Synthesis and spectroscopic studies of organometallic Mn(I) complexes containing the novel mixed donor ligands 2-{MeSeCH(2-n)(SiMe3)(n)}C5H4N (n=0-2)

摘要

Treatment of MnBr(CO)(5) with one equivalent of the bidentate ligand, 2-{RECH(2-n)(SiMe3)(n)}C5H4N (E = S, R = Me, Ph, n = 0; E = Se, R = Me, n = 0, 1, 2) affords the complexes [MnBr(CO)(3)L] as orange powders. The effect of stepwise substitution at the alpha-carbon of the ligand by a trimethylsilyl group was investigated using Se-77(H-1)- and Mn-55-NMR, and IR spectroscopies. In the case of the pyridyl-selenoether-containing complexes, each additional Me3Si - group increases the sigma-donating properties of the ligand, in turn reflected in increased Mn-->CO backbonding. The solid-state structure of the parent [MnBr(CO)(3){2-(PhSCH2)C5H4N}] showed the molecule to have distorted fac-octahedral geometry. All other compounds were assigned the same stereochemistry based on CdropO stretching frequency comparisons. (C) 2003 Elsevier Science B.V. All rights reserved. [References: 20]