ELECTRON-TRANSFER REACTIONS IN ORGANIC-CHEMISTRY .22. KINETICS AND PRODUCTS OF REACTIONS BETWEEN HEXACHLOROOSMATE(V) AND TETRAALKYLSTANNANES AND BENZYLTRIMETHYLSILANES

The reaction between tetraphenylphosphonium hexachloroosmate(V) and tetraalkylstannanes and benzyltrimethylsilanes has been studied in order to provide further evidence for its electron-transfer character. All reactions were first order in [R(4)M](M = metal) and [OsCl6-] and both kinetics and product studies indicated that the mechanism involves an initial, slow and reversible electron-transfer step, followed by very fast cleavage of the radical cation formed. The kinetic data are discussed in terms of the Marcus theory of outer-sphere electron transfer, and it is found that the OsCl6-/benzyltrimethylsilane reactions deviate somewhat from outer-sphere behavior.