Structure and EPR spectrum of binuclear copper complex with glutaric acid bis(salicylidene)hydrazone

The binuclear copper(II) complex with glutaric acid bis(salicylidene)hydraz one (H4L) of the composition [Cu2L . 2Py . 2CH(3)OH]. 2H(2)O is characteriz ed by X-ray crystallography. Crystallographic data are a = 21.383(16) Angst rom, b = 16.866(8) Angstrom, c = 10.712(11) Angstrom, beta = 114.75(7)degre es space group C2/c, Z = 4 (2672 reflections, R = 0.059, R-w = 0.065). The coordination polyhedra of copper cations have a geometry of a distorted tet ragonal pyramid. The base of the pyramid is formed by the nitrogen atom and two oxygen atoms from the doubly deprotonated salicylidenehydrazone and al so by the pyridine nitrogen atom. The apex of the pyramid is occupied by a weakly coordinated methanol molecule. The distance between the copper catio ns is 9.182 Angstrom. EPR spectra of diluted solutions (chloroform-pyridine ) of the complex feature seven lines (g = 2.106, a(Cu) = 39.9 x 10(-4) cm(- 1)), interpreted as a result of coupling the unpaired electron to two coppe r nuclei due to its delocalization over the chain of eight sigma bonds.