and C, and stopcock E was closed. Dried solvent was distilled into A which contained Linde Molecular Sieve 3A Vis-The solvent was then degassed by the freeze-thaw technique. After opening stopcock E, solvent was distilled into B, the stopcock was closed, and the apparatus was removed from the vacuum line at G. The capillary was then crushed by the magnet F, after which the solution was poured from B into C, and shaken well to dissolve the 1. The volume was measured and the cell was placed in the spectrophotometer for absorbance measurements at 546 nm. Kinetic measurements were made with both nitromethane and acetonitrile as solvent. Acetonitrile itself reacts very slowly with 1, whereas nitromethane solutions are stable indefinitely.

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E a I --~ 800 J 780 -760 E 6329 ----deep blue color in platinum complexes can arise for different r e a~o n s l *~'~ in different cases.Reactions of type 1 -3 also occur when substituents in the phenyl ring are changed. We are examining the general applicability of this type of hydroxylation reaction in other palladium complexes having pendant phenyl rings close to a reactive bond (e.g. PdC1). The reaction 2 -4 is only one example of a type of hydroxylation that also occurs in related molecules, e.g., where the ring substituent is C6H5 rather than CH,. This entire class of (presumably intramolecular) redox transformations in metal complexes of oximes is under active study. Acknowledgment.We are indebted to the Department of Science and Technology, New Delhi, India, and The Robert A. Welch Foundation (Grant A-494) for financial support. Supplementary Material Available:Tables of atomic parameters, bond lengths and angles, and observed and calculated structure factors for complex 3 (18 pages). Ordering information is given on any current masthead page. (18) Overbosch, P.; van Koten, G.; Grove, D. M.; Spek, A. L.; Duisenberg, (19) In our blue complex the color is undoubtedly due to charge-transfer (20) Note Added in Proof: The structure of 1 has now been accurately A.J.M. Inorg. Chem. 1982, 21, 3253. transitions involving both ligand and metal orbitals.determined.

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The elTect of variation of added anion type (I-, C1-, NOa-, CIO.I-, CE13COO-) on the kinetics of solvolysis of climethyl-t-butyl sulphonium ions is interpreted as evidence supporting a nucleophilic role for the anion in low-polarity solve~~ts. The specific case of acetate is discussed in terms of its relation to biochemical trans~llethylatiotl reactions involving methionine. ISTRODUCTIONIn the previous paper of this series (1) it was suggested that tlie anion plays an increasingly important role as a n~~cleophilic species in the solvolysis of s~~lphonium salts as the polarity of the solveilt mediuin is reduced. In tlie particular case of solvolysis of dimethyl-t-butyl sulphonium salts in ethanol-water mixtures, it has bee11 shown (1, 2 ) that in highly aqueous n~eclia the rate of solvolysis is independent of ailion character, in keeping \vitli the SN1-type mechanism involving the production and subsequent fast solvolysis of the t-but171 carboilium ion. As the solvent polaritj~ is decreased by increasing the ethanol content the observed rate of solvolysis becoilles increasingly dependent on anion type. The form of this dependence has beell analyzed in terms of a lriiletic expressioil involving the oilset of both ion pairing ancl a n~~cleophilic role of the anion (2) as solvent polarity climinishes. PI-evious experimental study of such solvolyses has been limited to a narro\v range of anions of relatively sinlilar nucleophilicities (e.g. the halides). In order to investigate further the possible n~~cleophilic role oi the salt anioils in solvolysis we report here a series of kinetic s t~~d i e s of the solvolysis of dimethyl-t-butj~l sulphonium salts in highly ethanolic solvent inedia with variation of anion over the series I-, C1-, KOa-, C10.,-, and CH;IC00-..?\I1 kinetic studies were carried out by the radiocheinical gas flow counting technique used in previous work (1, 2) ancl described by 1-1 yne and Wolfgang (3). Labelled (C1.'-methyl) dimethyl-t-butyl sulphonium iodide was prepared as described previously (3) and nletathesized with the corresponding silver salts. In a few cases this metathesis was not carried out so that the kinetic systenl contained ill iodide in addition to the anion concentration of the added salt. It was found that the effect of this iodide ion was very s~nall a t the high co~icentrations of added salt used and was within the experimental uncertainty of the kinetic data. .All \vorking solutions were ill sulphoni~im salt in 0.945 mole fraction ethanol-water mistures. Acldecl anions were I-, C1-, CI-I3COO-, SOX-, and C10-4in the form of their lithium salts. In a few selected runs potassium salts were used instcad of lithium to check the independence of rate on cation type. This \\;as foulid to be true in every case tested. All salts were vacu~lm-dried and assayed for water of crystallization. Since our primary interest in this work was in the dependence of ki,' (see equation [I.]) on anion nucleophilicity, rate investigations were limited to the linear portion of the kOb, vs. [S-] relations...