Silylenes are silicon analogues of carbenes and exist with neutral divalent silicon atoms. The first stable N-heterocyclic silylene (NHSi) was reported byWest et al., in 1994. Since then, many stable NHSis d,3 and other silylenes have been isolated. The reactivity pattern of NHSis is quite comparable with that of the N-heterocyclic carbenes (NHCs), where the latter led to many applications in c...

The singlet-triplet splittings of chlorine-substituted methylenes and silylenes have been studied by using the ab initio generalized valence bond (GVB) dissociation-consistent configuration interaction (DCCI) method. All chlorine-substituted methylenes and silylenes have singlet ground states, with calculated singlet-triplet splittings of 6.0, 20.5, 35.8, and 55.2 kcal/mol for CHCI, CCI2, SiHCI...

Disilenes Tbt(Mes)Si=SiTbt(Mes)(Mes:mesityl) bearing an efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl(Tbt), were synthesized and found to be extremely stable toward oxygen and water. In spite of the stability, they underwent thermal dissociation into silylenes under very mild conditions (ca. 50’ C). Silylenes thus formed reacted with alkenes, alkynes, benzene, n...

The effects of halogens; fluorine, chlorine and bromine, on the stability and multiplicity of phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at B3LYP/6-311++G**//B3LYP/6-31+G* level. The singlet-triplet energy gaps, ΔES-T , values for all the above speciesincrease through fluorinated up, ΔES-Ts and ΔEHOMO–LUMOs support the stability of the singlet statesinspite of...

the effects of halogens; fluorine, chlorine and bromine, on the stability and multiplicity of phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at b3lyp/6-311++g**//b3lyp/6-31+g* level. the singlet-triplet energy gaps, δes-t , values for all the above speciesincrease through fluorinated up, δes-ts and δehomo–lumos support the stability of the singlet statesinspite of...

Metal carbenes have for a long time been classified as Fischer or Schrock carbenes depending on the oxidation state of the metal. Since the introduction of N-heterocyclic carbene complexes this classification needs to be extended because of the very different electronic character of these ligands. The electronic structure of these different kinds of carbene complexes is analysed and compared to...