Journal article
Multiple metal-carbon bonds. 17. Preparation of monocyclopentadienyl benzylidene complexes of tantalum and the crystal structure of Ta(.eta.5-C5Me5)(CHPh)(CH2Ph)2
Journal of the American Chemical Society, Vol.102(22), pp.6744-6752
09/01/1980
DOI: 10.1021/ja00542a013
Abstract
A benzylidene complex, Ta(σ5-C5Me5)(CHPh)(CH2Ph)Cl, can be prepared by adding LiC5Me5 to Ta(CH2Ph)3Cl2. The analogous r;5-C5H5 complex apparently is unstable but a relative, Ta(σ5-C5H4Me)(CHPh)(CH2Ph)2, can be prepared by dehydrohalogenating Ta(σ5-C5H4Me)(CH2Ph)3Cl with Ph3P=CH2 while Ta(σ5-C5Me5) (CHPh) (CH2Ph)2 can be prepared from Ta(σ5-C5Me5)(CHPh)(CH2Ph)Cl and Mg(CH2Ph)2. Adding LiC5Me5 to Ta(CH2Ph)2Cl3 gives Ta(T-C5Me5)(CH2Ph)2Cl2 which can be forced to eliminate toluene by pyrolysis or photolysis to give Ta(σ5-C5Me5)(CHPh)Cl2 in low yield. An X-ray structural determination of Ta(σ5-C5Me5)(CHPh)(CH2Ph)2 shows a molecule of the expected “three-legged stool” type. The benzylidene ligand's large Ta-Cn-angle (166°) and short Ta=Cα bond (1.88Å) make it seem more like a benzylidyne ligand. We believe this circumstance is due primarily to the metal's need for more electron density (which it acquires from the C-Hα bond) and that any contribution to the large Ta=Cα-Cβ angle due to steric interaction between the benzylidene's phenyl ring and the σ5-C5Me5 ring is relatively small.
Details
- Title: Subtitle
- Multiple metal-carbon bonds. 17. Preparation of monocyclopentadienyl benzylidene complexes of tantalum and the crystal structure of Ta(.eta.5-C5Me5)(CHPh)(CH2Ph)2
- Creators
- L. W MesserleP JennischeR. R SchrockG Stucky
- Resource Type
- Journal article
- Publication Details
- Journal of the American Chemical Society, Vol.102(22), pp.6744-6752
- Publisher
- American Chemical Society
- DOI
- 10.1021/ja00542a013
- ISSN
- 0002-7863
- eISSN
- 1520-5126
- Language
- English
- Date published
- 09/01/1980
- Academic Unit
- Chemistry; Radiology
- Record Identifier
- 9984217454902771
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