Experimental and Computational Studies of the Metal-Metal Stretching Vibration in X3MMX3 Compounds (X = Alkoxid
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- 作者：Thomas M. Gilbert ; John C. Littrell ; Chad E. Talley ; Michael A. Vance ; Richard F. Dallinger ; and Robin D. Rogers
- 刊名：Inorganic Chemistry
- 出版年：2004
- 出版时间：March 8, 2004
- 年：2004
- 卷：43
- 期：5
- 页码：1762 - 1769
- 全文大小：125K
- 年卷期：v.43,no.5(March 8, 2004)
- ISSN：1520-510X
文摘
Raman spectra of a number of triply bonded M2X6 (M = Mo, W; X = alkoxide, alkyl) compounds have beenobtained. Several exhibit a band assignable to the metal-metal stretching vibration 
M
M. This band was notidentified in earlier studies of the M2(NMe2)6 compounds. We have attempted to correlate the Raman vibrationaldata with structural data from single-crystal X-ray diffraction studies. Diffraction studies of the M2(O-1-4-pentyl[2.2.2]bicyclooctyl)6 species show a crowded environment around the dimetal core, but the M-M-O angles differsubstantially from 90
. Thus, this angle does not solely determine the extent to which the metal-metal and ligand-based vibrational modes couple and, in turn, our ability to observe MM. Computational studies of model systemsconfirm the assignment of the band as being MM, although the predicted vibrational energies are consistently toohigh by ca. 7%. The computational results suggest that a MM band may be present in the published spectra ofthe M2(NMe2)6 pair.
MM. This band was notidentified in earlier studies of the M2(NMe2)6 compounds. We have attempted to correlate the Raman vibrationaldata with structural data from single-crystal X-ray diffraction studies. Diffraction studies of the M2(O-1-4-pentyl[2.2.2]bicyclooctyl)6 species show a crowded environment around the dimetal core, but the M-M-O angles differsubstantially from 90. Thus, this angle does not solely determine the extent to which the metal-metal and ligand-based vibrational modes couple and, in turn, our ability to observe MM. Computational studies of model systemsconfirm the assignment of the band as being MM, although the predicted vibrational energies are consistently toohigh by ca. 7%. The computational results suggest that a MM band may be present in the published spectra ofthe M2(NMe2)6 pair.