Synthesis, Magnetic Moment, Antibacterial, and Antifungal Studies of INH Incorporating Schiff Base Metal Complexes

Abstract

The Isoniazid (INH) ring system is one of the most important heterocycles in nature, as it represents an important structural motif of many biological compounds. It possesses significant antibacterial activity and is given in combination with Rifampicin, ethambutol, or pyrazinamide. There is, therefore, an urgent need to design rapid, efficient, and environmentally benign protocols for the synthesis of metal complexation of INH-based moiety to improve its stability and bioactivity. Herein, we have developed a novel tetradentate INH incorporated Schiff base as an organic ligand, formed by the condensation reaction of INH and 4-hydroxy benzaldehyde in ethanol using glacial acetic acid resulting in the formation of N-[(E)-(4-Hydroxyphenyl)methylen]isonicotinohydrazid as primary ligand and its Cu(II), Co(II), Mn(II), Ni(II) and Zn(II) complexes having general composition [M(L)(H₂O)₂]·2H₂O. Spectroscopic characterization such as mass, IR, UV, ¹HNMR, and ¹³CNMR of N-[(E)-(4-Hydroxyphenyl)methylen]isonicotinohydrazid led to the conclusion that the synthesized Schiff base acts as a tetradentate organic ligand and can be used for further metal complexation. IR’s functional group frequency change confirmed its complex formation with transition metal ions. The octahedral geometry for the [M(INH-L)].2H₂O is proposed based on analytical and spectroscopic data of complexes. Magnetic susceptibility study indicates newly prepared transition metal complexes are paramagnetic. Present research work has several advantages such as the eco-friendly method, easy work-up, excellent yield for the preparation of bioactive organic ligands, improved stability, and antibiotic, antifungal properties of organic ligands after complexation.

Graphical Abstract

Keywords:

• INH Schiff base
• transition metal ion
• μ_eff
• antibacterial
• antifungal

Acknowledgment

Authors are grateful to Dr. Maqdoom Farooqui, Principal, Dr. Rafiq Zakaria College for Women, Aurangabad, MS, India for providing necessary research facilities.

Disclosure statement

Authors state no conflict of interest.