Synthesis of Co(II), Mn(II), and Ni(II) complexes with 4-(4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)morpholine; X-ray structure, Hirshfeld, AIM, and biological studies

Three transition metal complexes of s-triazine ligand (^MorphBPT) were synthesized, characterized, and their supramolecular structures are explored. Their structures are confirmed to be [Co(^MorphBPT)₂](ClO₄)₂ (1), [Mn(^MorphBPT)₂](ClO₄)₂ (2), and [Ni(^MorphBPT)(H₂O)₃]Cl₂·2H₂O (3) using single crystal X-ray diffraction. In all cases, the ^MorphBPT is a tridentate N-chelator. Hence, the metal ions have hexa-coordination environment in all complexes. In the two homoleptic complexes 1 and 2, the O···H, C···H, and C···O contacts, in addition to some short N···O and H···H contacts detected only in 2, are the most important. For 3, the Cl···H, O···H, and C···H contacts are the most significant. Enrichment ratio was used to detect the atom pairs which have the highest probability to form non-covalent interactions. The nature of MN and MO coordination interactions is analyzed with the aid of AIM calculations. Also, the interactions with the ligand moieties lowers the charge of Co(II), Ni(II), and Mn(II) to 0.8411, 0.9332, and 0.8308 e, respectively. The three complexes 1, 2, and 3 exhibited antibacterial activity exceeds the reference drug gentamicin against P. vulgaris where the diameter of the inhibition zones (DIZs) are determined to be 28, 29, 27, and 25 mm, respectively. In addition, 1 and 2 have antifungal activity better (DIZ = 18 mm) and equal (DIZ = 17 mm) compared to ketoconazole against A. fumigatus, respectively. The Mn(II) complex 2 is the most active against MCF-7 (75.3 ± 3.1 μM) and A-549 (40.2 ± 2.7 μM) cancerous cell lines.