Novel Cu(II) and Zn(II) Nanocomplexes Based on 5,6-Diphenyl-1,2,4-Triazine: Preparation, Spectroscopic, TD-DFT Calculations, Molecular Docking and Solvatochromic Studies

The reaction between 2-hydroxy-1-naphthaldehyde and 3-hydrazino-5,6-diphenyl-1,2,4-triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)-DTHMN and tetrahedral Zn(II)-DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x-ray diffraction and thermal analysis. TEM analysis showed that Zn(II)-DTHMN complex has nano-rode morphology shape. On the other hand, Cu(II)-DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N-triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (E_T^N). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6-311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram-positive bacteria, Gram-negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ).