Two different coordination polyhedra in the crystal structure of a novel Zn(II) hybrid complex: DFT investigation, biological activities and emission properties

This work centers around the search for sophisticated hybrid compounds with versatile applications. A new compound, denoted as (C6H8NO)3[ZnCl4][ZnCl3(H2O)] (1), was synthesized and thoroughly characterized. The structural features were determined through the use of various analytical techniques, including spectroscopy (FT-IR, Raman), thermo-gravimetric analysis, and optical studies encompassing ultraviolet-visible spectroscopy, nonlinear optical (NLO), and fluorescence measurements. The crystalline arrangement was explored through single crystal X-ray diffraction analysis, revealing a triclinic crystal system with the P1¯ space group. The molecular composition comprises three distinct mono-protonated p-aminophenol (C6H8NO)+ cations alongside two isolated tetrahedral anions ([ZnCl4]2− and [ZnCl3(H2O)]−). The stabilization of this hybrid compound accounts for a wide array of interactions, including hydrogen bonds and π–π (ring-ring) interactions, as deduced from comprehensive analyses. Theoretical investigations were conducted employing density functional theory (DFT) at the Cam-B3LYP/Lanl2dz level, accompanied by a detailed examination of the atoms in molecules (AIM) utilizing the BCP point. Furthermore, the nonlinear optical (NLO) properties were assessed, encompassing the evaluation of dipole moment, linear polarizability, and second hyperpolarizability. Notably, the compound exhibited pronounced solid-state fluorescence when excited at 350 nm, displaying intense emission within the blue spectrum. The correlated color temperature (CCT) value was measured at 7011 K, indicative of a "cool" white light emission. Basically, the synthesized compound exhibited antibacterial efficiency against several strains of human pathogenic bacteria in vitro and considerable enzyme inhibitory activity against pathogenic microorganisms. This research underscores the characteristics of (1), making it an appealing contender for a variety of applications.