Organic salts of guanazole – Seeking for new materials for second harmonic generation

[Display omitted] ► The preparation and spectroscopic characterization of new NLO materials. ► Four novel salts of guanazole with dicarboxylic acids were prepared and described. ► The novel salts were chracterized by X-ray diffraction and vibrational spectroscopy. ► The noncentrosymmetric materials were additionaly tested for second harmonic generation. Four novel organic salts of 3,5-diamino-1,2,4-triazole (guanazole) with malonic, glutaric, adipic and L-malic acids have been prepared and X-ray structural analyses have been performed within our project focused on the preparation of new non-linear optical materials. The salts guanazolium(1+) hydrogen adipate and guanazolium(1+) hydrogen L-malate crystallize in the non-centrosymmetric space groups of monoclinic (Cc) and orthorhombic systems (P212121), respectively. Unfortunately, the remaining two salts guanazolium(1+) hydrogen malonate and guanazolium(1+) hydrogen glutarate belong to the centrosymmetric space group P-1 of the triclinic system. All salts were also characterized by the methods of vibrational spectroscopy (FTIR and FT Raman). The interpretation of the vibrational spectra is based on our previous ab initio calculations. The second harmonic generation’s quantitative measurements of powdered samples at 800nm and 1064nm were performed. The thermal behavior of the prepared compounds was studied by the DSC method in the temperature interval from 90K up to a temperature close to the melting points of the crystals.