Synthesis, structure and Mossbauer characterization of polymeric iron(II) complexes with bidentate thiourea ligands

Complexes of FeCl2 with the known bis(3-methyl-2-thione-imidazolyl) methane (L-1) and the new bis(3-tert- butyl-2-thione-imidazolyl) methane (L-2) are reported. For both [(LFeCl2)-Fe-1](n) (3) and [(LFeCl2)-Fe-2](n) (4) X-ray crystallography reveals that 1D-polymeric chain structures are present in the solid state, with the two mercaptoimidazolyl units of L-1 and L-2 coordinating to different metal ions. Complexes 3 and 4 are further characterized by Mossbauer spectroscopy and SQUID magnetometry. NMR spectroscopy suggests that the complexes largely dissociate in polar solvents. X-ray structures of L-2 and its precursor bis(imidazolium) salt are also reported. (C) 2010 Elsevier B.V. All rights reserved.