Co-ordinatively unsaturated alkyne complexes of molybdenum and tungsten. Reactions of [MCl(CF3CCCF3)2(η-C5H5)](M = Mo or W) with heterocyclic thiolates leading to η2-vinyl complexes

Abstract

Reactions of Tl(SR)(SR^–= pyridine-2-thiolate, pyrimidine-2-thiolate, or thiazoline-2-thiolate) with the bis(hexafluorobut-2-yne) complex [MoCl(CF₃CCCF₃)₂(η-C₅H₅)] give products [[graphic omitted]}(CF₃C-CCF₃)(η-C₅H₅)] containing a novel η²-vinyl ligand resulting from nucleophilic attack of nitrogen on a co-ordinated alkyne. The same pyridine-2-thiolate complex is obtained from the reaction of [MoCl(CF₃CCCF₃)₂(η-C₅H₅)] with the thallium(I) salt of 2-mercaptopyridine N-oxide, in addition to [[graphic omitted]}(η-C₅H₅)]. The complex [WCl(CF₃CCCF₃)₂(η-C₅H₅)] reacts with thallium(I) pyridine-2-thiolate to give the η²-vinyl complex [[graphic omitted]}(CF₃CCCF₃)(η-C₅H₅)], whereas with Tl(SC₅H₄NO) cyclopentadienyl-ligand displacement is also observed giving the co-ordinatively unsaturated bis(hexafluorobut-2-yne) complexes [W(SC₅H₄NO)₂(CF₃CCCF₃)₂] and [W(SC₅H₄N)(SC₅H₄NO)(CF₃CCCF₃)₂]