A novel iron (III) organic-inorganic hybrid with a thermochromic transition: Synthesis and structural characterisation of the dicystaminium dichloride aquapentachloridoferrate (III), monohydrate (C4H14N2S2)2[FeCl5(H2O)]Cl2*H2O

The magnetic hybrid material, based on the aquapentachloridoferrate (III), [FeCl5(H2O)](2-) and on the dicystaminium cation H(2)Cys, is reported for the first time in this paper exhibiting an interesting thermochromic behaviour. It was prepared as orange single crystals, suitable for single crystal X-ray diffraction, with the chemical formula (C4H14N2S2)(2)[FeCl5(H2O)]Cl-2*H2O (1). The characterization by X-ray diffraction was carried out at room temperature 296 K and at 120 K. The new derivative displays an asymmetric unit, formed by two H(2)Cys cations, one anionic complex [FeCl5(H2O)](2-) and two Cl- that ensure the electroneutrality, all trapped in the matrix with one water molecule. It crystallizes in the triclinic P (1) over bar space group with the following unit cell parameter at 120 K and 296 K respectively: a= 10.7913(4) angstrom, b = 11.4145(5) angstrom, c= 11.4225(5) angstrom and alpha = 99.010(4)degrees, beta= 102.529(4)degrees, gamma =90.466(3); a= 10.8747(4) angstrom, b = 11.4717(5) angstrom, c= 11.5483(4) angstrom and alpha = 98.907(3) degrees, beta= 103.169(3) degrees gamma =90.635(3). The compound was also characterized by IR spectroscopy and by DSC analysis and its magnetic behaviour was investigated. (C) 2019 Elsevier B.V. All rights reserved.