Synthesis and characterization of Group 6 transition-metal [70]fullerene derivatives containing dppb ligands.: Crystal structure of fac-Mo(CO)3(dppb)(CH3CN)

The thermal reaction of an equimolar quantity of fac-Mo(CO)3(dppb)(CH3CN) [dppb=1,2-bis(diphenylphosphino)benzene] (1) with C70 in chlorobenzene at 80–85 °C gave an isomeric mixture of fac/mer-Mo(CO)3(dppb)(η2-C70) (2) in 46% yield, whereas the photochemical reaction of an equimolar amount of Mo(CO)6, dppb and C70 in chlorobenzene at room temperature afforded the isomeric mixture 2 in 48% yield and a single isomer mer-[Mo(CO)3 (dppb)]2(η2,η2-C70) (3) in 19% yield. Similarly, while the thermal reaction of fac-W(CO)3 (dppb)(CH3CN) (4) with C70 produced a single isomer mer-W(CO)3(dppb) (η2-C70) (5) in 42% yield, the photochemical ‘one pot’ reaction of Cr(CO)6, dppb and C70 gave rise to a single isomer mer-Cr(CO)3(dppb)(η2-C70) (6) in 62% yield and a single isomer [mer-Cr(CO)3(dppb)]2(η2,η2-C70) (7) in 25% yield, respectively. All the new [70]fullerene mono- and dinuclear organometallic derivatives 2, 3 and 5–7 have been characterized by elemental analysis, and IR, 1H-, 31P-, 13C-NMR (partly), UV–vis and FAB-MS spectroscopic methods, as well as the crystal structure of one of their starting materials fac-Mo(CO)3(dppb)(CH3CN) (1) has been determined by X-ray diffraction analysis.