Characterization of ternary bivalent metal complexes with bis(2-hydroxyethyl)iminotris(hydroxymethy)methane (Bis–Tris) and the comparison of five crystal structures of Bis–Tris complexesq

Eleven bivalent metal complexes with bis(2-hydroxyethyl)iminotris(hydroxymethy)methane (Bis–Tris:hihm): [M(hihm)(H2O)]SO4· nH2O (M: Co, Ni, Cu, Zn), [MCl(hihm)]Cl·nH2O (M: Co, Ni, Cu), and [M(HCOO)(hihm)](HCOO) (M: Co, Ni, Cu, Zn) have been prepared and characterized by using their infrared absorption and powder diffuse reflection spectra, magnetic susceptibility, thermal analysis and powder X-ray diffraction analysis. The crystal structures of [Ni(hihm)(H2O)]SO4·H2O (2), [Cu(hihm)(H2O)]SO4 (3), [NiCl(hihm)]Cl·H2O (6), [CuCl(hihm)]Cl (7) and [Co(HCOO)(hihm)](HCOO) (8) have been determined by single crystal X-ray diffraction analysis. The crystals of [Ni(hihm)(H2O)]SO4·H2O (2) and [Cu(hihm)(H2O)]SO4 (3) are each orthorhombic with the space group P212121 and Pna21. For both complexes, the metal atom is in a distorted octahedral geometry, ligated by four hydroxyl oxygen atoms, a nitrogen atom and a water molecule. [NiCl(hihm)]Cl·H2O (6) is monoclinic with the space group P21/n. For complex (6), the nickel atom is in a distorted octahedral geometry, ligated by four hydroxyl oxygen atoms, a nitrogen atom and a chloride ion. [CuCl(hihm)]Cl (7) is orthorhombic with the space group P212121. Although in this copper(II) complex the copper atom is ligated by six atoms, it is more reasonable to think that the copper atom is in a trigonal bipyramidal geometry coordinated with five atoms: three hydroxyl oxygen atoms, a nitrogen atom and a chloride ion if the bond distances and angles surrounding the copper atom are taken into consideration. [Co(HCOO)(hihm)](HCOO) (8) is monoclinic with the space group P21. In cobalt(II) complex (8), the cobalt atom is in a distorted octahedral geometry, ligated by four hydroxyl oxygen atoms, a nitrogen atom and an oxygen atom of a formate ion. The structure of complex (8) is the same as the structure of [NiCl(hihm)]Cl·H2O (6) except for the formate ion coordinating instead of the chloride ion. [M(hihm)(H2O)]SO4·H2O (M: Co, Zn) (1, 4), [CoCl(hihm)]Cl·H2O (5) and [M(HCOO)(hihm)](HCOO) (M: Ni, Cu, Zn) (9–11) seem to have the same structures as the structures of [Ni(hihm)(H2O)]SO4·H2O (2), [NiCl(hihm)]Cl·H2O (6) and [Co(HCOO)(hihm)](HCOO) (8), respectively, judging by the results of IR and powder diffuse reflection spectra and powder X-ray diffraction analysis. Bis–Tris has coordinated to the metal atoms as a pentadentate ligand in all complexes of which the structures have been determined by single crystal X-ray diffraction analysis in this work. q 2004 Elsevier B.V. All rights reserved