1,1,1,3,3,3-Hexamethyltrisilanylene-bridged bis(cyclopentadienyl)tetracarbonyldiiron and its derivatives: Synthesis, properties and molecular structures

摘要

The title ring-bridged bis(cyclopentadienyl)diiron complexes [η5,η5-C5H4–Si(SiMe3)2–C5H4]Fe2(CO)L(μ-CO)2 [L = CO (1), P(OPh)3 (2), P(OMe)3 (3), PPh3 (4), PMe3 (5)] that contain exocyclic Si–Si bonds attached to the bridging silicon atom have been synthesized. The Si–Si bonds were found to be stable to the intramolecular iron centers under both thermal and photochemical conditions, in sharp contrast to the facile cleavage of the Si–Si bond in 1,1,2,2-tetramethyldisilanylene-bridged analogous complexes. The stability of the Si–Si bonds in the present cases may be attributed to the fact that these Si–Si bonds are spatially unapproachable by the intramolecular coordinatively unsaturated iron centers. Molecular structures of 1 and 2 have been determined by X-ray diffraction methods. An obvious conformational change due to substitution of CO for P(OPh)3 was observed.