Mono-η-cyclopentadienylniobium chemistry: ternary phosphine, carbonyl, 3,4-dimethylhexa-2,4-diene, halogeno-, and hydrido-derivatives

Abstract

The new compounds [Nb(η-C₅H₅)(dmpe)(CO)₂], [Nb(η-C₅H₅)(dmpe)(CO)X₂], X = Cl, Br, or I, [Nb(η-C₅H₅)(dmpe)₂], [Nb(η-C₅H₅)(dmpe)(CO)₂H][PF₆], [{Nb(η-C₅H₅)(dmpe)H (µ-H)}₂], [Nb(η-C₅H₅)(dmpe)H(µ-H₂BH₂)], and [Nb(η-C₅H₅)(dmpe) Cl][PF₆][dmpe = 1,2-bis(dimethylphosphino)ethane] are described. Sodium amalgam reduction of [Nb(η-C₅H₅)(dmpe)(CO)Cl₂] in the presence of but-2-yne followed by addition of hydrogen chloride gives [Nb(η-C₅H₅)(C₄H₂Me₄)] and a further reduction gives [{Nb(η-C₅H₅)(η-C₄H₂Me₄)(µ-Cl)}₂]. The compound [Ta(η-C₅H₅)(dmpe)(CO)₂] is also described.