Iron(II) and Nickel(II) Complexes of 4,4′-Bithiazole: Spectral, Magnetic and Structural Studies

Abstract

Iron(II) and nickel(II) complexes of 4,4′-bithiazole (L) have been prepared. Salts of [FeL₃]²⁺ undergo thermally induced spin-state transitions, in the solid state and in solution. The structures of both [FeL₃] [ClO₄]₂ and [NiL₃] [ClO₄]₂ have been determined by single-crystal X-ray diffractometry . The compounds are isomorphous : monoclinic with space group C2/c, with four molecules in a unit cell of dimensions (Fe, Ni): a 17.250(3), 17.379(3); b 9.8168(9), 9.685(1); c 16.867(3), 17.135(3) Ǻ; β 105.943(7), 104.860(7)°. The structures were refined by least-squares methods to residuals of 0.033 (Fe) and 0.033 (Ni) for 1917 (Fe) and 2017 (Ni) observed reflections. The cations have a distorted octahedral structure with the average Ni-N bond length being 0.11 Ǻ longer than the average Fe-N bond length.