Using the pyrazine- and triazine-modulated tripyridyldiamine ligand 6-phenyl-N²,N⁴-di(pyrazin-2-il)-1,3,5-triazine-2,4-diamine (H₂dpztzda), a new mononuclear copper(II) complex [Cu(H₂dpztzda)(NO₃)₂]∙2C₃H₇NO 1 has been synthesized, structurally characterized, and its antimicrobial properties studied. According to the single crystal X-ray analysis of complex 1, Cu(II) exhibits five coordination with a distorted trigonal bipyramidal geometry. The "inverted type" of EPR spectra (g_┴ > g_||~ g_e), alongside results from magnetic moment susceptibility and electronic spectrum studies, collectively support this observation. The calculated Addison value for 1 is τ₅ = 0.54, indicating also that the Cu(II) center possesses distorted trigonal bipyramidal geometry. The H₂dpztzda molecule coordinates with the Cu(II) as a tridentate ligand. Complex 1 exhibits two types of hydrogen bonding: classical and non-classical. It has been shown that the interactions involving C-H‧‧‧π, π-π, and hydrogen bonding significantly influence the crystal packing of synthesised complex 1 and play a crucial role in the formation of supramolecular motifs. The antimicrobial activity of the compounds was evaluated using the traditional well diffusion method. Both compounds (complex 1 and H₂dpztzda ligand) analyzed for antimicrobial activity showed highly effective results against the bacteria Pseudomonas aeruginosa, Mycobacterium phlei, and the fungi Aspergillus niger and Penicillium chrysogenum in lubricants and coolants.

doi.org/10.32737/0005-2531-2025-4-23-33