New bioactive 1D Ag(I) coordination polymers with pyrazole and triazine ligands; Synthesis, X-ray structure, Hirshfeld analysis and DFT studies

Abstract

The two new Ag(I) complexes [Ag(4BrPyz)2(NO3)]n(1) and [Ag2(2ClDAT)2(NO3)2(H2O)]n (2) of 4-bromo-1H-pyrazole (4BrPyz) and 2-chloro-4,6-diamino-1,3,5-triazine (2ClDAT) were synthesized and characterized using elemental analysis, FTIR and NMR spectroscopic techniques. Single crystal X-ray diffraction revealed that both complexes are 1D coordination polymers but differ in their nitrate anion coordination modes. Complex 1 contains silver atom in a distorted tetrahedral coordination environment, while complex 2 shows two different coordination modes for the silver atoms, a trigonal and a distorted square pyramidal environments. Hirshfeld surface analysis predicted many intermolecular contacts affecting the molecular packing, particularly the N···H and O···H hydrogen bonds, which are the most important. The charge transferences from ligand molecules to Ag(I), and also the interaction strength of the coordinate bonds, were determined using natural bond orbital (NBO) analysis. The anticancer activity of 1 and 2 was screened against breast (MCF-7) and lung (A-549) carcinoma cell lines which demonstrated superior substantial growth inhibition against both cell lines, particularly complex 2, which exhibits significantly higher activity against lung and breast carcinoma cell lines with IC50 of 1.85 μg/mL and 3.01 μg/mL, respectively compared to cis-platin (IC50 = 2.46 and 3.23 μg/mL, respectively). The two complexes along with the free ligands were examined for their antimicrobial and antioxidant activities. Complex 1 (DPPH; 273.6 ± 11.84 µg/mL) has a slightly improved antioxidant activity compared to 4BrPyz (DPPH; 355.5 ± 20.93 µg/mL). The Ag(I) complexes have no antifungal activity at the applied concentration against A. fumigatus and C. albicans but could be considered as a broad spectrum antibacterial agents.