Synthesis, growth, thermal, optical and mechanical properties of 2-Aminopyridinium 4-methylbenzoate Dihydrate

Abstract

Organic NLO material of 2-Aminopyridinium 4-methylbenzoate Dihydrate (2A4M) was synthesized using 2-Aminopyridinium and 4-methylbenzoic acid as starting materials. Single crystals of 2A4M were grown by the slow evaporation solution growth technique at room temperature using water as a solvent. The grown crystal was characterized by single crystal XRD to confirm the crystal system and lattice parameters. From the optical studies the optical band gap and the refractive index of the material are found to be 2.9 eV and 1.40 at 1200 nm. Functional groups of the crystallised material were confirmed by FTIR vibrational spectrum. Thermal behaviour of the title compound was studied using thermogravimetric (TG) and differential thermal analyses (DTA). The initial weight loss is found up to 125 °C, which corresponds to 13.2% i.e. presence of 2 mole of water in the lattice. The grown crystal was subjected to Vickers hardness test and the brittleness index, fracture toughness, yield strength were estimated. The etching studies reveal the growth pattern and dislocations present in the grown crystal. The second harmonic generation (SHG) behaviour of 2A4M was tested by Kurtz–Perry powder technique. The relative SHG efficiency of 2A4M is found to be 3.03 times that of the reference material KDP.