Synthesis, crystal structure, vibrational study, optical properties and thermal behavior of a new hybrid material bis(3-amino-4-phenyl-1H-pyrazolium) tetrachloridocobaltate (II) monohydrate

Abstract

The title organic–inorganic hybrid compound, (C9H10N3)2[CoCl4]·H2O, was synthesized by slow evaporation at room temperature. Single-crystal X-ray diffraction analysis indicates that the asymmetric unit in this compound consists of one tetrahedral geometry [CoCl4]2-, two protonated organic cations (C9H10N3)+ and one water molecule of crystallization. In the crystal structure, the inorganic layers are built from tetrachloridocobaltate anions [CoCl4]2- and free water molecules, linked together by Ow—H…Cl hydrogen bonds and halogen···halogen interactions. The organic cations are intercalated between the mineral layers via N–H⋯Cl hydrogen bonds and form chains through cycle stacking interactions. The atomic arrangement can be described as an alternation of organic and inorganic layers along the c-axis. Crystal cohesion is achieved through N–H⋯Cl, Ow—H…Cl, N–H … Ow hydrogen bonds between organic cations, inorganic anions and the water molecules building up a three-dimensional network. The vibrational properties were investigated experimentally by means of IR spectroscopy. The powder X-ray diffraction was used to confirm the phase purity. Also, The UV–visible and the photoluminescence (PL) properties of the compound were investigated at room temperature in the solid state. The crystal morphology was carried out using Bravais–Friedel–Donnay–Harker (BFDH) model. Electronic properties such as HOMO and LUMO energies were also obtained. Thermal behavior was characterized by thermogravimetric and differential scanning calorimetry TG-DSC.