The mechanism of the formation of σ2P, σ4P-1,2-diphosphetes from phosphaacetylene and phosphinocarbene has been explored by quantum chemical methods. A stepwise mechanism has been established, and no transition state for a concerted pathway could be obtained. The electron distribution of the ring can be understood in terms of a MO model, where the two substituents at phosphorus act as a pseudo π center. Amino substituents on the σ4 phosphorus and silyl group on the neighbouring carbon change the stability order of the possible isomers, stabilizing the 1,2-diphosphete ring. Substitution at the σ2P-by increasing its valence-destabilizes the diphosphete ring, which remains stable only as a result of the amino and silyl substituents.
|Number of pages||4|
|Journal||Journal of the Chemical Society. Perkin Transactions 2|
|Publication status||Published - Nov 1 2000|
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