X-ray structure and spectroscopic properties of some lanthanides(III) complexes derived from 2,6-diacetylpyridine-bis(benzoylhydrazone)

A series of trivalent lanthanide complexes of type [Ln(L) NO3)(S)n](NO3)m(S′)n, have been synthesized by the reaction of 2,6-diacetylpyridine-bis-(benzoylhydrazone) (H2L) with lanthanide(III) nitrates in ethanol. These complexes have been characterized by analysis, molar conductance, magnetic measurements, infrared spectral studies and X-ray diffraction. The analytical data revealed the formation of 1:1 (metal:ligand) stoichiometry. Molar conductance in dmf gives 2:1 electrolytes in all the complexes. Magnetic moment values are close proximity of the Van Vleck values. IR study suggests the coordination of the ligand through the azomethine and the oxygen of the hydrazonic moiety. The nitrate ion is also found to be bidentate in all the complexes. The crystal structures were determined. 6, C27H31N6O7S2Gd: a=b=8.6821(4) Å, c=84.363(5) Å, tetragonal P41212 and Z=8. bf 7, C25H25N6O6SDy: a=11.750(3) Å, b=13.250(3) Å, c=36.000(6) Å, β=98.50(2), monoclinic, C2/c, Z=8. 9, C24H25N6O7Yb: a=10.750(2) Å, b=17.750(3) Å, c=14.250(4) Å, β=99.00(2), monoclinic, P21/n, Z=4. In these complexes the lanthanide ion assumes a nine coordinated geometry for Gd and an eight coordinated geometry for Dy and Yb.