Reactions of (SiMe_2)(SiRR') doubly-bridged biscyclopentadienes (RR0 = MePh, Ph_2) with iron and molybdenum carbonyls

摘要

In the reaction of the doubly-bridged biscyclopentadiene (C_5H_4(SiMe_2))(C_5H_4(SiMePh)) (1b) with Fe(CO)_5, migration of the bridging SiMe_2 or SiMePh group from the ligand to an iron atom gives the corresponding compound (SiMePh)(η~5-C_5H_3)(η~5:η~1-C_5H_3)[(SiMe_2)Fe(CO)_2][Fe(CO)_2] (4) or (SiMe_2)(η~5-C_5H_3)(η~5:η~1-C_5- H_3)[(SiMePh)Fe(CO)_2][Fe(CO)_2] (5), containing one Fe-Si bond. The reaction also affords the product [(η~5-C_5H_4)2(SiMePh)]Fe_2(CO)_2(l-CO)2 (6), in which the SiMe_2 group is totally cleaved, and the corresponding doubly-bridged Fe-Fe bonded products [(η~5-C_5H_3(SiMe_2))(η~5-C_5H_3(SiMePh))]Fe_2(CO)_4 (2 and 3) as a pair of isomers. A similar reaction of 1b with Mo(CO)_6 only results in the SiMe_2 cleaved product [(η~5-C_5H_4)_2(SiMePh)]Mo_2(CO)_6 (9), as well as the normal doubly-bridged Mo-Mo bonded complexes [(η~5- C_5H_3(SiMe_2))(η~5-C_5H_3(SiMePh))]Mo_2(CO)_6 (7 and 8) as a pair of isomers. Reaction of the doubly-bridged biscyclopentadiene (C_5H_4(SiMe_2))(C_5H_4(SiPh_2)) (1c) with Fe(CO)_5 or Mo(CO)6, similarly, yields the corresponding SiMe_2 removed product (11 or 13) and the doubly-bridged dinuclear complex (10 or 12). The molecular structures of complexes 2, 4, 5 and 7 were determined by X-ray diffraction