Beschreibung:
Pure single crystals of Lewis acid-base salt, hydrazinium hydrogen phthalate monohydrate (HHPMH)has been synthesized, crystallized and isolated as a single crystal by slow evaporation method at roomtemperature (22 ºC). Analysis of analytical, spectral, thermal and structural data confirmed the saltformation in aqueous medium. The analytical data is in favour of the proposed compositionHOOC-C6H4COO N2H5·H2O. The compound crystallized in a monoclinic crystal system and P21/Cspace group with cell parameters, a = 15.409(3) Å, b = 10.292(2) Å and c = 6.7087(12) Å. Thoughstrong intramolecular hydrogen bonding interaction is anticipated between acidic hydrogen of HHPMHand deprotonated carboxylate oxygen surprisingly in the present case it is absent and a weak interactionis observed between acidic hydrogen and water molecule, which is quite evident from the ORTEPdiagram. The nature of interactions between hydrazine cation and hydrogen phthalate ion and thecrystal packing diagram from various types of intermolecular contacts were determined by Hirshfeldsurface analysis. The compound was stable up to 40 ºC and undergoes dehydration from 40-70 ºC withan endotherm at 47 ºC. The experimental and theoretical infrared spectra are also in favour of theformation of ionic crystal. The molecular structure was optimized using B3LYP method by 6-311G(d,p) basis set. The energy gap between HOMO and LUMO is 7.7340 eV. Theoretical calculationbased on DFT studies and natural bond orbital analyses has been carried out to evaluate the molecularelectrostatic potential. The structure was optimized by DFT and the vibrational frequencies werecalculated. Comparison of experimental and optimized structures revealed that there is a goodcoincidence between the two.