Metal

Catalysis

Density functional theory

Receptor

Crystal structure

Single crystal

Enol

Biochemistry

Octahedral molecular geometry

Deprotonation

Stereochemistry

Ligand (biochemistry)

Organic chemistry

Natural bond orbital

Coordination complex

Powder diffraction

Hydrazone

Computational chemistry

Tautomer

Crystallography

Chemistry

Covalent bond

Schiff base

Moiety

Journal of Molecular Structure

A new iron(III) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing isoniazid and 3-ethoxysalicylaldehyde, with Fe(acac)3. The structure of the complex was explored spectroscopically through FT-IR, UV–Vis, PXRD and by elemental composition (CHN) through combustion analysis. The structure of the complex was explored by using single crystal X-ray crystallographic studies. It was revealed from the diffraction studies that both the keto and enol tautomeric forms of the ligand are present simultaneously in the Fe(III) complex. X-ray results showed that one of the ligands, due to keto-enol tautomerization, is doubly deprotonated and coordinated to the metal centre through one nitrogen and two oxygen atoms, while the other ligand behaves as a monoanionic moiety and is coordinated via phenolic oxygen, iminic nitrogen, and oxygen of the carbonyl group. Furthermore, it was also investigated by diffraction studies that the Fe(III) centre adopts a distorted octahedral geometry. HSA, QTAIM, MEP, and NCI calculations were performed to explore the presence of different kinds of non-covalent interactions. NBO analysis was also used to show the donor-acceptor interactions between the HOMO and LUMO of the molecule. Theoretical calculations performed by DFT at the B3LYP/Def2-TZVP method show that the theoretically calculated results are in close association with the experimental outcomes.

Diverse coordination of isoniazid hydrazone Schiff base ligand towards iron(III): Synthesis, characterization, SC-XRD, HSA, QTAIM, MEP, NCI, NBO and DFT study