Synthesis and Characterization of Bridged Bimetallic Complexes. I. Copper(II) Complexes with Conjugated Diimine Ligands

Abstract

A series of binucleating Uganda with fully conjugated π‐systems have been synthesized. Homobinuclear copper(II) complexes of the form [(Cu(dien)ClO4)2L]‐(ClO4)2, where dien is diethylenetriamine and L is binucleating ligand, were prepared. Mononuclear complexes, with structure similar to that of the preceeding compounds, [Cu(dien)L′(ClO4)](ClO4) were synthesized as reference compounds. The infrared spectra, elctronic spectra and magnetic properties were studied. The inductive effect, steric effect and the effect of the length of the conjugated π‐system on the magnetic exchange interaction between the two copper ions are discussed. The electrochemical properties of these complexes were investigated by cyclic voltammetry. The copper ions showed the cooperative phenomena and a quasi‐reversible sequential transfer of two electrons at the same potential.

Binuclear Complexes. II. Electron Paramagnetic Resonance Study of Binuclear Copper Complexes with α‐Diimine Ligand

“…The ligands, pyridyl ketimine, were prepared by the method of J.S. Walia et al 8 The solution EPR spectra of (1), (3), (5), (7) are shown in Fig. 2.…”

“…Again, the appearance of spectra of (2), (4), (6) and (8) are identical with (I), (3), (5), and (7), respectively,so that they are not shown. The spectra of (1), (5) and (7) can be analyzed with a set of g values and hyper fine coupling constants with cylindrical symmetry. In the spectrum of (3), though quite different from the other three spectra, two small humps which correspond to the components of g and A are observed.…”