Trimethyl(pentacarbonylmanganese)-silane, -germane, and -stannane: vibrational spectra and electron-impact studies

Abstract

The complexes Me₃MMn(CO)₅[M = Si, (I); M = Ge, (II); and M = Sn, (III)] have been examined using vibrational and mass spectroscopy. The i.r. and Raman spectra are consistent with C_4v symmetry at the Mn atom; Raman bands at 297 (I), 194 (II), and 178 cm^–1(III) are assigned to ν(M–Mn). Appearance potential measurements for ions Me₃M⁺ lead to bond dissociation energy values D(M–Mn) near 2·5 eV for all M; a decrease in metal–metal bond strength between (I) and (II) is indicated by approximate force-constants calculated from the ν(M–Mn) frequencies.