The crystal structures and electronic properties of bis(di-2-pyridylamine)copper(II), bis(tetrafluoroborate) and bis[bis-aquabis(di-2-pyridylamine)copper(II)] sulfate heptahydrate

In the [Cu(C10H9N3)(2)][BF4](2) (1) complex, the Cu(II) ion is in a compres sed tetrahedral environment of four N atoms from two di-2-pyridylamine liga nds, with an average Cu-N distance of 1.962(7) Angstrom; the dihedral angle between the N-Cu-N planes of the two ligands is 55.0(2)degrees. The asymme tric unit of [Cu(C10H9N3)(2)(H2O)(2)][SO4]. 7H(2)O (2) contains two units o f one-half [Cu(C10H9N3)(2)] moieties (the other half is inversion related), one sulfate and nine water molecules. Each Cu(II) ion involves the elongat ed rhombic octahedral CuN4O2 chromophore, and is surrounded by four N atoms from the two inversion related dpyam ligands, with an average Cu-N distanc e of 2.019(2) Angstrom. The axial positions of Cu(II) are occupied by the c entrosymmetrically related O atoms of the two water molecules at 2.496(3) A ngstrom giving it a tetragonally distorted Cu(1)N4O2 octahedron. Similarly, the inversion related water oxygens at 2.465(3) Angstrom give a Cu(2)N4O2 chromophore. The electronic and ESR spectra of 1 and 2 are consistent with the compressed tetrahedral and the elongated rhombic octahedral stereochemi stries, respectively, as reported for other related complexes. (C) 1999 Els evier Science S.A. All rights reserved.