Synthesis, Molecular Structure and Theoretical Investigation of Optical and Electronic Properties of New Crystalline Polymer: [(C6H5NH3)2Cd(SCN)2Cl2]n

A new crystalline polymer compound {(C6H5NH3)2Cd(SCN)2Cl2}n was synthesized and analyzed using single crystal XRD,UV–Vis spectroscopy. The crystal structure refinement shows that this ionic material crystallizes at 298 K in the monoclinic system (C2/c space group). The cohesion and the stability of the polymeric structure is assured by (i) the establishment of N–H···Cl and N–H···N (NCS) hydrogen bonding contacts between the (C6H5NH3)+ cations and the [Cd(SCN)2Cl2]n2n− chains, (ii) the π–π interactions between the centroids of the phenyl rings of (C6H5NH3)+ cations and (iii) the C(6)–H(6)···π (phenyl) interactions. The indirect optical band gap energy deduced from the UV–Vis spectroscopy is Eg = 3.91 eV. Electronic structure, and optical properties were determined using density functional theory (DFT) calculations. The atomic coordinates and the lattice parameters were optimized while the space group symmetry was kept fixed during the refinements. The estimated band gap between HOMO and LUMO calculation is 3.67 eV. Moreover in order to understand the optical properties of {(C6H5NH3)2Cd(SCN)2Cl2}n, the dielectric function, optical reflectivity, refractive index, optical conductivity and electron energy loss are calculated and discussed for radiation up to 38 eV.