Synthesis and molecular structure of a new metal-organic complex based on Zn(II) and quinoline, a precursor for fabrication of ZnO nanoparticles applicable in the photocatalytic reactions

A novel zinc-based pseudohalide metal–organic complex formulated as [Zn(NCS)4].2(C9H8N) (1) (C9H7N = quinoline) has been synthesized by a sonochemical process. The structure of 1 has been characterized by elemental analysis, atomic absorption spectroscopy (AAS), Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), differential thermal analysis (DTA) and single-crystal X-ray diffraction (SC-XRD). Complex 1 crystallizes in a monoclinic system, space group P21/c with unit cell parameters a = 8.5406(6) Å, b = 35.6706(17) Å, c = 8.6418(6) Å, and β = 107.093(7)º. Its structure consists of a tetrahedral [Zn(NCS)4] complex and two molecules of quinoline. In the crystal lattice of complex 1, the [Zn(NCS)4]2- complex anion is stacked in hexagonal-like columns forming 2D layers, each column includes an organic chain formed from one of [C9H8N]+ organic cations where the other cation separates between layers. The hydrogen bonds and some weak interactions are responsible for linking and strengthening the whole structure. Magnetic measurements revealed that complex 1 is a weak ferromagnet at room temperature. Nanoparticles of ZnO have been successfully synthesized by thermal decomposition of 1 and characterized by FT-IR spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller N2 adsorption-desorption analysis. The photocatalytic activity of commercial ZnO and as-obtained ZnO was investigated for degradation of methyl orange (MO) and Bisphenol A (BPA) under UV irradiation. The results revealed that the synthetic ZnO had higher catalytic activity than the commercial ZnO and the highest degradation occurs at pH = 4 and pH = 8 for MO and BPA, respectively.The financial support from University of Zabol (Grant No-9618-39), Spanish Ministerio de Economía y Competitividad (MAT2016-78155-C2-1-R and FPI grant BES-2011-046948 to MSM.A.), Gobierno del Principado de Asturias (GRUPIN-IDI/2018/170) are acknowledged