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Zwitterionic Mixed‐Carbene Coinage Metal Complexes: Synthesis, Structures, and Photophysical Studies
Author(s) -
Chotard Florian,
Romanov Alexander S.,
Hughes David L.,
Linnolahti Mikko,
Bochmann Manfred
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900573
Subject(s) - carbene , chemistry , phosphorescence , excited state , crystallography , photochemistry , malonate , cyclic voltammetry , intermolecular force , homo/lumo , ligand (biochemistry) , copper , acetonitrile , alkyl , molecule , fluorescence , organic chemistry , electrochemistry , biochemistry , physics , receptor , electrode , quantum mechanics , nuclear physics , catalysis
A series of three zwitterionic mixed‐ligand bis(carbene) complexes of copper ( 1 ), silver ( 2 ) and gold ( 3 ) have been synthesized, based on a combination of ethyl‐substituted cyclic (alkyl)(amino)carbene ( Et2 CAAC) and an anionic methyl‐malonate‐derived N‐heterocyclic carbene ( malo NHC). The crystal structures confirm the linear two‐coordinate geometry without close intermolecular contacts. The compounds show blue‐white phosphorescence consistent with a wide HOMO‐LUMO energy gap (2.87–3.07 eV) estimated by cyclic voltammetry. The excited state lifetimes of crystalline powders decrease in the series Cu > Ag > Au, from 400 µs for copper 1 to 50 µs for the gold complex 3 . DFT calculations indicate a large change in the transition dipole moment on excitation, of up to 16 D.