Synthesis, spectral and magnetic properties of two different 2-nitrobenzoatocopper(II) complexes containing N,N-diethylnicotinamide

Two structurally different complexes, [Cu-2(2-NO(2)Bz)(4)(denia)(1)](n) (1) and [Cu(2-NO(2)BZ)(2)(denia)(2)(H2O)(2)] (2), were prepared from the same reaction (where 2-NO(2)Bz = 2-nitrobenzoate, denia = NN-diethyinicotinamide) and they are reported together with (Cu-2(2NO(2)BZ)(4)(DMF)(2)] (3) (DMF = NN-dimethylformamide). The compounds under study were characterized by elemental analysis, electronic, IR and EPR spectra, magnetic measurements over the temperature range of 1.8-300 K and X-ray analysis. The molecular structure of (1) is polymeric, (2) is monomeric and (3) is dimeric. In the polymeric chain of (1), the denia molecules serve as bridges between dimeric Cu-2(2-NO(2)bz)(4) units. Each Cu(II) atom has a square-pyramidal arrangement with different chromophores, (CuO4O)-O-1' and (CuO4N)-O-2. The Cu-Cu distances are 2.699(1) angstrom in the dimeric unit and 7.980(3) angstrom between the dimeric units. In (2) the Cu(II) atom has a tetragonal-bipyramidal environment CuO2N2O'(2). In (3) two Cu(II) atoms are bridged by four carboxylate groups of four 2-NO(2)bz anions in a syn-syn arrangement which create a square base about each Cu(II) atom and an apical position is occupied by the O atom of a DMF molecule (CuO4O'). The Cu-Cu distance of 2.633(1) angstrom is somewhat shorter than in (1). Spectral and magnetic data of the complexes are discussed with their structures. (C) 2008 Elsevier Ltd. All rights reserved.