Synthesis of metallacarborane clusters derived from the monocarbon carborane 9-(CH3)2S-7-[((CH3)3Si) 2CH]CB10H11

Article abstract of DOI:10.1021/om00091a026

A single-crystal X-ray study of 9-Ph₃P-7-[((CH₃)₃Si)₂CH]CB ₁₀H₁₁ (I) has confirmed that the compound has a structure based on an 11-vertex nido cage geometry. Crystal data for I: space group P2₁/n; Z = 4; a = 17.154 (3) ?, b = 11.999 (2) ?, c = 17.469 (4) ?, β = 108.2 (1)°; V = 3414.2 ?³. The structure was refined to a final R = 0.061 and R_w = 0.073 for the 2916 reflections having F_o² > 3μ(F_o²). The dimethyl sulfide analogue of I, 9-(CH₃)₂S-7-[((CH₃)₃Si) ₂CH]CB₁₀H₁₁, has been shown to be a versatile ligand for transition metals. The reaction of 9-(CH₃)₂S-7-[((CH₃)₃Si) ₂CH]CB₁₀H₁₁ and (η-C₅H₅)Co(CO)₂ in refluxing toluene resulted in a complex mixture from which three metallacarborane products could be characterized. Compounds II and III were shown to be the isomeric sandwich complexes 7-(CH₃)₂S-2-(η-C₅H ₅)-1-[((CH₃)₃Si)₂CH]-2,1-CoCB ₁₀H₉ and 12-(CH₃)₂S-2-(η-C₅H ₅)-1-[((CH₃)₃Si)₂CH]-2,1-CoCB ₁₀H₉, respectively. Also isolated in trace amounts was the zwitterionic compound IV, 12-[(η-C₅H₅)Co(η-C₅H₄)] ⁺[2-(η-C₅H₅)-1-[((CH₃) ₃Si)₂CH]-2,1-CoCB₁₀H₉]^-. Reaction of [(η-C₅H₅)Ni(CO)]₂ and 9-(CH₃)₂S-7-[((CH₃)₃Si) ₂CH]CB₁₀H₁₁ gave 2-(η-C₅H₆)-1-[((CH₃)₃Si) ₂CH]-2,1-NiCB₁₀H₁₀ (V), while reaction of the carborane with cobalt vapor and toluene gave 2-(η⁶-C₆H₅CH₃)-1-[((CH ₃)₃Si)₂CH]-2,1-CoCB₁₀H₁₀ (VI). The sandwich structures of compounds of V and VI were confirmed by single-crystal X-ray crystallographic studies. Crystal data for V: space group P1; Z = 2; a = 8.856 (1) ?, b = 17.165 (5) ?, c = 8.647 (1) ?, α = 103.14 (1)°; β = 114.51 (1)°; γ = 85.63 (2)°; V = 1164.5 ?³. The structure was refined to a final R = 0.056 and R_w = 0.069 for the 3726 reflections having F_o² > 3σ(F_o²). Crystal data for VI: space group P1; Z = 2; a = 8.803 (2) ?, b = 18.007 (5) ?, c = 8.663 (2) ?, α = 101.09 (2)°, β = 114.16 (2)°, γ = 83.07 (2); V = 1228.1 ?³. The structure was refined to a final R = 0.087 and R_w = 0.096 for the 2355 reflections having F_o² > 3σ(F_o²).