Crystal and molecular structure of copper(II) (pyridine-2,6-dicarboxylato)( 2,6-dimethanolpyridine)

Copper(II)(pyridine-2,6-dicarboxylato) (2,6-dimethanolpyridine) has been pr epared and studied by the single crystal X-ray diffraction methods at 293(2 ) K. The compound crystallises in an orthorhombic system, space group Pbcn with a = 8.196(2), b = 13.124(3), c = 25.612(5) Angstrom, and Z = 8 (R = 0. 0374 for 3175 independent reflections with I>2 sigma(I)). Crystal structure analysis revealed that the copper(II) atom is surrounded by two non-equiva lent terdentate ligands making up an 'all-trans' elongated octahedral arran gement. In consequence of Jahn-Teller distortion, considerable differences are found between the ligands for the pyridine-2,6-dicarbuxylate anion with the values Cu-N 1.892(3), Cu-O 2.033(2) and 2.064(2) Angstrom, while for t he 2,6-dimethanolpyridine ligand the values are 1.943(3), 2.341(3) and 2.43 3(3) Angstrom. Then is a relationship between the Cu-L bond distances and t he five-membered metallocyclic rings (O-Cu-N). The data are compared and di scussed with those found in familiar Cut, compounds with the CuO4N2 chromop hore. Based on the molecular structure, the electronic, IR and EPR spectra are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.