Donor-acceptor adducts of a 1,3-disila-2-oxyallyl zwitterion.
In the presence of a Lewis acid or base, cyclotrisilene cSi3Tip4 (Tip = 2,4,6-triisopropylphenyl) reacts with CO to form stable adducts of a 1,3-disila-2-oxyallyl zwitterion. Coordination of an N-heterocyclic carbene (NHC) to one silicon center results in a localized Si=C bond, whereas B(C6F5)3 bonds to the carbonyl moiety leading to the delocalization of the positive charge over the oxyallyl moiety. Computational analysis of the electronic structure of the Lewis acid adduct reveals a considerable interaction between the two silicon atoms in 1,3-position and thus aromaticity akin to the homocyclopropenium cation.
Chair in General and Inorganic Chemistry, Saarland University, 66125 Saarbrücken (Germany), Fax: (+49) 681/302-71642; New address: School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ (UK).
Michael J
MJ
Cowley
Volker
V
Huch
David
D
Scheschkewitz
density functional calculations; donor-acceptor systems; silicon; small molecule activation; small ring systems