Investigation of crystal structure, nonlinear optical and magnetic properties of a new tetrachlorocobaltate(II) anion salt with benzyl pyridinium cation based on DFT calculation

Abstract

The crystal of a new tetrachlorocobalt(II) anion salt, [BzPy]2[CoCl4] (1) ([BzPy]+ = benzyl pyridinium), was grown by the slow evaporation solution growth method at room temperature. The salt 1 crystallizes in the monoclinic space group P2(1)/c and consists of two [BzPy]+ cations and one [CoCl4]2− anion in which the Co(II) ion is coordinated by four Cl atoms in a close to tetrahedral geometry. The crystal packing is stabilized by electrostatic interactions and C − H···Cl hydrogen bonds between [BzPy]+ cations and [CoCl4]2− anions. Powder XRD diffraction study confirms the crystalline nature and purity of the title compound. The Fourier transform infrared (FT-IR) spectrum was recorded and analyzed with the aid of DFT calculations in order to make a suitable assignment of the observed bands. The thermal stability of the hybrid crystal was analyzed by TG-DTA techniques revealing that the title crystal was stable up to 195 °C. The title salt exhibits violet and cyan fluorescence emissions upon excitation at 345 nm and weak antiferromagnetic interactions in the temperature range 2-300 K. The nonlinear optical (NLO) effect of this compound was predicted using DFT, suggesting that the title crystal is a good material for NLO applications.