Synthesis, Characterization and Molecular Structure of Iron(III) Complex with Tridentate Diazene Ligand Having O,N,S Donor Set: Coexistence of Octahedral and Tetrahedral Iron(III) Sites in the Asymmetric Unit

Abstract

The reaction of 2-hydroxy-1-(2′-methylthiophenylazo)naphthalene (HL) with iron(II) chloride results in the formation of a hitherto unknown complex, [Fe(L)2][FeCl4] (1). The azo-thioether ligand binds iron(III) center through the O−,N,S donor set to form the octahedral [Fe(L)2]+ cation. Solid state molecular structure of (1) has been determined by single crystal X-ray diffraction technique. Compound (1) crystallizes in the monoclinic P21/c space group of unit cell dimensions a = 10.3904(19) A, b = 23.735(4) A, c = 15.815(3) A; α = 90°, β = 102.248(4)°, γ = 90° and Z = 4. The structure was solved by direct method and refined to R1 value 0.0975 on 3796 observed reflections. There are one octahedral cationic unit of [FeIIIL2], a tetrahedral anionic unit of [FeIIICl4] and 0.5(C2H5OH)2 as solvent molecules in an asymmetric unit of the crystal lattice of (1). There are two intramolecular C–H⋯O interactions and the crystal packing is stabilized by interionic C–H⋯Cl and intermolecular C–H⋯Cg interactions. Single crystal X-ray diffraction study of an iron(III) complex bearing an azo-thioether ligand, 2-hydroxy-1-(2′-methylthiophenylazo)naphthalene (HL) is presented, crystal packing of the complex, [FeIIIL2]+[FeIIICl4]− (1) has been found to be stabilized by interionic C–H⋯Cl and intermolecular C–H⋯Cg interactions.