Insertion products from photolysis of Tp{prime}(CO){sub 3}WH and alkynes
Irradiation of Tp{prime}(CO){sub 3}WH in the presence of alkynes produces a diverse array of products, including {eta}{sup 2}-vinyl, {eta}{sup 2}-acyl, metallafuran, and carbyne complexes. A common mechanistic feature consistent with the observed distribution of products is cis insertion of alkynes into a photogenerated Tp{prime}(CO){sub 2}WH species. Initial cis 2,1-insertion of the alkynes leads to {eta}{sup 2}-vinyl and {eta}{sup 3}-allyl products, while cis 1,2-insertion ultimately produces {eta}{sup 2}-acyl, metallafuran, and carbyne products. An X-ray structure of a metallafuran product, Tp{prime}(CO){sub 2}W({eta}{sup 2}(C,O)-C(Bu{sup n})CHC({double_bond}O)CH{double_bond}CHBu{sup n}), shows trans stereochemistry for the double bond of the pendant 1-hexenyl group, which indicates that cis 1,2-insertion of the first equivalent of alkyne forms an intermediate {eta}{sup 1}-vinyl complex. Additional support for {eta}{sup 1}-vinyl intermediates is present in the {eta}{sup 2}-acyl product Tp{prime}(CO){sub 2}W({eta}{sup 2}(C,O)-C({double_bond}O)CH{double_bond}CHC(CH{sub 3}){sub 3}), which evinces a trans double bond as assayed via {sup 1}H NMR. Irradiation of Tp{prime}(CO){sub 3}WH in the presence of Me{sub 3}SiC{triple_bond}CCH{sub 3} produces two isomers of Tp{prime}(CO){sub 2}W({eta}{sup 3}-syn-CH{sub 2}CHCHSiMe{sub 3}) which differ in the orientation of the allyl fragment relative to the metal center. Heating of the allyl complex results in an unusual {eta}{sup 3}-allyl to carbyne rearrangement.
- Research Organization:
- Univ. of North Carolina, Chapel Hill, NC (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-96ER14608
- OSTI ID:
- 20075587
- Journal Information:
- Organometallics, Vol. 19, Issue 8; Other Information: PBD: 17 Apr 2000; ISSN 0276-7333
- Country of Publication:
- United States
- Language:
- English
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