley has been nominated by the Council of the Society for Analytical Chemistry as President designate to take office at the Annual General Meeting in March. Professor E. Lederer of the Institut de Biologie Physico-Chimique Paris will visit King’s College in the University of Durham Newcastle upon Tyne from March 3rd to 21st and for a further period after Easter. Dr. F. H. McDowall Chief Chemist the Dairy Research Institute New Zealand has been awarded the Gold Medal of the Australian Society of Dairy Technology.This is the first award of the Medal outside Australia. The title of Reader in Crystallography in the University of London has been conferred on Dr. C. H. Carlisle in respect of his post at Birkbeck College. Professor P. V.Danckwerts Professor of Chemical Engineering Science at the Imperial College of Science and Technology has been elected Shell Pro- fessor of Chemical Engineering at Cambridge from October 1st next in succession to Professor T. R. C. Fox who has resigned. MY. E. W. M. Fawcett Technical Director and Mr. H. P. P. Hodgkins Commercial Director of Howards of Ilford Ltd. have been appointed to the Board of the parent company Howards & Sons Ltd.Mr. W. C. Garratt has accepted a position as Senior Analyst Research Department British Enka Ltd. Liverpool. Mr. K. M. Grifin has retired from the position of Government Analyst Auckland N.Z. On the occa- sion of his retirement he was the guest of honour at a luncheon tendered by the Auckland Branch of the New Zealand Institute of Chemistry. It is believed that his tenure of office-34 years-during which he featured in a number of important trials is a record for a civil servant in one position in New Zealand. Mr. 0.H. Keys formerly Government Analyst Dunedin New Zealand has been appointed Government Analyst Auckland. Dr. W. E. Harvey has been promoted to a Senior Lectureship in the Chemistry Department Victoria University of Wellington New Zealand.Professor D. H. Hey has been elected a Fellow of King’s College London. Dr. D. F. Rushman has left the Paint Research Station to take up an appointment as Chief Chemist with Kay Brothers Ltd. Reddish Stockport. Dr. D. W. Stammers of Imperial Chemical Industries Limited Dyestuffs Division has been ap- pointed section leader of the research team working in the colour-photographic field under the terms of the agreement between Imperial Chemical Industries Limited and Ilford Ltd. Mr. F. Schollick of British Industrial Plastics Ltd. travels to Natal in April to take up the appointment of General Manager British Industrial Plastics (S.A.) Pty. Ltd. Professor M.Sfacey F. R. S. has been invited to give the Nicolaysen Lecture in the University of Oslo this spring. He has also been invited to give papers at the Boston Meeting of the American Chemical Society in April. Dr. D. M. Stead of James Anderson & Co. (Colours) Ltd. has been appointed a Managing Director. Dr. H. Suschitzky Senior Lecturer in Organic Chemistry in the Department of Pure and Applied Chemistry at the Royal Technical College Salford has been appointed Reader in the same Department. Mr. G. A. TayZur has been elected to a Senior Demyship in Chemistry at Magdalen College Oxford with effect from October lst 1959. Professor R. L. Wain has just completed a period at the University College of Ibadan Nigeria as Visiting Nuffield Professor.Dr. J. G. Watkinson has been appointed Lecturer in Chemistry at the University of Manchester as from October lst 1959. Recently at a small ceremony in the Chemistry Department of the University of Birmingham Mr. P. C. Wheeler was presented with a cheque and a book of signatures of Staff Technical Staff and Research Students in the department. This marked his 41 years of service as Lecture-Demonstrator and Photographer in the department for he joined the celebrated C. P. Proctor in 1917. He has been a Fellow of the Chemical Society for over 20 years. PROCEEDINGS FORTHCOMING SCIENTIFIC MEETINGS London Thursday May 7th at 7.30 p.m. Meeting for the Reading of Original Papers. “Recent Developments in the Chemistry of the Ipecacuanha Alkaloids,” by A.R. Battersby R. Binks G. C. Davidson B. J. T. Harper and S. Garratt. “Aldol Pinacol and Benzoin-type Reactions of dl-Pyrroline 1-oxides,” by R. F. C. Brown V. M. Clark M. Lamchen B. Sklarz and Sir Alexander Todd. “Perpendicular Conjugation in Some Octahedral Metallo-phthalocyanine Derivatives,” by J. A. Elvidge and A. B. P. Lever. To be held in the Rooms of the Society Burlington House W.l. Coffee will be served in the Library from 7 p.m. (Abstracts of the Papers are available from the General Secretary.) Birmingham Friday May lst at 4.30 p.m. Lecture “The Structure and Reactivity of Reduced Metallic Surfaces,” by Professor K. W. Sykes M.A. D.Phil. Joint Meeting with Birmingham University Chemical Society to be held in the Chemistry Department The University.Cambridge Monday April 27th at 5 p.m. Lecture by Dr. G. Smith. To be given in the Univer- sity Chemical Laboratory Lensfield Road. Durham Monday May 4th at 5 p.m. Lecture “Carbon-14 Compounds,” by Dr. J. R. Catch. Joint Meeting with the Durham Colleges Chemical Society to be held in the Science Labora- tories The University. Exeter Friday May 22nd at 5 p.m. The lecture by Professor R. A. Raphael will not now be given and Dr. W. Klyne will deliver a Lecture “Optical Rotatory Dispersion in Structural Organic Chemistry.” To be given in the Washington Singer Laboratories Prince of Wales Road. Hull Tuesday April 28th at 5 p.m. Lecture “Recent Developments in the Chemistry of Organometallic Compounds,” by Professor G.E. Coates D.Sc. F.R.I.C. Joint Meeting with the University Student Chemical Society to be held in the Organic Chemistry Lecture Theatre The University. Irish Republic April 29th May lst and May 4th. Lecture “A Generation of Chemotherapeutic Research,” by Dr. F. L. Rose O.B.E. F.R.I.C. F.R.S. Joint Meeting with the Institute of Chemistry of Ireland The Royal Institute of Chemistry and the Society of Chemical Industry. To be held as follows April 29th at 7.45 p.m. in the University Chemical Laboratory Trinity College Dublin. May lst at 7.45 p.m. at University College Cork. May 4th in the Chemistry Department University College Galway. Friday May 8th at 7.45 p.m. Lecture “The Nature of the Active Centre of Chymotrypsin and other Esterases,” by Professor H.N. Rydon D.Sc. D.Phil. F.R.I.C. Joint Meeting with the Werner Society to be held in the University Chemical Laboratory Trinity College Dublin. Northern Ireland Tuesday May 5th at 7.45 p.m. Official Meeting and Tilden Lecture “Nucleotides and Bacterial Cell-wall Components,” by Professor J. Baddiley D.Sc. Ph.D. To be given in the Chem- istry Department Queen’s University Belfast. oxford Monday May 4th at 8.15 p.m. Lecture ‘(Magnetic Properties of Molecules,” by Dr. J. A. Pople. Joint Meeting With the University Alembic Club to be held in the Inorganic Chemistry Lecture Theatre The University. St. Andrews and Dundee (Meetings will be held in the Chemistry Department St.Salvator’s College St. Andrews.) Friday April 17th at 5.15 p.m. Lecture b‘Explosion,” by Mr. S. Paterson. Joint Meeting with the University Chemical Society. Friday May lst at 5.15 p.m. Lecture “Chemical Effects due to Fission Frag- ments,” by Dr. R. Spence C.B. D.Sc. F.R.I.C. Joint Meeting with the University Chemical Society. Southampton Friday April 24th at 7 p.m. Lecture “Nitrogen-containing Sugars,” by Professor M. Stacey Ph.D. D.Sc. F.R.I.C. F.R.S. Joint Meeting with the Royal Institute of Chemistry to be held at the College of Technology Portsmouth. South Wales Monday April 27th at 7 p.m. Meeting for the Reading of Original Papers. To be held in the Chemistry Department University College Cardiff.MARCH1959 OBITUARY NOTICES DAVID LEONARD CHAPMAN 1869-1958 DAV~,LEONARDCHAPMAN was born at Wells Norfolk on December 8th 1869 the elder son of a builder in Manchester and a lady of a family long connected with N.E. Norfolk. He died in his 90th year on January 17th 1958. He will be remembered with respect and affection by a large number of colleagues and old pupils. Chapman was educated at Manchester Grammar School. He gives a glimpse of his school days and of the contemporary attitude towards science in an appreciation he wrote of his science master Francis James in 1926. He writes that in 1886 he entered the scienceV “the refuge of the incorrigibly stupid,” the High Master warning him that his chance of be- coming a well-educated man would thereby be lost.In due course he was elected to an open Exhibition at Christ Church Oxford and proceeded in 1893 to a 1st Class in Chemistry in the Final Honours School of Natural Science. In the following year he was placed in the 2nd Class in Physics. During his under-graduate career he acquired a high degree of mathe- matical competence a fact that was of great importance in his scientific career. Chapman left Oxford to become a science master at Giggleswick; ten years later he joined H. B. Dixon at Manchester in whose laboratory he worked for another ten years. In 1907 he was recalled to Oxford as a Fellow and Tutor of Jesus College where he took charge of the newly built Sir Leoline Jenkins laboratory.He retired in 1944 when he took up the study of philosophy to which he was led by the im- plications of relativity theory and certain aspects of modern physics. He also became an authority on the works of Agatha Christie. In 1918 Chapman married Muriel Catharine Canning Holmes daughter of the Rev. Samuel Holmes; she and their daughter survive him. Mrs. Chapman collaborated with him in some of his earlier work and they were always closely associated in their campaign against blood sports. It was characteristic of him that he was always profoundly moved by injustice and cruelty a fact which often appeared in striking contrast to his reserved and rather austere bearing. His pupils and his assistants were devoted to him; a colleague writes of his “gift for winning affection and respect owing something to his gentleness of manner and to his artless un- affected nature”.Chapman’s scientific work lay mainly in the field of gaseous reactions and it is remarkable how much of it was and remains of fundamental importance. What may perhaps be called its first phase began with his paper in 1899 on “The Rate of Explos- ion in Gases,” which contained the first sound treatment of what is now called “detonation” it gave a rational explanation of the detonation velo- cities found by Dixon. He regarded the exploded and the unexploded gases on each side of the “explosive wave” in which reaction takes place as having after initial turbulance uniform densities and velocities and applied Riemann’s equation relating the gas movement to the pressures and densities of the gases before and behind the wave front.He also made the further assumption which has since been fully justi- fied that the observed velocity is the minimum con- sistent with the other conditions and notes that this is equivalent to a postulate of maximum entropy. An equation to the velocity of an explosive wave must involve the heat of reaction and the specific heats of the exploded gases present. The latter were calculated by working back from Dixon’s observed velocities in certain cases assuming that the values were nearly independent of temperature. With data thus ob- tained Chapman was able to calculate the explosion velocities for some 40 other mixtures.In this work he laid the foundations and the theory of detonation on a firm and lasting basis. The same conclusions were reached independently by Jonguet and the con- ditions behind an advancing explosive wave are now referred to as the “Chapman-Jonguet state”. By 1905 Chapman’s interest in gaseous reactions had led him into a field where his pioneering work was of even greater importance. His Note with C. H. Burgess on the cause of the period of induction in the union of hydrogen and chlorine marks the be- ginning of the long series of photochemical investiga- tions with which his name is associated. When Chapman entered the field of photokinetics Draper’s view that the agency which affects the chance is “tithonicity an essential constituent of sunlight” was still an acceptable hypothesis.The mechanism of this process in the hydrogenxhlorine reaction was sup- posed to be either “a gradual breakdown of a resist- ance which opposed the force of affinity” or to an increase in the electronegative properties of chlorine which thereby “exalts the affinity between chlorine and hydrogen.” The enormous difference between the feeble light energy required to initiate the reaction and the energy subsequently liberated appeared to exclude any idea of primary atom formation. Furthermore the reported facts of the reaction qualitative and quantitative were often contradio tory capricious and befogged by years of contro- versy and disagreement. In this dif€icult field Chapman and his collaborators including his wife worked steadily with great experimental skill and scientific prescience ultimately to place the subject on a firm factual and theoretical basis.When Chapman began his photochemical work the importance of quantum theory was not recog- nised and the self-repeating chain concept of Nernst (1918) had not yet provided a rational explanation of exalted quantum efficiencies. We now know that it is characteristic of chain reactions that changes of rate with experimental conditions such as reactant concentrations other substances present in the system walls and so on depend very critically on “chain-ending” processes. It was Chapman’s work that established unequivocably what the facts and conditions are.Its most striking triumph was prob- ably its first (1906) for it solved the mystery of “induction” and “deduction” in hydrogen-chlorine systems. Earlier workers had claimed that reaction did not begin immediately the apparatus was illu- minated but did so after an “induction period.” Chapman and Burgess showed that pre-illumination of the chlorine alone never led to a period of “deduc- tion” or induced initial activity of the chlorine when mixed with the hydrogen. In the end he showed that the induction periods were caused by traces of ammonia and other nitrogenous substances in the water used in the apparatus. Thus the presence of chain breakers was established long before the actual mechanism of their behaviour was per-ceived.Study of the inhibiting effect of oxygen was now begun and extended to other inhibitors not only in hydrogen and chlorine but also in other systems such as chlorine and carbon monoxide. The fact that inhibitors were observed to be effective in photo-reactions but not in the purely thermal reactions in the same system at higher temperatures no doubt explains Chapman’s reluctance to accept the sugges- tion of a photochemical dissociation of the chlorine molecule into atoms as the first step in the Nernst chain mechanism. Nevertheless his attitude gradually changed particularly as the details of the dependence of photoreaction rates on light-intensity became more clearly established. In 1924 Mrs. Chapman showed that in the hydrogen-chlorine system rates of reaction were slightly less than directly proportional to the light intensity.Two years later Berthoud and Bellemont by an early use of “flash photometry” showed that if the light was reduced in intensity by a rotating sector wheel the rate depended on the speed of rotation. Chapman worked out the com- plete mathematical theory of the “sector effect”. In 1931 he showed (with F. B. Gibb) that for very pure hydrogen-chlorine mixtures in large vessels in which reaction was to all intents and purposes homo- geneous rates follow a square-root intensity law. On PROCEEDINGS the other hand rates in the hydrogen-bromine system in the presence of the powerful inhibitor nitric oxide become directly proportional to light- intensity.Passing from homogeneous reactions in large vessels to the measurement of rates in capillary tubes which ensured the removal of “catalyst” practically entirely on the walls he was able (with P. P. Grigg) to evaluate the catalyst mean life. He now formally accepts the Nernst repeating- chain mechanism and uses it in an explanation (with J. S. Watkins 1933) of the very complex photo- sensitised reaction between hydrogen chloride and water. It was natural that Chapman should become interested in heterogeneous catalysis. It had long been known that metallic gold and silver can be activated by heating them in hydrogen. This he showed to be due to the removal of an oxide film. However at low temperatures a catalytically active oxide is formed.Chapman extended his observation to platinum surfaces. Active surfaces became in- active when reduced in hydrogen and then treated with oxygen at 1OOO”. This effect was traced to the presence of an impurity very probably copper which forms an inactive and immobile oxide but which diffuses from the interior to the surface when heated in hydrogen. Work in this field was elegantly and carefully developed and has been of great value to later workers in the field of heterogeneous catalysis. Chapman’s attitude to research was in what may perhaps be called the classical tradition. He was un- hurried and quite impersonal. He was strictly ac- curate in experiment and in thought and was always clear as to what had and what had not been proved. It is probably true to say that nearly all the problems he examined were taken up because the supposed facts seemed inadequate or incorrect.Apart from his two main preoccupations in the fields of gaseous reactions we may notice his demonstration from measurements of vapour pressures that “metallic” and red phosphorus are identical that the vapour molecule is P, and that the so-called suboxide was impure red phosphorus. In fact he displayed clearly and for the first time the interphase relations in the phosphorus system. He showed that during an electric discharge through water vapour hydrogen appears at both electrodes thus disproving the cur- rent view that the ordinary electrolysis was involved. He confirmed from conductivity and voltameter methods the existence of the ion Is-and established the presence of a reactive addition compound in the reaction between acetylene and mercuric chloride.He wrote on the subject of electrocapillarily and as was not uncommon among physical chemists of the period was interested in equations of state. In par- ticular he derived with M. P. Appleby an interest- ing relation between latent heats of volatilisation and MARCH1959 the volume relations of the liquid and the vapour state. In Annual Reports for 1914 Chapman contributed the section in General and Physical Chemistry in which he made what was probably the first clear and informative account for chemists of the new physics of Bohr and Planck. Chapman’s last paper appeared in the Journal in 1937.With Mrs. Chapman he disproved H. B. Baker’s claim that intensive drying inhibited the re- action between nitrogen peroxide and nitric oxide. During the early part of the last war until his retire- ment in 1944 he worked with a small team on gaseous diffusion for the secret “Tube alloy” programme. After his return to Oxford in 1907 Chapman remained for 37 years as a College tutor growing in academic stature and in the regard of all. He was a kindly man reticent but by no means unsociable. His lectures were difficult to listen to owing to his slow and somewhat harsh delivery. But he had the ability to display his subject concisely and clearly and to the discerning his guidance was invaluable. He played a full part in College and University affairs.He should be remembered for the considerable part he played with W. H. Perkin in the introduction of the fourth year for research (Part 11) into the Final Honour School of chemistry at Oxford. He became Senior Proctor in due course it being considered at the time rather remarkable that a scientist could combine the management of a laboratory with the very considerable duties of that important university office. He served on the Hebdomadal Council and other Boards and Committees. For ten years he was Bursar of his College and showed practical ability and great common-sense. He was Vice-Principal for a number of years. He was hale and active until a few years before his death. The writer’s grateful thanks are offered to Dr.E. J. Bowen F.R.S. and Dr. J. W. Linnett F.R.S. for making available the material on which this memoir is based. D. LL. HAMMICK. FRIEDRICH ADOLF PANETH 1887-1958 ON September 17th 1958 after 50 years of uninter- rupted activity in the field of science and research Professor F. A. Paneth died most unexpectedly as the result of a sudden illness. He died in Vienna the town where he was born 71 years ago on August 31st 1887. The son of a doctor he received a classical educa- tion at the well-known “Schotten Gymnasium” in Vienna. Later he studied at the Universities of Vienna Munich and Glasgow in the laboratories of Z. Skraup A. von Baeyer and F. Soddy and in 1910 received the degree of Dr. Phil. with a thesis “On the transformation of quinidine and cinchonidine by sulphuric acid” and “On the effect of nascent hydrogen on egg albumin”.But it was the influence of Soddy which determined the direction of his future research and in 1912 he became a research assistant at the Radium Institute of the Vienna Academy of Sciences then under the direction of Stephan Meyer co-author of the most important textbook on radioactivity at that time. Here he was given the task of separating radium-D from lead a problem which was simultaneously pursued by von Hevesy at Manchester. After many varied experi- ments both came independently to the conclusion that these materials were inseparable. It was one of the first rigid experimental proofs of isotopic be- haviour (discovered in 1911 by Soddy) and during a meeting in Vienna both Paneth and Hevesy realised the possibility of the use of radioactive iso- topes as indicators.Within a year they presented two very important papers “On attempts to separate Ra-D from lead” and “On the radioactive elements as in- dicators in analytical chemistry”. In 1913 this tech- nique could only be applied to the few known natural radioelements but today when radioactive isotopes of almost any element of the Periodic Table are avail- able cheaply this method has become of paramount importance in almost every field of science and technology. The same year Fritz Paneth was married to Else Hartmann daughter of the Professor of History her- self a student of medicine and later a practising doctor.The new discovery of isotopic behaviour and its subsequent applications opened the door to a pro- mising academic career. In 1917 Paneth joined Honigschmidt as Assistant at the Technische Hoch- schule in Prague. In 1919 he became Assistant Professor at the University of Hamburg and in 1922 head of the inorganic department of the First Chem- ical Institute of the University of Berlin. Finally in 1929 he received a call to the University of Konigs- berg as Professor and Director of the Chemical Institute. During his Prague and Hamburg periods the tracer techniques were applied in the field of in- organic chemistry where they led directly to the discovery of the gaseous hydrides of bismuth polon- ium and lead as well as those of tin and germanium.The formation of the first three was proved by the transfer through the gas phase of minute quantities of their radioactive isotopes. This resulted in the fundamental recognition that not only the lighter elements but all elements with atomic numbers which have one to four units less than a rare gas are capable of forming gaseous hydrides. The technique developed in the work with volatile hydrides led to a new discovery-the production of organic free radicals by decomposition of organometallic com- pounds. This opened up a rich new field of research into the life-times and reactions of such gaseous radicals as methyl ethyl and benzyl. Paneth’s interest in radioactivity led to yet another newfield.One product of a-decay is the gas helium and in trying to measure decay products quantitatively by chemical means special gas-analytical techniques were evolved with sensitivities up to ml.(N.T.P.). This simple technique depending on the removal of hydrogen by catalytic combustion with oxygen over palladium followed by the removal of all other gases (except neon) by two-stage adsorption on charcoal formed the basis of much subsequent work. To this class also belongs one of the most ambitious experiments begun in 1923 and continued for almost fifteen years. This was the attempt to transform hydrogen into helium by bombarding hydrocarbons with a-particles. Now in the age of ZETA and other thermonuclear tools we know that helium cannot be produced in measurable quantities under these conditions but we must admire the courage and optimism with which this problem was approached by Paneth thirty-five years ago.Very often the appearance of an excess of helium seemed to indicate success but so critical was Paneth’s atti- tude towards his own experimental results that he did not rest until eventually this phenomenon was traced back to a quite different source. During this work it was discovered that glasses and especially silica and Pyrex glasses were porous to helium (a phenomenon which very recently has been suggested as a method for the large-scale purification of helium from natural gases). This most fertile period of his career was sadly interrupted by the racial persecutions in Germany which in 1933 forced Paneth to relinquish his chair at Konigsberg.He emigrated to England where he worked at first as guest and later as Reader in Atomic Chemistry at the Imperial College of Science and Technology in London until in 1939 he was invited to the Chair of Chemistry at the Durham Colleges in the University of Durham. During this period the microanalytical work with rare gases was applied to the determination of the PROCEEDINGS minute quantities of helium produced in artificially- induced nuclear reactions e.g. from boron under the influence of neutron bombardment and from beryllium by y-rays. Under the stimulus of Chap-man’s work on the upper atmosphere this was further developed to obtain accurate determinations of the helium and neon contents of atmospheric air both on the ground and in the stratosphere leading to the recognition that the composition of the permanent gases in the atmosphere remains constant up to a height of at least 60 km.As the gravitational field of the earth would cause an enrichment of helium in the higher layers in the absence of large- scale convection this result proved that large-scale mixing persists up to very great heights in the stratosphere. His laboratory’s investigations of the atmosphere also included the development of analytical methods for the ozone content of air at ground level where it exists in varying concentrations of the order of several parts per hundred million. One of the most fascinating applications of the helium technique was the determination of the ages of both minerals and meteorites a method which led to much controversy and to most interesting develop- ments.Originally all the helium found in the iron meteorites was interpreted as being of radiogenic origin which led to ages of up to 5 x lo9years. But later it was realised and proved in very detailed investigations that most of the helium in these meteorites was not produced by normal radioactive decay but arose together with small quantities of neon and argon from fragmentation processes under the impact of cosmic radiation. Although in 1953 at the age of 66 Paneth had to retire from his chair at Durham he felt unable to relinquish his scientific interests and much of this work was completed at Mainz where he accepted the post of Director at the Max Planck-Institute for Chemistry.Here he remained active until his death. Although during this period his personal interests centred mainly on problems of the meteorites much other valuable work was carried out in these laboratories in the fields of radiochemistry and isotope separation. It is not possible here to mention all the numerous publications carrying his name many of which have found a permanent place in the textbooks of the world. Many of his writings dealt with history with met hods of scientific presentation with nomencla- ture and with the Periodic System. Indeed it may be said that he excelled in historic researches (like those on “Thomas Wright’s Original Theory of the Universe,” or on “The true manuscript of Albert the Great ‘de Alchimia’ ”) which gave full scope both to his critical mind and to his classical interests.He was a very painstaking writer and lecturer with an MARCH 1959 artistic gift for beautiful yet simple and lucid presentation. His special lectures like the Liversidge lecture in London (1936) the Halley lecture in Oxford (1940) the Schonheimer Memorial lecture in New York (1951) the Hugo Miiller lecture in London (1952) and many others were worth listening to not only for their scientific content but equally for their aesthetic design and presentation. His text- book on radioactivity written jointly with Hevesy remained for many years the standard work in this branch of science.Of his numerous honours from the scientific societies of Britain Austria Belgium France Germany and the U.S.A. he valued most highly the Fellowship of the Royal Society of London. His other treasured possession was the. citizenship of this country and although he returned to Germany after his retirement from Durham he never relinquished his British nationality. Looking back on Paneth’s life as a scientist it is immediately apparent that wherever he went he greatly stimulated scientific research. Obviously his widespread researches (over 250 publications) were not produced single-handed and numerous students and assistants have contributed with their work and ideas. Yet without Paneth as focus and organiser much of this work would never have been done and much would not have been done so well.Both at Konigsberg and at Durham chemical research was at a very low level before his arrival. Now the radio- chemical laboratories at Durham (built during his tenure) and the school of workers in radiochemistry left behind at Maim testify to the success of his life’s work. So do his numerous former students and col- laborators many of whom now hold leading posi- tions in the scientsc and industrial world. Paneth’s most striking personal characteristics were his charm and humour his cultured speech and appearance his sincerity and his generous helpful- ness towards others. Those who knew Paneth will always remember him. E. GLUECKAUF.WILLIAM HAY STAFFORD 1927-1958 WILLIAM whose early death at the HAYSTAFFORD age of 31 on March 20th 1958 came as a shock to his many friends was born in Bathgate on January 3rd 1927. He was educated at Bathgate Academy and was one of the distinguished pupils from that school who in recent years by their personality and scholarship have made their mark at Edinburgh University. A brilliant undergraduate career (1944-1948) culminated in Stafford’s gaining his B.Sc. degree with first-class honours in chemistry and was followed by the award of a Carnegie Scholarship which enabled him to undertake research in Edin- burgh University on the chemistry of aromatic hydrocarbons and thus form an interest in that branch of chemistry which he retained for the rest of his life and to which he made notable contribu- tions.He was awarded his Ph.D. degree in 1951 for a thesis entitled “Studies in the fluorene series”. For two years Stafford with the assistance of a Carnegie Senior Scholarship was a member of the team in Cambridge working under Sir Alexander Todd on vitamin BIZ.Stimulated by this experience Stafford returned to his old University in 1952 as a lecturer in chemistry; and it was not long before he was attracting enthusiastic collaborators to investigate the chemistry of the azulenes and other non-benzenoid hydrocarbons. Part of this work was described in three papers (J. 1958,1100,1110,1118) and gives some idea of the loss chemistry has sus- tained by Stafford’s untimely death.It is hoped that the remainder of his completed work will soon be published. Stafford was fascinated by the problem of aromaticity. He was impressed by the close paral- lelism between the structure and properties of the anhydro-salts and the azulenes and with D. H. Reid proposed a betaine structure for azulene (Chem. and Ind. 1954 277) a similar structure from another viewpoint being advanced by A. G. Anderson in America. Later investigations on the azulenes were based on this formulation (Reid Stafford and Ward J. 1955 1193) and in these Stafford supplemented chemical evidence by the use of infrared visible and ultraviolet spectral measurements particularly in the study of the fine structure of his products. At the time of his death Sword was engaged on syn-thesising non-benzenoid heterocycles (e.g.Proc. Chem. Soc. 1957 352) and studying their properties. In addition to these activities Stafford under the aegis of the Atomic Energy Authority investigated the chemical effects of radiation on organic com- pounds in non-aqueous solution. In this field also Stafford made a reputation for himself as was testified by the numerous invitations he received to lecture at home and abroad and by the number of visitors who sought his advice and guidance. Sword was a Scot through and through and his return to Edinburgh brought him the greatest happiness and satisfaction. He enjoyed his teaching duties in the classroom and laboratory but possibly was at his best in those informal discussions (not necessarily on chemistry for every subject was grist to Stafford’s mill) which formed part of his daily routine and were invariably stimulating and profit- able.His restless zest and animation made an im- mediate impression on all who encountered him and it is not surprising that one so gifted and generous should have inspired loyalty and affection from an ever-increasing number of students. Chemistry was PROCEEDINGS his passion but he was keenly interested in painting design and music and he enjoyed a game of bridge golf or tennis. Those who knew Stafford will remember him not only for his intellectual gifts but also for his integrity and selflessness. Stafford was married on July 7th 1956 to Winifred L.Galloway who collaborated with him in some of his researches. N. CAMPBELL. 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The Nurseries Batley Road Kirkhamgate Yorks.Walton Richard Alan. 27 Prince Street Ryde Isle of Wight. Warwicker Laurence Albert. 41 Fulham Park Gardens Fulham London S.W.6. Wasley Jan William Francis. 3 Frederick Avenue Ilkeston Derbyshire. Whitaker Granville B.Sc. 16 Harrogate Place Rochdale Lancs. Whyman Derek B.Sc. 19 Tunstall Road Addiscombe Croydon Surrey. Wilson John Mack B.Sc. Ladysmith Ardayre Road Prestwick Ayrshire. Winter John B.A. Department of Chemistry The University Manchester 13 Lancs. Wright Patrick George M.A. Ph.D. School of Chem- istry The University beds 2 Yorks. Zaugg Harold E. A.B. Ph.D. Abbott Laboratories North Chicago Illinois U.S.A. ADDITIONS TO THE LIBRARY Chemical constitution an introduction to the theory of the chemical bond.J. A. A. Ketelaar. 2nd edn. Pp. 448. Elsevier Publishing Company. Amsterdam. 1958. Die chemische Analyse. Vol. 42. Die Methoden der Mikromassanalyse.J. Mika. 2nd edn. Pp.375. Ferdinand Enke Verlag. Stuttgart. 1958. Vapour-liquid equilibrium. E. Hhla J. Pick V. Fried, and 0.Vilim. 2nd edn. Translated from the Czech by G. Standart. Pp. 402. Pergamon Press. London. 1958. Surface phenomena in chemistry and biology. Edited by J. F. Danielli K. G. A. Pankhurst and A. C. Riddi- ford. Volume dedicated to Neil Kensington Adam. 28 contributors. Pp. 330. Pergamon Press. London. 1958. The chemistry and physics of clays and other ceramic materials. A. B. Searle and R. W.Grimshaw. 3rd edn. Pp. 942. Ernest Benn Limited. London. 1959. (Presented by the publishers.) Free radicals as studied by electron spin resonance.D. J. E. Ingram. Pp. 274. Butterworths Scientific Publica- tions. London. 1958. Om kemiske reaktioner og deres hastigheder. J. A. Christiansen. Pp. 124. Ejnar Munksgaard. Copenhagen. 1958. (Presented by the publishers.) Some problems in chemical kinetics and reactivity. N. N. Semenov. Vol. 1. 2nd edn. Translated from the Russian by M. Boudart. Pp. 239. Princeton University Press Princeton New Jersey. 1958. (Presented by Oxford University Press.) Fast reactions in solids. F. P. Bowden and A. D. Yoffe. Pp. 161. Butterworths Scientific Publications-London. 1958. Catalysis. Vol. 6. Edited by P. H. Emmett. 11 con-tributors. Pp. 706. Reinhold Publishing Corporation. New York.1958. The enzymes. Vol. 1. Edited by P. D. Boyer H. Lardy and K. Myrback. 2nd edn. Kinetics thermodynamics mechanism basic properties. 20 contributors. Pp. 785. Academic Press Inc. New York. 1959. Outlines of enzyme chemistry. J. B. Neilands and P. K. Stumpf. 2nd edn. Pp. 41 1. John Wiley and Sons Inc. New York. 1958. The science of photography. H. Baines. Pp. 319. Fountain Press. London. 1958. Photographic chemistry. P. Glafkides. Vol. 1. 2nd edn. Translated from the French by K. M. Hornsby. Pp. 491. Fountain Press. London. 1958. (Presented by the publishers.) Phosphorus and its compounds. J. R. Van Wazer. Vol. 1. Chemistry. Pp. 954. Interscience Publishers Inc. New York. 1958. The polonium chemistry project (August 1953-April 1958).K. W. Bagnall et af. Issued by the United Kingdom Atomic Energy Authority Research Group. (A.E.R.E. C/R 2566.) Pp. 14. Atomic Energy Research Establishment. Harwell. 1958. Gmelins Handbuch der anorganische Chemie. 8th edn. Silicium. Teil C. Organische Siliciumverbindungen. System-nummer 15. Pp. 501. Verlag Chemie G.m.b.H. Weinheim. 1958. The chemical behavior of zirconium. W. B. Blumenthal. Pp. 398. D. Van Nostrand Company Inc. Princeton New Jersey. 1958. Organic chemistry. I. L. Finar. 3rd edn. Vol. 1. The fundamental principles. Pp. 822. Longmans Green and Co. London. 1959. (Presented by the author.) Standard methods of clinical chemistry. American Assocation of Clinical Chemists. Edited by D. Seligson. Vol. 2. 28 contributors.Pp. 217. Academic Press Inc. New York. 1958. Analysts’ handbook. Issued by the British Transport Commission British Railways Research Department Chemical Services. 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Proceedings of the International Symposium on En- zyme Chemistry Tokyo and Kyoto 1957; organised by Science Council of Japan under the auspices of Inter- national Union of Biochemistry. Compiled by Organising Committee International Symposium on Enzyme Chem- istry. Pp. 541. Pergamon Press. London. 1958. Steric effects in conjugated systems proceedings of a symposium held at Hull 1958 by the Chemical Society.Edited by G. W. Gray. Pp. 181. Butterworths Scientific Publications. London. 1958. Growth and perfection of crystals proceedings of an International Conference on Crystal Growth held at Cooperstown New York 1958. Edited by R. H. Doremus B. W. Roberts and D. Turnbull. Sponsored by the Air Force Office of Scientific Research Air Research and Development Command; and the General Electric Research Laboratory Schenectady. Pp. 609. John Wiley and Sons Inc. New York. 1958. (Presented by Chapman and Hall Ltd.) The structure and properties of porous material. Edited by D. H. Everett and F. S. Stone. Proceedings of the tenth symposium of the Colston Research Society held at Bristol 1958 and organised by the Department of Physical and Inorganic Chemistry of the University of Bristol.Pp. 389. Butterworths Scientific Publications. London. 1958. CIBA Foundation symposium on amino-acids and peptides with antimetabolic activity held at London 1958. Edited by G. E. W. Wolstenholme and C. M. O’Connor. Pp. 286. J. and A. Churchill Ltd. London. 1958. Gas chromatography 1958 proceedings of the second symposium organised by the Gas Chromatography Dis- cussion Group under the auspices of the Hydrocarbon Research Group of the Institute of Petroleum and the Koninklijke Nederlandse Chemische Vereniging held at Amsterdam 1958. Edited by D. H. Desty. Pp. 383. Butterworths Scientific Publications. London. 1958. Fundamental aspects of the dehydration of foodstuffs papers read at the conference held at Aberdeen 1958, with discussions; organised by the Society of Chemical Industry.Pp. 238. Society of Chemical Industry. London. 1958. (Presented by the publishers.) The protection of motor vehicles from corrosion com- prising papers read at a symposium organised by the Corrosion Group of the S.C.I. held at London 1958. (S.C.I. Monograph No. 4.) Pp.229. Society of Chemical Industry. London. 1958. (Presented by the publishers.) NEW JOURNALS Advances in Chemical Physics from 1958 1. Advances in Clinical Chemistry from 1958,l. Biochemical Pharmacology from 1958 1. Fortschritte der Hochpolymeren-Forschung from 1958 1. Toxicology and Applied Pharmacology from 1959 1.
ISSN:0369-8718
DOI:10.1039/PS9590000073
出版商:RSC
年代:1959
数据来源: RSC
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