Crystal structure, crystal growth and characterization of novel organic NLO material: 2,4,4′-Trimethoxybenzophenone

Single crystals of 2,4,4′-Trimethoxybenzophenone (TMB) were grown by slow evaporation solution growth technique using acetone as a solvent. TMB crystallizes in monoclinic system with noncentrosymmetric space group, P21, and the cell parameters are a = 8.485(5) Å, b = 8.173(5) Å, c = 10.254(5) Å, β = 102.085(5)° and V = 695.3(7) Å3. Gaussian 98W has been used to calculate the first-order hyperpolarizability of TMB. Fourier transform infrared (FTIR) spectroscopic studies were performed for the identification of different modes present in the compound. TMB crystals are transparent in the entire visible region and have a lower optical cutoff at 400 nm. The powder second harmonic generation efficiency of TMB was determined to be 6 times that of urea. The observed SHG response for TMB is due to effective charge transfer arising from the donor–π–acceptor–π–donor (D–π–A–π–D) structure of the molecule. From the thermogravimetric/differential thermal analysis, the TMB was found to be thermally stable up to 79 °C. The dielectric and mechanical properties of the TMB were also studied.