Organometallic derivatives of the transition metals : VIII. Bonding and molecular motions in silyl transition metal complexes studied by 29Si NMR

Abstract

Complexes of the general type [(η 5-C 5H 5)Fe(L) 2R], L  CO, PR′ 3; R  silyl, polysilyl, and silylmethyl, have been studied using 29Si NMR. Chemical shift and nuclear Overhauser effect data have been obtained and related to the chemical bonding and molecular motion of the complexes. For the various dicarbonyl complexes sigma inductive effects by the iron substituent are noted, while upon phosphine substitution pi effects are observed with directly bonded silicon atoms present. From NOE η values segmental motion of the various chains may be noted, with the Fe iron atom effectively anchoring one end of the system.