Disconnection of the organic moiety in chromium and tungsten complexes [(dithiin)M(CO)₅]

Abstract

The reaction of 5‐alkylthio‐3H‐1,2‐dithiole‐3‐thione derivatives with Fischer alkoxy carbenes gives 1,3‐dithiin dithioorthoesters derivatives complexed with M(CO)5 (M = Cr or W). We report here that the dithiin derivative free of metal can be obtained by ligand exchange using acetonitrile, methanol, phenyl methyl sulfide or (Ph)3P. Methanol gives the best results from a preparative point of view. The reaction with acetonitrile was shown to be reversible and the kinetic of ligand exchange and the activation parameters were determined. From these data it is concluded that the mechanism is predominantly dissociative for M = Cr and it has some contribution of the associative mechanism for M = W. Copyright © 2007 John Wiley & Sons, Ltd.