@huebleriac

Dinuclear bis(phosphine)copper(I) complexes with 2,2'-bipyrimidine as bridging ligand: Structural analogy to \dqblue\dq copper centers and reduction to paramagnetic species

, , and . Zeitschrift fuer Naturforschung, B: A Journal of Chemical Sciences, 48 (11): 1470--1480 (1993)
DOI: 10.1515/znb-1993-1104

Abstract

(PR3)2Cu(m:h4-bpym)Cu(PR3)2(BF4)2 with the bis-chelating bridging ligand 2,2'-bipyrimidine (bpym) and various monodentate and bidentate phosphines were synthesized via a 4-component self-assembly reaction. The reversible electrochem. redn. to monocationic radical complexes was studied by cyclic voltammetry and ESR. Highly resolved ESR spectra revealed the bpym anion radical ligand via resolved hyperfine coupling with 1H, 14N, 31P, 63Cu, and 65Cu. The variation of phosphine ligands was accompanied by significant changes of electrochem. potentials which were rationalized considering electronic and structural effects. The configurational flexibility of Cu(I) in this environment is evident from the x-ray crystal structure anal. of (PPh3)2Cu(m:h4-bpym)Cu(PPh3)2(BF4)2.H2O.MeOH for which the coordination at the metal can be described as 3 + 1 (NNP + P'), qual. similar to the (NN'S + S') arrangement around the type 1 Cu centers of blue Cu proteins. Intramol. cooperative p donor/p acceptor/p donor sandwich interactions provide parts of the driving force for this highly distorted coordination geometry which illustrates the proclivity of Cu(I) towards such an entatic state arrangement. on SciFinder(R)

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