Synthesis, structure and electronic properties of new NON linear optical material: Cd(SCN)2(L-C9H11NO2)·H2O

Abstract

The design and synthesis of new hybrid organic-inorganic nonlinear optical (NLO) crystals are a promising area of current research in material science. Much attention has been focused to this hybrid compounds due to their opportunities to combine the advantageous properties of organic molecules (polarizability, flexibility, luminescence, photosensitivity) and the inorganic molecules (conductivity, magnetic, thermal stability) with a same compound. The synthesis and the crystal structure of Cd(SCN)2(L-C9H11NO2)·H2O are reported and discussed in the present paper. Cd(SCN)2(L-C9H11NO2).H2O crystallizes in the orthorhombic P212121 space group. Asymmetric unit consists of one l-phenylalanine zwitterion, two thiocyanate anions, one water molecule and one cadmium atom. Each cadmium atoms is bridged by three μ1,3-SCN ions, forming a polymeric chain approximately expanded along the crystallographic direction [1 0 0] and give rise to twelve-membered (Cd3(SCN)3) macrocycles as subunits. Intermolecular N–H⋯S, N–H⋯O(W) and O(W)–H⋯O hydrogen bond interactions contribute significantly to the stability and the cohesion of the structure. The powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and quantum chemical calculations using the DFT/B3LYP/GenECP methods have been also carried out to characterize this new hybrid material. The direct optical band gap energy deduced from the UV–VIS spectroscopy is Eg = 4.73 eV. The first hyper polarizability in Cd(SCN)2(L-C9H11NO2)·H2O is twice greater than that of KH2PO4 which make it have microscopic NLO behavior.