title: TAS+(Z)-Me3CNSN- and TAS+(E)-Me3SiNSN-: does the anion-cation interaction influence the configuration?
abstract: TAS+ salts (TAS = (Me2N)3S) of the sulfur diimide anions Me3XNSN- (X = C (1a), Si (1b)) were prepared by Si-N bond cleavage from the corresponding sulfur diimides Me3XNSNSiMe3 and TAS-fluoride ((Me2N)3S+Me3SiF2-) and characterized by X-ray crystallography and multinuclear NMR spectroscopy. According to the experimentally determined bond lengths and theoretical calculations, the Me3XNSN- anions are best described as thiazylamides Me3X-N-S identical to N rather than sulfur diimides Me3X-N=S=N. In agreement with the calculated and experimentally determined structures of the isoelectronic thionylimides RNSO, 1a adopts the Z-configuration, which is electronically favored due to anomeric effects. The electronically disfavored E-configuration of 1b in the solid state can be explained by weak anion-cation interaction.
authors.affiliation: Institute of Organic Chemistry, University of Bremen, Postfach 33 04 40, 28334 Bremen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Borrmann
authors.forename: A V
authors.initials: AV
authors.lastname: Zibarev
authors.forename: E
authors.initials: E
authors.lastname: Lork
authors.forename: G
authors.initials: G
authors.lastname: Knitter
authors.forename: S J
authors.initials: SJ
authors.lastname: Chen
authors.forename: P G
authors.initials: PG
authors.lastname: Watson
authors.forename: E
authors.initials: E
authors.lastname: Cutin
authors.forename: M M
authors.initials: MM
authors.lastname: Shakirov
authors.forename: W D
authors.initials: WD
authors.lastname: Stohrer
authors.forename: R
authors.initials: R
authors.lastname: Mews