Electronic studies, biological activities and nonlinear optical properties of a new non-centrosymmetric piperazinediium tetrabromidozincate(II)

The new non-centrosymmetric hybrid crystal (C4H12N2)[ZnBr4] was synthesized under slow evaporation method at ambient temperature. The obtained compound is crystalized in the orthorhombic system, space group P212121, a = 8.473 (16) A, b = 11.469 (18) A, c = 12.256(2) A, V = 1191.1 (4) A3 and Z = 4. The isolated [ZnBr4]2− tetrahedra and (C4H12N2)2+cations associated together by N–H⋯Br hydrogen bonds to form layers parallel to (a, b) plane characterize the crystal structure of the Zn(II) complex. The presence of the functional groups in the crystal was proven by the real-time infrared (RTIR) spectroscopic results. The first-principles density functional theory was conducted to explore the band structure and total and partial densities of state. The hybrid compound shows a direct band gap of 4.04 eV. The evaluation of the biological activity of the synthesized compound was carried out by agar well diffusion method, indicating strong antibacterial and moderate antifungal inhibitory activities. The tested compound’s MIC was 500 µg/mL against Bacillus subtilis. As for the Kurtz–Perry powder method, it demonstrated that the second-harmonic generation measurements showed a nonlinear optical activity for the title compound (C4H12N2)[ZnBr4] with a maximum intensity of ca. 19% and 60% compared with the reference samples of urea and KDP, respectively.