CRYSTAL-STRUCTURE, SPECTROSCOPIC AND MAGNETIC STUDIES OF DIACETATO-BIS(2-AMINOPYRIDINE) COPPER(II) COMPLEX

The crystal and molecular structure of diacetato-bis(2-aminopyridine) copper(II) complex has been determined by X-ray diffraction studies. T he complex crystallizes in the orthorhombic space group Pbca with a = 15.691(3)Angstrom, b = 15.212 Angstrom, c = 15.158(4)Angstrom, Z = 8. The structure was solved by direct methods using program SHELXS-86. Se veral cycles of refinement of the coordinates and thermal parameters ( anisotropic for non-hydrogen and isotropic for hydrogen atoms) reduced R values to 0.036 and Rw to 0.035. The copper atom in molecule is six coordinated (4+2). The four closest donor atoms are two pyridine-nitr ogen atoms of the 2-aminopyridine molecules and two oxygen atoms of th e carboxylate groups. They form slightly distorted squar-planar arrang ement with Cu-N distances of 1.988(3)Angstrom and 1.994(3)Angstrom and Cu-O distances of 1.965(3)Angstrom and 1.969(3)Angstrom respectively. Two Longer out of plane Cu-O bonds to the remaining oxygen atoms of t he carboxyl groups with distances 2.588(3)Angstrom and 2.593(3)Angstro m respectively complete strongly distorted square bipyramidal coordina tion of copper atom. The hydrogen atoms of each amino group of the 2-a minopyridine molecules form inter and intramolecular hydrogen bonds wi th oxygen atoms of the carboxylate groups. The measurements of magneti c susceptibility in temperature range 77-300 K (mu(eff)= 1.78+/-0.02) and the results of the spectroscopic investigations (UV-VIS, IR, EPR) are in excelent agreement with X-ray structure determination.