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Updated: Apr 26, 2026

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
N-heterocyclic carbene coordinated neutral and cationic heavier cyclopropylidenes
Anukul Jana1, Isabell Omlor, Volker Huch
1Krupp-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).
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.
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