MAGNETOSTRUCTURAL CHARACTERIZATION OF [CU-4(PRZ)(4)(CH3OH)(2)L(2)''](CLO4)2 (L''H=1,1-DI-(2-PYRIDYL)-1-METHOXIMETHANOL, PRZH=PYRAZOLE)

The title compound [Cu2C19H20N6O7Cl](2) is a copper(II) complex, in wh ich each bicationic moiety is bridged by two pyrazolate ligands. In th e centrosymmetric, tetrameric dications pairs of copper atoms, one squ are planar and one square pyramidal, are bridged by an oxygen from the pyridylmethoxymethanol ligand and a pyrazolate moiety, with one examp le of five coordination completed by a methanol solvent molecule. Thes e dimers are then bridged by two pyrazoles, to give the tetramer. Two perchlorate counter-anions are bound to the tetrameric unit by hydroge n bonds, which stabilize the crystal structure. The copper(II) complex presents antiferromagnetic behaviour with T-M=190 K. Supposing that t he alkoxo oxygen bridge is the main pathway for the superexchange inte raction, the experimental magnetic susceptibilities were fitted to the Bleaney-Bowers equation for dimers, yielding a 2J value of -211.2 cm( -1).