Übergangsmetall-carbin-komplexe : LXXXIII. Neue anionische mer-dihalogeno-tricarbonyl-dialkylamino-carbin-komplexe des wolframs

The reaction of trans-X(CO)₄WCNR₂ (X = Br, R = ^c hex (cyclohexyl); X = Cl, R = ^c hex, ⁱpr (isopropyl) with M⁺X⁻ (M⁺ = NEt₄⁺, X⁻ = Br⁻; M⁺ = PPN⁺, X⁻ = Cl⁻) leads under substitution of one CO ligand to new anionic dihalo(tricarbonyl)carbyne-tungsten complexes of the type M⁺ mer-(X)₂(CO)₃WCNR₂]⁻ (M⁺ = NEt₄⁺, X = Br, R = ^c hex; M⁺ = PPN⁺, X = Cl, R = ^c hex, ⁱ pr), whose composition and structure were determined by elemental analysis as well as by IR, ¹H and ¹³C NMR spectroscopy. In the anionic carbyne complexes the entered halogen ligand, coordinated in a cis position relative to the carbyne ligand on the metal, can be easily substituted by neutral nucleophiles, as the reaction of PPN⁺ mer-(Cl)₂(CO)₃WCN^chex₂]⁻ with PPh₃ demonstrates yielding the neutral carbyne complex mer-Cl(CO)₃(PPh₃)WCN^chex₂].