Self-Assembly, Crystal Structure and Analysis of Intermolecular Interactions of the Supramolecular Compound Based on Hexamolybdochromate(III), Sulfate and Piperazine

A new supramolecular compound based on Anderson-B hexamolybdochromate, (H2Pz)3[Cr(OH)6Mo6O18H](SO4)2·12H2O (1) (Pz = piperazine) was synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction (Mo Kα). The compound crystallizes in monoclinic system, P21/c space group with a = 13.5708(6) A, b = 17.3711(8) A, c = 22.2387(9) A, β = 110.631(2)°; V = 4906.3(4) A3, Z = 4, Dc = 2.290 g/cm3, F(000) = 3364.0; μ = 1.905, S = 1.033. The final R = 0.0398 and wR = 0.0971. The H2pz2+ ions and sulfate anions in 1 are arranged through hydrogen bonds into a hexagonal network in [202] plane and hexamolybdochromates anions (CrMo6) fill in the hexagonal vacancies. The networks stack in such a way that each anion links two sulfate ions from adjacent networks via hydrogen bonds with short (CrMo6)O···OSO3 distances of 2.637–2.697 A. A lot of hydrogen bonds are formed between water molecules, sulfate, H2pz2+ ions and CrMo6 anions, which are the dominating force constructing the supramolecular structure. Hirshfeld surface analysis of 1 gives us the details of intermolecular interactions in the crystals of 1 in a visual manner and shows that the CrMo6 anion acts as a stronger hydrogen bond donor than as an acceptor.