Structural and spectral studies of an iron(III) complex [Fe(Pranthas)2][FeCl4] derived from 2-acetylpyridine-N(4), N(4)-(butane-1, 4-diyl) thiosemicarbazone (HPranthas)

A novel iron(III) complex of 2-acetylpyridine N(4), N(4)-(butyl-1, 4-diyl) thiosemicarbazone (HPranthas), [Fe(Pranthas)2]FeCl4 was synthesized and physico-chemically characterized by means of partial elemental analysis, magnetic measurements (polycrystalline state), UV-Vis and IR spectroscopies. The presence of spin-paired iron(III) cation with dxz2dyz2dxy1 ground state is revealed by the EPR and Mössbauer spectral data. Structure of the free ligand HPranthas and the complex [Fe(Pranthas)2]FeCl4 were solved by single crystal X-ray diffraction. The framework of iron(III) complex consists of a discrete monomeric cationic entity containing low spin iron(III) in a slightly distorted octahedral environment. The metal ion is bonded to one sulfur and two nitrogens of each thiosemicarbazone molecule. The tetrachloroferrate(III) ion acts as counterion.