Crystal structure, thermochromic and magnetic properties of organic-inorganic hybrid compound: (C7H7N2S)2CuCl4

The synthesis, thermal analysis, crystal structure and magnetic properties of (2-aminobenzothiazolium)(2)CuCl4, organic-inorganic hybrid compound, have been described. The compound crystallizes in the monoclinic space group P2(1)/c with two formula units in a unit cell of dimensions a = 6.9522(4) angstrom, b = 9.6979(4) angstrom, c = 13.9633(6) angstrom, beta = 97.849(3) and volume 930.83(8) angstrom(3) at 150(2) K. The structure consists of isolated nearly square planer [CuCl4](2-) units, with somewhat longer than normal Cu-Cl bond lengths [Cu-Cl (average) = 2.2711 angstrom]. The magnetic measurements of (2-aminobenzothiazolium)(2)CuCl4 using SQUID magnetometer show paramagnetic nature of the compound. Thermal measurements (TG-DTA and DSC) on this compound showed reversible phase transition at 83 degrees C. This transition is accompanied by the reversible change in colour of the prismatic crystal from green to dark brown, thermochromic behaviour. Temperature dependent EPR measurements on powdered sample ascertain change in coordination sphere around Cu(II) with shift in g(parallel to) = 2.150 and g(perpendicular to) = 2.071 at room temperature, typical of square planar, to g(parallel to) = 2.201 and g(perpendicular to)= 2.182 at 170 degrees C, typical of distorted tetrahedral geometry. (C) 2017 Elsevier B.V. All rights reserved.