Organometallic tantalum complexes with phosphine, phosphanido and phosphinidene ligands. Syntheses and crystal structures of [Cp′TaCl4{PH2(2,4,6-Pri3C 6H2)}], [Cp′Ta(μ-PPh2)(PPh2)]2·C 7H8

Article abstract of DOI:10.1016/0277-5387(96)00269-0

The reaction of [Cp′TaCl₄] (Cp′ = C₅H₄Me) with KPPh₂(dioxane)₂ (1 : 1) in diethyl ether at room temperature gave the phosphanido-bridged tantalum(III) complex [Cp′Ta(μ-PPh₂)(PPh₂)]₂ (1)·C₇H₈ as black crystals. [Cp′TaCl₄] reacted with 2,4,6-triisopropylphenylphosphine with formation of the adduct [Cp′TaCl₄{(PH₂(2,4,6-Prⁱ ₃C₆H₂)}] (2). Attempts to eliminate HCl from 2 with DBU (DBU = 1,8-diazabicyclo-[5,4,0]-undec-7-ene) gave the phosphinidene-bridged tantalum(IV) complex [Cp′TaCl{μ-P(2,4,6-Prⁱ₃C₆H ₂)}]₂ (3)·C₇H₈. It was shown independently that DBU acts as a base and as a reducing agent. 1-3 were characterized spectroscopically (IR, MS, NMR) as well as by crystal structure determinations. Copyright