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Proceedings of the Chemical Society. May 1964 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue May,
1964,
Page 129-160
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PROCEEDINGS OF THE CHEMICAL SOCIETY MAY 1964 TILDEN LECTURE* A Glow in the Dark-the Rationale of Phosphorylation By V. M. CLARK (UNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) “Phosphorus affords us so many wonderful phenomena that to explain them all would take up a large treatise a perfect Phosphorologia being what would exceed the limits of this short Account.”l IN the earlier part of the seventeenth century the the development of an organic phosphorus chem- term “phosphorus” was applied to designate any istry concerned mainly with the study of phosphate substance which was capable of becoming luminous esters3 and of the processes of pho~phorylation.~ In in the dark. The element itself was probably first pre- the event information derived from this chemistry pared in 1669 by H.Brand in Germany; Robert of phosphorus is only now beginning to be used in Boyle independently described its preparation in a the understanding of biochemical reactions and in note dated September 3Oth 1680 and published the course of this lecture I hope to show how two posthumously in 1693.2 Both Brand and Boyle ob- widely differing biochemical sequences viz.,oxidative tained the element from a natural source,viz. urine. pho~phorylation~ and phosphagen action might be However until relatively recently investigation of interpreted on a common chemical basis. In this the chemistry of phosphorus was regarded as being sense one can return to the original description of within the province of the inorganic chemist. elemental phosphorus and describe the recent Recognition of the rijle played by phosphorus in illumination of biochemistry by chemistry as per- the nucleic acids and in many coenzymes has led to haps “a glow in the dark.” * Delivered before The Society on January 24th 1964 at the University of Exeter; on February 19th on Tees-side ; on February 27th,at the School of Pharmacy London W.C.l; and on April 27th at the University College Cardiff.Hanckewitz Phil. Trans. 1733,38,58. Boyle Phil. Trans. 1693 17,583. Khorana “Some Recent Developments in the Chemistry of Phosphate Esters of Biological Interest,” J. Wiley and Sons New York 1961. Brown “Advances in Organic Chemistry. Methods and Results.” Edited by Raphael Taylor and Wynberg. Interscience New York 1963 Vol. 3 p.75. Cf. Racker Ah. Enzymol. 1961,23,323. Cf. Momson and Ennor “The Enzymes,” Edited by Boyer Lardy and Myrback Academic Press New York, 1960 Vol. 2 p. 89. 129 PROCEEDINGS The phosphorylation process.-The phosphoryla-tion of an alcohol (I 111:X = RO) an amine (I 111 X = R-NH) or of a phosphate (I 111 X = [RO],P[O]O-) requires the addition to the substrate of one phosphorus atom three oxygen atoms and one hydrogen atom i.e. the addition of the elemental HO 0 HO 0 \ p//HX + \ p//-+ + HZ HO' 'Z Hd 'X (1) ('1) ("1) . . . (1) equivalent of metaphosphoric acid HP03. This can be achieved for example when Z the group bonded to the phosphorus atom in the phos- phorylating agent (11) is readily displaced as Z- reagents of the acid-anhydride type are expected to be phosphorylating agents.However phosphoric acid is tribasic and the free hydroxyl groups in (11) can compete with external nucleophiles to give poly- meric byproducts. In practice anhydride type re-agents are useful only if they bear two protecting groups as in (PhO),P(O)Cl.* Many of the naturally occurring phosphorus com- pounds are mono- or di-esters of ortho- pyro- or poly-phosphoric acids (e.g. sugar phosphates and nucleotides) a few are N-substituted phosphorami- dates (e.g. the phosphagens). In their synthesis protecting groups may have to be removed and although methods have been developed to accom- plish this the aim of much recent work has been to devise reagents which can directly transfer an unsubstituted phosphoryl group viz.(HO),P(O). Two approaches have been used with some success. In one the phosphorylating agent is generated in situ from an appropriate phosphate anion or phosphoric acid e.g. in the carbodi-imide3s7 (eq. 2) and tri- chloracetonitrile* methods whereas in the other a ,NHR' -o;P-@q II ,\NR' ' less reactive reagent e.g. a phosphoramidates (eq. 3) is used. In both cases the potential leaving group is first protonated in order that a neutral molecule be dis- placed. The leaving group whether Z-or HZ must accommodate the electron pair originally forming the P-Z bond. Consideration of how this can best be done is important not only for an understanding of the phosphorylation process in general but also for the better design of reagents for particular purposes.Oxidative phosphorylation in vivo.-In substrate level oxidative phosphorylation the biological oxida- tion of an aldehyde or a keto-acid is often accom- panied by the formation of ATP from ADP and inorganic ph~sphate.~ Obviously the heterolysis of the P-Z bond in (11) to give a phosphorylating entity could follow the withdrawal of electrons from Z. When Z = NH, heterolysis of the phosphorus- nitrogen bond follows protonation at nitrogen. Oxidation i.e. removal of electrons from nitrogen should serve a similar purpose. However the ease of cleavage of the P-N bond under acidic conditionslO precludes its being studied under a wide range of oxidising conditions and we have turned our atten- tion to systems in which the phosphorus atom is combined solely with oxygen atoms.A general consideration of the process of oxidation indicates that a system which in the oxidised form is electron deficient (i.e. is a Lewis acid) and in the reduced form has electrons available (ix.,is a Lewis base) should provide an acceptable model for the redox reactions observed in biological systems. One of the simplest of such systems is that of a quinone and a hydroquinone.ll Originally we envisaged the oxidation of a hydro- quinone phosphate giving rise to a phosphorylating intermediate ( ? metaphosphate) together with the parent quinone as follows The anticipated oxidation and concomitant phos- phorylation have been fully substantiated by experi- ment.l29l3 Thus whereas the diesters of hydro-quinone monophosphates are reasonably stable to oxidising agents (the 2,3-dimethylnaphthohydro-Khorana Chem.Rev. 1953 53 145. Cramer Angew. Chem. 1960,72.236; Cramer and Weimann Chem. Ber. 1961,94,996. Clark Kirby and Todd J. 1957 1497; Khorana and Moffatt J. Amer. Chem. SOC.,1959,81 1265. lo Stokes Amer. Chem. J. 1893 15 198. l1 Clark 14th Mosbacher Symposium Springer Verlag Heidelberg 1964 p. 276. l2 Clark Hutchinson Kirby and Todd J. 1961 715. l3 Clark Hutchinson and Todd J. 1961 722. MAY1964 131 quinone derivative being unaffected by bromine in methanol after 10 minutes at room temperature) the monoesters and the free hydroquinone phosphates undergo rapid oxidation to the parent quinone with concurrent formation of various products derived from the hypothetical monomeric metaphocphate namely trimetaphosphate pyrophosphate and orthophosphate.Bromine oxidation of 2,3-dimethyl- 4-hydroxynaphthyl-1-phosphatein dry NN-dimethyl- formamide in the presence of the mono(tetrabuty1- ammonium) salt of AMP led to ADP isolated in 26% yield. Subsequent work by Lapidot and Samuel1* on the point of bond fission in the oxidative hydrolysis of 2,3-dimethyl-4-hydroxynaphthyl-l-phosphate (IV R = R’ = H) showed that using bromine at pH 4,the cleavage leading to acylation (cleavage a) occurred to the extent of 30% whilst the displacement of intact orthophosphate (cleavage b) occurred to the extent of 70%. Taking this into account the isolated yield of ADP in our reaction sequence appears to be approximately 80%.As monoesters of hydroquinone phosphates are also susceptible to oxidative attack we attempted to synthesise ADP by transference of AMP to inorganic phosphate. Diesters of hydroquinone monophos- phates are readily available from the reaction of a quinone and a phosphorus diester :12J5 reaction of 2,3-dimethylnaphtho-l ,Cquinone with the nucleo- side phosphite (V R =C,H,CH, R’ =2’,3’-0-iso-prop ylideneadenosine-5') led after anionic debenzyla- tion by sodium thiocyanate16 to the naphthohydro- quinone ester of the nucleotide (IV R = H R’ = 2,3-O-isopropylideneadenosine-5’).Bromine oxida- tion then transferred the nucleotidic moiety to added inorganic phosphate to give ADP in 22% yield.qGO-Me 8 aMe OR 0 In earlier experiments we had noted that the acetate phosphate (VI:R = P(O)(OH)a on oxida-tion with bromine in aqueous solution gave 3-bromo- 2-methylnaphtho-l,4-quinone(VII). Since the di-acetate (VI R = CH,CO) was unaffected by bromine in aqueous dioxan the phosphorylated phenolic oxygen atom appeared to have been polarised prior to the cleavage of the P-0bond and an analogous intermediate (VIII) in which “oxon- OCOMe QCO-Me n (VII1) ium” oxygen is bonded to hypothetical metaphos- phate would account for the observations of Lapidot and Samuel cited above. The phosphugens.-N-phosphorylcreatine (IX) was isolated from muscle by Fiske and SubbaRowl* in 1927.Measurement of its heat of hydrolysis19 led Lipmann,20 in 1941 to classify it as an “energy-rich” phosphate and its r61e in the formation of ATP from ADP (eq. 4) in muscle contraction seemed to confirm this view. HO \ Y2 COzH + ADP + P-N=C /II \/ HO 0 N-CHS I (IX) CHI H02C \ H2N \ C-N + ATP HN// \CH . . . (4) At approximately the same time phosphoryl derivatives of other substituted guanidines for l4 Lapidot and Samuel Biochem. Biophys. Acta 1962 65 164. l6 Ramirez and Dershowitz J. Org. Chem. 1957 22 1282. l6 Clark and Todd J. 1950,2030; Morrison and Atherton B.P. 675,779. l7 Clark Kirby and Todd Nature 1958,181 1650. l8 Fiske and SubbaRow Science 1927,65,401; J. Biol. Chem. 1929,81,629. lS Meyerhof Schulz and Schuster Biochem.Z. 1937 293 309. 2o Lipmann Adv. Enzymol. 1941 1 99. PROCEEDINGS example N-phosphoroarginine (X),were identified as participants with the adenine nucleotides in phosphoryl transfer reactions and the term “phos- phagen” was applied to the group of naturally occurring phosphoroguanidates.6*21 CH2 /\CH CH, I RO HO CH \ \ /NH / \ P-NH2 /I1 P-N=C I HOZC NHZ /11 R‘O 0 HO 0 NH2 (XI (XI) The transfer of a phosphoryl residue from a phosphoroguanidate (for example IX or X) requires pn4noverlap and enhances the possibility of nucleo- philic attack at phosphorus2’ providing concurrently cleavage of the phosphorus-nitrogen bond. Such a cleavage is facile with phosph~rarnidates~~~~ e.g. (XI) however in vitru a variety of phosphoro- guanidates has failed to function as phosphorylating agents under conditions comparable with those used with the simple phosphoramidates.22 Moreover the parent phosphoroguanidic acid undergoes hydrolysis in acid solution some thirty times more slowly than phosph~rocreatine~~ which is itself hydrolysed more slowly than phosphoroglycine.24 In addition whereas a monoester of phosphoramidic acid (e.g.XI R = CGH,CH, R’ = H) will convert ADP into ATP in ~itt-0,~ no such reaction occurs with the corres- ponding monoester of phosphoroguanidic acid nor indeed can the parent phosphoroguanidic acid be substituted for phosphorocreatine in the reaction catalysed by ATP-creatine transpho~phorylase.~~ These observations indicate that the P-N bond in certain phosphoroguanidic derivatives is not “energy- rich” and that some form of activation might need to be postulated to explain the in vivo reactivity of the phosphagens.26 In (XI) the P-N bond order is enhanced by overlap of the orbital of nitrogen-occupied by the lone pair of electrons-with the d-orbitals of the phosphorus atom.Thus phosphoramidates unlike carboxylic acid amides do not yield amines on treatment with alkali:for example diphenyl phosphoramidate (XI R = R’ = C,Ha is smoothly converted by caustic soda to the sodium salt of the acid (XI R = R’ = H) without cleavage of the P-N link.l0On the other hand protonation of the nitrogen atom removes this 21 Eggleton and Eggleton Biochem.J. 1927 21 190. 22 G. W. Kirby Ph.D. thesis Cambridge 1958. 23 Fawaz and Zeile 2.physiol. Chem. 1940,263 175. 24 Winnick and Scott Arch. Biochem. 1947 12,201. 26 Fawaz and Seraidarian. J. Biol. Chem.. 1946.165. 97. a good leaving group namely the neutral ammonia molecule (eq. 3). In consequence phosphoramidates are unstable under acidic conditions and can for example be converted to phosphorochloridates on treatment with gaseous hydrogen chloride (eq. 3 x = Cl)? Phosphoroguanidates present a more complicated picture since at least two prototropic forms (XI1 and XIII) are possible. In (XII) each of the two nitrogen atoms not attached to phosphorus has a lone-pair of RO NHZ RO NH, \ / &H+ \ t / 2 P-N=C ‘\ P-NH=C 7 /11 I1 R’O 0 NH2 R’O/0 \NH2 ow IL RO NH RO NH, \ // ?it+\ // -1 P-NH-C P-NH-C /11 \ T-//I \ R’O 0 NH R’O 0 NH2 (XIII) (XW electrons which on protonation of the nitrogen atom of the P-N bond can facilitate the delocalisa- tion of the positive charge as expressed in (XIV) such delocalisation inhibits the displacement re- action indicated in eq.3. On the other hand proto- nation of (XIII) could yield inter alia (XV) which would undoubtedly behave as a phosphorylating agent in accordance with eq. 3. RO NH \+ // P-NHZ-C /II \ R’O 0 NH2 (XV) Our infrared and nuclear magnetic resonance evidence2s shows that the normal esters of phos- phoroguanidic acid have structures consonant with (XII). Their stability is not therefore unexpected and it seems likely that a phosphagen might be activated in vivo by a tautomeric shift of the type (XI1 4XTII).The P-X YZ sy~tern~~.-Phosphoryla ting agents although often represented as phosphoryl systems 26 Cf.,Clark and Warren,’Experientia 1963 19 514; Clark,Todd and Warren Biuchem. Z. 1963,338 591. 27 Dostrovsky and Hahnann J. 1953 503; Hudson and Keay J. 1956,2463; 1960 1859. Skrowaczewska and Mastalerz Roczniki Chem. 1955,29,415. 2g S. G. Warren Ph.D. thesis Cambridge 1963. Clark Hutchinson Kirby and Warren Angew. Chem. 1964 in press. MAY 1964 (c.Q. > P-X) have in fact a more complex 11 0 orbital structure. Bonds involving phosphorus and highly electro- negative elements are particularly strong since the lone-pair electrons possessed by all such elements can be donated into vacant 3d orbitals of the phos- phorus atom thereby augmenting the binding energy in virtue of the pn-dn contribution.However it is often the case that dn orbitals are too diffuse for significant overlap but overlap can increase with increase of positive charge on pho~phorus.3~1~~ In the phosphorochloridates for example it has been suggested that the electrons in the 3d orbitals of the phosphorus atom are partially ionised and located on the chlorine atom.31 This creates a posi- tive charge on the phosphorus atom which by causing preferential contraction of the more polaris- able d-orbitals makes these more nearly compatible with the 3p orbitals of the chlorine atom.Even with the phosphoramidates infrared evidence suggests somepn-dn bonding.= For ease of displacement at a phosphorus centre one would wish to remove this pn-dn component of the bond between the phosphorus atom and the group to be displaced. A molecule of type (XVI) (where X Y and Z are atoms of any element but more commonly H C N 0 S and Hal) is a potential phosphorylating agent if the electrons of the P-X bond can formally be accommodated on Z. ........ (5) Examination of this generalised P-XYZ system suggests that it may have important advantages over simple P-Z type reagents. Two extra centres can be involved in the transition state of the phosphorylation step and it is therefore possible to alter the activa- tion energy of the process by varying X and Y for a given Z without necessarily varying the overall free energy change for the reaction.Moreover if Y,Z are singly bonded a fragmentation reaction must occur the number of molecules present increasing in the phosphorylation step (eq. 5). The entropy change and probably the entropy of activation should be positive for this type of reaction. Both in principle and in practice one might therefore design stable unprotected phosphorylating agents with effective leaving groups. The essential requirements for a P-XYZ system to be a phosphorylating agent are (i) that the P-X bond should be relatively weak and (ii) that Z should be as “electron-attracting” as possible which means that it must be strongly electronegative or must become so in virtue of an attack by an electrophile or an oxidising agent.In the P-XYZ system,p7r-h overlap is eliminated if X has no lone-pair electrons e.g. when X = sp3 hybridised carbon. Thus the ,f?-halogenophos-phonate (HO),P(O)-CH,CHRCl (R = n-octyl) in contrast to the highly reactive phosphorochloridic acid (HO),P(O)CI is stable for some time in aqueous acid solution in alkali however rapid decomposi- tion with accompanying phosphorylation ensues.34 \ A-$~~-CHR-CI0 -,F-A -+ CH,=CHR 0 0 4-c1-........ (6) Alternatively when X has lone-pair electrons available pr-dn bonding can be reduced by intro- ducing pn bonding with an sp2 hybridised Y,as in P P -X -Y =bZ. This is the case with the carbo- di-imide intermediate (X = 0 Y = C Z = N vide supra eq.2). Thus P-XYZ systems can be divided into two general categ~ries,~~ viz. (i) those with no n contri-bution to the P-X bond as exemplified by the ,f?-halogenophosphonates(eq. 6),and (ii) those with attenuation of the P-X n-bonding either in the ground state (for X = N or 0,Y = N or C;Z = N or 0)or in virtue of an electrophilic (or oxidative) attack on Z. In considering oxidative attack two cases are important viz. when given Z = H X = Y = N or 0. (X = Y = N Z = H) The phosphorohydrazidates act as phosphorylating agents under two quite I+ ....... (7) U 31 Craig Maccoll Nyholm Orgel and Sutton J. 1954 332; Craig and Magnusson J. 1956,4895. 32 Cruickshank,J. 1961 5486.33 Bellamy and Beecher J. 1952 1701. 34 Maynard and Swan Austral. J. Chem. 1963 16 596. 134 PROCEEDINGS different sets of conditions. In the presence of acid electrophilic or oxidative attack on Z. Acetyl phos- their behaviour can parallel that of the phos-phate,% acetyl carbamyl phosphate,4O and whilst under oxidising conditions 1,3-diphosphoglyceric acida are of the type (X = Z phoramidate~,~,~~,~~ they can react either in accordance with eq. 7 or 8. = 0 Y = C) in which there is ground-state The actual course of this oxidative acylation bonding over X Y and Z as noted in the case of the reaction has not yet been determined. carbodi-imide intermediate (eq. 2). For phospho- (X = Y = 0,Z = H) The reaction between Sarin en01 pyruvateg2 (X = 0,Y = Z = C) (XVII) (isopropyl methylphosphonofluoridate) and hydro- electrophilic attack on Z effects the P-X cleavage.gen peroxide proceeds by attack of the perhydroxyl CO-H ion on phosphorus. The perphosphate so formed (X = Y = 0;Z = H) can be oxidised to give oxygen and isopropyl methyl phosphonate.= H+ (I DP= Ino5me-5‘ pyrophosphate) Turning to the phosphagens their consideration as P-XYZ systems will depend on which of the ~7?P-W + 0 tautomers (XI) or (XIII) is predominant. For Mecl attack to proceed as indicated in eq. 6 (XIII) is to Hydroquinone phosphates are in a formal sense be preferred to (XII). Acylation by a carboxyl group vinylogous perphosphates. These too transfer of one of the nitrogen atoms not attached to phos- phosphate (as an acylating entity) under oxidising phorus could provide such a mode of activation for condition^.^^^^^ in the equilibrium system (XVIII XX XX) (XIX) -the appropriate P-XYZ system-is likely to pre- dominate provided that R or R’ is hydrogen since delocalisation over the carboxylic amide group would then be the more important feature in line with the acid dissociation constants of carboxylic acids lying er+ between the first and second dissociation constants 0+ + HBr of phosphoric acid.43 Biological implications.-In vivo phosphorylating We have confirmed that acylation on nitrogen can agents capable of converting ADP into ATP are convert a phosphoroguanidate into a phosphorylat- P-XYZ types in which one has attenuation of the ing agent.44 p-ah contribution by competitive p bonding or by All the naturally occurring phosphagens6 have an RO NH* RO NH \ / fH+ \+ / P-N=C R” -A P-NH=C R” /It h-C / R’O 0 “HZ R’O 0 /11 / I \O .t.\O (XVII I) RO NH RO 4 NH* ’ R“ ‘P-NH-C / R” ‘P-NH-C \\s*l-c/ /II R‘O/0 \N-/ R’O 0 11 / \o \O H (XW ow s6 Brown Flint and Hamer J. 1964 326. Larsson Svensk kem. Tidskr. 1958 70 405. *’ Wieland and Pattermann Chem. Ber. 1959 92 2917. aa Lipmann Adv. Enzymol. 1946 6 231. 39 Berg J. Biol. Chem. 1956 222 991. 40 Jones Spector and Lipmann J. Amer. Chem. Soc. 1955 77 819. 41 Biicher Biochim. Biophys. Acta 1947 1 292. 42 Kurahashi Pennington and Utter J. Biol. Chem. 1957 226 1059; A. J. Kirby Ph.D. thesis Cambridge 1962. 4s Albert and Serjeant “Ionization Constants of Acids and Bases,” Methuen London 1962.44 Clark and Warren Nature 1963 199 657. MAY1964 additional acidic function attached directly to the carbon skeleton (e.g. IX X) and could readily cyclise with acylation of one of the nitrogen atoms of the guanidine residue. The cyclic form of creatine (XXI) viz. creatinine (XXII) is well known and is produced under just those conditions in which (IX) H2N COSH HN-co I I I I C CH2 C CHz // \N/ // \N/ HN HN I I CHs CHs ow (XXII) 46 Gaede and Gruttner Naturwiss.,1952 39 63. is labile.& The mode of action we suggest is in agree-ment with all data at present available. What I have presented in this lecture are chemical speculations supported in some instances by experi- mental evidence.Where they impinge on biological systems they require biochemical confirmation. At the molecular level these distinctions between chemistry and biochemistry disappear. In closing I must apologise for introducing a new a1 bei t unpronounceable "four-letter word ," P-XYZ noting only that it may perhaps code for my four gifted and enthusiastic collaborators Drs. D. W. Hutchinson A. J. Kirby G. W. Kirby and S. G. Warren without whose unfailing help and skill I could not have started this story. SYMPOSIUM ON ASPECTS OF MOLECULAR DISSYMMETRY THISsymposium was held at the Battersea College of Technology London S.W.11 on Thursday March 19th 1964. THEChemical Society and visitors were welcomed by problems e.g.the quaternary compound (111) has a Dr. J. E. Salmon Head of the Chemistry Depart- very low specific rotation. ment who was chairman of the opening session. Professor R. C. Cookson (Southampton) opened the symposium with a paper on "The Ultraviolet Spectrum and Circular Dichroism of Dehydro-camphor." Professor Cookson showed how simple theory could be used to provide from a molecular model conclusions concerning the optical rotatory power of the nominal n+* and charge-transfer transitions. Applied to 5-p-anisylborn-5-en-2-one for example the prediction is that the dichroism of the two transitions will be equal and opposite. This is found in practice (at 320 mp E = 7,600 and Lk = $53; at 279 mp E = 19,600 and A€ = -55). Dr. D. M. Hall (Bedford) presented a paper on "Optical Stabilities in Bridged and Unbridged Bi- phenyls," in which it was pointed out that a number of optically active 2,2'-bridged biphenyls with and without additional ortho-substituents are now known and in some cases their optical stabilities are anomalous in comparison with the related unbridged compounds.In particular the spiran salt (I) is unexpectedly optically stable (half-life of 24 minutes in dimethyl- formamide at 160") and the dibenzazepinium picrate (11) is unexpectedly optically labile (half-life of 21-5 minutes in acetone at 26"). Comparison between bridged and unbridged bi- phenyls has to be made with diphenic acid derivatives since so many optically active biphenyls are of this type.Synthesis of other more analogously ortho-substituted optically active biphenyls introduces new 2Br-In the discussion Dr. F. G. Mann (Cambridge) was able to describe some 2,2'-bridged biphenyls having large heterocyclic systems. The compounds (IV; n = 1 2 and 3) and (V) were prepared by the union of 2,2'-bisdimethylarsinobiphenyl with the appropriate alkylene dibromide. The series has the following values for [MI, +174" -179"; +306" -307"; +487" -501"; and +557" -560" respec-tively. The first of these compounds racemises readily in cold aqueous solution the second race- mises in hot solution and the third and fourth do not racemise at 150". The fist three compounds represent the first set of three consecutive homo- logues of 2,2’-bridged biphenyls to be obtained in optically active forms.The last paper in the first session “The Resolution of a-Hydroxyamidines and an Investigation of Their Optical Stabilities at Elevated Temperatures,” was presented by Dr. D. G. Neilson (Dundee). It was shown that melting point observations on (-)-man- delamidinium chloride (+)- and (-)-Zethoxy-mandelamidinium chlorides led to the detection that these compounds were optically labile at elevated temperatures (giving the racemates) and attention was directed to the mandelamidinium mandelates. (-)-2-Methoxymandelamidinium (-)-mandelate heated for several minutes just below its melting point was found to undergo complete inversion at the a-hydroxyamidinium centre only and the pro- duct was optically pure (+)-2-methoxymandel-amidinium (-)-mandelate.Similar epimerisations have been observed with other members of this series; the unsubstituted (-)-mandelamidinium (-)-mandelate simultaneously undergoes marked chemical decomposition. No evidence of second-order asymmetric trans- formations during the resolution of the (&)-amidines with mandelic acids in solvents of low boiling point has been found. During the second session the chair was taken by Sir Christopher Ingold. The first paper presented by Dr. C. L. Arcus (Battersea) was on “Dissymmetric Catalytic Hydro- genation of Substituted Ally1 Alcohols.” By catalytic hydrogenation of the optically active forms of 3-ethylhept-3-en-2-01 to 3-ethylheptan-2-01 followed by oxidation to optically active 3-ethylheptan-2-one it was demonstrated that asymmetric syntheses to the extent of approximately 70% had occurred during the hydrogenation.It was pointed out that introduction of gas-liquid chromatography permitted evaluation of an asym- metric synthesis by means of optically inactive com- pounds as was done with two other ally1 alcohols and that as previously suggested with optically in- active materials the term “asymmetric synthesis” is better replaced by “percentage dissymmetric re- action.” In the case of (-)-3-methyl-4-phenylbut-3-en-2-01, the configuration of the preponderating diastereo- isomeric saturated alcohol was successfully predicted from a deduction of the preferred adsorption con- formation;the general validity of assumptions made concerning adsorption on the catalyst was reviewed.Dr. C. F. Wells (Birmingham) presented a paper on “The Reactivity of Alcohols and Ethers in the Transfer of Hydrogen to Photo-excited Quinones.” In aerobic aqueous conditions in the presence of alcohol photo-excited sodium anthraquinone-2-PROCEEDINGS sulphonate Q* reverts to the ground state via processes one of which is Q* + R,R&HOH kl ‘QH + RIRZCOH 4 This is a hydrogen-atom transfer the attack of Q being restricted to C-Hbonds alpha to the hydroxyl group* Values (independent of temperature) for kR = (k,)substrate/(k,)ethanol have been calculated for a range of substances and for alcohols kB increases with increasing alkylation on the a-carbon atom (but decreases for ethers).The fact that kR follows a Hammett linear free-energy relationship suggests that the effect of increasing a-alkylation in alcohols is to increase the probability of transfer of energy from Q* into the a-C-H bond. In polyalcohols kR per CHOH group (= kRs) decreases with increasing number of hydroxyl groups. It is suggested that one reason for this lies in the steric hindrance from hydration accompanying the hydroxyl groups; a correlation is found between kRsand the entropy of hydration of the alcohol. It is also found that kR varies with orientation of the CHOH groups in the cyclohexanediols and the sugars; in the former equatorial hydrogen atoms are more reactive than axial and in the sugars there is marked dependence of reactivity on the “screening” of hydrogen atoms by the hydroxyl groups and their accompanying hydration.The last paper in the symposium was presented on “The Stereochemistry of Reactions at the Phosphorus Centre,” by Dr. M. Green (Manchester). Dr. Green commented on the renewed interest in the prepara- tion and resolution of asymmetric phosphorus com- pounds particularly those with a replaceable group attached to the phosphorus atom and showed that it had been proved experimentally that reaction of methyl ethylphenylphosphinate (VI) with sodium methoxide in methanol proceeds with complete inversion of configuration. The possibility that the stereochemistry of reactions at a phosphoryl centre could be influenced by electrostatic forces was investigated using re- actions of (+)&methyl ethylphenylphosphino-thiolate (VII).The ester (VII) reacts with sodium methoxide to give (-)-methyl ethylphenylphos-phinate (VI) and reaction with silver perchlorate in methanol gives the (-)-0-methyl ester (VI) with essentially the same rotation; thus there is no change in the stereochemistry of the transition state when the leaving group is positively charged. The investigations have been extended to the stereochemistry of reactions at a thiophosphoryl centre. Alkaline hydrolysis of a mixture of (+)-di- ethyl pyromethylphosphonothionate and the meso- MAY1964 isomer indicates that there is predominant inversion of configuration. Recent studies of the hydrolysis of optically active mixed anhydrides were described and there was some discussion of the transition states in reactions at the phosphoryl and thiophosphoryl centres.Dr. A. J. Lambie (Fisons Pest Control Ltd.) commented on the observation that mixed an-hydrides of the diesters of thionophosphoric acid and acetic acid undergo reaction with nucleophiles at the carbonyl group. Dr. Green said efforts were currently being made to hinder the carbonyl group in order to favour reaction taking place at the phos- phorus atom. Dr. Lambie said that he had found that in the case of the oxygen analogues the mixed an- hydride of diethylphosphoric acid and 2,3,5,6-tetra- chlorobenzoic acid (or pentachlorobenzoic acid) undergoes reaction with nucleophiles such as aniline at the phosphorus atom.The topic of the Symposium was chosen as being close to the life-long interest of the late Dr. Joseph Kenyon F.R.S. for thirty years Head of the Chemistry Department of the College. At the close of the proceedings Sir Christopher Ingold paid a simple and sincere tribute to the capability enthusiasm for chemistry and humanity of Dr. Kenyon and invited Mrs. Kenyon to unveil a memorial plaque to her husband. This ceremony on the main staircase of the College was attended by Mrs. P. V. Muston (Dr. Kenyon's daughter) and her son Robert Professor J. Monteath Robertson (Presidentof the Chemical Society) and Dr. D. M. A. Leggett (Principal of the College). Several of Dr. Kenyon's colleagues and former research students were also present.Closed-circuit television was used to relay the ceremony for the benefit of the main audience (who could not be accommodated on the staircase). The newly rebuilt Joseph Kenyon Re- search Laboratories were open for inspection and in the evening a memorable informal dinner (limited to sixty including the speakers from the Symposium) was held in the Department of Hotel and Catering Management in the College at which Mrs. Kenyon was the principal guest. Although the organisation of the symposium and the erection of the memorial plaque were provided for by public subscription the Chemistry Depart- ment of the College acknowledges gratefully the help received from the Chemical Society in mounting this very successful function.L. A. CORT. COMMUNICATIONS Phosphazen-1'-ylcyclotriphosphazatrienes By R. KEAT,M. C. MILLER and R. A. SHAW* A CONSIDERABLE number of cyclic and a smaller number of linear phosphazenes are kn0wn.l We now report the first cyclophosphazenes with phos-phazenyl side-chains. On treatment of aminophos- phazenes in carbon tetrachloride with halogeno- phenylphosphoranes in the presence of a strong tertiary base such as triethylamine one or more amino-groups can be converted into phosphazen- 1'-yl groups. Thus the diamino-compound (I) is con- verted by means of dibromotriphenylphosphorane into the phosphazenyl compound (11) m.p. 172". In so far as cyclotriphosphazatriene has some superficial structural analogy to benzene this phos- phazenyl-derivative bears a similar relationship to styrene.Similar compounds synthesised include N,P,CI,(N= PPh,) m.p. 214-215" N,P3(NMe2),-(N=PPh3) m.p. 150" and N,P,(NMe,),(NH,)-(N=PPh3) m.p. 181". By suitable choice of the phosphorane groups suitable for further reaction can be introduced into the phosphazen-1'-yl side- chain e.g. NEt NH3 (I) + PPh2C1 -+ N,P3Clp(N=PPhzCl)z -+ N3P3C14(N=PPhzNHz), (m.p. 209'). The method has obvious applications for the controlled step-wise building up of phosphazene units. Satisfactory analyses were obtained for all compounds reported here. (Received March 3rd 1964.) * Department of Chemistry Birkbeck College MaIet Street London W.C.l. Shaw Fitzsimmons and Smith Chern.Rev. 1962 62 247. PROCEEDINGS The Neighbouring Group Effect in the Conversion of Tetramethyl-(+)-catechin into 2-Chlorotetramethyl-(-)-isocatechin By K. WEINGES* establishes the absolute configuration of C-3 in (111) already been established by Mehta and Whalley7by (IV) and (V). The spin-spin coupling constants of pyrolysis (E elimination) of the acetates. The abso-* Organisch-ChemischesInstitut Universitat Heidelberg Germany. Drumm Proc. Roy. Irish Acad. 36 B 49; Drumm MacMahon and Ryan ibid. p. 149. Freudenberg Fikentscher Harder and Schmidt Annalen 1925 444,135. Freudenberg Carrara and Cohn Annalen 1925 446,87. Freudenberg Sitzungsber. Heidelberger Akad. Wiss. 1927 10 Abh. Freudenberg Sci. Proc. Royal Dublin Soc. 1956 27 153; Hardegger Gempeler and Ziist Helv.Chirn. Acta 1957,40,1819; Birch Clark-Lewis and Robertson J. 1957,3586. Freudenberg Karimullah and Steinbrunn Annalen 1935 518 37. Mehta and Whalley J. 1963 5327. 5,7,3',4'-TETRA-@METHYL-( $-)-CATECHIN (I) Was converted by Drumml in almost quantitative yield into an optically active chloride by using phosphorus pentachloride in carbon disulphide. The optical activity of this chloride assumed greater significance when Freudenberg et aL2 elucidated the structure of catechin and showed3 that rearrangement of the catechin molecule occurs during this reaction and that the chloride has structure (111). This was the first example of a rearrangement in which all the centres of asymmetry of the molecule participate but which nonetheless proceeds with retention of optical activity although this fact was not recognised by Drumm.l The rearrangement was interpreted by Freudenberg4 to involve participation of the neigh-bowing 3,4-dimethoxyphenyl group and to entail an intramolecular cyclic cation viz.the phenonium ion @I) as an intermediate. This was probably the first instance4 of the postulation of a neighbouring group effect of an aryl substituent in a rearrangement reaction. Now that the absolute configuration of tetra-methyl-($)-catechin (I) has been established it was of interest to elucidate the absolute configuration of the rearranged product 011) on direct experimental basis. The chloride (111) can be converted by two procedures6 into two diastereoisomeric 2-0-acetyl-isocatechins (IV) m.p.155-156" [a] + 202" and (V) m.p. 97-99" [a] -125". Optical rotations are recorded at 25" and 578 mp in C2H2Cl, unless otherwise stated. Reduction of these acetates with lithium aluminium hydride and subsequent methylation of the phenolic hydroxyl group released lead to the same 2-(3,4-dimethoxyphenyl)-3-(2,4,6-trimethoxyphenyl)propan-l-ol (VI) m.p. 124-125" [a]+ 22*9",+ 82.5" (in EtOH). The latter was transformed via its methanesulphonate and iodide into the corresponding propane (VII) n1.p. 109" [a] + 78.5". Treatment of (W) with ozone and subsequent oxidation with peroxide-formic acid yielded (-)-methylsuccinic acid (VIII) the absolute configuration of which is known. This the proton on C-2 (8 = 6.46 p.p.m.JZs3= 4.3 c./sec.) indicate that the hydrogens on C-2 and C-3 are in tramrelationship in (III) and (V) and cis in (IV) (6 = 6.47 p.p.m. .I2. = 1-0c./sec.). This proves that the absolute configurations of (III) (IV) and (V) are those shown. The configurations of the starting materials (I) and of the rearranged product (111) indicate that the rearrangement follows the norrnal stereochemical course of a Wagner-Meer-wein rearrangement. \ Meom!-Me0 H,H Meoat' / \ H2 QOMe OMe The relative configurations of (IV) and (V) had MAY1964 lute codigurations given by these authors are how- ever based only on theoretical deliberations of Clark-Lewi~.~~~ Neither the lzvorotatory 1-propano1 derivative (the antipode of VI) obtained by Brown and Sommerfieldlo by reduction of (+)-catahin tetramethyl ether with lithium aluminium hydride- aluminium chloride nor the dextrorotatory 1-pro-panol derivative (VI) obtained form the acetate (IV) with sodium in liquid ammoniaa was related experi- mentally to any compound of known absolute con- figuration.For this reason it was impossible to determine which of two rearrangements leading to the two antipodal forms of (VI) proceeds by a Wagner-Meenvein mechanism. (Received February 19th 1964.) * Clark-Lewis Proc. Chem. SOC.,1959 388; Clark-Lewis,J. 1960 2433. Clark-Lewis and Ramsay Proc. Chem. SOC.,1960,359. lo Brown and Sommerfield Proc. Chem. SOC.,1958 236. Electron-transfer at Alumina Surfaces By J.A. N. SCOTT and R. C. PINK* B. D. FLOCKHART FOLLOWING reports1 of the formation of hydrocarbon radical-ions on silica-alumina surfaces several investigations have failed to detect similar activity in aluminas dehydrated at 500°.2 Silica-alumina cata- lysts which have been activated at this temperature retain the ability to form radical-ions when stringent precautions are taken to remove oxygen although the oxidising power appears to be greater when some oxygen is pre~ent.~ We have now been able to show that when gibbsite is dehydrated at much higher temperatures sites are produced on the alumina surface which are capable at room temperature of oxidising poly- nuclear hydrocarbons to the corresponding ion- radical provided oxygen is present.The hyperfine and total splitting in the partially resolved electron spin resonance (e.s.r.) spectrum obtained with pery- lene for example identify the radical as the perylene cation. Aromatic amines also undergo one-electron oxidation to the free-radical form. Fully dehydrated alumina (corundum) is inactive as is gibbsite de- hydrated below 450". Maximum activity occurs in samples heated at 900" in which the crystalline phase was identified by X-ray diffraction as y-al~mina.~ The concentration of oxidising centres in the most active aluminas was estimated to be 2 x 1017/g. which is comparable with that in some silica-alumina catalysts activated at 500°.5 Molecular oxygen plays a decisive part in the oxidation process.When oxygen is removed from an active alumina by prolonged evacuation at 10-5 mm. Hg no e.s.r. absorption is observed on adding a well-degassed solution of perylene in benzene. When oxygen is admitted to the system the strong partially resolved spectrum of the perylene cation is im-mediately observed. The same result is obtained when oxygen is admitted to the alumina surface before the perylene solution is added. No e.s.r. absorption is observed at the same spectrometer sensitivity with the alumina-oxygen system or with the alumina-benzene-oxygen system in the absence of the polynuclear hydrocarbon. Aalbersberg Hoijtink Mackor and Weijland have shown that in strongly acidic oxidising solvents electron transfer occurs between polynuclear hydro- carbons and oxygen.s By analogy with these systems electron transfer may take place at the alumina sur- face to form the complex Ar+02-where Ar+ is a hydrocarbon radical-ion.It should be noted that the behaviour of the alumina described in these experi- ments cannot readily be accounted for by the presence of iron (<20 p.p.m.) or by its silicon con- tent (< 20 p.p.m.). Pre-treatment with dilute solu- tions of iron salts made a negbgible difference to the activity. Also the behaviour of the active aluminas with respect to oxygen differed materially from that of silica-aluminas which retain activity after stringent removal of oxygen by pumping. The bearing of these results on the catalytic activity of high-temperature aluminas and of silica-aluminas will be discussed elsewhere.(Received April 9th 1964.) * Department of Chemistry The Queen's University Belfast N. Ireland. Brouwer Chem. and Ind. 1961 177; Rooney and Pink Proc. Chem. SOC.,1961 70; Rooney and Pink Trans. Furaday SOC.,1962 58 1632. Brouwer J. Catalysis 1962 1 372; Terenin Barachevsky Kotov and Kolmogorov Spectrochim. Acta 1963 19, 1797. Hall J. Catalysis 1962 1 53. * Stumpf Russell Newsome and Tucker Ind. Eng. Chem. 1950 42 1398. Rooney and Pink ref. 1 ;Terenin Barachevsky Kotov and Kolmogorov ref. 2. Aalbersberg Hoijtink Mackor and Weijland J. 1959 3049. PROCEEDINGS Direct Evidence for an Acylated Thiol as an Intermediate in Papain- and Ficin-catalysed Hydrolyses of Esters By G.LOWEand A. WILLIAMS* ABUNDANT evidence is available to show that the proteolytic enzyme papain depends for its enzymic activity on a thiol residue.l On the basis of extensive kinetic studies Smith has suggested a mechanism of action for papain involving an intermediate in which the acyl residue of the substrate (e.g.,N-a-benzamido- acid esters and amides) has been transferred to the essential thiol residue of the enzyme.2 Although reasonable evidence has been provided for an acyl- enzyme intermediate,1-4 no compelling experiment . is available to establish the site of attachment. We now report direct evidence that the site of attach- ment is indeed a thiol residue. The experiment was based on the known ultra- violet absorption properties of dithio-esters [MeCS,Et Amax.(heptane) 4600 (log E 1-25) and 3050 8 (log E 4~08)].~ If an acylated thiol is an inter- mediate in the papain-catalysed hydrolysis of N-a-acylamino-acid esters and amides then by using a thiono-ester as a substrate it should be possible to measure directly the steady-state concentration of the dithio-ester (provided that kdeacylationekac lation) since its intense absorption band near 3050 81 is at longer wavelength than the absorption bands of the enzyme itself.6 Treatment of the nitrile (I)’ in methanol with anhydrous hydrogen chloride provided the imino- ether hydrochloride (II) which on treatment in pyridine with hydrogen sulphide gave methyl thiono- hippurate (111). MeOH-HC1 PhCO.NH.CH,CN -.f (1) PhC0.NHCH2C( :NH2+C1-)-OMe (11) H,S-PY -+ Ph-CO.NHCH,CS.OMe (111) The Michaelis-Menten parameters (KO= 6.3 x mole l.-l k = 0.14 sec-l at pH 6.0 and 35”) were determined for the hydrolysis of the thiono- ester (111) catalysed by activated8 twice-crystallised papain (ex B.D.H.) a Radiometer type TTTl titrator and type SBR2 titrigraph being used.These parameters demonstrate that met hy 1 thi ono hip- purate is a specific substrate for the enzyme; cf. methyl hippurate (KO= 2.05 x mole L-l k = 2.7 sec.-l at pH 6.0 and 35°).4 Four 1-cm. quartz cells were placed in the cell compartment of a Unicam SP800 spectrometer. Into one of the cells in the compensating beam was placed the enzyme solution (0.69 x 1 0-4~ ;phosphate buffer pH 6.0; p = 0.3~), into the other was placed a solu-tion of methyl thionohippurate (2.53 x 10-3~ phosphate buffer pH 6.0).Into one of the cells in the “solution” beam was placed buffer solution and into the other (i.e. the reaction cell) enzyme solution (0.69 x ~O-*M; phos-phate buffer pH 6.0; p = 0.3~). When the solutions had reached thermal equilibrium (ca. 20”)the thiono- ester (111) in acetone was added to the reaction cell and the solution thoroughly mixcd; the initial sub- strate concentration was 2-53 x 10-3~and the acetone water ratio 1 :62.5. The spectrum was quickly (ca. 30 sec. after mixing) scanned from 3600-2000 A and showed a single peak at 3130 A (optical density 0.26). The optical density of the peak decayed as shown in Table 1.TABLE 1. Variation with time of the opticaI density of the absorption maximum at 3130 A for papain-catalysed hydrolysis of methyl thionohippurate (111). t (min.) 0.5 4-0 5.5 7.0 9.0 12-5 00 O.D. 0.26 0.23 0.18 0.12 0.04 0 0 The optical density at 3130 8,was also determined under the same conditions but with different initial substrate concentrations about 30 sec. after mixing in a Unicam SP500spectrometer (see Table 2). TABLE 2. Substrate (x 104~) 5.5 11 22 O.D. at 3130 8 0.065 0-108 0.170 * The Dyson Perrins Laboratory Oxford University. Smith Hill and Kimmel in “Symposium on Protein Structure,” ed. by A. Neuberger Methuen and Co. Ltd., 1958 p. 182 and references there cited. Smith J. Bid. Chern. 1958 233,1392.* Smith and Kimmel in “The Enzymes,” ed. by Boyer Lardy and Myrback 2nd edn. 1960 VoI. 4 p. 133 and references there cited. Lowe and Williams unpublished results. ti Rao “Ultraviolet and VisibIe Spectroscopy,” Butterworths London 1961 p. 20. Glazer and Smith J. Biol. Chem. 1961 236,2948. Klages and Haack Ber. 1903 36 1646. Svejima and Shimura J. Biochem. Japan 1961,49 260. MAY1964 Addition of methyl hippurate (to give an initial concentration of 3.34 x 10-2~)to a solution of the enzyme (0.69 x 10-4~) and the thiono-ester (111; 4.1 x 10-3~) lowered the optical density (measured ca. 30 sec. after mixing) from El = 0.523 to E = 0-276,i.e. E1/E2= 1.9. From the Michaelis-Menten parameters it was possible to calculate El/E2 = 2.0 assuming kdeacylation< kacylation.When a solution of the thiono-ester (111) and the enzyme was adjusted to pH 2.5 the optical density of the absorption maximum (shifted to 3090 A) was maintained. These experiments provide a clear demonstration that an acyl-enzyme intermediate is involved in papain-catalysed hydrolyses. The thioacylated resi- due had Amax. 3130 A (log E 4.3 f0.3) assuming that kdeacylatfon< kacylation. The known U.V. absorption properties of the probable intermediates indicate that the site of attachment to the enzyme is a thiol group thiono-esters4(Amax 2300 A log E 4*26) thioamides5 (Amax. 2680 log E 4.05; and 3580 A log E 1*25) and dithio-esters5(Amax 3050 log E 4.08; and 4600 A log E 1-25). Similar experiments with the proteolytic enzyme ficin have shown that an acyl-enzyme intermediate is formed also through a thiol residue.(Received March 19th 1964.) Photochemical Space Intermittency and the Diffusion Coefficients of Polymeric Radicals By P. B. DAVIES and A. M. NORTH* THE diffusion coefficient D of a free radical has commonly been calculated from the radical-radical termination rate constant by using equations derived for diffusion-controlled pr0cesses.l Verification of these equations particularly in high-polymer systems requires an independent evaluation of D. The photo- chemical space intermittency technique2 offers a method for such a measurement. Numerical solutions of the diffusion equations have been evaluated by Noyes2 for so-called “zebra” and “leopard” light patterns and the method has been used to measure the diffusion of iodine atoms3 Despite the importance of radical diffusion in poly- merisations no application of the method to these systems has yet been reported.In this work light patterns were obtained in methyl methacrylate by passing a parallel light beam (collimated by two 4-inch square apertures 31 feet apart) through rhodium-plated copper screens and then through a reaction cell. Each emerging light beam had six equidistant nearest neighbours and beams ranging in thickness from 5 x to 2 x cm. were used. The dimensions of the light pattern were obtained by microscopic measurement of both the screen and a photographic image of the emerging beams.A series of screens allowed variation of both beam diameter and the light-to-dark ratio. The mean diffusive displacement of the growing radicals was calculated2 from the ratio of the rates of polymerisa- tion (measured dilatometrically) under “complete” and “patterned” illumination. An independent con- ventional measurement of the radical lifetime (using light intermittent in time) then allowed evaluation of the diffusion coefficient. The mean diffusion coefficients for growing poly- (methyl methacrylate) radicals at four temperatures and for various final degrees of polymerisation are recorded in the Table. Mean difusion coefficient and final degree of poly-merisation of propagating poly(methy1 methacrylate) radicals. Temp.(“c) lo6D (cm.2sec.-1) 20 1-5 30 2.1 30 2.5 30 1.2 30 0.8 40 3.8 50 3.7 10-3 F 3.6 4.3 4.4 8.3 40.6 7.1 9.0 D increases with temperature and at 30”c D.F* is constant within the experimental error. These diffusion coefficients averaged over the growth of the radical are about ten times larger than values obtained for dead polymers with the same final degree of p~lymerisation.~ (Received March 6th 1964.) * Department of Inorganic Physical and Industrial Chemistry University of Liverpool. Noyes “Progress in Reaction Kinetics,” Vol. 1 Ch. 5 Ed. Porter Butterworths 1961. Noyes J. Amer. Chem. SOC.,1959 81 566. Salmon and Noyes J. Amer. Chem. Sac. 1962. 84 672. * North and Reed Trans. Faraday Soc. 1961 57 859. 142 s PROCEEDING The Reaction of Acetylacetone with Oct-l-ene By J.I. G. CADOGAN and J. T. SHARP* D. H. HEY ALLEN,CADOGAN,-IS and HEY have shown1 that the free-radical reaction between oct-l-ene and an excess (30 mole) of acetylacetone initiated by peroxides leads to the 1:1-adduct(67 %) considered to be 3-acetylundecan-2-one (I). More recently de Mayo and Takeshita reported2 that the photo- initiated reaction between the same compounds oct-l-ene being in excess in this case gave two pro- ducts considered to be 5-acetylundecan-2-one (IIIB) and 4-acetonyldecan-2-one (IlIA) (Scheme 2). The occurrence of free-radical addition to give (I) was not reported. The Occurrence of two entirely different reactions between the same two compounds when initiated by a peroxide and when initiated by ultra- violet light is so unusual and unexpected (if not unique) that it was considered desirable to obtain further experimental evidence.1:1-adduct tridecane-2,4-dione (II) was also formed to a smaller extent. These p-diketones have been characterised by analysis comparison of g.1.c. reten- tion times and infrared spectra with those of authentic specimens and by mixed m.p. determina- tions carried out on the corresponding copper salts (152" and 124" respectively). The isomeric p-diketones (I and 11) are considered to have arisen by addition of the isomeric radicals (IV) and (V) formed by abstraction of hydrogen atoms from carbon-3 and -1 of acetylacetone respectively (Scheme 1).1 :1 -Adducts corresponding to those described by de Mayo and Takeshita were not formed in this reaction nor were they obtained from a peroxide-induced reaction carried out in the presence of excess of oct-1-ene (i.e.,at concentrations used by de Mayo and Takeshita). SCHEME 1 RCH:CH2 (CH3C0)2CHm___-RkHCH2*CH(C0CH3) C8Hl ,*CH(CO*CH3).r. -4 (1) (IV) ?' (CHS*CO)&H2 i RCH:CH2 CH ,-CO*CH ,-CO*CH ,* --+ RkHCH,.CH ,*CO.CH ,-CO*CH -+ C,H &O-CH2.CO-CH (V) (11) (R = C6Hl,) SCHEME 2 Me Me R'. 7H.CHiCO. CH R~WCOCH (a> Repetition of Allen Cadogan Harris and Hey's A photochemical reaction with acetylacetone and experiment gave a product with the reported physical an excess of oct-1-ene gave four products however characteristics.Gas-liquid chromatography (g.l.c.) two of which correspond to those described by de with apparatus and columns not available to the Mayo and Takeshita the others being the isomeric earlier workers confirmed the presence of 3-acetyl-1:l-adducts (1) and (II)formed in the peroxide- and showed that the isomeric induced reaction. Variation of the ratio of oct-1-ene undecan-2-one (I) * (J. I. G. C.) St. Salvator's College University of St. Andrews; @. H. H. and J. T. S.) King's College Strand London w.c.2. Allen Cadogan Harris and Hey J. 1962 4468. * de Mayo and Takeshita Cunud. J. Chem. 1963,41 440. MAY1964 Photo-induced reaction of oct- 1 -ene and acetylacetoite CGH,,.CH :CH Products as % of total (CH,*CO),CH (mole/mole) 0.055 (I)64 1:1 -adduct (11) (IIIA)22 9 (IIIBI 5 0.21 34 18 27 21 0-47 15.5 12 40 32.5 1.0 9 8 44 39 5.8 2 2 48 48 to acetylacetone (Table) showed that excess of oct- 1-ene leads to a predominance of de Mayo and Takeshita's products whereas the reverse leads to a greater yield of the isomeric /3-diketones.The apparent divergence is thus resolved. It is note- worthy that the ratio compound O:compound (II) varies as the ratio of reactants is changed. The theoretical implications of these and related results will be discussed fully elsewhere. (Received March 12th 1964.) Uncatalysed Hydrogenolysis of Metal-Metal Bonds By R. J. CROSSand F. GLOCKLING* COMPLEXES containing germanium bonded to transi-chloride to give the octahedral platinum(rv) deriva- tion metals are already known e.g.Ph,Ge.M(PR,),- tive (II) which subsequently undergoes elimination (M = Cu Ag Au),l Ph,Ge.Mn(C0),,2 and of chlorotriphenylgermane and direct cleavage of the H2Ge[Mn(C0),]2.3 remaining triphenylgermyl group Ph,GeH + trans -(Et3P)2PtC12 ,7 [I] + HCl/ \\ We have now prepared the germanium-platinum complex (I) cis-or trans-(Et,P),PtCl + 2Ph,GeLi + (Et3p) &(ePh3) 2 (I). The ('1 forms pale yellow crysta1s in air and water which decompose at 160". The Ge-Pt bonds are cleaved not only by halogens but also by a smooth reaction with 1,2-dibromoethane7 involving in our view four-centred transition inter- mediates (Et,P),Pt(GePh,) + 2C2H4Br2-2C2H4 + 2Ph3GeBr -t and trans-(Et3P)2RBr2 If the Ge-R bond in 0) is polar in the sense (&-)Ge-R(&+) as is me for the germanium-gold bond in Ph3&.AuPPh3 then cleavage by hydrogen chloride would expected to yield triphenyl- germane and chloroplatinum(n) complexes.In fact all combinations of products are formed evidently due to competition between direct cleavage of the Ge-Pt bonds and primary addition of hydrogen * University of Durham. Glockling and Hooton J. 1962 2658. JHCl (Et3P),Pt(H)Cl + Ph,GeH Similarly with methyl iodide at 115" both iodotri- phenylgermane and methyltriphenylgermane are produced. The most significant reaction of (I) so far en- countered is its cleavage with molecular hydrogen at atmospheric pressure and room temperature without added catalyst (I) + H -+(Et,P),Pt(H)GePh + Ph,GeH Addition of Adam's catalyst does not result in cleavage of the second Ge-Pt bond.The complex hydride decomp. 150° easily separated from Ph,GeH is insufficiently soluble for n.m.r. study but its i.r. spectrum contains a sharp absorption due to v(Pt-H) at 2051 Cm.-' (in benzene) close to v(e-H) at 2037 cm.-l in Ph,GeH. Examples of homo- geneous hydrogenations Occurring under Similar conditions are rare. Mn,(CO), forms the hydride HMn(CO), at 200" under Pressure? and several examples of the UnCatalYsed hYdrogenoIYsis of metal-carbon bOnds are (Received February 14th,1964.) Seyferth Hofrnann Barton and Helling Inorg. Chern. 1962 1 227. Stone Massey and Park,J. Amer. Chem. SOC.,1963 85 2021.Hieber and Wagner 2.Nuturforsch 1958 136 399. Hein and Weiss 2.anorg. Chem. 1958,295 145. ' Chatt and Shaw J. 1962 5075. PROCEEDINGS Carbenoid Decomposition of Cyclopropanecarboxaldehyde Tosylhydrazone Formation of Bicyclobutane By H. M. FREYand I. D. R. STEVENS* THEdecomposition of cyclopropanecarboxaldehyde tosylhydrazone by sodium methoxide in “diethyl- carbitol” and 1-methylpyrrolidone has been reported to give1 cyclobutene as the major product together with smaller amounts of ethylene acetylene and butadiene and with trace amounts of other hydro- carbons. We have been unable to substantiate these findings. Cyclopropanecarboxaldehydewas prepared from cyclopropanecarboxylic acid by reduction of the NN-diethylamide with diethoxy lithium alumin- ium hydride in a yield of 59% based on the acid.2 The aldehyde was converted essentially quantitatively into the tosylhydrazone (m.p.104-5”) by treating it in aqueous ethanol with toluenesulphonylhydrazine. Decomposition of the tosylhydrazone with sodium methoxide in both “diethylcarbitol” and also in “triglyme,” essentially by the same procedure as Friedman and Shechter? yielded the hydrocarbons reported by these authors in similar relative yields. However these products totalled less than 20% of the hydrocarbon products. The main product was a hydrocarbon of considerably longer retention time on a di-(Zcyanoethoxy) ether chromatographic column at 0” (cyclobutene 7.8 butadiene 9.4 and major product 14.7 min.).This hydrocarbon was shown by mass spectrometry to have a molecular weight of 54 and its infrared spectrum did not cor- respond to any known compound of this molecular weight. Unlike cyclobutene it was thermally stable at 180” but decomposed to butadiene at 250”. This evidence indicated that it was probably bicyclo- butane. We have now found that the infrared spectrum of bicyclobutane prepared by the pro- cedure of Wiberg and Lampman3 is identical with that of the “unknown” hydrocarbon. The formation of the bicyclobutane presumably results from cyclo- propylcarbene by an intramolecular insertion reac- tion into one of the four equivalent secondary carbon hydrogen bonds. Since cyclopropanecarbox- ylic acid is available commercially this provides an attractive route to bicyclobutane.(Received March 19th 1964.) * Chemistry Department Southampton University. Friedman and Shechter J. Amer. Chem. SOC.,1960 82 1002. Brown and Tsukamoto J. Amer. Chem. SOC.,1959 81 502. Wiberg and Lampman Tetrahedron Letters 1963 2173. Photo-decarbonylation of Tetramethylcyclobutane-1,3-dione By R. C. COOKSON, M. J. NYE,and G. SUBRAHMANYAM* LIKE Turro Byers and Leermakersl we had examined the photolysis of tetramethylcyclobutane- 1,3-dione (I) and further obtained evidence of an intermediate (11) in non-hydroxylic solvents by isolation of an adduct (111) with furan.2 While irradiation of the dione in benzene with a medium-pressure mercury arc through Pyrex glass gives mainly carbon monoxide and tetramethyl- ethylene in furan a liquid adduct is also formed (15% yield after purification by distillation).The structure (111) is based on elementary analysis and molecular weight infrared [inter al. Vmax. 735 805 1070 1385 and 1700 cm.-l] ultraviolet [in ethanol Amax. 301 mp E 36 and end-absorption E 2760 at 210 mp] and particularly proton magnetic reson- ance spectra [in CCl sharp singlets at T 3.68t (intensity 2) 5.687 (2) 8-74(6) and 9-15 (6)]. When irradiated in furan under the same conditions the monoanil was recovered. H + co Loss of carbon monoxide appears to give an intermediate (11) that can either cyclise to tetra- * The University Southampton. t No coupling is observable in the signals from the corresponding protons in the furan adduct (V).a*a 1 Turro Byers and Leermakers J.Amer. Chem. SOC.,1964 86 955. Nye Ph.D. Thesis Southampton 1963. 8 Cookson and Nye Proc. Chem. SOC.,1963 129; Fort J. Amer. Chem. SOC.,1962,84,4979. MAY1964 145 methylcyclopropanone (IV) which loses a second inability to switch to a long-lived acyclic singlet state molecule of carbon monoxide to give tetramethyl- ethylene or can react with furan to give the adduct (111). Although we have no conclusive evidence on whether the intermediate (11) is initially formed in the triplet or singlet state the singlet should be more stable? By contrast irradiation of trans-1 ,Zdibenzoyl-cyclopropane or trans-1 -benzoyl-2-phenylcyclo-propane in furan merely equilibrated the compounds with their cis-isomers.The failure of the supposed intermediate diradicals (VI) to add to furan may be connected with their Burr and Dewar J. 1954 1201. like (11). A 2% AOPh PhCO COPh PhC A...-hV 04 Ph COPh Ph COPh R -COPh .. (v0 (Received April 7th 1964.) Ring Inversion in Cyclohexane By F. A. L. ANET,M. AHMAD, and L. D. HALL* SEVERAL have recently studied the kinetics of the ring inversion of cyclohexane by low-temperature n.m.r. spectroscopy. Although there is good agreement on the value of AF~, there is only poor agreement on the values of AH3 and AS as is shown in the Table (first three entries). In order to obtain easily interpretable spectra over a wide temperature range we have used undeca- deuterocyclohexane instead of cyclohexane itself and have measured the proton n.m.r.spectra with simultaneous strong irradiation at the deuterium resonance frequency (deuterium decoupling). The spectrum (60 Mc./sec.) changed from a single sharp line at room temperature to two sharp lines of rela- tive chemical shift 28.7 c./sec. below -100". With-out deuterium decoupling the higher-field axial proton> expected4 to have the largest vicinal JHD gave a broader band than that of the equatorial proton. The rates of inversion from -32" to -94" were obtained in the usual ~ay.~,~ Except at the extremes of this temperature range when the exponential decay of the signal on fast passage was measured,2s6 the normal slow passage conditions were used to record the spectra.We have found that cyclohexane and undeca- deuterocyclohexane both give the same line widths at the same temperature provided this is well above the coalescence temperature in agreement with theory.6 This also shows that the difference in inver- sion rates of the two isotopic species is so small as to be within the experimental error. No great difference in rate is expected,' since the compression of non- bonded hydrogen atoms is likely to contribute8 only a small amount to the energy of the transition state for inversion. Values of AFS (at -67") AH$ (in kcal./mole) and AS (in e.u.) for the ring inversiona of cyclohexane. AF~ AH$ AS Ref. 10.1 -lo-1 11.5*2 1 10.3 9.0kO-2 -6.5 f1.0 2 10.7 11.5 +4*0 3 10.3 10.9f0-6b +2.9f2-3b present work 10.2 10-5f0.5 +1-4fl.0 9 10.3 10.3 -0.2 10 a The boat form is assumed to be an intermediate in the inversion process and thus the transmission coefficient is taken as 0.5.The values of AH and AS3 of ref. 2 are corrected accordingly. 90% confidence limits. An Arrhenius plot of the rate data gave a good straight line from which the activation energy was calculated to be 11.3&0-6 kcal./mole where the error limits refer to 90% confidence limits obtained * Department of Chemistry University of Ottawa Ottawa Ont. Canada. Jensen Noyce Sederholm and Berlin J. Amer. Chem. Soc. 1962 84 386. Harris and Sheppard,Proc. Chem. Soc. 1961 418. Meiboom Symposium on High Resolution Muclear Magnetic Resonance Boulder Colo.July 1962. See also Leffler and Grunwald "Rates and Equilibria of Organic Reactions," Wiley New York N.Y. 1963 p. 116. * Pople Schneider and Bernstein "High-resolution Nuclear Magnetic Resonance," McGraw Hill Book Co. New York N.Y. 1959. Anet and Hartman J. Amer. Chem. Soc. 1963 85 1204. Piette and Anderson J. Chem. Phys. 1959 30 899. Cf. Mislow Graeve Gordon and Wahl J. Amer. Chem. SOC.,1963 85 1199. * Hendrickson J. Amer. Chem. SOC.,1961 83 4537. from a least-squares analysis. The values of AH$ and dS$are given in the Table. After these results were obtained we learned of similar work on undeca- deuterocyclohexane by Dr. Boveyg (see Table) ;the two investigations are in excellent agreement. Drs. Sheppard and Harris have informed us that recon- siderationlo of their data2 gives values of AH$ and AS* in good agreement with the present work so that previous discrepancies are resolved.The mean and at present probably best values of AH* and AS$ * Bovey et a!. following communication. lo Harris and Sheppard private communication. PROCEEDINGS are then 10.8 kcal./mole and 2-0 e.u. respectively. For comparison Hendrickson* has calculated the energy required for the ring inversion of cyclohexane to be 12.7 kcal./mole a little higher than the experi- mental value of AH^ On symmetry grounds alone it can be calculatedl that dS$should be 4.9 e.u. also a little higher than the experimental value. Possible reasons for these deviations will be presented in a fuller account of our work.(Received January 16th 1964.) Conformational Isomerisation of Undecadeuterocyclohexane By F. A. BOVEY F. P. HOODIII,.E. W. ANDERSON, and R. L. KORNEGAY* PREVIOUS studies by nuclear magnetic resonance (n.m.r.) of the rate of conformational isomerisation of cyclohexane (cited in reference 1) have yielded fairly concordant results for dF$,but the results for AS$have been less than satisfactory reflecting the fact that it is not easy to measure this rate accurately over a wide temperature range. At temperatures well above “coalescence” the resonance line is narrow and accurate measurement of its width is difficult; near coalescence there is spurious broadening due to coupling of axial and equatorial protons. Below the coalescence temperature the spectrum becomes very complex representing the envelope of many thousands of lines of a 12-spin system and is not really well represented as an AB quartet still less as a doublet.These difficulties appear to be circum-vented in Meiboom’s pulse method.2 It appeared that they could also be circumvented by employing undecadeuterocyclohexane and double resonance (deuterium irradiation) in the manner already demonstrated for pentadecadeuterocyclo-octane by Anet and Hartman.3 In this and ref. 1 the results of such studies are reported. The undecadeuterocyclohexane (Merck Sharp and Dohme of Canada Ltd.) was studied as a 50 v01.-% solution in carbon disulphide containing 2 % of tetramethylsilane as reference. Spectra were obtained on a Varian DP-60 (60 Mc./sec.) instru- ment with deuterium decoupling (accomplished by means of a model SD-60 spin decoupler unit manu- factured by the Nuclear Magnetic Resonance Specialties Company New Kensington Penn-sylvania) adjusted to give minimal peak widths.Temperature control was provided as previously de~cribed.~ Rate constants were calculated by com- parison of observed line widths and (below coale- scence) peak-to-valley ratios to those of plots of the line shape function of Gutowsky and Holm ob-tained with the aid of an I.B.M. 7090 computer. Line widths were corrected for field inhomogeneity and other sources of instrumental broadening by sub- tracting the apparent width of the reference peak which was ca.1 c./sec. at all temperatures. Approxi- mate calculations indicated that the natural T2 (estimated from Meiboom’s results2 on cyclopentane and cycloheptane) was sufficiently long that it would not affect the low-temperature line width (w)within experimental error. The low-temperature spectrum of C,HD, consists of a peak at r 8.40 (w = ca. 6.0 c./sec.) for the equatorial proton and a broader peak (w = ca. 7.5 c./sec.) at r 8-88 for the axial proton (dv = 28-7 =k 0.1 c./sec. at 60 Mc./sec. or 0.478 i0.002 p.p.m.). Deuterium decoupling of course narrows the peaks the effect being greatest at the lowest temperatures and minimal near coale-scence. It is found that AFS is 10-50 & 0.05 kcal./mole and is independent of temperature within experi- mental error; therefore dSt (chair-to-chair) must be nearly zero and ASS (chair-to-boat) must be ca.1.4 e.u. Symmetry considerations alone lead to pre- dictions of positive chair-to-boat activation entropies of approximately the magnitude observed in these studies so apparently there are no other major contributions. The areas of the equatorial and axial peaks for C,HD, at -79” were found to be equal within experimental error (& ca. 2 %) and therefore there is no appreciable isotope effect on the axiakqua- toria’ (Received,January 27th 1964.) * Bell Telephone Laboratories Incorporated Murray Hill New Jersey U.S.A. Anet Ahmad and Hall preceding communication. S. Meiboom Symposium on High Resolution Nuclear Magnetic Resonance Boulder Colorado July 1962.Anet and Hartman J. Amer. Chem. SOC.,1963 85 1204. Bovey Anderson Hood 111 and Kornegay J. Chem. Phys. 1964 in the press. Gutowsky and Holm J. Chem. Phys. 1956,25 1228. MAY1964 147 The Hexafluoroarsenate Ion-a Probe for Ion Association By K. J. PACKER and E. L. MUETTERTIES* THE19F n.m.r. spectrum of potassium hexafluoro- arsenate in water is as expected a quartet of lines of equal intensity and height arising from spin coupling with the 75As nucleus which has a spin quantum number I = 3/2. Solutions of potassium hexafluoroarsenate in acetone acetonitrile and ethyleneglycol dimethyl ether cglyme) give 19F spectra which show the whole range of line shapes predicted and demonstrated recently by Gillespie et a/.,1for the n.m.r.spectrum of a nucleus of spin I = 1/2 coupled to a nucleus of spin I = 3/2. Thus it would appear that in these solutions the arsenic nucleus is experiencing rates of quadrupole relaxa- tion varying from slow to fast. Measurements of the viscosities and of the line widths at half-height in the 19F n.m.r. spectra for a series of solutions of different concentrations of potassium hexafluoro- arsenate in acetonitrile showed a linear relationship between these quantities at the lower concentrations with deviations to larger line widths at higher con- centrations. Solutions of potassium hexafluoro-arsenate in different solvents having comparable viscosities showed markedly different line widths. Increasing line widths were observed in the spectra of solutions of comparable concentrations of potas- sium hexafluoroarsenate in solvents of decreasing dielectric constant.Thus the order of increasing line widths and hence the rate of quadrupole relaxation was water < acetonitrile < acetone < glyme. There are three major variables which can affect the rate of quadrupole relaxation in hexafluoro- arsenate solutions ; viscosity solvent polarisability and ion association. These effects have been dis- cussed recently by Richards and Yorke2 for the n.m.r. spectra of various metal bromide solutions. In the hexafluoroarsenate anion we believe there is a unique opportunity to assess the importance of ion- association effects because it can be studied by con- ventional high-resolution n.m.r.techniques is highly stable and because it is possible to prepare a wide range of hexafluoroarsenates many of which are soluble in a variety of solvents. By evaluating changes in quadrupole relaxation for a wide range of salts of the hexafluoroarsenate ion in a series of solvents and solvent mixtures it may be possible to separate the various factors affecting the overall relaxation time and to determine therefore the importance of ion association and its dependence on solvent charac- teristics and the nature of the cation. In principle it is feasible to ascertain the geometry of an ion aggregate by this technique providing the aggregate's life-time is long enough compared to the n.m.r. parameters involved. In this instance an anion con- taining no quadrupolar nuclei would be preferable e.g.hexafluorophosphate. Work is being carried out along the lines suggested above. (Received March 12th 1964.) * (K.J.P.) School of Chemical Sciences University of East Anglia Norwich; (E.L.M.) Central Research Dept. E. I. du Pont de Nemours & Co. Wilmington 98 Delaware U.S.A. Bacon Gillespie and Quail Canad.J. Chern. 1963 41 3063. Richards and Yorke Mol. Phys. 1963 6 289. Proton Magnetic Resonance Spectra of Tertiary Alkyl Cations By D. M. BROUWER and E. L. MACKOR* CONCENTRATED and stable solutions of a series of tertiary alkyl cations have been prepared in HF-SbF and their proton magnetic resonance spectra re-corded. The solutions were made by dissolving iso- olefins alkylcyclopropanes t-alkyl derivatives (bromide alcohol ether) t-alkylbenzenes or iso- paraffins in the acid.The n.m.r. spectrum of the t-butyl cation consists of one sharp single line at -3.85 p.p.m. from tetra- methylsilane [positions were measured with respect to the collapsed peak at -2-35 p.p.m. of the methyl signals of hexamethylbenzenium cation (cf. ref. l)] corresponding to the nine equivalent hydrogens of this cation. The spectrum of the t-pentyl cation (I) shows the multiplet (-4.2 p.p.m.) of the methylene group the &-methyl? triplet (-3-8 p.p.m.) and the /!-methyl triplet (-1-65 p.p.m.) with the expected intensity ratios 2:6 3. The hyperfine splittings are caused by the normal coupling (5.3 c./sec.) between the methylene group and the p-methyl group and the remarkably large (4-5 c./sec.) long-range coupling between the methylene and a-methyl groups.Both triplets are well resolved the CH multiplet but partially. Above -2O"c the triplets broaden as a result of the rearrangement reaction (1) which places each of the methyl groups alternately in a-and b-positions. The rate constant of reaction (l) as * Koninklijke/Shell-Laboratorium, Amsterdam. t a" refers to groups directly bonded to the charged carbon atom ''8"to those separated from it by one carbon etc. MacLean and Mackor Mol. Physics 1961 4 261 ;MacLean and Mackor Discuss. Faraday SOC.,1962,34 165. deduced from line broadening is given by k = 5.10L2 exp(- 14,3OO/RT) sec.-l; (k25 = 150 sec.-l).+ + (CH&C*CH,.CH $ CH,.CH,.C(CH,) . (1) (1) (1) The spectrum of the methylcyclopentyl cation consists of three groups of lines at -4.05 p.p.m. (four a-methylene hydrogens) -3.8 p.p.m. (three a-methyl hydrogens) and -2.45 p.p.m. (four p-methylene hydrogens) respectively. Above -20"c the signals at -4.05 and -2-45 p.p.m. broaden as the result of the methyl group shifting along the ring. Equilibrium is rapidly established even at -4O"c between the three tertiary isohexyl cations (II)-(lV) PROCEEDINGS and the spectrum is that of the equilibrium mixture. In addition to signals at -4.2 -3.8 and -1.65 p.p.m. for a-methylene a-methyl and @methyl groups of (11) and (III) the spectrum shows a doublet (J = 5 c./sec.) at -2.75 p.p.m.This doublet is the collapsed signal of the a-and /%methyl hydrogens of cation (111) in which the tertiary hydro- gen shifts rapidly between the two tertiary positions. The relative abundances at equilibrium of cations (11) (111) and (lV) calculated from peak areas are 2 :1:1. As this ratio is the same as for the correspond- ing isohexane molecules we conclude that the stabilising effects exerted by methyl and methylene groups bonded to the charged carbon atom are about equal. The positions of a-and p-methyl(ene) groups correspond well with those reported recently by Olah2 for t-butyl and t-pentyl cations in liquid sulphur dioxide. The deshielding effect of the positive charge results in downfield shifts of 3.0 and 0.85 p.p.m.for a-and /3-groups respectively. (Received February 17th 1964.) Olah et al. J. Amer. Chem. SOC.,1963 85 1329; Olah Angew. Chem. 1963 75 800. A Stereospecific Favorsky Rearrangement N. J. MCCORKINDALE W. T. SCOTT, By J. KENNEDY R. A. RAPHAEL and B. ZWANENBURG* A COMPARATIVELY neglected aspect of the Favorsky rearrangement has been its application to geminal dihalogeno-ketones. We now report that base-catalysed rearrangement of the readily-available 1,l -di bromo-ketones under specified conditions is completely stereospecific to yield cis-@-unsaturated esters.l RCH,*C_CH RCH,-COCHBr (1) (11) cis RCH =CHC0,Me (111) This specificity was first discovered during the course of attempts to synthesise trans- 10-hydroxydec-2- enoic acid (royal jelly acid) by Favorsky rearrange- ment of the dibromo-ketone (11; R = HO.[CH,],) with methanolic sodium methoxide.This unex-pectedly produced the cis-royal jelly acid identical with an authentic sample (kindly provided by Dr. R. H. Jaeger) and no trace of the trans-acid could be detected. In order to examine the generality of the process a series of 1,l -di bromo-ketones were made by treat- ment of the corresponding terminal acetylenes (I) with N-bromosuccinimide or NN-dibromodimethyl- hydantoin in aqueous acetic acid buffered with sodium acetate. Reaction of the dibromo-ketones with methanolic sodium methoxide (20 min. at 0") or methanolic triethylamine (2-3 hr. at 20") followed by chromatography on silica gave the pure cis-ap-unsaturated esters in the yields shown.No trans-isomer could be detected at any stage by i.r. or n.m.r. spectroscopy or by g.1.c. R Yield (%) (11) (111) Et 65 65a Prn 60 60&,75b "GHl 61 60a 75b Me0,C. [CH,] 87 79 73b a NaOMe b Et,N-MeOH A cyclopropane intermediate is generally favoured for Favorsky rearrangements of this type.2 The stereospecifici ty of the present examples would strongly suggest that both the formation and cleavage of the intermediate 3-alkyl-2-bromocyclo- propanones must involve concerted processes. This in turn implies that the exclusive production of a cis-ap-unsaturated ester demands the exclusive inter- * Department of Chemistry The University Glasgow W.2. Part of this work was reported at the XIXth International Congress of Pure and Applied Chemistry London 1963.Kende Org. Reactions 1960 11,267. MAY1964 mediacy of the cis-cyclopropanone (V). Examination of models strongly suggests that minimal unfavour- able steric interaction is attained by a concerted trans-anti-parallel 1,3-elimination involving the transition state (IV). This is precisely the transition state which would give rise to the cis-cyclopropanone intermediate (V). It has recently been shown that the 1,l-dibromo- ketones (11; R = H) and (11; R = Me) undergo rearrangement at room temperature to 1,3-dibromo- Rappe Acfa Chem. Scand. 1963 17 2140. Rappe Acfa Chem. Scand. 1963 17 2766. ketone^.^ The higher homologues shown in the Table showed no such tendency to rearrange.For com- parison the two ketones 1,3-dibromopentan-2-0ne and 1,3-dibromo-octan-2-0ne were subjected to the above Favorsky rearrangement conditions. The un- saturated esters thus obtained were predominantly CIS but they did contain about 10% of the trans- isomer as shown by g.1.c. Very recently it has been reported4 that 1,3-di bromo-ketones produce cis-$-unsaturated acids exclusively by sodium bicar- bonate treatment. Satisfactory spectral (i.r. and n.m.r.) and analytical data have been obtained for all compounds described. (Received March 9th 1964.) NEWS AND ANNOUNCEMENTS Fellowship Elections Committee.-Dr. A. I. Vogel and Professor B. C. L. Weedon have been appointed to the Fellowship Elections Committee in succession to Professor D.P. Craig and Dr. W. Gerrard whose period of office on the Council of the Society has expired. Local Representative for Leicester.-The Council has appointed Dr. S. Trippett as Local Representa- tive at Leicester in succession to Mr. R. W.Bott who is leaving the area. Liaison Officers.-Dr. C. Gardner and Dr. A. H. Turner have been appointed Liaison Officers at Imperial Chemical Industries Ltd. (Dyestuffs Divi- sion) and Petrochemicals Ltd. (Carrington Works) respectively in succession to Dr. G. de W. Anderson and Dr. A. V. Mercer who have resigned as Liaison Officers. Election of New Fellows.-72 Candidates were elected to the Fellowship in April 1964. Deaths.-We regret to announce the deaths of the following Mr.F. Buckley (27.3.64) Bexhill-on-Sea a Fellow for 57 years; Mr. J. Cameron (17.3.64) Arran formerly of Peiping Medical College; Mu. A. Clark DoulZ (1.2.64) Director of George Younger and Son Ltd. Alloa; Mr. J. Parkin (29.3.64) Wigton a Fellow for 58 years; Colonel R. B. Turbutt (1 7.2.64) of the House of Urrard Killiecrankie and Ogston Hall Higham Derbyshire; and Dr. R. Williams (8.4.64) Managing Director of Nipa Laboratories. Corday-Morgan Medal and Prize 1963.-This Award consisting of a Silver Medal and a monetary Prize of 500 guineas is made annually to the chemist of either sex and of British Nationality who in the judgement of the Council of the Chemical Society has published during the year in question and in the immediately preceding five years the most meritor- ious contribution to experimental chemistry and who has not at the date of publication attained the age of thirty-six years.If in the opinion of the Council two or more candidates are of equal merit a medal may be awarded to each and the prize equally among them. Copies of the rules governing the Award may be obtained from the General Secretary of the Society. Applications or recommendations in respect of the Award for the year 1963 must be received not later than December 31st 1964 and applications for the Award for 1964 are due before the end of 1965. Ethel Behrens Fund.-The purpose of this Fund is to provide grants towards travelling expenses in- cluding maintenance to enable Fellows of the Society studying at a University or Technical College in the British Isles for the first University degree or other equivalent qualification to attend the Anni- versary Meetings of the Society and any Scientific Symposia or Discussions in conjunction therewith.The next awards are to be made in connection with the Anniversary Meetings to be held in Glasgow in April 1965. Forms of application together with regulations governing the award of travel grants may be ob- tained from the General Secretary of the Society and must be returned by February 15th 1965. Research Fund.-The Research Fund of the Chemical Society provides grants for the assistance of research in all branches of Chemistry. Applica- tions for grants will be considered in December 1964 and should be submitted on the appropriate form not later than November 16th 1964.The total amount available for distribution is approximately El ,100 and applications from Fellows will receive prior consideration. Forms of application together with the regula- tions governing the award of grants may be obtained from the General Secretary of the Society. Deutsche Bunsen-GeseUschaft.-Dr. L. E. Sutton represented the Society at the General Meeting of the Deutsche Bunsen-Gesellschaft on May 7-10th 1964. Visiting Scientists-Professor Dr. H. Funk of the Department of Inorganic Chemistry Freie Univer- sitat Berlin is on a visit to the Department of Chemistry University of Aberdeen until late September.Professor Funk’s interests include silicate chemistry silicate gels low-molecular weight silicate species in solution. The Society of Chemical Industry Canada Medal.- This Medal has been awarded to Dr. R. R. McLaugh-Zin Dean of the faculty of Applied Science and Engineering University of Toronto Toronto Ontario. The Medal awarded not more often than every two years and at the discretion of the Canadian Council of the Society may be awarded to anyone interested in or associated with the Canadian chem- ical industry for services to the industry for out- standing industrial or scientific chemical achieve- ment. St. Salvator’s College University of St. Andrews.- The following appointments in the Department of Chemistry of St. Salvator’s College have been made Dr.B. C.Challis of Cornell University and Dr. J. F. Nixon and Dr. C. Thornsun of Cambridge Univer- sity have been appointed Lecturers Dr. M. Webster of King’s College London has been appointed Assistant Lecturer and Dr. J. Dyson Dr. F. Hampson and Dr. J. T. Sharp have been appointed Postdoctoral Fellows in Organic Chemistry. British Association for the Advancement of Science. -The 126th Annual Meeting of the British Associa- tion for the Advancement of Science at Southampton on August 26th-September 2nd 1964 will be in- augurated by Lord Brain F.R.S. when he delivers his Presidential Address entitled “Science and Be- haviour” in the Guildhall Civic Centre Southamp- ton on August 26th. Copies of the preliminary programme which outlines arrangements for the Meeting and gives details of registration and accom- modation may be obtained without charge from the Secretary of the Association 3 Sanctuary Buildings 20 Great Smith Street London S.W.l or from the Joint Hon.Local Secretary B.A. Office (a) Civic Centre Southampton or (b) 95 University Road Southamptm. Oxford Inorganic Discussion.-The third Oxford Inorganic Discussion sponsored by the Society will PROCEEDINGS be on “Organometallic Chemistry of Transition Metals,” and is to be held in the Inorganic Chem- istry Laboratory Oxford on Friday September 25th 1964. Speakers will include Professor H. C. Longuet-Higgins Professor G. Wilke Dr. M. L. H. Green and Dr. 0. S. Mills. Full details will be circulated later.Engineering Information Retrieval.-A course of lectures on Engineering Information Retrieval by Mr. B. E. Holm of E. I. Du Pont de Nemours and Company Wilmington Delaware is to be given at the Imperial College of Science and Technology London S.W.7 on June 29th to July 2nd 1964 to a limited audience. Further information can be obtained from the sponsors The Institution of Chemical Engineers 16 Belgrave Square London s.w.l. Symposia etc.-An International Conference on the Physics and Chemistry of Solid Surfaces will be held at Providence on June 2 1st-26th 1964. Further enquiries should be addressed to H. E. Farnsworth Corresponding Secretary Brown University Provi- dence Rhode Island U.S.A. A Spectrometer Conference (Spektrometer-Tagung) will be held at Frankfurt-am-Main on June 29th-July 2nd 1964.Further enquiries should be addressed to Dr. K. Picard c/o August Thyssen- Hutte A.G. Chemische Hauptlaboratorium 4100 Duisburg-Hamborn Germany (Fed. Rep.). An International Conference on Nuclear Physics organised by the I.U.P.A.P. and United Nations Educational Scientific and Cultural Organisation on the occasion of the 30th Anniversary of the Dis- covery of Artificial Radioactivity will be held at Paris on July 2nd-8th 1964. Further enquiries should be addressed to the Congrks International de Physique NuclCaire B.P. No. 14 Orsay Seine-et- Oise France. An International Symposium on the Chemistry of Carbohydrates will be held at Miinster on July 13-17th 1964.Further enquiries should be ad-dressed to Professor Dr. F. Micheel Organisch- Chemisches Institut Universitat Hindenburgplatz 55 Miinster Germany (Fed. Rep.). The Twelfth International Conference on High Energy Physics will be held in Dubna U.S.S.R. on August 10-20th 1964. Further enquiries should be addressed to Professor M. I. Goldberger U.S. Representative Commission on High Energy Physics International Union of Pure and Applied Physics c/o Princeton University Princeton New Jersey U.S.A. A Symposium on High Temperature Inorganic Chemistry will be held at Ottawa on September 2nd4th 1964. Further enquiries should be addressed to The Chemical Institute of Canada 48 Rideau Street Ottawa 2 Ontario. MAY1964 An International Conference on Mass Spectro- metry will be held in Paris on September 14-18th 1964.Further enquiries should be addressed to the Secretariat Groupement pour 1’Avancement des Methodes Spectrographiques 1rue Gaston-Boissier Paris 15e France. The Eighth International Conference on Co-ordination Chemistry sponsored by the Society of Austrian Chemists and the International Union of Pure and Applied Chemistry will be held in Vienna on September 14-18th 1964. Further enquiries should be addressed to Professor Viktor Gutmann Verein Osterreichischer Chemiker 1 Eschenbach-gasse 9 Vienna 1 Austria. The Thirty-fifth International Congress of In-dustrial Chemistry will be held in Warsaw on September 1 5-26th 1964. Further enquiries should be addressed to Stowarzy szenie Inzynierow i Tech-nikow Przemyslu Chemicznego (NOT) Czackiego 3/5,Warsaw 6 Poland.The Fifteenth Meeting of the International Com- mittee of Electrochemical Thermodynamics and Kinetics will be held at London and Cambridge on September 21st-26thY 1964. Further enquiries should be addressed to Dr. M. Fleischmann Secretary General of CITCE Department of Physical Chemistry The University Newcastle upon Tyne 1. The Ninth International Cancer Congress under the auspices of International Union Against Cancer will be held in Tokyo on October 23rd-29thY 1966. Further enquiries should be addressed to the National Organising Committee Ninth International Cancer Congress Secretariat c/o Cancer Institute Nishisugamo Toshima-ku Tokyo Japan.Personal.-Dr. F. L. Allen Head of the Chemistry Department at West Ham College of Technology is retiring in the Summer after 44 years in the one College. Professor J. S. Anderson has been elected to Fellowship of the Imperial College of Science and Technology London. Dr. A. Bhati formerly of the Medical Research Council’s Carcinogenic Substances Research Unit University of Exeter has joined the Department of Chemistry and Biology College of Technology Liverpool as Senior Lecturer in Organic Chemistry. Dr. E. 7‘. Borrows has been appointed to the Board of Directors of John Wyeth and Brother Limited. Dr. D. A. Brown has been appointed Professor of Inorganic Chemistry at University College Dublin. During May and June he will be a Visiting Professor at the Israel Institute of Science and Technology Haifa Israel.Dr. D. H. Buss is now at the Department of Medicinal Chemistry at the State University of New York Buffalo. Professor J. I. G. Cadogan has been elected to the Fellowship of the Royal Society of Edinburgh. Mr. H. A. Collinson Managing Director of Leicester Lovell & Company Limited of South- ampton has been elected Chairman of the British Plastics Federation for 1964-1965. The Honorary Degree of D.Sc. has been conferred on Sir Gordon Cox by the University of Newcastle upon Tyne. Mr. J. A. Eggleston has retired from his post as Senior Science Master Methodist Boys’ High School Oron Eastern Nigeria. Dr. A. G. Freeman has been appointed Lecturer at the University of Wellington New Zealand.Professor S. H. Harper and Mr. A. J. Eve of the University College of Rhodesia and Nyasaland are on a visit to England until the middle of June and Dr. D. J. Eve will be in England on sabbatical leave from September next. Dr. H. A. 0. Hill has been elected to a Weir Junior Research Fellowship in Chemistry at Univer- sity College Oxford from October 1964. Dr. J. A. Hill formerly of the Radiochemical Centre Amersham has been appointed as a Research Chemist in the Research Department Southern Dyestuff Company Charlotte North Carolina U.S.A. The Honorary Degree of D.Sc. is to be conferred on Sir Cyril Hinshelwuod of Oxford University during the meeting in Southampton of the British Association for the Advancement of Science from August 26th to September 2nd.Dr. J. D. Levi has been appointed Lecturer in Microbiological Chemistry and Dr. J. S. Davies Assistant Lecturer in Organic Chemistry at Univer- sity College of Swansea. Professor D. R. Llewellyn formerly of the Univer- sity of Auckland has been appointed Vice-Chancel- lor at the University of Waikato Hamilton New Zealand. Dr. D. J. Manners Lecturer in Organic Chemistry University of Edinburgh has been appointed Reader in Chemistry from October 1st. Dr. D. L. Mitchell formerly at Makerere Univer- sity College has been appointed Consultant and Scientific Adviser to the Lango Development Cor- poration Limited a subsidiary of the Uganda. Development Corporation Limited.Professor R. S. Nyholm of University College London is to receive the Royal Society of New South Wales’ Medal for 1963 for his contributions to chemistry and his service to the Society. Mr. G. A. C. Pit? formerly of Potter & Moore Limited has been appointed London Area Works Manager of W. J. Bush and Company Limited. Dr. J. H. Skellon of Brunel College London has been appointed Superintendent of Further Educa- PROCEEDINGS tion for Northern Rhodesia from September 1964. Dr. H. Leverne Williams has been appointed Professor J. B. Stenlake of the Royal College of Principal Scientist and Dr. J. E. Manton a Super-Science and Technology Glasgow has been elected visor at Polymer Corporation Limited Sarnia a Fellow of the Royal Society of Edinburgh.Canada. Dr. D. R. Stranks formerly of the University of Mr. M. B. Williams Westinghouse Electric Melbourne has been appointed to the newly created Corporation Alabama has been awarded the Chair of Inorganic Chemistry in the Department of Honor Scroll of the North Alabama Chapter of The Physical and Inorganic Chemistry in the University American Institute of Chemists. of Adelaide. Mr. J. H. Wood formerly Divisional Chief Associateship of the Royal College of Science Analyst Scientific Department North Western honoris causa has been conferred on Professor F. C. Division National Coal Board is now Divisional Tompkins,Professor of Physical Chemistry. Chief Scientist. Anniversary Meetings 1965 THE programme of the Meetings to be held in Glasgow on April 7-9th will be circulated to all Fellows with Proceedings for January 1965 ; scientific contributions are expected from the following SYMPOSIA Aspects of Acetylene Chemistry J.F. kens (Utrecht State University The Netherlands). F. Bohlmann (Berlin Technical University Germany). J. D. Bu’Lock (University of Manchester). J. Cymerman-Craig (University of California U.S.A.). F. Sondheimer (University of Cambridge). H. Zeiss (Monsanto Research SA Zurich Switzerland). Physical Methods of Structure Determination K. Biemann (Massachusetts Institute of Technology U.S.A.). L. F. Dahl (University of Wisconsin U.S.A.). F. W. McLafferty (Dow Chemical Co. Massachusetts U.S.A.). R. E. Richards (University of Oxford).J. M. Robertson (University of Glasgow). J. N. Shoolery (Varian Associates California U.S.A.). Non-aqueous Solvents and Melts C. C. Addison (University of Nottingham). J. D. Corbett (Iowa State University U.S.A.). G. W. A. Fowles (University of Southampton). N. N. Greenwood (University of Newcastle-upon-Tyne). C. K. J~brgensen (Cyanamid European Research Institute Geneva Switzerland). H. L. Roberts (Imperial Chemical Industries Ltd. Northwich). Non-Fellows who wish to receive the final programme when it is available should notify the General Secretary The Chemical Society Burlington House London W. 1. FORTHCOMING SCIENTIFIC MEETINGS London Imperial College of Science and Technology Imperial Institute Road S.W.7. Thursday June 11th 1964 at 6 p.m.[British Railways are offering concessionary fares Centenary Lecture “Applications of Optical Rota- (single fare plus one half for the return journey) for tory Dispersion and Circular Dichroism in Stereo- this meeting and a travel voucher will be sent by the chemistry,” by Professor C. Djerassi Ph.D. To be General Secretary on receipt of a stamped and given in the Large Chemistry Lecture Theatre addressed envelope.] MAY1964 Cambridge Monday June 8th 1964 at 5.30 p.m. Centenary Lecture “Applications of Optical Rota- tory Dispersion and Circular Dichroism in Stereo- chemistry,” by Professor C. Djerassi Ph.D. Joint Meeting with the University Chemical Society to be held in the University Chemical Laboratory Lensfield Road. Nottingham Wednesday June 3rd 1964 at 5 p.m.Centenary Lecture “Applications of Optical Rota- tory Dispersion and Circular Dichroism in Stereo- chemistry,” by Professor C. Djerassi Ph.D. To be given in the Chemistry Department The University. Sheffield Monday June lst 1964 at 4.30 p.m. Centenary Lecture “Applications of Optical Rota- tory Dispersion and Circular Dichroism in Stereo- chemistry,” by Professor C. Djerassi Ph.D. To be given in the Department of Chemistry The Uni- versity. OBITUARY NOTICE HENRY TIZARD G.C.B. A.F.C. F.R.S. 1885-1959 SIR HENRY TIZARDwas a remarkable man who by his quick mind his ready speech and flashes of wit soon made his presence felt in any company in which he was found. He probably had a greater influence on his country’s scientific policy than any Fellow of the Chemical Society since Lyon Playfair.Born in 1885 he came of stock who had distinguished them- selves in engineering and the fighting services. One of his ancestors was Sir Paul Rycaut F.R.S. and his father Captain Thomas Henry Tizard R.N. F.R.S. had been the navigator of the Challenger and Assistant Hydrographer of the Navy. So it was natural that young Henry should go into one of the services but defective eyesight deprived the Navy of an officer who would certainly have had a brilliant career as Tizard had all the qualities that were needed; a clear quick brain decision in action and the gift of leadership. However instead he went to Westminster first as an Exhibitioner and then as a Scholar where he studied science and mathematics and learnt to write good English.In 1903 he was elected to a Demyship at Magdalen College Oxford which he entered in 1904 gaining a fist class in Mathematical Moderations in 1905. He then read Chemistry his tutor being N. V. Sidgwick and gained a First Class in 1908. Tizard’s brilliant tribute to his old tutor in the Obituary Notices of the Royal Society for 1954 was one of the most delightful things he wrote. The fact is that in their partnership the student played the predominant part Sidgwick‘s austere bachelor life was reshaped by his lively pupil and his future brother-in-law Henry Willett who introduced him to the delights of bridge and golf. Tizard started research with Sidgwick with a note in the Chemical Society Proceedings of 1908 on radium emanation which as he said “turned out to be all wrong,” and a paper on the colour of cupric salts in aqueous solution in the Journal of the same year.He then spent a semester (1908-9) in Nernst’s laboratory in Berlin where he learnt thermo-dynamics met F. A. Lindemann and was given two problems to investigate by Nernst-the condensation of acetylene to benzene and the reaction of hydrogen on carbon bisulphide at high temperatures. Neither gave the result which Nernst had hoped for and so Tizard returned to Oxford for the summer of 1909 when he published another paper with Sidgwick on the colour and ionisation of copper solutions. He then spent a year in the Davy Farady Laboratory of the Royal Institution investigating the behaviour of indicators using the colorimetric technique he had developed with Sidgwick.This led to the publication of two papers in the JournaZ of 1910 on “The colour changes of Methyl Red and Methyl Orange in acid solution” and “The hydrolysis of aniline salts measured colorimetrically,” followed by a Report to the British Association on “The sensitiveness of indicators” which was published in extenso in their Transactions. These papers at once established Tizard‘s reputation as an investigator. Indicators were being studied at that time in many labora- tories. The clarity and elegance of Tizard’s approach did much to clear the air in the minds of his con- temporaries. This was the only investigation which Tizard did single-handed and it revealed the clearness of mind and directness with which he attacked a practical problem.During the year he also revised the third English edition of Nernst’s “Theoretical Chemistry” published in 1911 ,much of which needed fresh translation. In 1911 he returned to Oxford to a tutorial fellow- ship at Oriel when Townsend offered him a demon- PROCEEDINGS stratorship in the Electrical Laboratory which re- sulted in several papers on the motion of ions in gases of which Tizard was one of the authors. The outbreak of war in 1914 found him in Australia attending a meeting of the British Associa- tion to which he had travelled with Rutherford. He returned at once and joined the Royal Garrison Artillery where his unorthodox methods of training recruits were supported by higher authority.In April 19 15 he married Kathleen Wilson and in June his Oxford friend and best man R. B. Bourdillon who was then starting experimental work with G. M. B. Dobson at the Central Flying School at Upavon asked that Tizard should be transferred to the Royal Flying Corps. Shortly afterwards he was appointed to Upavon as an Experimental Equip- ment Officer 2nd Lieutenant. That was the decisive moment in Tizard’s career. He soon learnt to fly and developed Dobson’s scheme for tracking and timing the fall of bombs by a camera obscura. A hut was erected on the bombing ground with a large camera lens in the roof. Tizard installed a crude radio trans- mitter in the ’plane to give a signal when the pilot released the bomb a syphon recorder in the hut received the signal and gave a kick followed by another when the hut was shaken by the explosion.Meanwhile the course of the ’plane was plotted by hand on paper fixed below the lens in the roof. The pilot steered for the hut but released the bomb before reaching too dangerous a point. Later Tizard turned his attention to the testing of new aeroplanes and in 1917 Bertram Hopkinson who was responsible for research and development in aeronautics put Tizard in charge of the testing of aircraft at the experimental station at Martlesham the site of which they had chosen together It was there that Tizard developed a scientific system for investigating the performance of aircraft.A paper by him describing these methods of measuring aircraft performance was published by the Aeronautical Society in 1917. Martlesham was the prototype of future experimental stations like Boscombe Down. Tizard flew as one of his own test pilots and his skill and imaginative foresight certainly saved his own life and his observer’s on one occa- sion. He also showed great courage. When Hopkin- son suggested that they should fly into a thunder- storm cloud to see what it was like they did and discovered. On another occasion Tizard on a test flight saw a squadron of German bombers ap- proaching which he at once attacked and when his machine gun jammed he flew on with the squadron taking notes of their speed and performance and finally waved goodbye to them.When Hopkinson went to the Headquarters of the Ministry of Muni- tions at the end of 1917 Tizard went with him as his Deputy with the rank of Lieutenant-Colonel and after Hopkinson’s tragic death in 1918 he carried on in his place. All this experience of aircraft problems and the reputation he gained as a test pilot were of inestimable advantage to him in years to come. In the spring of 1919 Tizard returned to Oxford to pick up the threads again and prepare for a course of experimental lectures on physical chemistry which was much appreciated. In 1920 he was made Reader in Chemical Thermodynamics and he had then resumed his research on indicators and was also working in a new field the internal combustion engine.During the war Tizard had met Ricardo who was investigating the performance of petrol engines and when Ricardo was enabled to extend his opera- tions by the generous support of Sir Robert Waley- Cohen the Chairman of Shell he invited Tizard and Pye to join in the research. Tizard agreed to do so on condition that the results of the work were pub- lished to which Sir Robert agreed. By the summer of 1919 Tizard and Pye had prepared a monumental analysis of all the physical and chemical properties of the range of fuels which were to be examined and Ricardo had built a new variable compression engine. Tizard’s help was particularly valuable in devising ingenious tests and in his astuteness in analysing the results.As they expected the incidence of detonation was found to be the most important single factor limiting the performance of the petrol engine. Tizard suggested the term toluene number to express the detonation characteristics of each fuel. Toluene was the least prone of all the fuels they examined to detonate and the “toluene number” was the proportion of toluene that was added to heptane the more prone to detonation in order to match the performance of each fuel they examined. Several years later the Americans substituted the use of iso-octane for toluene and today the expres- sion “octane number” is universal. The results of this classic investigation were published in two papers “The characteristics of various fuels for internal combustion engines’’ by Tizard and Pye and “The influence of various fuels on the performance of internal combustion engines” by Ricardo and Thornycroft.Both appeared in the Automobile Engineer in 1921. Tizard and Pye also published two papers in the Philosophical Magazine in 1922 and 1926 on “The ignition of gases by sudden compression.” This was Tizard’s major contribution to scientific literature and it marked a new era in the understanding of the internal combustion engine. Tizard’s lecture to the North East Coast Institu- tion of Engineers and Shipbuilders on “The causes of detonation in internal combustion engines” was published in their Journal in 1921. He continued to take an active interest in these investigations and read a paper to the Faraday Society in 1926 on “Explosion in petrol engines” and a year later pub- lished a paper with Fenning in the Proceedings of the MAY1964 RuyaZ Society on “The dissociation of carbon di- oxide at high temperatures’’ in which they showed that there is a simple relation between the composi- tion of a mixture of carbon monoxide and oxygen which gives a maximum pressure on explosion and the dissociation of the carbon dioxide produced.Tizard was elected into the Royal Society in 1926. In 1920 Tizard had accepted Sir Frank Heath’s invitation to go to the D.S.I.R. as Assistant Secre- tary. His reasons for leaving Oxford are fairly clear. He was ambitious and by then he had realised that he was unlikely to do outstanding work in pure research.He had come across no fundamental prob- lems that gave him the urge to investigate and he was not really interested in the details of laboratory tech- nique. On the other hand he had seen the great opportunities offered in the application of science in practical problems for which he felt himself to be better suited. He spent nine years in the D.S.I.R. He was first in charge of a new Division created to implement a Government decision charging the D.S.I.R. with the co-ordination of the scientific work of the Defence and Civil Departments. A number of Co-ordinating Research Boards were set up which certainly led to numerous cross-contacts at scientific working level between the departments and this con- tinued when the rather cumbrous machinery of the Boards was abandoned.Meanwhile they gave Tizard a most valuable bird’s-eye view of what was happen- ing. He became Principal Assistant Secretary in 1922 and Permanent Secretary in 1927. During these years he exercised an increasing influence on the policy of D.S.I.R. and was largely responsible for establishing the Chemical Research Laboratory at Teddington renamed later the National Chemical Laboratory. He left the D.S.I.R. in 1929 when he became Rector of the Imperial College an office he held until 1942. Tizard went to the Imperial College at a very opportune moment. He soon found that the plans for the new Beit Building were unsatisfactory; he quickly put them right and raised funds to complete the building.His great service to the College was his imaginative grasp of the site planning needed for its future expansion. He fought tooth and nail and with his customary opportunism to secure the use of the whole site north of Imperial Institute Road for educa- tion and to move all museums south of it. His fore- sight undoubtedly made the present development of the College possible. In many other ways the College benefited by his imaginative approach to its problems such as the introduction of an undergraduate course in chemical engineering and a scheme for entrance scholarships for boys who had not specialised in science at school. He had the great gift of being able to talk on seemingly equal terms to people of all kinds and all ages and find out what they were think- ing about things.He wanted to know their views and his happy knack of throwing out a challenging remark would stimulate response. In this way he kept his finger effectively on the pulse of the organisa- tion and inspired people with his own enthusiasm for getting things done. Faced with an alternative course of action he was usually prepared to give a quick and clear-cut decision. During the years of his Rectorship Tizard was also occupied increasingly with the problems of defence. He had been a member of the Aeronautical Research Committee since 1919 and in 1933 he suc- ceeded Glazebrook as Chairman. He was also Chair- man of the Engine Sub-Committee. It was a period of revolutionary advances in aircraft and engines and Tizard with his background of experience in the First War and his knack of putting his finger on the significant factors was an admirable choice.While he did not contribute much in the way of original ideas he was a most stimulating chairman and he gave great encouragement to those like Whittle with his jet engine who were endeavouring to break fresh ground. The following extract from one of his letters to the Chairman of Power Jets the company which was financing Whittle’s work shows his judicial attitude and foresight “You ask for my opinion about Whittle’s scheme. I think there is nothing inherently unsound in his ideas. He may possibly be somewhat optimistic in some of his predictions but even allowing for that I think it highly probable that if he has the necessary financial support and encouragement he will succeed in producing a new type of power plant for aircraft.I am particularly interested in this work because I think that if we are to provide the high powers which will be necessary for aircraft of the future we must develop some type of turbine. Further the fact that such an engine would use heavy oil is of great importance from the point of view of defence and of commerce. “I have a very high opinion of Flight-Lieutenant Whittle. He has the ability and the energy and the enthusiasm for work of this nature. He has also an intimate knowledge of practical conditions-this combination of qualities is rare and deserves the utmost encouragement.I sincerely hope he will get the necessary finance because I think you will have to make up your mind that a large expenditure will be necessary before final success is reached. My general opinion of the importance of this work leads me to express the hope that the money will be raised privately so that the knowledge that it is going on will not be widespread. “PS.-Of course I do not mean to imply that success is certain. All new schemes of this kind must be regarded as ‘gambles’ in the initial stages. I do think however that this is a better gamble than many I know of on which money has been spent.” As Chairman of the A.R.C. he encouraged free and friendly discussions between those holding different points of view.He was at pains to inform himself about the matters that were on the agenda and he would pose the problems for discussion and only if nobody took up the challenge would he start with some suggestion to provoke comments. He was always ready to listen to the engineer and designer and showed great respect for their views. In summing up at the end of a discussion he showed a shrewd judgment of the relative merits of the opinions that had been expressed. In 1938 at the end of his five- year term of office he was invited by the Air Council who wished to retain his “invaluable assistance,” to serve for a second five years and he continued as Chairman until 1943. By 1934 the clouds of war were gathering and at the suggestion of H.E. Wimperis the Director of Scientific Research the Air Ministry appointed a small committee for the Scientific Survey of Air Defence with Tizard as Chairman. The other members were Wimperis A. V. Hill and P. M. S. Blackett all of whom had had war experience and A. P. Rowe was Secretary. The task of the committee was to examine scientific means of strengthening our air defences. At that date the duty of detecting the approach of hostile aircraft was still the responsi- bility of the War Office and the control of the Air Defence Experimental Establishment was in its hands. It now became increasingly clear that the acoustical apparatus employed by the War Office on which it solely relied was much too slow in view of the growing speed of aircraft and could only operate at short distances.Some more effective means of plotting the approach of hostile aircraft to facilitate their interception was needed. Wimperis had already consulted Watson-Watt the Head of the Radio Department at the National Physical Laboratory about the possibility of interfering with hostile air- craft by an electromagnetic “death ray”. Watson- Watt had pointed out in reply the possibility that the reflection of a radio beam might be used to detect the presence of aircraft. Wimperis reported this to the first meeting of the Tizard Committee on January 28th 1935 and at its second meeting in February the committee had a memorandum from Watson-Watt setting out his proposal for radio detection. It was then decided that experimental work should be put in hand at once at Orfordness with the aid of the N.P.L.radio staff. The Air Council asked for a preliminary test to be made before sanctioning the expenditure of E10,OOO and a trial at the end of February gave most encouraging results. In March it was decided to regularise the work of the Tizard Committee which was engaged on a prob- PROCEEDINGS lem which was officially the concern of the War Office by making it the operative element of an Inter-Service Committee appointed for the purpose under the Committee of Imperial Defence. This Committee of which Tizard was a member met in April 1935 and was told of the promise of the experi- mental work in progress. Sir Warren Fisher the Head of the Treasury was a member of the Com- mittee and Air Chief Marshal Sir Wilfrid Freeman joined it in 1936.Freeman was enthusiastic about radar and a word from him to Fisher always secured the financial support that was necessary. By June 1935 the range of detection had reached 28 miles and soon afterwards 60 miles and by September sufficient progress had been made for the Air Council to recommend the construction of a chain of ground stations from Southampton to the Tyne. Tizard had foreseen that not only would the new device revolutionise air defence but that it would be essential for the R.A.F. to learn how to use it if the maximum value was to be got out of it. Accordingly in July 1936 he proposed that interception experi- ments by a small team should begin without delay to ascertain the limitations and reliability of R.D.F.as it was then called. He said that he was prepared to devote two months to advising on the precise nature of the experiments but although his Com- mittee was to guide them on broad lines he himself must decline to take executive control. This set the pattern for much of Tizard’s association with the Air Ministry in that he preferred to guide and advise rather than commit himself to detail. These experiments suggested by Tizard at this early date were responsible for the eventual develop- ment of the tactical use of radar by the Royal Air Force which made it such a vital factor throughout the war specially during the Battle of Britain. The Germans also had developed a radar system but they failed to grasp its proper tactical applications.Tizard was anxious that the story of the Biggin Hill experiments should be put on record and the following account of their initiation and progress is based on a detailed account written by Dr. B. G. Dickins (then an Air Ministry scientist now Director- General of Guided Weapons Ministry of Aviation) who was one of a small team including Squadron Leader R. L. Ragg (now Air Vice-Marshal Ragg) a navigation expert from Bomber Command Flight- Lieutenant W. P. G. Pretty (now Air Vice-Marshal Sir Walter Pretty) and Flight-Lieutenant A. W. B. McDonald (now Air Marshal Sir Arthur McDonald). They met in the office of the Station Commander Wing Commander Grenfell at R.A.F.Station Biggin Hill and were speculating on the purpose of their meeting when Tizard arrived. He explained that the problem they were to investigate was the best way of intercepting an enemy MAY1964 formation of bombers if by some mysterious means they were given 15 minutes warning of its approach and its position and altitude at minute intervals. Three Hawker Hinds would be allocated from Bomber Command to simulate the bombers and the Gloster Gauntlets of No. 32 Squadron were to be set aside for use as fighters. Tizard stressed the great importance of the experiments and promised his support in obtaining any necessary ancillary equipment. At the time these experiments started very little warning of approaching bombers was obtainable before they reached the coast and it was the normal practice in “exercises” to put fighters up on patrol at suitable points in anticipation of attacks.They would then be moved to other points in the path of any raid that might develop. The fighters were ex- pected to reach the ordered points without any assistance from the ground even in cloudy weather conditions. With the new mysterious “aid” which gave adequate early warning the fighters could remain on the ground until the bombers were detected and then they would be directed to the bombers by working out the correct course to steer to achieve interception using an appropriate calculator. The experiments started off in the simplest possible way. The bombers were instructed to fly only on straight courses.On early warning the fighters were ordered to take off on a given course approximately in the direction of the bombers. They would report when they were airborne and on course over the air- field. This time was noted and the resultant track drawn on a chart the positions several minutes ahead being marked off. The positions of the bombers which were received over the telephone were also plotted on the same chart and the track determined and future positions predicted. The navigator having decided the time and hence the position of the fighters when the change in course to effect interception should be made gave the con- troller the course to steer after making the necessary calculation allowing for the wind.The controller then passed the message to the fighters over the R/T. The time of interception could of course also be calculated and this together with the rough height and other information regarding the enemy was also passed to the fighters. It was possible to carry out about five experiments during a day and within a few weeks it was estab- lished that it was possible to direct the fighters with sufficient accuracy to enable them to intercept the bombers flying on a straight course with a very high percentage of success. Alterations in the bombers’ course at irregular intervals were then introduced to simulate either evasive action or more substantial errors in location. Every alteration in course when detected involved a recalculation of the interception problem.Several months were spent while various calculators and other devices were being tried out for this purpose until Tizard then paid one of his visits to see how the experiments were progressing. The problem was explained to him and he suggested that if the angle between the bombers’ track and the line joining the positions of the bombers and fighters at any time was measured and the fighters ordered to steer a course corresponding to a track making an equal angle with the above line the two tracks would meet at the apex of an isosceles triangle. Then because the fighters’ speed was invariably greater than that of the bombers the fighters would get there first and could circle until the bombers were sighted.The determination of this angle was much simpler than solving the normal interception prob- lem and therefore valuable time would be saved. The plotting of the bombers’ and fighters’ posi-tions and finding the “Tizzy Angle” was done on a blackboard using two airmen plotters under super- vision. This also enabled the Controller to see what was going on and hence enabled him to give additional assistance over the R/T to the fighters. A fortunate accident then simplified the whole procedure. The navigator had set his calculator wrongly and in desperation the Controller made a rough estimate of the course from the plot and said “If you can’t give me the new course in 10 seconds I shall tell them to steer 050°.” This he did and the successful series of interceptions was unbroken.Trials were then made without calculators estimating the course by eye and correcting it if it seemed wrong when plotted. The results were so satisfactory that this method became standard procedure. To make the trials more realistic the bearings of both bomber and fighter were determined by high- frequency direction finding at two Stations and trans- mitted to Biggin Hill to give a “fix” of their positions on a vertical ground glass screen which had been substituted for the blackboard. A system was soon developed by which one Controller could cope with two or even three raids at a time. When the first R.D.F. Station at Bawdsey came on the air experi- ments using R.D.F. information soon proved that this system of interception was entirely practicable.The Biggin Hill experiment had proved a great success and Fighter Command now took over the task of introducing the interception technique into the air defence organisation. Methods for sorting out the mass of information received from the coastal chain of R.D.F. Stations coming into opera- tion were developed by the Service and Civilian staff of the Bawdsey Research Station. The R.D.F. chain and methods of using the information it provided were ready just in time to provide the new system of air defence. This was the beginning of a period of increasing co-operation between the scientists and the Royal Air Force which Tizard had done so much to foster. This was only one of the practical steps Tizard took to ensure that the maximum advantage was taken of radar.He foresaw the need for a number of scientists to man the stations and early in 1938 he enlisted the help of John Cockcroft (then working in the Cavendish Laboratory) to organise teams of physicists for this purpose. Cockcroft went twice to Bawdsey to see the preparations for R.D.F. and after a visit by Watson-Watt to Cambridge plans were made for a group of 80 scientists to spend September in the chain of stations. So they were there when war broke out and many of them played an important part in the war effort. Tizard’s part in all this is beyond praise. It is one thing to design a piece of apparatus which will track a hostile aeroplane.It is quite another thing to con- struct a defence system which will fly a fighter to the right spot at the right time and shoot it down. This calls for operation rooms controllers land lines and W/T communications training and know-how. It was Tizard’s greatest contribution that he helped in a quite dramatic way to bridge this yawning gulf between a brilliant idea and a working system of defence. Tizard was able to make this remarkable contribu- tion because among his other qualities he was a practical flying man. As one of the team has put on record “Tizard’s very practical approach and his willingness-and even insistence-on flying in the aeroplanes which we were using in the experiments soon endeared him to us. I have no hesitation in saying that he was the inspiration to the work we did during those years.” Tizard had suggested in 1936 that an attempt should be made to make a radar set small enough to go into an aircraft for use in night interceptions.In July 1939 together with Mr. Winston Churchill and Lindemann he was given a practical demonstration in the air of the experimental equipment developed for this purpose. When its reliability was in question in 1940 before it was introduced operationally Tizard expressed his view strongly in a paper to the Night Interception Committee of which he was a member that the principles of the system’s design and construction were perfectly sound. This unequi- vocal support was very timely as doubts were then being expressed as to whether the confidence of air- crews in such equipment could be won.Subsequent events proved the rightness of his judgement and his personal influence with the aircrews did much to ensure its success. From the outbreak of war Tizard was seized with the importance of winning the sympathy and tech- nical support of the United States of America. He PROCEEDINGS was the first to say and he kept on saying it that we could not win the war in a finite time unless America came into it. At his suggestion A. V. Hill went to Washington in 1940 as “Supernumerary Air AttachC” to our Ambassador Lord Lothian to act as his scientific adviser. Hill’s exploration of the posi- tion made it clear that the President would welcome a proposal from Britain to share all scientific know- ledge of weapons and equipment.Lothian strongly supported the plan to send a British Scientific Mis- sion for this purpose. After some delay owing to political discussions the Mission led by Tizard went to America in August 1940. Tizard however very wisely went to Canada ahead of the Mission to bring the Canadians into the picture. At this time Canada was feeling rather sore that most missions had gone direct to Washington and had neglected Canada’s war potential and her capacity for research and development. Tizard‘s visit bringing with him the details of our war inventions and a list of problems in which she might help gave Canada her first start in war research. Tizard won the regard and affection of all the Canadians he met who were associated with the war effort both service and scientists.His influence with Canadians did not end with the war. He was frequently their guest subsequently and they attached great value to his advice on their military and scientific problems. When he left for Washing- ton Tizard took with him C. J. Mackenzie as Canada’s representative on his Mission. It was a stroke of genius on Tizard‘s part to bring with him on the Mission a mixed teamof scientists and serving officers from the Army Navy and Air Force with battle experience. This gave him the entree to the armed services in Washington not easy for civilians at that time and within a few days Tizard Cockcroft and other civilians were lecturing to the military services and establishing a confidence and co-operation that were maintained throughout the war.Tizard also took with him in his famous black box the prints of our war devices such as radar and Whittle’s jet engine and a specimen of Randall and Boots’ 9.5 cm. resonant cavity magnetron which gave the American work on radar a new stimulus. Tizard handled the situation magnificently and it is not too much to say that his Mission marked the “take off’ of American technology in World War I1 and this was to pay massive dividends for Britain in the years ahead. Tizard’s brilliant leadership of the Mission was one of his greatest services to Britain. An assessment of its importance is given in J. P. Baxter’s book published in 1946 “Scientists Against Time.” During the first ten months of the war Tizard had advised the Chief of the Air Staff on scientific matters in addition to continuing the Chairmanship MAY1964 of the Defence Committee which in October 1939 had been amalgamated with the Offence Committee as the Committee for the Scientific Study of Air War- fare.When Churchill went to the Admiralty in 1939 relying on Lindemann as his scientific adviser Tizard’s position became more and more difficult and in June 1940 he resigned from his Air Ministry commitments. After his return from America he became tempor- arily responsible for research and development at the Ministry of Aircraft Production and when that was reorganised in July 1941,he retained something of a roving commission in regard to scientific research.He was a member of the Aircraft Supply Committee-an advisory body-and represented the M.A.P. on the Air Council from June 1941 to August 1943. He continued to be much occupied with the need for a greater use of scientific evaluation of our operations against the enemy and his efforts in this direction bore fruit in the expansion of operational research at R.A.F. Commands. A further develop- ment also inspired by Tizard was the decision to send a mission to North Africa under Zucker- man to assess the results achieved by war weapons-a new kind of scientific survey which was to have important consequences on the future con- duct of our operations. Then again the appointment in 1939 of R.V. Jones a physicist already in the Air Ministry to initiate the new service of Scientific Air Intelligence was due to Tizard who pointed out this weakness in the organisation. In 1942 Tizard felt that his whole-time service in the Ministry of Aircraft Production was neither necessary nor desirable and he accepted the invita- tion of the Fellows of Magdalen his old College to become President. It was a difficult period when the College was preparing for the adjustments that would be needed in a post-war world. Tizard quickly acquired an excellent grasp of the rather complicated College Statutes and he gave much thought to the financial fortunes of the College incidentally re- organising the Bursary. He soon made up his mind about what he wanted the College to do and he gave a clear lead to those who worked closely with him in small committees.He was less successful in * handling a large College meeting when he had to pilot controversial issues through a very varied and independent-minded body of Fellows. Perhaps he had too authoritarian a background to fit easily into the democratic ways of a College. Meanwhile he had kept in close touch with scientific developments in the Services so it was no surprise after the Election of 1945 that he left Magdalen at the invitation of the Labour Government to become Chairman of the new high level advisory bodies the Defence Research Policy Committee and the Advisory Council on Scientific Policy positions he held for those im- portant six years when Britain’s economy was being reshaped from war to peace.As Blackett says in his Tizard Memorial Lecture to the Institute for Strategic Studies . . . “These last six years of his active life were in a real sense the fulfilment of his quarter-of-a-century-old belief in the importance to the life and prosperity of Great Britain of a close relationship between the administrative and scientific worlds a belief which was one of the factors which led him in 1920 to forsake an academic for a Civil Service career.” Under Tizard‘s guidance the Defence Committee became an invaluable means of co-ordinating the scientific and technical aspects of our policy and his influence was felt in many important developments. He shared much of the responsibility for the development of the rocket range at Woomera helped by his previous contacts with the Australian authorities and their confidence in his judgment.The return of Churchill’s Government to power in 1951 with Chenvell as his adviser made Tizard’s resignation inevitable and the remaining years of his life were largely devoted to the interests of several chemical companies on the boards of which he served and to the National Research Development Corporation of which he was a member from 1951 to 1957. He was a Director of Glaxo Laboratories Ltd. of Humphreys and Glasgow of Solvay Chem- icals and of Albright and Wilson and he took a very active interest in their activities frequently visit- ing their plants and research laboratories where his presence was always welcomed for the encourage- ment he gave to the younger chemists and engineers.He talked with them on equal terms asked them searching questions which made them think and generally acted as a catalyst in accelerating the con- sideration of new aspects of a problem. His colleagues were all impressed by the soundness of his technical judgment and the courage with which he was pre- pared to back new developments. The Goldsmiths’ Company also benefited from his practical wisdom in the years in which he served as Warden and particu- larly in the year of his Prime Wardenship 1955 to 1956. Tizard never lost his interest in education and as Chairman of the Goldsmiths’ Education Committee for two years he took an active part in re-orientating the post-war activities of their benefactions.From 1952 he was a Pro-Chancellor of the University of Southampton and he seldom missed a meeting of the Council. He foresaw the need for a large expansion of University education especially in science and engineering and his advice was eagerly sought on his frequent visits to Southampton. He resented strongly the artificial distinction between science and the humanities when the future of humanity depends so largely on scientific progress and its practical applica- tion. Tizard was always insistent on the need to make more use of the knowledge that we already possess. One of Tizard’s great strengths was the clarity and conciseness of his memoranda.He learnt to write well at Westminster he was an omnivorous reader with a well-stocked memory which was always able to produce a relevant quotation or allusion and so with his wide experience he was often invited to deliver public lectures on important occasions. All these addresses are worth reading as they are full of shrewd comments on a wide variety of subjects-his Presidential Address to the British Association in 1948 on “The Passing World,” his Messel Memorial Lecture in 1952 on “The Strategy of Science Chem- istry and Industry” his Haldane Memorial Lecture in 1955 on “A Scientist In and Out of the Civil Service” describing his own experiences and most brilliant of all his Arthur Dehon Little Memorial Lecture at the Massachusetts Institute of Technology in 1951 on “Science and Democracy”.The Lecture contains a remarkable anticipation and analysis of many of the problems that are puzzling us today illuminated by apt questions which showed the wide range of his mind. His dream of the decisions made by a central government of scientists is full of wise quips and he did not hesitate to question some of the assumptions underlying the thinking of his hosts. The searching examination papers which he set for the School of Humanities and Social Studies at M.I.T. on Industrial Productivity and Standard of Living contained several questions that are still unanswered. Tizard was at his best in throwing out challenging questions that forced people to think he had no respect for accepted dogma and often saw things in a new light.He was always ready to challenge authority though his puckish interventions were not always taken in good part. No scientist has ever made a more valuable contribution to Britain at a time of crisis and his country has every reason to be grateful that Tizard made the right choice at the turning point of his life in 1920. Tizard’s public service and his intellectual distinc- tions won for him many honours an Air Force Cross in 1918 a C.B. in 1927 a K.C.B. in 1937 and a G.C.B. in 1949 and the American Medal for Merit in 1947. He was elected into the Royal Society in 1926 was Foreign Secretary for 1940-45 and Vice- President for 1940-41 and 1944-45. He was an Honorary Doctor of ten British and Commonwealth Universities an Honorary Fellow of Oriel and Magdalen at Oxford and of the Imperial College and University College in London.He was awarded the Gold Medals of the Society of Arts and the Franklin Institute and the Messel Medal of the Society of Chemical Industry. Many learned Societies ac-claimed him as an Honorary Member in 1948 he was President of the British Association from 1937-59 he served as a Trustee of the British Museum. This widespread recognition reflects the diversity of his activities and the value of his many achievements during his busy life. HAROLD HARTLEY.
ISSN:0369-8718
DOI:10.1039/PS9640000129
出版商:RSC
年代:1964
数据来源: RSC
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