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Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex
Author(s) -
Dahl Eric W.,
Szymczak Nathaniel K.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201511527
Subject(s) - copper , chemistry , coordination geometry , crystallography , isostructural , coordination sphere , hydrogen bond , ligand (biochemistry) , halide , coordination complex , geometry , square pyramidal molecular geometry , inorganic chemistry , metal , crystal structure , molecule , organic chemistry , biochemistry , receptor , mathematics
6,6′′‐Bis(2,4,6‐trimethylanilido)terpyridine (H 2 Tpy NMes ) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H 2 Tpy NMes )copper(I)‐halide (Cl, Br and I) complexes is dictated by the strength of the NH–halide hydrogen bond. The Cu I Cl and Cu II Cl complexes are nearly isostructural, the former presenting a highly unusual square‐planar geometry about Cu I . The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid Cu I /Cu II electron‐transfer self‐exchange rates. Cu(H 2 Tpy NMes )Cl shows similar fast electron transfer (≈10 5 m −1 s −1 ) which is the same order of magnitude as biological systems.