Synthesis, Hirshfeld surface analysis, thermal, and selective α-glucosidase inhibitory studies of Schiff base transition metal complexes

Abstract

A synthesized Schiff base ligand 4-{(Z)-[(2-hydroxy-1-naphthyl)methylene]amino}-4-antipyrene (H-NAPP) was confirmed by single crystal diffraction analysis. The H-NAPP was crystalized in the P 21 21 21 space group and orthorhombic crystal system. The Schiff base ligand H-NAPP bears potential donor sites and therefore it was reacted with transition metal ions Co2+, Ni2+, Cu2+, and Zn2+ to yield respective metal complexes. All reaction products were investigated by elemental analyses and IR spectroscopic techniques. The combined spectroscopic characterizations revealed the distorted square planar geometries for all the synthesized metal complexes. The metal complexes were further studied for their thermal stabilities using TG techniques and proved to be thermally cleaved in the temperature range of 30–1,000°C in air. Pseudo-mirrored 2D fingerprint plots were used for the short interatomic interactions in the crystal structure. The major short interatomic interactions involve the hydrogen bonding which covers the Hirshfeld surfaces {H···H, O···H and C···H}. The ligand and complexes were investigated for a potential α-glucosidase inhibitory activity. While relatively inactive throughout, some notable differences were observed and, surprisingly, the ligand was found to be more active than its complexes.

Keywords

• schiff base ligand
• transition metal complexes
• spectroscopy
• hirshfeld surface analysis
• thermogravimetry
• enzyme inhibition study