The coordination chemistry of mono and bis(di-2-pyridylamine)copper(II) complexes: preparation, characterization and crystal structures of [Cu(L)(NO2)(2)], [Cu(L)(H2O)(2)(SO4)], [Cu(L)(2)(NCS)](SCN)center dot 0.5DMSO and [Cu(L)(2)(SCN)(2)]

摘要

The crystal structures of two mono(dpyam)copper(II) complexes, [Cu(dpyam)(NO2)(2)] (1) and [Cu(dpyam)(H2O)(2)(SO4)] (2) and two dithiocyanate compounds containing bis(dpyam)copper(II) units, [Cu(dpyam)(2)(NCS)](SCN).0.5DMSO (3) and [Cu(dpyam)(2)(SCN)(2)] (4) have been determined by X-ray crystallography. The second orthorhombic form of the monomeric Cu(II) complex 1 was obtained by the reaction of di-2-pyridylamine (dpyam) with CuCl and NaNO2 in water-methanol solution. Each copper(II) ion in 1 exhibits a tetrahedrally-distorted square base of the CuN2O2 chromophore, with off-the-z-axis coordinated nitrito groups weakly bound in approximately axial positions. Complex 2 is an example of a polymeric copper(II) derivative containing the bidentate bridging sulfate ligand in the long-bonded axial positions. Each copper(II) ion in 2 shows an elongated tetragonal octahedral stereochemistry. The CuN4N' chromophore of 3 involves a square-based pyramidal structure, slightly distorted towards a trigonal bipyramidal stereochemistry, tau = 0.13. One of the SCN- anions is bonded to the copper(II) ion via the N atom in the axial position of the square pyramid. Complex 4 is centrosymmetric and octahedrally elongated, with the SCN- anions coordinating in axial positions via the S atom. The structures of complexes 1-4 and their ESR and electronic reflectance spectra are compared with those of related complexes. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 59]