Synthesis, crystal structure, and vibrational and DFT simulation studies of benzylammonium dihydrogen phosphite

Abstract Single crystals of a new organophosphite compound, C 7 H 12 NPO 3 , were grown by the slow evaporation technique and characterized by X-ray diffraction, IR absorption spectroscopy, Raman scattering spectroscopy, UV-visible spectroscopy, photoluminescence measurements, and thermal analysis. This salt crystallizes at 120 K in orthorhombic symmetry with space group Pbca and cell parameters a  = 14.0377 (12) A, b  = 8.0915 (7) A, and c  = 16.2980 (2) A. The same symmetry, Pbca , is shown by X-ray diffraction at 298 and 350 K. To minimize the thermal effects, the crystal structure determined at 120 K was used as the reference. In the crystal structure, the phosphite anions, H 2 PO 3 − , are connected to the organic cations, C 6 H 5 CH 2 NH 3 + , through N–H...O hydrogen bonds that form infinite parallel two-dimensional planes. Theoretical calculations were performed with density functional theory at the B3LYP/6-31G (d,p) level of theory to study the molecular structure and vibrational spectra of C 7 H 12 NPO 3 . The optimized geometry and the calculated frequencies are in good agreement with the experimental data. The UV-visible spectrum shows characteristic absorption bands in the region from 300 to 800 nm, which suggests that C 7 H 12 NPO 3 is potentially suitable for optical applications. The absence of absorption in the visible region might enable achievement of microscopic nonlinear optical response with nonzero values. In addition, photoluminescence measurements showed that this compound exhibits green emission at 502 nm at room temperature.