332 Analyst, A@& 1978, Vol. 103, 99. 332-340 Polarographic Studies on Some Organic Compounds of Arsenic Part IV." Diphenylarsinic Acid A. Watson Department of Chemistry, The New University of Ulster, Coleraine, Co. Londonderry, BT52 1SA , Northern Ireland A study has been made of the polarographic behaviour of diphenylarsinic acid. It gives rise to a single cathodic wave below pH 6, displaying an adsorption pre-wave, and some limited inhibition effects. The latter are removed by addition of a surface-active agent, thus yielding a well formed, diff usion-controlled wave, the height of which is proportional to concentration (up to 1 x The current - potential relation- ships and the reduction mechanism are discussed. An irreversible reduction to tetraphenyldiarsine has been found.The use of polarography is proposed for the quantitative determination of diphenylarsinic acid. In mixtures with phenylarsonic acid and/or triphenylarsine oxide, the wave at pH 1 gives the total concentration of all three, while that at pH 5.3 gives the concentration of diphenyl and triphenyl species and that at pH a7 triphenylarsine oxide alone. M) and independent of pH. Keywords : Diphenylarsinic acid ; polarography The organic compounds of arsenic have many important applications in agriculture and industry, and as laboratory reagents. They display an interesting, varied polarographic behaviour, thus permitting specific determination according to oxidation state and number of organic substituents. This property is valuable as the compounds vary considerably in toxicity.Previous papers in this series have been studies of phenylarsonic acid,l phenyl arsenoxide2 and triphenylarsine oxide.3 A detailed study of diphenylarsinic acid is necessary to complete the investigation of this range of compounds. Diphenylarsinic acids are formed as by-products4 in the preparation of phenylarsonic acids, some of which are used as additives in animal fee ding stuff^.^ Previously, determina- tion of the arsinic acid impurity had proved very difficult. Diphenylarsinic acid is a stable, simple product easily obtained by hydrolysis and oxidation of unstable irritants, such as diphenylcyanoarsine and diphenylchloroarsine, and is, therefore, useful in their de termina- tion. The latter compounds, known as Clarke I and 11, have military applications.6 For these reasons, the following study of the polarographic behaviour of diphenylarsinic acid was undertaken.Experimental Apparatus with the Radiometer DLTl drop-life timer (Copenhagen). was used in combination with the saturated calomel electrode. apparatus were described in Part 1.l Current - potential curves were recorded by using the Polariter PO4 polarograph equipped The dropping-mercury electrode Details of the Instantaneous current veYsZts time curves were recorded oscillographically. Reagents Diphenylarsinic acid was obtained from Kodak Ltd. and was checked for purity by thin- layer chromatography and elemental analysis. Further purification of the reagent was not necessary. M were prepared in distilled water and were found to be stable for several weeks. Stock solutions of 5 x * For details of Part I11 of this series, see reference list, p.340.WATSON 333 The supporting electrolytes, 0.1 M hydrochloric acid and buffers of phosphate, acetate and borate were prepared from AnalaR-grade reagents; details were given in Part 1.l Experimental Techniques These were described in detail in Part 1.l Results and Discussion The polarographic behaviour of solutions of diphenylarsinic acid in 0.1 M hydrochloric acid was examined over the concentration range 2.5 x to 1 x 1 0 M 3 ~ . One main cathodic wave was found at -0.8 V, which displayed a maximum and was preceded by an adsorption pre-wave (Fig. 1). The potential of the main wave lay at a similar potential to the waves given by phenylarsonic acid1 and triphenylarsine oxide.3 6.0 5.0 4.0 21 --.9 c 3.0 L 3 0 2.0 1 .o I I I I I I I I I 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 Potential/-V Fig. 1. Current - potential curves for A, 0.0003 M and B, 0.0005 M solutions of diphenylarsinic acid in 0.1 M hydrochloric acid. The adsorption pre-wave has been shown to correspond to the classical adsorption pre- wave as described by BrdiEka.7 The height of the pre-wave becomes limited at about 1 x 1 0 - 4 ~ , and above this concentration the remaining current is carried by the main diff usion-controlled wave. Instantaneous current - time curves were recorded a t -0.71 V on the upper plateau of the pre-wave for a series of concentrations from 1 x to 1 x 1 0 - 3 ~ and were found to possess the same typical shape predicted by BrdiCka,7 that is, a sharp increase to a maxi- mum near the birth of the drop followed by slower decrease in the current [Fig.2 ( a ) ] . The graphs of the logarithm of the current veYsZts the logarithm of the time were found to be strongly curved near to the beginning of the drop life time. The slope measured over the last 2 s of the drop life time, corresponding to the exponent x in the instantaneous current - time relationship i = k t x , was found to lie close to the theoretical value of -0.33 that was calculated by BrdiEka' for an adsorption process. The relationship between the height of the pre-wave and the height of the mercury column was determined by linear regression analysis of the wave height veysZts the height and the square root of the height of the column (these being the independent variables) for several concentrations between 1 x and 1 x M of diphenylarsinic acid in 0.1 M hydro- chloric acid.The high positive values of the correlation coefficients indicated that the wave was not a kinetic or a catalytic hydrogen wave, while the higher coefficients against the height of the column suggested adsorption control. However, correlation coefficients alone do not offer sufficient proof and so the intercepts of the regression line on both the axis for the height and for the square root of the height were compared with the intercepts334 WATSON : POLAROGRAPHIC STUD~ES ON SOME Analyst, Vol. 103 predicted1 for adsorption and diffusion control and the set of eight heights of the mercury column used. The predicted intercepts for adsorption control fell within the tolerance range of the experimentally obtained intercepts while those for diffusion control did not.al 3 L 0 0.5 0 Time (2 s per division) Fig. 2 . Instantaneous current - time curves for a 0.0002 M solution of diphenylarsinic acid in 0.1 M hydrochloric acid: ( a ) , a t -0.710 V; ( b ) , a t -0.99OV; and in the presence of 0.01% of Triton X-100 at (c), -0.99OV and (d), -0.750 V. Finally, the pre-wave showed the characteristic decrease in height with increasing tempera- ture or on the addition of surface-active agents. The pre-wave can thus be seen to display all the characteristics of the classical adsorption-controlled wave. Linear regression analysis showed that a proportional relationship exists between the combined heights of the main wave and pre-wave and the concentration of diphenylarsinic acid.In the absence of a surface-active agent the standard error of estimate of the line ( 5 4 % of the average wave height) is higher than would be expected. Higher correlation coefficients were found om linear regression analysis of the combined wave height versus the square root of the height of the mercury column than were found versus the height of the column, indicating diffusion control. The predicted intercepts on the axis of the height and the square root of the height of the column for diffusion control fell within the tolerance interval of the experimentally obtained intercepts, while those for adsorption control did not. Instantaneous current - time curves on the rising part and upper plateau of the main wave showed the rising curve characteristic of diffusion control, with a distinct maximum superimposed near the beginning of the drop life time indicating the presence of inhibition effects [Fig.2 ( b ) ] . The small, sharp discontinuity in current a t much more negative potentials (Fig. 1) is also characteristic of a limited degree of inhibition. The presence of this inhibition on the reduction explains the poor reproducibility in the wave height. The behaviour of diphenylarsinic acid in this respect is intermediate between monophenylarsonic acid, which shows no inhibition effects, and triphenylarsine oxide,3 which shows strong, complex inhibition effects as a result of adsorbed species. The effect of a surface-active agent was investigated by recording the current - potential curve for 2 x 10-4 M diphenylarsinic acid in 0.1 M hydrochloric acid in the presence of an increasing concentration of Triton X-100.The small discontinuity moved rapidly to more positive potentials to merge with the main wave while the pre-wave and maximum were suppressed. By a concentration of 0.005~0 of Triton X-100 a single, well formed wave resulted (Fig. 3). Above this concentration no further change was detectable. The half- wave potential and the over-all height underwent no major change, indicating that there had been no change in the basic reduction process.April, 1978 ORGANIC COMPOUNDS OF ARSENIC. PART IV 335 In the presence of O.Olyo of Triton X-100 good proportionality has been found between the wave height and the concentration of diphenylarsinic acid, with much improved standard errors of estimate of the graph (2-3y’ of the average wave height).Calibration graphs 1 .a 4 t 1.2 z 3 3 0 0.6 I I I 0.6 0.8 1.0 1.2 o i ’ Potential/-V Fig. 3. Current - potential curve for a 0,0002 M solution of diphenyl- arsinic acid in 0.1 M hydrochloric acid containing 0.01% of Triton X-100. were prepared from several solid samples of diphenylarsinic acid. Within the limits of experimental error the slopes for all of the samples are equal, confirming that solid diphenyl- arsinic acid yields a reproducible concentration of the electroactive form (Table I). TABLE I CALIBRATION GRAPHS (TEN POINTS, 0.1-1.0 mmoll-1) IN HYDROCHLORIC ACID CONTAINING O.Olyo TRITON X-100 FROM SIX SOLID SAMPLES OF DIPHENYLARSINIC ACID Slope/pA per mmol 1-1 - Sample Slope Tolerance 1 8.01 0.27 2 8.15 0.17 3 8.31 0.20 4 8.24 0.24 5 8.08 0.29 6 8.29 0.18 Intercept on the wave height axislpA & Intercept Tolerance 0.04 0.18 0.01 0.10 0.06 0.12 -0.02 0.16 0.02 0.18 -0.03 0.11 Intercept on the concentration axis/ mmoll-1 & Intercept Tolerance -0.005 0.022 -0.001 0.012 -0.004 0.014 0.002 0.018 -0.006 0.002 0.003 0.013 Standard error of estimate/ 0.11 0.07 0.08 0.10 0.12 0.07 PA Mean value of the wave height/pA 4.41 4.48 4.55 4.52 4.47 4.57 Re-investigation of the relationship between the height of the wave and the height of the mercury column in the presence of O .O l ~ o of Triton X-100 showed an increase in all of the correlation coefficients, while the predicted intervals for diffusion control agreed more closely with those determined experimentally.Instantaneous current - time curves on the upper plateau and on the rising part of the wave show, in the presence of 0.01% of Triton X-100, the rising curve typical of diffusion control, without the maxima which previously indicated inhibition effects [Fig. 2 (c)]. Graphs of the logarithm of the current veysus the logarithm of the time were found to be curved near the beginning of the drop lifetime. The slope, measured over the last 2 s of the drop life- time, corresponding to the exponent x in the instantaneous current - time relationship i = At”, was found to decrease with increasing potential until it reached the theoretical value 0.19 for a diffusion-controlled process,* at the upper plateau of the wave (Table 11).The increase in the exponent towards the base of the wave is characteristic of irreversible processes.8 At potentials on the very lowest part of the wave maxima in the instantaneous current - time curves showed that inhibition effects still persisted, which increasing the concentration of Triton X-100 did not eliminate [Fig. 2 (41.336 WATSON : POLAROGRAPHIC STUDIES ON SOME Analyst, Vol. 103 Because of the greater simplicity of behaviour, increased general precision and the near elimination of inhibition effects in the presence of a surface-active agent, the remaining work described in this paper was carried out in the presence of O.Olyo of Triton X-100. TABLE I1 EXPONENT X I N THE INSTANTANEOUS CURRENT - TIME RELATIONSHIP i = kt' FOR FIVE SOLUTIONS OF DIPHENYLARSINIC ACID I N 0.1 M HYDROCHLORIC ACID AND O.Olyo TRITON X-100 ConcentrationlM Potential/V 0.000 1 0.0002 0.0005 0.0007 -0.825 0.49 0.53 0.51 0.46 - 0.850 0.45 0.46 0.47 0.47 -0.875 0.38 0.41 0.43 0.43 - 0.900 0.35 0.36 0.37 0.35 -0.925 0.33 0.34 0.35 0.34 - 0.950 0.32 0.29 0.31 0.31 - 0.975 0.29 0.24 0.29 0.25 - 1.000* 0.24 0.19 0.22 0.16 - 1.050* 0.23 0.22 0.21 0.22 - 1.100* 0.18 0.22 0.19 0.18 - 1.150* 0.21 0.20 0.26 0.23 1 0.001 0.52 0.44 0.39 0.38 0.33 0.30 0.26 0.24 0.22 0.21 0.20 * Upper plateau.Current - Potential Relationship and the Effect of pH Current - potential curves were recorded in a variety of buffers over the pH range 1-13 at intervals of 0.5 unit. From pH 1 the height of the wave remains constant until about pH 6 in the vicinity of the pK, value of diphenylarsinic acid, when the height falls away rapidly until, at higher pH values, diphenylarsinic acid as an anion is no longer electroactive.This behaviour contrasts with triphenylarsine oxide, which without any acidic protons is electroactive throughout the pH range, and with the more strongly acidic phenylarsonic acid, which is electroactive only below pH 3. At some values between pH 3 and 5 the wave due to diphenylarsinic acid may be partially obscured by the dissolution of the hydrogen ion. The wave moves to more negative potentials with increasing pH and below pH 6 the half-wave potential displays an almost linear relationship with pH without any breaks and with a slope suggesting an irreversible reduction. The reversibility of the electrode process was investigated by logarithmic analysis of the shape of the wave.Five functions of the current were plotted against the electrode potential on the rising part of the wave, corresponding to six possible current - potential relationships and six different types of process, for a series of eleven concentrations of diphenylarsinic acid in 0.1 M hydrochloric acid containing 0.01% of Triton X-100. The functions of current used were log [ (&--i)/i], corresponding to most irreversible and simple reversible reduc- t i o n ~ , ~ log(id-i) for reversible reduction to an insoluble product,lO log [ (id-i)'/i], corre- sponding to reversible reduction followed by reversible dimeri~ation,~ log [ (id-i)/i2] for the reversible reduction of a dimerg and, finally, log [ i d ( & ~ - i ) ~ / i ~ ] , corresponding to a reversible reduction followed by an irreversible dirneri~ation.~ In these functions, i d is the limiting diffusion current and i the current at each potential. The potential was chosen as the independent variable in linear regression analysis.As inhibition and adsorption processes were shown, by the instantaneous current - time curves, to remain unsuppressed at the base of the wave, and as these processes would alter the current - potential relationship, the logarithmic analysis was confined to the larger, upper part of the wave where the instantaneous current - time curves indicated simple diffusion control in the absence of inhibition effects.The current was recorded during the last 15% of the drop life time without damping. The reciprocal value of the slope of these plots, corresponding to the value 2.303RT/a%F in the current - potential relationship, is not in any instance a simple fraction of 0.059 V, indicating that the process is irreversible (Table 111).April, 1978 ORGANIC COMPOUNDS OF ARSENIC. PART IV TABLE I11 PREDICTED VALUE OF 2.303RTlanF (V) FROM REGRESSION COEFFICIENTS OF SEVERAL FUNCTIONS OF CURRENT verszIs POTENTIAL AT ELEVEN CONCENTRATIONS (0.05-1.0 mmol l-l) OF DIPHENYLARSINIC ACID IN 0.1 M HYDROCHLORIC ACID 337 Function of current r A > i d -2 Log(id -2) Log- i d -2 i d ( i d - 2) 22 Log- 2 . 303RT {Msean . . . . 0.089 0.118 0.074 0.052 0.039 anF . . . . 0.006 0.006 0.003 0.003 0.002 0.79 1.26 1.79 2.38 Mean correlation coefficient versus potential .. . . 0.99974 0.991 81 0.997 24 0.997 84 0.999 11 The correlation coefficients are consistently higher for the graphs of log [ (id-i)/i] versus potential, suggesting that this function of the current has the most linear relationship with potential. For each of these functions, and the corresponding current - potential relationships, there exist equivalent relationships between half-wave potential and the logarithm of the concentration of the depolari~er.~?~~ For processes in which log [ ( i d - i ) / i ] is linearly dependent on potential, the half-wave potential is independent of the concentration. For those in which log[(id-i)/i2] is linearly dependent on potential, the half-wave potential should shift to more negative potentials at a rate of 2.303RTlanF (V) for an increase in concentration of one decade, while for the remaining processes the shift is to more positive potentials at an equal rate. A correlation coefficient of 0.1905 for ten concentrations from 1 x 104 to 1 x M, well below the critical value, shows the half-wave potential to be independent of concentration, again indicating a linear dependence of log [ (id-i)/i)] on potential.Finally, the predicted value of 2.303RT/anF, calculated from the reciprocal of the slope of the graph for each function, can be compared with the value obtained by use of an independent method. To this end, the relationship between half-wave potential and pH was examined in greater detail in steps of 0.2 pH unit in the range pH 1-2.4 for several concentra- tions of diphenylarsinic acid in a mixture of hydrochloric acid and potassium chloride. Good linear relationships were found, of which the slope, dE+/d(pH) = -0.093 & 0.005 V, should equal the product of the number of protons involved in the reduction prior to the potential determining step and the value of 2.303RTlanF. This value was found to be an integral multiple only of the reciprocal of the slope, 0.089 O.O06V, of the graphs of bg[(id-i)/i] versus potential, confirming the h e a r dependence of this function on potential, and as the integral was unity (Table 111) one protonation in the reduction prior to the potential determining step was indicated.The value of 2.303RTlanF = 0.09 V corresponds to a value of an = 0.66, a value greater than the value (0.49) for phenylarsonic acid,l while the value for triphenylarsine oxide3 tends to a value of 2. The value of 0.65 and the linear dependence of log[(;d-i)/i] on potential indicate a typical irreversible process obeying the relationship However, the correlation coefficients alone do not offer sufficient proof.2.303RT ( i d - i ) 2.303RT ccnF log- -~ x PH 2 anF E = Ef,pH=O +------- As diphenylarsinic acid (I) is electroactive only a t pH values below the pKl value, and as no breaks occur in the half-wave potential versus pH graphs, only one electroactive form is indicated, that being the undissociated acid. One protonation occurs prior to the potential determining step and if, as is generally true with most irreversible processes, this step is the addition of the first electron, then it can be suggested that the potential is deter- mined by the following process :338 WATSON : POLAROGRAPHIC STUDIES ON SOME Anaiyst, Vol.103 I Reduction Mechanism A study of relationships involving potential yields information only about the initial potential-determining step. Elucidation of the total reduction mechanism requires direct determination of the total number of electrons per molecule consumed in the reduction. For diphenylarsinic acid this was carried out by use of microcoulometry, that is, by means of prolonged electrolysis on a small volume (1 m1) at the potential of the upper plateau of the wave. From the decrease in the concentration and the current passed the number of electrons per molecule was calculated for four concentrations of diphenylarsinic acid in 0.1 M hydrochloric acid and was found to be 2.95 & 0.16.The potential determining step proposed above yields the diphenyldihydroxyarsine radical, 11. Rapid addition of a second electron - proton pair will form the hydroxide monomeric form, 111, of diphenylarsine oxide. The literature2J1 suggests that this hydroxide form can be reduced at more positive potentials (about -0.1 V) while the microcoulometric result shows that it is not the final product. Under these conditions formation of the less easily reduced dimer is unlikely. Phenylarsonic acid1 and triphenylarsine oxide3 have both been shown to be reduced initially to the arsine. The highly reactive pftenylarsine was then found to combine with the intermediate product phenyl arsenoxide, by interaction and loss of the hydride and 1 Ill IV As--H +-April, 19'18 ORGANIC COMPOUNDS OF ARSENIC.PART IV 339 hydroxy groups, to yield the insoluble oligomer arsenobenzene, containing arsenic-arsenic bonds.1 With no hydride groups triphenylarsine cannot react in this fashion and remains the final product of the reduction of triphenylarsine oxide.3 Diphenylarsine, IV, with one hydride group, is more similar to phenylarsine and is very reactive. The equivalent reaction of diarylarsines with diarylarsine oxides has been reported12 for the preparation of tetra- aryldiarsines such as that illustrated (V). A reduction path analogous to that determined €or phenylarsonic acid could therefore be expected for diphenylarsinic acid.Such a reduction mechanism requires six electrons in order to reduce two molecules of diphenylarsinic acid, that is, three electrons per molecule. The experimentally obtained value of 2.95 & 0.16 electrons per molecule confirms that this is the reduction mechanism which occurs. Further support for this belief comes from the early work of Fichter and Elkind,13 who in 1916 prepared tetramethyldiarsine by the electroreduction of dimethylarsinic acid at a large mercury pool. Note that the final product depends on the solvent. Dessy et d.ll have shown that dimeric diphenylarsine oxide in anhydrous ethylene glycol dimethyl ether (glyme) is reduced to [(C,H,),As]- and [(C,H,),AsO]-. These species could not remain stable in aqueous acid and would protonate to yield the species combining in the final reaction shown above.Dessy et aZ.ll also showed that other diphenylarsenic(II1) species in anhydrous glyme are reduced to tetra- phenyldiarsine, V. This undergoes further reduction to [ (C,H,),As]- only at the most negative potentials (-2.8 V) by virtue of the solubility of the tetraphenyldiarsine and the stabilisation of the anion product in the anhydrous solvent. In aqueous conditions the insoluble tetra- phenyldiarsine must remain the final product. Analytical Applications Diphenylarsinic acid gives rise to a single, well defined, diffusion-controlled wave in 0.1 M hydrochloric acid containing O.Olyo of Triton X-100. The wave height is reproducible, proportional to concentration in the range 2 x 10-5-10-3 M and is independent of pH.These are suitable conditions for analytical use. In analyses of known solutions of diphenylarsinic acid by use of the standard additions technique with five additions of standard solution, errors of about 2y0 were obtained. Chloride, sulphate, nitrate, phosphate and acetate were found not to interfere. The polarographic analysis of diphenylarsinic acid in hydrochloric acid lends itself to the determination of irritants, such as diphenylcyanoarsine or diphenylchloroarsine. Hydro- lysis and oxidation to diphenylarsinic acid yields a single electroactive species with simple reproducible polarographic behaviour, while hydrolysis alone yields diphenylarsine oxide, the behaviour of which is complicated by its existing both as a monomeric hydroxide and as an oxide dimer.Direct polarographic determination of the cyanoarsine is also much less convenient as it requires strictly anhydrous solvents. In 0.1 M hydrochloric acid, the waves of diphenylarsinic acid and phenylarsonic acid are not resolved but give a combined wave height. By increasing the pH above 3 the phenyl- arsonic acid becomes electroinactive. The practical working range for diphenylarsinic acid above pH 3 is considerably narrowed by partial overlap with decomposition of the hydrogen ion and the need not to work too close to the pK value. By working at pH 5.3 in phosphate buffer containing 0.01 yo of Triton X-100 specific determination of diphenylarsinic acid is possible in up to a 100-fold excess of phenylarsonic acid.Accuracies of about 3% have been obtained by using the standard additions technique with five additions. The phenylarsonic acid content is obtained from the combined wave height in solution in 0.1 M hydrochloric acid. Similarly, in 0.1 M hydrochloric acid or at pH 5.3 resolution from the wave of triphenyl- arsine oxide is not possible. Thus, by choice of a suitable pH, specific determination of phenylarsonic acid, diphenylarsinic acid and triphenylarsine oxide in mixtures is possible. Inorganic arsenic( V) is electroinactive while the tetraphenylarsonium ion is reduced at much more negative potentials.14 Arsenic(II1) species are reduced at more positive potentials. Polarography is thus of value for the quantitative speciation of organoarsenic samples. At pH 2 7 only the latter species is active.340 WATSON 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. References Watson, A., and Svehla, G., Analyst, 1975, 100, 489. Watson, A., and Svehla, G., Analyst, 1975, 100, 573. Watson, A., and Svehla, G., Analyst, 1975, 100, 584. Freedman, L. D., and Doak, G. O., J . Am. Chem. Soc., 1951, 73, 5656. Malawyandi, M., MacDonald, S. A., and Barette, J. P., J . Agric. Fd Chem., 1969, 17, 51. “McGraw-Hill Encyclopedia of Science and Technology,” Volume 3, McGraw-Hill, New York and London, 1966, entry “Chemical Warfare,” p. 44. BrdiCka, R., Colln Czech. Chem. Commun., 1947, 12, 522. Zuman, P., “Elucidation of Organic Electrode Reactions,” Academic Press, New York and London, 1969, p. 16. Perrin, C. L., in Cohen, S. G., Streitwieser, A., and Taft, R. W., Editors, “Progress in Physical Organic Chemistry,” Volume 3, John Wiley, New York and London, 1965, pp. 177-184. Delahay, P., “New Instrumental Methods in Electrochemistry,” Interscience Publishers, New York, 1954, p. 57. Dessy, R. E., Chivers, T., and Kitching, W., J . Am. Chem. SOC., 1966, 88, 467. Blicke, F. F., and Webster, G. L., J . Am. Chem. SOL, 1937, 59, 537. Fichter, F., and Elkind, E., Berichte, 1916, 49, 239. Horner, L., Rottger, F., and Fuchs, H., Chem. Ber., 1963, 96, 3141. NOTE-References 1-3 are to Parts 1-111 of this series, respectively. Received Augwst 25th, 1977 Accepted October 12th, 1977