Synthesis, crystal growth, optical, thermal, mechanical and dielectric properties of mono(bis(2-(4-butylphenyl)imino)methyl)phenoxy)zinc(II)dichloride (MBPMP) single crystal as a nonlinear optical (NLO) material

A new mono(bis(2-(4-butylphenyl)imino)methyl)phenoxy)zinc(II)dichloride (MBPMP) single crystal was grown by slow evaporation technique in ethanol. Single crystal XRD studies confirm that the MBPMP crystal is mononuclear, with tetragonal coordination geometry and P4₁2₁2 noncentrosymmetric space group. The FT-IR spectral analysis was used for identifying the functional groups and bonding nature present in the MBPMP crystal. The UV–Visible-NIR studies reveals that the MBPMP single crystal exhibits a very broad transparency window in the near infrared and visible regions between 220 to 1200 nm and the optical transparency of the MBPMP crystal is 99.49% with the lower cut-off wavelength of 220 nm. The optical energy band gap evaluated from the transmission spectrum was found to be 5.63 eV. The Vickers microhardness number [1.8544 P/d² kg/mm³] and the work hardening coefficient number (n = 2.326) indicates that the MBPMP single crystal is soft natured. TGA/DSC analysis of the title coordination compound indicated that there is no weight loss up to 209 °C indicating that the grown MBPMP crystal is thermally stable up to 209 °C. MBPMP single crystal exhibits lower dielectric constant and lower dielectric loss at higher frequencies indicating good quality optical crystal. The second harmonic generation efficiency of the MBPMP crystal by using Kurtz’s powder technique employing Q-switched Nd: YAG laser found that the intensity of bright green light emission is 1.2 times greater than that of standard KDP crystal. The laser damage threshold value of the MBPMP single crystal was calculated to be 3.86 GW/cm².