COPPER(II) COMPLEX WITH PYRAZINE-AND TRIAZINE-MODULATED TRIPYRIDYLDIAMINE LIGAND: SYNTHESIS, CRYSTAL STRUCTURE, MAGNETIC, AND ANTIMICROBIAL PROPERTIES

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

~ ge), 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. © 2025, Azerbaijan National Academy of Sciences. All rights reserved.