Synthesis, Structural Characterization, Biological Activity, and DFT Studies of Cd(II) Complexes With Tridentate <i>s</i> ‐Triazine Ligands

ABSTRACT The [Cd(DPPT)Cl 2 ] ( 1 ) and [Cd(DMPT)(NO 3 ) 2 (H 2 O)].H 2 O ( 2 ) complexes of the 1,3,5‐triazine ligands DPPT and DMPT were reported. 1 has slightly distorted square pyramidal geometry around the Cd(II) ion, while 2 adopted distorted triangular dodecahedral coordination geometry. Hirshfeld energy framework analysis showed that electrostatic and dispersion energies have a significant influence in stabilizing their crystal lattice. DFT calculations predicted that 1 and 2 have 36 and 35 times greater hyperpolarizability than urea suggesting the new Cd(II) complexes as promising candidates for nonlinear optical applications. Both complexes exhibit broad‐spectrum activity against tested bacteria with inhibition zone diameters (IZDs) within the range of 17–35 mm and fungi (IZD = 15–20 mm), except for 1 against A. fumigatus . Both complexes outperformed the positive control gentamicin toward S. aureus . While gentamicin produced a 24 mm inhibition zone, complexes 1 and 2 achieved zones of 35 and 31 mm, respectively. Additionally, the Cd(II) complexes effectively inhibited the growth of HCT‐116 and A‐549 tumor cells. 1 is more active (IC 50 = 11.44 ± 0.23 and 7.86 ± 0.14 μ M) than 2 (IC 50 = 16.30 ± 0.49 and 32.50 ± 1.12 μ M) against these cells, respectively. Furthermore, the selectivity indices of Cd(II) complexes exceeded 1, suggesting their potential as antineoplastic factors.