Reactivity of electron-rich binuclear hydrides. Synthesis, structure, and reactions of [{(i-Pr)2PCH2CH2P(i-Pr)2}Rh]2(μ-H)(μ-OC6H5)

Abstract

The reaction of phenol with the binuclear rhodium hydride [{(i-Pr)2PCH2CH2P(i-Pr)2}Rh]2((μ-H)2 generates [{(i-Pr)2PCH2-CH2P(i-Pr)2}Rh]2(μ-H)(μ-OC6H5), 2, which was characterized by both solution spectroscopic techniques and a single crystal X-ray diffraction study. The structure was solved using Patterson and Fourier methods and refined to R = 0.019 (Rw = 0.027) for 6062 reflections; crystals of the compound are triclinic, space group P1¯, with a = 9.018(2), b = 12.988(2), c = 17.558(3) å, α = 99.42(1), β = 92.62(2), γ = 91.85(2)°, and Z = 2. Further reaction with excess phenol leads to the mononuclear complex (η5-C6H5O)Rh{(i-Pr)2PCH2CH2P(i-Pr)2}-2C6H5OH, which contains two phenol units hydrogen bonded to the oxygen of the T|5-cyclohexy]dienylone ligand. The presence of the bridging phenoxide ligand in 2 results in reduced reactivity as compared to the starting binuclear hydride dimer.