Ag(I)‐mediated hydrolysis of hydrazone to azine: Synthesis, X‐ray structure, and biological investigations of two new Ag(I)‐azine complexes

Abstract

Reactions of 2‐(1‐hydrazonoethyl)pyridine with silver salts AgX (X = NO3¯ or ClO4¯) proceeded via the hydrolysis of the pyridine ligand and the formation of the dinuclear [AgL1]2(ClO4)2 (1) and [AgL1(NO3)]2 (2) complexes of the azine ligand, 1,2‐bis(1‐(pyridin‐2‐yl)ethylidene)hydrazine (L1). The structures of the obtained complexes were determined by single crystal X‐ray diffraction. The azine ligand (L1) is acting as a bidentate ligand and connects the two Ag‐sites via the pyridine and the azine nitrogen atoms. In complex 1, the Ag(I) ion is tetra‐coordinated, while in complex 2 the Ag(I) ion is penta‐coordinated due to the presence of additional interaction with one of the oxygen atoms of the nitrate ion. As a result, the azine ligand is significantly twisted in complex 2 compared to complex 1. The optimized geometries of three conformers of L1 were calculated using DFT calculations, and their kinetic and thermodynamic stability were analyzed. It was found that a free rotation of L1 is required prior to the chelation of the Ag(I) ion. The packing in complex 1 is controlled by H…H, O…H, and Ag…O interactions, but in complex 2, the O…H and N…H interactions are the most significant. Complex 2 has better antifungal activity against Aspergillus fumigatus and Candida albicans than the antifungal drug Ketoconazole. Also, the nitrato complex 2 has a promising antioxidant activity compared to the perchlorate complex 1. The cytotoxicity against colon carcinoma HCT‐116 cell line is higher for complex 1 (IC50 = 19.72 ± 0.94 μg/ml) than complex 2 (IC50 = 68.31 ± 2.97 μg/ml).

Modified Polyacrylonitrile Fiber Silver Complexes To Display Semiconducting Behavior: Synthesis, Characterization, and Photocatalytic Oxidative Capacity

“…In addition to three peaks, a strong absorption peak of the Ag element was also found in the XPS survey spectra of Ag-AO-PAN, indicating the existence of Ag­(I) ions on the Ag-AO-PAN surface. Besides, the two different peaks in the spectrum of Ag3d (Figure e) were ascribed to Ag3d 5/2 (373.18 eV) and Ag3d 3/2 (368.08 eV), respectively; the result matched well with the previous literature. , It was worth noticing that the Ag3d with the binding energy at 368.18 eV in Ag-AO-PAN was lower than the corresponding value in AgNO 3 (368.20 eV), suggesting that the Ag­(I) ions had coordinated with AO-PAN as acceptor atoms. On the other hand, the spectra of N1s was deconvoluted into three subpeaks and is displayed in Figure f; two peaks at 399.88 and 400.88 eV were attributed to different N atoms in CN and NH 2 groups respectively, which were higher than those of the corresponding bonds in AO-PAN (399.2 and 400.2 eV) reported in our previous work. , More importantly, a new peak centered at 399.08 eV possibly corresponded to the generation of N–Ag bonds, demonstrating that the N atom from amidoxime groups could coordinate with Ag­(I) ions.…”

“…As seen from Figure 3d spectrum of Ag3d (Figure 3e) were ascribed to Ag3d 5/2 (373.18 eV) and Ag3d 3/2 (368.08 eV), respectively; the result matched well with the previous literature. 31,32 It was worth noticing that the Ag3d with the binding energy at 368.18 eV in Ag-AO-PAN was lower than the corresponding value in AgNO 3 (368.20 eV), 33 suggesting that the Ag(I) ions had coordinated with AO-PAN as acceptor atoms. On the other hand, the spectra of N1s was deconvoluted into three subpeaks and is displayed in Figure 3f; two peaks at 399.88 and 400.88 eV were attributed to different N atoms in C�N and NH 2 groups respectively, 34 which were higher than those of the corresponding bonds in AO-PAN (399.2 and 400.2 eV) reported in our previous work.…”