Normal coordinate analysis of M-Si2H5-moieties in transition metal complexes and comparison to Br-Si2H5

In order to examine the influence of the transition metal on the metal-disilanyl-fragment and especially the M-Si and Si-Si-bond polarized Raman spectra of the complexes (C5R5)(CO)2Fe-Si2H5 {R=H (1a); R=Me (1b)} and (C5R5)(CO)2(PMe3)M-Si2H5 {R=Me, M=Mo (2); R=H, M=W (3)} have been recorded. The spectral data have been evaluated and interpreted on the basis of a normal coordinate analysis of the M-SiH2-Si-fragment including Br-Si2H5 (4) and comparison with examinations of the M-SiH3-fragment.