Hexanuclear copper(II) complex of a novel poly(pyridine) ligand exhibiting unique long distance ferromagnetic interactions through a nitrato-O,O′ bridge

A novel hexanuclear copper complex [Cu-6(NO3)(12)(opytrizediam)(2)(H2O)][(CH3)(2)CO](0.5)(CH3CHCH2OH)(0.5) (1) with a NO3 bridge has been synthesized by reaction of Cu(NO3)(2)(.)3H(2)O with the new potentially octadentate ligand opytrizediam in n-propanol/ acetone solution (opytrizediam=N,N-{2,4-di[(di-pyridin-2-yl)amine]-1,3,5-triazinel ethylenediamine). A single-crystal X-ray diffraction analysis showed the presence of six structurally different copper centres. The coordination spheres of four copper(II) ions are best described as square-pyramidal CuN2O3 chromophores while the two other copper(II) ions are in a trigonal-bipyramidal CuN4O environment. Variable-temperature studies on I revealed a unique ferromagnetic coupling of two copper(II) ions bridged by a didentate nitrate anion and separated by a distance of 6.391(6) Angstrom, with J = 8.6(1) cm(-1). (C) 2003 Elsevier B.V. All rights reserved.