title: N-heterocyclic carbene coordinated neutral and cationic heavier cyclopropylidenes.
abstract: Cyclopropylidene is a transient intermediate of the allene-propyne-cyclopropene isomerization. The incorporation of heavier Group 14 elements into the cyclopropylidene scaffold has to date been restricted to the formal replacement of the carbenic carbon atom by a base-coordinated silicon(II) center. Herein we report the synthesis and characterization of NHC-coordinated heavier cyclopropylidenes (Si2GeR3X, and Si3R3Br; X=Cl, Mes; R=Tip=2,4,6-iPr3C6H2) in which the three-membered ring is exclusively formed by silicon and germanium. In case of the chloro-substituted Si2Ge-cyclopropylidene, a stable heavier cycloprop-1-yl-2-ylidene cation is obtained by NHC-induced chloride dissociation.
authors: Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66125 Saarbrücken (Germany) http://www.uni-saarland.de/fak8/scheschkewitz/index.html; Current address: Tata Institute of Fundamental Research, Centre for Interdisciplinary Sciences, 21, Brundavan Colony, Narsingi, Hyderabad-500075 (India).
authors: Anukul
authors: A
authors: Jana
authors: Isabell
authors: I
authors: Omlor
authors: Volker
authors: V
authors: Huch
authors: Henry S
authors: HS
authors: Rzepa
authors: David
authors: D
authors: Scheschkewitz
keywords: cations; germanium; silicon; small rings; subvalent compounds