SYNTHESIS AND CRYSTAL-STRUCTURE OF AN AMINO-BRIDGED BIS(SILYLENE)IRONCOMPLEX

Photolysis of a C6D6 solution of the (aminodisilanyl)iron complex Cp'F e(CO)2SiMe2SiMe2-Net2 (Cp' = eta-C5Me5) resulted in the formation of t he amino-bridged bis(silylene)iron complex 1. The Si-29 NMR spectrum o f 1 shows a signal at very low field (94.0 ppm). X-ray crystal structu re analysis of 1 (monoclinic, space group P2(1)/a, a = 28.031(8) angst rom, b = 19.541(6) angstrom, c = 8.089(3) angstrom, beta = 93.62(2)-de grees, V = 4422(3) angstrom3, Z = 8) revealed very short Fe-Si bonds ( 2.22-2.23 angstrom), fairly long Si-N bonds (1.93-1.96 angstrom), and almost planar geometry at each silicon atom with respect to it and the attached C and Fe atoms, excluding the bridging nitrogen. These struc tural and spectroscopic data for 1 strongly indicate that the Fe-Si bo nds take on partial double-bond character (bis(silylene) structure), w hile the Si-N bonds can be described as a hybrid of a covalent and wea k dative bond.