Synthesis of a Stable Methylidyne Complex

Abstract

The successive treatment of [W(CO)6] with LiSiPh3, (OCBr)2, and 4-picoline (pic) affords the silylcarbyne complex [W(≡CSiPh3)Br(CO)2(pic)2], which reacts with 1,2-bis(dicyclohexylphoshino)ethane (dcpe), 1,2-bis(diphenylphosphino)ethane (dppe), and tetramethylethylenediamine (tmeda) to provide the complexes [W(≡CSiPh3)Br(CO)2(L2)] (L2 = dcpe, dppe, tmeda). Fluoride-mediated protodesilylation of [W(≡CSiPh3)Br(CO)2(dcpe)] with moist [Bu4N]F provides the stable and structurally characterized terminal methylidyne complex [W(≡CH)Br(CO)2(dcpe)] (shown) in addition to traces of the ethene-1,2-diylidyne complex {Br(dcpe)(CO)2W}2(μ-≡CCH═CHC≡).