Reactivity of ruthenium and niobium trihydrides with gold fragments. Crystal structure of the hexanuclear raft cluster [Au3Nb3(µ-H)6(η-C5H4SiMe3)6]

Abstract

The reactions of [MH₃(L)L′][M = Ru, L =η-C₅Me₅, L′= P(C₆H₁₁)₃1; M = Nb, L = L′=η-C₅H₄SiMe₃2; M = Nb, L = L′=η-C₅H₃(SiMe₃)₂-1,3 3] with [Au(PPh₃)]PF₆ produce the trinuclear clusters [L(L′)M(µ-H)₂{Au(PPh₃)}₂]PF₆[L =η-C₅Me₅, L′= P(C₆H₁₁)₃, M = Ru 4; L = L′=η-C₅H₄SiMe₃, M = Nb 5; L = L′=η-C₅H₃(SiMe₃)₂, M = Nb 6]. Complex 1 also reacts with one or two equivalents of [Au{N(SiMe₃)₂}(PPh₃)] to yield respectively the neutral derivatives [(η-C₅Me₅){(C₆H₁₁)₃P}Ru(µ-H)₂Au(PPh₃)]7 and [(η-C₅Me₅){C₆H₁₁)₃P}Ru(µ-H){Au(PPh₃)}₂]8. The same reaction with [NbH₃(η-C₅H₄SiMe₃)₂] yields the novel hexanuclear raft cluster [Au₃Nb₃(µ-H)₆(η-C₅H₄SiMe₃)₆]9. Spectroscopic (IR and NMR) data are provided for all the compounds. Crystals of 9 are triclinic, space group P, with a= 14.927(2), b= 15.083(2), c= 15.632(2)Å, α= 103.81(1), β= 99.20(1), γ= 112.55(1)°, and Z= 2. The molecule consists of a central almost equilateral triangle of gold atoms, with each Au–Au bond bridged by a niobium atom which completes its co-ordination sphere with two η-C₅H₄SiMe₃ groups. Additionally, each Au–Nb is bridged by one hydride ligand. The most interesting feature of this molecule is the planarity of the six metal atoms.