Preparation of Carbyne Complexes

Fischer first prepared carbyne complexes by the action of boron halides on carbene compounds of chromium, molybdenum, and tungsten. 

Elimination of alkoxy group may be also affected by using aluminum and gallium halides. In the case of elimination of halides from halocarbene complexes, silver salts may be used. 

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In fact, the first isolation ofthe vinylidene pentacarbonyltungsten complexes was reported by Mayr et al. in 1984 [6]. The vinylidene complexes 16 were obtained by the alkylation of anionic pentacarbonyltungsten t-butylacetylide complex 15, obtained by the reaction of [Et4N ] [W(CO)5Cl ] with lithium acetylide, with FS03Me or [Et30 ] [Bp4 ]. Further protonation with CF3SO3H in the presence of Me4N P afforded a unique method for the preparation of carbyne complexes 17 (Scheme 5.4). 

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