New N-heterocyclic aroyl hydrazone containing 4-oxopiperidine nucleus and its metal complexes: synthesis, spectroscopic, thermal, DFT, molecular docking and antimicrobial studies

In order to resist the growth of human pathogenic microorganisms, we have synthesized a new N-heterocyclic hydrazone ligand of ( E )–N'–(2-hydroxynaphthalen-1-yl)methylene-4-oxopiperidine-1-carbohydrazide (H 2 L) from the condensation reaction of 4-oxo-1-carbopiperidone hydrazide and 2-hydroxy-1-naphthaldehyde. The ligand reacted with metal salt of (M(II/III).Cl 2 ).nH 2 O formed the two types of complexes [M(III)C 17 H 19 N 3 O 5 Cl] and [M(II)C 17 H 20 N 3 O 5 Cl] adopted octahedral geometry; where M = Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) ion. The ligand was thoroughly characterized by elemental analysis, FT − IR, UV − Vis, NMR ( 1 H, 13 C), HR-mass spectroscopy. Furthermore, the structural properties of metal complexes have been established on the basis of elemental analysis, UV-vis spectra, molar conductivity, magnetic susceptibility, ESR, TG-DTA analysis. The ligand behaves dibasic, linkages via phenolic-O, azomethine-N, enolic-O atoms in metal (III) complexes and monobasic in metal(II) complexes. The decomposition pattern were ascertained by thermal analysis, and kinetics accountability from Coats–Redfern relation. The compounds were excited at λ ex  = 380 nm and observed good emission intensity at λ em  = λ527–533 nm. The surface morphology of ligand was distinct from complex proven an imaging by SEM analysis. The molecular geometry optimization, and quantum chemical properties have been retrieved from DFT. ADMET score have been predicted as a drug-likeness prospect from admetSAR method. The molecular docking outcomes displayed the good binding score of ligand with Adenylate kinase, Peptide deformylase (bacterial enzyme) and DNA polymerase (fungal enzyme).The in vitro antimicrobial potency of ligand and its complexes were showed the promising activity against the bacterial colony ( Escherichia coli , Salmonella typhi , Staphylococcus aureus, Bacillus substilis) , and fungal colony ( Candida albicans , Aspergillus niger) .