A Novel Na(I) Coordination Complex with s-Triazine Pincer Ligand: Synthesis, X-ray Structure, Hirshfeld Analysis, and Antimicrobial Activity

Journal article, 2023

The pincer ligand 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (bpmt) was used to synthesize the novel [Na(bpmt)(2)][AuCl4] complex through the self-assembly method. In this complex, the Na(I) ion is hexa-coordinated with two tridentate N-pincer ligands (bpmt). The two bpmt ligand units are meridionally coordinated to Na(I) via one short Na-N(s-triazine) and two slightly longer Na-N-(pyrazole) bonds, resulting in a distorted octahedral geometry around the Na(I) ion. In the coordinated bpmt ligand, the s-triazine core is not found to be coplanar with the two pyrazole moieties. Additionally, the two bpmt units are strongly twisted from one another by 64.94 & DEG;. Based on Hirshfeld investigations, the H & BULL;& BULL;& BULL;H (53.4%) interactions have a significant role in controlling the supramolecular arrangement of the [Na(bpmt)(2)][AuCl4] complex. In addition, the Cl & BULL;& BULL;& BULL;H (12.2%), C & BULL;& BULL;& BULL;H (11.5%), N & BULL;& BULL;& BULL;H (9.3%), and O & BULL;& BULL;& BULL;H (4.9%) interactions are significant. Antimicrobial investigations revealed that the [Na(bpmt)(2)][AuCl4] complex has promising antibacterial and antifungal activities. The [Na(bpmt)(2)][AuCl4] complex showed enhanced antibacterial activity for the majority of the studied gram-positive and gram-negative bacteria compared to the free bpmt (MIC = 62.5-125 & mu;g/mL vs. MIC = 62.5-500 & mu;g/mL, respectively) and Amoxicillin (MIC > 500 & mu;g/mL) as a positive control. Additionally, the [Na(bpmt)(2)][AuCl4] complex had better antifungal efficacy (MIC = 125 & mu;g/mL) against C. albicans compared to bpmt (MIC = 500 & mu;g/mL).