Comprehensive analysis of crystal structure, thermal stability, optical and dielectric properties of the hybrid compound (C6H11N3O2)(H2PO4)2

The research explores the characteristics of the organic-inorganic hybrid material l-histidinium dihydrogen phosphate (LHDP), with the chemical formula (C 6 H 11 N 3 O 2 )(H 2 PO 4 ) 2 . This compound crystallizes in the non-centrosymmetric monoclinic P2 1 space group. This compound exhibits notable thermal stability, with a decomposition temperature of 187 °C. Furthermore, the DSC reveals an irreversible phase transition at 113 °C, suggesting an order-disorder, and first-order phenomenon within the material. In addition, UV–Vis measurements offer insights into the compound's behavior in the visible spectrum, revealing an activation phenomenon and indicating an indirect wide optical band gap evaluated at 4.96 eV. Expanding upon this research, the dielectric studies examine the electrical properties and the phase transition observed in DSC. Impedance spectroscopy reveals a non-Debye-type relaxation, with Nyquist curves fitting well to an equivalent circuit model, offering valuable insight into the compound's electrical behavior.