Autocatalytic degradation of white phosphorus with silylenes.
White phosphorus (P(4)) is prone to undergo degradation by nucleophiles and is reluctant to do so with electrophiles. Silylenes possess a strong singlet character but at the same time bear a largely inert lone pair orbital at the silicon atom. Thus they predominantly react in a similar way to electrophilic carbenes. Due to the poor pi-character of the P-P bonds in white phosphorus, the overlap with the empty orbital for the electrophilic silylene is less facile and results in a relatively large barrier for the addition reaction. The electrophilic approach of the silylene to white phosphorus is catalyzed by addition of a second P(4), forming a trigonal bipyramidal transition state geometry. Its stability towards fragmentation is essentially lower than that of the silyl cation. The entropy contributions for bimolecular versus termolecular reactions are discussed.
Schoeller
Wolfgang W
WW
Department of Chemistry, University of California, Riverside, CA 92521-0403, USA. wolfgang.schoeller@ucr.edu
D001331:Automation; D002384:Catalysis; D005030:Ethylenes / Q000737:chemistry*; D015394:Molecular Structure; D010758:Phosphorus / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013816:Thermodynamics
D005030:Ethylenes; D012821:Silanes; D010758:Phosphorus