Formation of metal-element double bonds by chlorosilane elimination

Abstract

Transition metal complexes, capable of chlorosilane elimination to give metal—element double bonds, are generated as transient species by two novel methods. The first one involves reaction of anionic silyl complexes with geminal dihalides and is exemplified by reactions of [MeCp(CO)2Mn-SiR3]− with dihalides of carbon and main-group V elements. Formation of carbene complexes and phosphinidene-bridged complexes, [MeCp(CO)2Mn]2PR, proves that the anionic silyl complex can be used as an equivalent for [MeCp(CO)2Mn]2− in the synthesis. The second method proceeds by oxidative addition of the CCl bond of (α-chlorovinyl)silanes to electronically unsaturated transition-metal complex moieties to give vinylidene complexes, e.g. (η6-C6R′6)(CO)2CrCCR2 or MeCp(CO)(L)MnCCR2. With an excess of(α-chlorovinyl)silane, butatriene complexes are formed instead.