Synthesis, Structural Investigations, and Potential Antimicrobial and Anticancer Activity of Mononuclear Zn(II) and Cd(II) Complexes Decorated by Morpholine/Pyrazole s-Triazine Ligand

Abstract

The structure and biological diversities of [Zn(BPT^Morph)(H₂O)₃](ClO₄)₂ (1), [Zn(BPT^Morph)(NO₃)₂] (2), and [Cd(BPT^Morph)(NO₃)₂] (3) complexes were described. In all complexes, the Zn(II) and Cd(II) ions are coordinated with one 4-(4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)morpholine (BPT^Morph) molecule as a pincer NNN-chelate. The rest of the coordination sphere was found to depend on the type of anion. In 1, there are three coordinated water molecules leading to a distorted octahedral geometry around Zn(II). In 2 and 3, there are two coordinated NO₃⁻ groups that differ in their coordination modes. The two NO₃⁻ groups are monodentate in 1 and bidentate in 3. Hence, the coordination numbers of Zn(II) and Cd(II) are 5 and 7, respectively. Supramolecular structure investigations indicated the importance of O···H contacts in the molecular packing. The percentages of O···H contacts are 35.4%–36.1%, 44.8%, and 39.7% in complexes 1–3, respectively. The energy breakdown for the intermolecular interactions was performed using energy framework analysis to explore the forces that dominate these interactions. Anticancer activity of complexes 1–3 and BPT^Morph against HepG-2, MCF-7, and A-549 cancerous cells was presented. The best result is found for complex 3 against A-549 where the IC₅₀ is 2.77 ± 0.26 μg/mL and selectivity index is 12.5 although the corresponding values for BPT^Morph are 32.39 ± 2.82 μg/mL and 2.7, respectively. In addition, 3 outperformed the anticancer drug cis-platin against all cell lines. The antimicrobial activity of 3 is the best compared to 1, 2, and BPT^Morph. Interestingly, 3 showed antibacterial efficiency comparable to gentamycin against Proteus vulgaris.