Synthesis of a New Ag(I)-Azine Complex via Ag(I)-Mediated Hydrolysis of 2-(((1-(Pyridin-2-yl)ethylidene)hydrazineylidene) Methyl)phenol with AgClO₄; X-ray Crystal Structure and Biological Studies

Abstract

A new Ag(I)-azine complex of the formula [Ag(La)]2(ClO4)2.1/2(Lb) was synthesized and characterized using elemental analysis, FTIR, XPS and single-crystal X-ray diffraction. The [Ag(La)]2(ClO4)2.1/2(Lb) complex was obtained via Ag(I)-mediated hydrolysis of 2-(((1-(pyridin-2-yl)ethylidene)hydrazineylidene)methyl)phenol (L) with AgClO4 leading to the formation of the azines (1E,2E)-1,2-bis(1-(pyridin-2-yl)ethylidene)hydrazine (La) and 2,2’-((1E,1’E)-hydrazine-1,2-diylidene bis(methanylylidene)) diphenol (Lb). The former underwent complexation with AgClO4, while the latter was co-crystallized with the resulting Ag(I) complex, leading to the complex formula [Ag(La)]2(ClO4)2.1/2(Lb). In this complex, the azine La is acting as a bridged bidentate chelate connecting the two Ag(I) sites, leading to a tetra-coordinated Ag(I) with a distorted square planar coordination environment. Hirshfeld analysis indicated the importance of the H…H (38.4%), O…H (17.9%), H…C (13.2%), C…C (9.0%) and N…H (8.9%) interactions in the molecular packing. The antimicrobial, antioxidant and cytotoxic activities of the [Ag(La)]2(ClO4)2.1/2(Lb) complex were examined and compared with those of [Ag(La)]2(ClO4)2. The former was found to have lower bioactivity than the latter, which shed light on the lowering of biological actions as a consequence of the incorporation of the azine Lb within the Ag(I) complex. In other words, lowering the %Ag decreases the biological actions. The [Ag(La)]2(ClO4)2.1/2(Lb) complex (ΜIC = 39 μg/mL) has higher activity against the fungus A. fumigatus than the control Ketoconazole (ΜIC =156 μg/mL). This complex also has good cytotoxic activity against colon carcinoma and weak antioxidant activity.

Keywords

• Ag(I)
• azine
• supramolecular structure
• X-ray
• antimicrobial
• cytotoxicity