title: Stable N-heterocyclic carbene adducts of arylchlorosilylenes and their germanium homologues.
abstract: The first N-heterocyclic carbene adducts of arylchlorosilylenes are reported and compared with the homologous germanium compounds. The arylsilicon(II) chlorides SiArCl(Im-Me(4)) [Ar=C(6)H(3)-2,6-Mes(2) (Mes=C(6)H(2)-2,4,6-Me(3)), C(6)H(3)-2,6-Trip(2) (Trip=C(6)H(2)-2,4,6-iPr(3))] were obtained selectively on dehydrochlorination of the arylchlorosilanes SiArHCl(2) with 1,3,4,5-tetramethylimidazol-2-ylidene (Im-Me(4)). The analogous arylgermanium(II) chlorides GeArCl(Im-Me(4)) were prepared by metathetical exchange of GeCl(2)(Im-Me(4)) with LiC(6)H(3)-2,6-Mes(2) or addition of Im-Me(4) to GeCl(C(6)H(3)-2,6-Trip(2)). All compounds were fully characterized. Density functional calculations on ECl(C(6)H(3)-2,6-Trip(2))(Im-Me(4)), where E=Si, Ge, at different levels of theory show very good agreement between calculated and experimental bonding parameters, and NBO analyses reveal similar electronic structures of the two aryltetrel(II) chlorides. The low gas-phase Gibbs free energy of bond dissociation of SiCl(C(6)H(3)-2,6-Trip(2))(Im-Me(4)) (Delta(calcd) degrees=28.1 kJ mol(-1)) suggests that the carbene adducts SiArCl(Im-Me(4)) may be valuable transfer reagents of the arylsilicon(II) chlorides SiArCl.
authors.affiliation: Institut für Anorganische Chemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany. filippou@uni-bonn.de
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Filippou
authors.forename: Oleg
authors.initials: O
authors.lastname: Chernov
authors.forename: Burgert
authors.initials: B
authors.lastname: Blom
authors.forename: Kai W
authors.initials: KW
authors.lastname: Stumpf
authors.forename: Gregor
authors.initials: G
authors.lastname: Schnakenburg