Synthesis, growth and characterization of guanidinium hippurate monohydrate single crystals: A new third order nonlinear optical material

Abstract Single crystals of a novel organic nonlinear optical (NLO) material-guanidinium hippurate monohydrate (GuHM) -are grown using slow evaporation solution growth technique. GuHM is an anion-cation system to which water molecules are attached by hydrogen bonding. The lattice parameters and crystalline purity of the crystal have been measured using single-crystal and powder X-ray diffraction (XRD) methods. Quantum chemical calculations using density functional theory (DFT) have been employed to calculate the vibrational modes and the first and second hyperpolarizabilities. Thermogravimetric (TG) and differential thermal (DT) analyses were carried out to characterize the thermal behaviour of the grown crystals. The role of intramolecular charge transfer and hydrogen bonds in making the molecule NLO-active are interpreted on the basis of the hyperpolarizability values. Along with DFT calculations, the natural bond orbital (NBO), the Atoms In Molecules (AIM), and the Hirshfeld surface imply the presence of a strong intra- and intermolecular N–H….O and O–H….O hydrogen bonding interactions between the charged species of GUHM crystal. The third-order optical nonlinearity of the crystal was studied using open-aperture Z-scan technique. From the experimental and theoretical data, it is concluded that GuHM is a potential NLO material.