THE FIRST OXYGEN-BRIDGED DIORGANOARSENIC(V) COMPOUND - THE CRYSTAL-STRUCTURE OF ASME2(S)OAS(S)ME-2

The oxidation of tetramethyldiarsinedisulfide, (AsMe2S)(2), with t-BuO OH under anhydrous conditions leads to both AsMe2(S)-S-As(O)Me-2 1 and AsMe2(S)-O-As(S)Me-2 2. The formation of the oxygen-bridged isomer 2 is unexpected and can he rationalised as resulting from either oxidati on of the As(III)/As(III) form of the disulfide, (AsMe2-S-S-AsMe2), or by an oxotropic rearrangement of 1 via a cyclic As2OS transition stat e. RHF/3-21G ab initio calculations predict that the ore-bridged spec ies 2 is more stable than the thio-bridged form 1. The molecular struc ture of 2 has been determined by single crystal X-ray diffraction. (C) 1997 Elsevier Science S.A.