Effect of glycine on structural, optical and dielectric properties of solution grown samarium chloride coordinated with salicylic acid

Samarium chloride coordinated with salicylic acid (SMS) and samarium chloride coordinated with two organic ligands glycine and salicylic acid (SMGS) have been grown by low temperature solution technique i.e., slow evaporation method. The crystalline nature of the material was firstly confirmed by single crystal X-ray diffraction analysis and secondly by powder X-ray diffraction analysis. It has been observed that the material prepared crystallizes in monoclinic system having space group P12₁/c1. The modes of vibration of different molecular group present in SMS and SMGS have been confirmed by Fourier transform infrared (FTIR) analysis. It indicates the coordination of ligands in complexes i.e., salicylic acid coordinated through oxygen atoms of carbonyl group (C=O) and glycine ligand coordinated through nitrogen atoms. UV–Vis transmittance study analyzes the optical transparency of SMS and SMGS and it has been found that with the incorporation of glycine in SMS transmittance decreases. Moreover, the impact of glycine in SMS single crystal on its various optical parameters such as optical band gap, refractive index and optical conductivity has been calculated. The decrease in the value of optical band gap from 3.43 to 3.29 eV with the incorporation of glycine in SMS has been observed. The calculated values of refractive index at 425 nm for SMS and SMGS complexes are 1.30 and 2.46 respectively and the optimum value of optical conductivity at 425 nm for SMS and SMGS is 4 $\times$ 10⁵ and 1.4 $\times$ 10⁷ Sm⁻¹ respectively. Luminescence of Sm³⁺ ion is strongly sensitized by salicylic acid as compared to glycine thereby fluorescence of the SMGS complex diminished. Decrease in the dielectric constant was observed with the incorporation of glycine in SMS single crystal. Complex electric modulus analysis confirms the non-Debye type of relaxation in both the materials. Activation energy value depends on frequency as well as on glycine coordination in SMS single crystal.