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Synthesis, structure and reactivity of terphenyl-substituted germylium-ylidene cations

DOI: 10.1016/j.poly.2020.115006 DOI Help

Authors: Robert J. Mangan (University of Oxford) , Alexander R. Davies (University of Oxford) , Jamie Hicks (University of Oxford) , Christian P. Sindlinger (University of Oxford; Georg-August-Universität Göttingen) , Amber L. Thompson (University of Oxford) , Simon Aldridge (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Polyhedron

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 20876

Abstract: The first examples of isolable terphenyl-substituted germylium-ylidenes are reported. These systems, of composition [(NHC)(Ar)Ge]+, exploit a range of aryl and NHC substituents (ArMes, ArTrip; IMe4, IPrMe) and are isolated by employing weakly coordinating borate or aluminate counter-ions. The use of the smallest combination of substituents used in this study (IMe4 and ArMes) results in the formation of a dicationic dimer, [(IMe4)(ArMes)Ge=Ge(ArMes)(IMe4)]2+, which can also be viewed as an imidazolium-functionalized digermene. Increasing the steric loading (at either the NHC or terphenyl ligand) leads to the formation of the monomeric germylium-ylidene cations [(IMe4)(ArTrip)Ge]+, [(IPrMe)(ArMes)Ge]+, and [(IPrMe)(ArTrip)Ge]+, stabilized in the solid state to varying degrees by secondary interactions with the peripheral arene π systems or C–H bonds. These three systems are characterized by widening C–Ge–C angles (101.7(1), 105.0(2) and 107.2(1)°, respectively) as the steric profiles of the germanium-bound substituents increase. In the case of dication [(IMe4)(ArMes)Ge=Ge(ArMes)(IMe4)]2+, its ability to act as a functional source of the corresponding monomeric germylium-ylidene, [(IMe4)(ArMes)Ge]+, is demonstrated through its reaction with PhSiH3 in bromobenzene solution, which generates the monomeric GeIV species [(IMe4)(ArMes)Ge(H)(SiH2Ph)]+ via Si–H oxidative addition at germanium.

Journal Keywords: Germanium; cation; low valent; bond activation; N-heterocyclic carbene

Subject Areas: Chemistry

Instruments: I19-Small Molecule Single Crystal Diffraction

Added On: 05/01/2021 11:36

Discipline Tags:

Chemistry Inorganic Chemistry

Technical Tags:

Diffraction Single Crystal X-ray Diffraction (SXRD)