Synthesis of molybdenum-triosmium cluster complexes: Reaction of (μ-H) 2Os 3(CO) 10 with (η-C 5H 5)(CO) 2MOCC 6H 4Me

Abstract

The reaction of Cp(CO) 2MoCTol (Cp = η 5-C 5H 5, Tol = p-C 6H 4Me) and (μ-H) 2Os 3(CO) 10 under mild conditions (5–20°C) produces three molybdenum-triosmium mixed-metal cluster compounds, CpMoOs 3(CO) 11[μ 3-η 2C(O)CH 2Tol] ( 4, 65%) as a major product together with two minor products CpMoOs 3(CO) 10(μ 3-CTol) 2(μ-H) ( 5, 10%) and CpMoOs 3(CO) 10)(μ 3-(η 2-C 2Tol 2))(μ-H) ( 6, 6%). Compounds 4, 5 and 6 have been isolated as crystalline solids and characterized by spectroscopic methods. Fluxionality of compound 4 has been examined by variable temperature 13C NMR spectroscopy. Compound 5 in solution undergoes a degenerate metal framework rearrangement. 1H NMR analysis of the tolyl methyl resonances of 5 for the rearrangement process gives Δ G c ≠ = 15.2 ± 0.2 kcal/mol at the temperature of coalescence.