Reactions of Cyclohexyl Isocyanide with η5-Substituted Cyclo-pentadienyl MoMo Triply Bonded Complexes. Crystal Structure of [Mo(CO)2(η5-C5H4CO2CH3)]2(μ-η2-CNC6H11)

Reactions of one or two equiv. of cyclohexyl isocyanide in THF at room temperature with MoMo triply bonded complexes [Mo(CO)2(η5‐C5H4R)]2 (R=COCH3, CO2CH3) gave the isocyanide coordinated MoMo singly bonded complexes with functionally substituted cyclopentadienyl ligands, [Mo(CO)2(η5‐C5H4R)]2(μ‐η2‐CNC6H11) (1a, R=COCH3; 1b, R=CO2CH3) and [Mo(CO)2(η5‐C5H4R)(CNC6H11)]2 (2a, R=COCH3; 2b, R=CO2CH3), respectively. Complexes 1a, 1b and 2a, 2b could be more conveniently prepared by thermal decarbonylation of MoMo singly bonded complexes [Mo(CO)3(η5‐C5H4R)]2 (R=COCH3, CO2CH3) in toluene at reflux, followed by treatment of the resulting MoMo triply bonded complexes [Mo(CO)2(η5‐C5H4R)]2 (R=COCH3, CO2CH3) in situ with cyclohexyl isocyanide. While 1a, 1b and 2a, 2b were characterized by elemental analysis and spectroscopy, 1b was further characterized by X‐ray crystallography. MoMo singly bonded isocyanide complexes, [Mo(CO)2(η5‐C5H4R)]2(μ‐η2‐CNC6H11) (1a, R=COCH3; 1b, R=CO2CH3) and [Mo(CO)2(η5‐C5H4R)(CNC6H11)]2 (2a, R=COCH3; 2b, RCO2CH3), have been prepared by reaction of MoMo triply bonded complexes [Mo(CO)2(η5‐C5H4R)]2 with cyclohexyl isocyanide or by thermal decarbonylation of MoMo singly bonded complexes [Mo(CO)3(η5‐C5H4R)]2 and subsequent treatment of the resulting MoMo triply bonded complexes with cyclohexyl isocyanide.