Synthesis, structural characterization, thermogravimetric, molecular modelling and biological studies of Co(II) and Ni(II) Schiff bases complexes.

Abstract Schiff bases complexes of Co(II) and Ni(II) ions with diethyl 3,3'-(ethane-1,2-diylbis (azaneylylidene)) (3E, 3′ E)-dibutyrate (H 2 L1) and (3E, 3′ E)-3,3'-(ethane-1,2-diylbis (azanylylidene))bis (N -(pyridin-2-yl)butanamide) (H 2 L2) have been synthesized, characterized and analytically formulated as [Co 2 (L1)Cl 2 ·2H 2 O]·H 2 O (1) , [Ni 2 (L1)Cl 2 ·6H 2 O]·2H 2 O (2) , [Co 2 (H 2 L2)Cl 4 ·2H 2 O]·H 2 O (3) and [Ni(H 2 L2)Cl 2 ]·H 2 O (4). The IR spectral data revealed that H 2 L1 ligand behaves as a N 2 O 2 binegative tetradentate in (1) and (2) through the oxygen of both enolized carbonyl (C O) groups and the nitrogen of two newly formed (C N)∗ groups. While H 2 L2 acts as neutral NNOONN hexadentate in (3) and as a neutral NNOO tetradentate in (4). The spectral and magnetic studies suggests a tetrahedral coordination geometry for complex (1) and octahedral geometry for other complexes. In addition, thermal degradation curves have been discussed for complexes in order to estimate their kinetic and thermodynamic parameters by two comparable methods. Various descriptors have been estimated using DFT calculations. Moreover, the anti-microbial activities and MTT cytotoxicity assay of the compounds have been examined. Graphical abstract Image 1 Highlights • Co(II) and Ni(II) complexes of new Schiff base ligands have been isolated. • 1HNMR, 13CNMR and mass spectra of both Schiff base ligands were determined. • Thermal behavior were studied for the metal complexes using TGA technique. • DFT studies were utilized to confirm the geometry. • Antimicrobial activity and MTT assay were tested for the investigated compounds. [ABSTRACT FROM AUTHOR]