Synthesis of a New Dinuclear Ag(I) Complex with Asymmetric Azine Type Ligand: X-ray Structure and Biological Studies

Abstract

Aspects of the molecular and supramolecular structure of the new dinuclear [Ag(L)(NO3)]2 complex, where L is 2-((E)-(((E)-1-(thiazol-2-yl)ethylidene)hydrazono)methyl)phenol, were discussed. The complex was crystallized in the monoclinic crystal system and P21/n space group. The unit cell parameters are a = 10.3274(2) Å, b = 11.4504(3) Å, c = 12.7137(3) Å and β = 108.2560(10)°. The asymmetric unit comprised one [Ag(L)(NO3)] formula in which the azine and nitrate ligand groups act as NN- and OO-bidentate chelates, respectively. The coordination environment of the Ag(I) is completed by one weak Ag-O bond with another [Ag(L)(NO3)] unit, leading to the dinuclear formula [Ag(L)(NO3)]2. This was clearly revealed by Hirshfeld analysis. Additionally, the Ag…C, O…H and C…C intermolecular interactions played an important role in the molecular packing of the studied complex. The antimicrobial, antioxidant and cytotoxic activities of the [Ag(L)(NO3)]2 complex and the free ligand (L) were discussed. While the [Ag(L)(NO3)]2 complex showed very weak antioxidant activity, the results of the antifungal and cytotoxic activities were promising. The inhibition zone diameters (IZD) and the minimum inhibitory concentration (MIC) values were determined to be 31 mm and 20 μg/mL, respectively, against A. fumigatus, which is compared to 17 mm and 156 μg/mL, respectively, for the positive control Ketoconazole. Generally, the Ag(I) complex has better antimicrobial activities than the free ligand against all microbes except for S. aureus, where the free ligand has higher activity. Additionally, the IC50 value against colon carcinoma (HCT-116 cell line) was determined to be 12.53 ± 0.69 µg/mL, which is compared to 5.35 ± 0.49 µg/mL for cis-platin. Additionally, the Ag(I) complex displays better cytotoxicity than the free ligand (L) (242.92 ± 8.12 µg/mL).