SYNTHESIS, CRYSTAL-STRUCTURE, AND MAGNETIC-PROPERTIES OF A PYRAZOLATE-BRIDGED BINUCLEAR COPPER(II) COMPLEX

A new pyrazolate-bridged binuclear Cu(II) complex, [LCu2(prz)] (2), where prz is the monoanion of pyrazole and L3− is the trianion of the Schiff-base ligand formed from the condensation of 2 mol of salicylaldehyde and 1 mol of 1,4-diaminobutan-2-ol, is characterized by single-crystal X-ray diffraction techniques. Complex 2 crystallizes from a DMF solution in the space group P21/c with dimensions a = 11.813 (6) Å, b = 18.049 (6) Å, c = 9.680 (4) Å, β = 105.67 (4)°, and Z = 4. The crystal structure of 2 shows a disordering of the carbon atom positions of the five- and six-membered chelate rings. A satisfactory model of the disorder was achieved by refining the disordered atoms in positions of 50% occupancy. Agreement factors of R = 5.4% and Rw = 7.2% were obtained after final cycles of anisotropic refinement of all non-hydrogen atoms. The magnetic susceptibility of complex 2 has been measured in the temperature range 297.5–5.0 K. The exchange coupling parameter, 2J, was determined to be −545.6 cm−1 from least-squares fitting of the data. The magnetic properties of 2 have been compared with those reported recently for two structurally similar compounds. © 1990, American Chemical Society. All rights reserved.