{pi}-donor spectrochemical series for X in (Me{sub 5}C{sub 5}){sub 2}TiX, and {beta}-agostic interactions in X=Et and N(Me)Ph
Journal Article
·
· Journal of the American Chemical Society
- Lawrence Berkeley Lab., CA (United States)
The EPR and electronic spectra of d{sup 1}-bent metallocene compounds of the type Cp{sup *}{sub 2}TiX, where X is halide, alkoxide, amide, alkyl, or hydride and Cp{sup *} = Me{sub 5}C{sub 5}, have been studied. Several of these compounds are new, and those with X = N(Me)H and F were characterized by X-ray crystallography. The crystal structure of Cp{sup *}{sub 2}TiN(Me)H showed that the N(Me)H ligand lies on the plane defined by Cp{sup *}(centroid)-Ti-Cp{sup *}(centroid). This is the sterically most unfavorable conformation but allows maximum Ti-N {pi}-bonding. The anisotropic frozen solution EPR spectra were analyzed by the method used by Petersen and Dahl for the d{sup 1} metallocenes, Cp{sub 2}VX{sub 2}, which gives g{sub x}, g{sub y}, and g{sub z}. Although the values of g{sub x} and g{sub z} are relatively constant throughout the series, the value of g{sub y} varies with the {pi}-donor ability of X. The {beta}-agostic interaction in Cp{sup *}{sub 2}TiEt and in Cp{sup *}{sub 2}TiN(Me)Ph was investigated by variable-temperature EPR spectroscopy giving an enthalpy and entropy for the agostic interaction. For Cp{sup *}{sub 2}TiEt the parameters for the agostic interaction are given. 45 refs., 11 figs., 6 tabs.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 232445
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 7 Vol. 118; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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