title: Moving toward Ylide-Stabilized Carbenes.
abstract: The effect of ylide substitution at the α position to the carbene carbon (Cc ) atom on the stability and σ-donating ability of a number of cyclic carbenes has been studied theoretically. The stabilities of all of the carbenes were investigated from an evaluation of their singlet-triplet energy gaps and stabilization energies. All carbenes were found to have a stable singlet state. The energy of the σ-symmetric lone-pair orbital at the Cc atom increases as a result of the introduction of ylide centers near to the Cc atom. This indicates an enhanced σ-donating ability of the ylide-containing carbenes. The calculated carbonyl-stretching frequencies of the corresponding rhodium complexes, proton affinities, and nucleophilicity index values correlate well with the σ basicity of the carbenes.
authors.affiliation: Department of Chemical Sciences, Tezpur University, Napam-784 028, Assam (India).
authors.forename: Bitupon
authors.initials: B
authors.lastname: Borthakur
authors.affiliation: Department of Chemical Sciences, Tezpur University, Napam-784 028, Assam (India). ashwini@tezu.ernet.in.
authors.forename: Ashwini K
authors.initials: AK
authors.lastname: Phukan
keywords: boron; carbenes; electron donation; rhodium; ylides