319016-52-9Relevant articles and documents
Synthesis, characterization, and electrochemical properties of organotransition metal fullerene derivatives containing dppf ligands. Crystal structures of fac-Mo(CO)3(dppf)(CH3CN), W(CO)4(dppf), and mer-W(CO)3(dppf)(η2-C60)
Song,Liu,Hu,Wang,Zanello,Fontani
, p. 5342 - 5351 (2008/10/08)
Reaction of Mo(CO)3(CH3CN)3 with an equimolar amount of 1,1′-bis(diphenylphosphino)-ferrocene (dppf) in refluxing acetonitrile gives rise to fac-Mo(CO)3(dppf)(CH3CN) (1) in 51% yield. While 1 reacts with [60]fullerene in chlorobenzene at about 90°C to produce an isomeric mixture of fac/mer-Mo(CO)3(dppf)(η2-C60) (2) in 21% yield, the photolysis of Mo(CO)4(dppf) and [60]fullerene in chlorobenzene at ambient temperature affords 2 in 87% yield. Similarly, mer-W(CO)3(dppf)(η2-C60) (3), [mer-W(CO)3(dppf)]2(η2,η2-C60) (4), mer-W(CO)3(dppf) (η2-C70) (5), and [mer-W(CO)3 (dppf)]2(η2,η2-C70) (6) can be prepared by photolysis of W(CO)4(dppf) with [60]- or [70]fullerene in 87%, 13%, 51%, and 48% yields, respectively. While all the new compounds 1-6 have been characterized by elemental analyses and spectroscopic techniques, the structures of 1, W(CO)4(dppf), and 3 have been confirmed by single-crystal X-ray diffraction analyses. The cyclic voltammetric responses of 2 and 3 show that their sequential fullerene-centered reductions are shifted toward more negative potential values by about 0.2 V with respect to those of free C60. Such a negative shift is quite similar to that previously observed for the related complexes W(CO)3(dppb)(η2-C60) and Mo(CO)3(dppe)(η2-C60). Moreover, the fullerene-centered reductions of 5 are negatively shifted by about 0.1 V with respect to free C70, thus supporting that the η2-coordination of the W(CO)3(dppf) fragment to fullerenes causes a higher electronic interaction with C60 than with C70.
