Synthesis, crystal structure, infrared spectroscopy, thermal analysis and Hirshfeld surface analysis of a new hemihydrate of [Zn(H2O)6] [{(CH2)6N4}ZnCl3]2•0.5H2O

The new organic-inorganic hybrid material [Zn(H2O)(6)] [{(CH2)(6)N-4}ZnCl3](2)center dot 0.5H(2)O, is the second hydrate in this system, the first having been the hexahydrate. The new solid was prepared by slow evaporation of a solution of the reactants at room temperature and was structurally characterized by X-ray crystallography. This compound crystallizes in the trigonal system, space group P-3c1 with a = 9.8303(2)angstrom, c = 17.5460(2)angstrom, V = 1468.38(4)angstrom(3) and with Z = 2. The complex was characterized by FT-IR, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and with a detailed analysis of Hirshfeld surfaces and fingerprint plots. The structural unit of the title compound consists of a [Zn-II(H2O)(6)](2+) cation, two [(ZnCl3)-Cl-II(hmt)](-) anions and half of a water molecule, partially occupied and disordered [hmt is hexamethylenetetramine, (CH2)(6)N-4]. Crystal packing is mediated by O-H center dot center dot center dot N and O-H center dot center dot center dot Cl hydrogen bonds between the anions and cations, and to a lesser extent by O-H-O contacts, which are present only part of the time as a consequence of the partial occupancy of the isolated water molecules. The relationship between the packing in the new structure and that of the previous hexahydrate is described. (C) 2018 Elsevier B.V. All rights reserved.