Facile preparation of the new organic ligands, schiff bases and metal complexes in well

For mitigating the wide spread antibiotic-resistant bacteria. This study aims: Simple synthesis of new series of coordination metal complexes: Cu(II), Co(II), Sm(III), Gd(III) and Tb(III) from the prepared Schiff base bis-hydrazones ligands I-VIII (derivatives of glyoxal, biacetyl and benzyl-hydroxybenzaldhyde and methoxysalicaldhyde). Structural features derived from elemental analysis (empirical formula), melting point (purity), nuclear magnetic resonance (¹H, ¹³C) spectra and mass spectra. Vibrational IR spectra confirmed strong bonding between metal ions and ligands assumed the coordination sites are oxygen and nitrogen atoms of carbonyl C = O and azomethine CH = N groups. ¹H-NMR spectra (chemical shift 3.5 ppm-10.388 ppm) confirmed all protons in the Schiff bases. Surface analysis SEM micrographs confirmed modified microstructure of 5^th ligand (LV) on complexation to Cu(II). Complex CuLV showed particle size range 276-367 nm. Optical activities of the metal complexes confirmed from electronic absorption spectra. Cu(II) complexes showed internal charge transfer bands. Powder X-ray diffraction pattern confirmed that CuLV complex formed in nm scale crystal with particle size range 13.91-35.49 nm. This complex is a potent antimicrobial agent in terms of the wide inhibition zone and low minimum inhibitory concentration (MIC) except for the fungi A.Niger and C.Glabrata (MIC 100 µgL^-1 and 400 µgL^-1 respectively).The promising inhibition of bacteria growth and low MIC suggested this metal complex as a new antibiotic. For its optimized geometry, molecular docking analysis predicted antibacterial activity and confirmed the observed weak antifungal activity corresponding to high MIC for A.Niger and C. Glabrata fungal species.