Three new tetradentate NNNS Schiff bases (L1–L3) derived from2-(piperidin-4-yl)ethanamine
were prepared in high yields. UV–Visible and FTIR spectroscopy were used to monitor the dehydration
reaction between 2-(piperidin-4-yl)ethanamine and the corresponding aldehydes. Structures of the
derived Schi bases were deduced by 1H and 13C NMR, FTIR, UV–Vis, MS, EA, EDS, and TG-derived
physical measurements. DFT/B3LYP theoretical calculations for optimization, TD-DFT, frequency,
Molecular Electrostatic Potential (MEP), and highest occupied molecular orbital (HOMO) and lowest
unoccupied molecular orbital (LUMO) / were performed for L2. The in vitro antimicrobial activities
of the three Schi bases were evaluated against several types of bacteria by disk diusion test
using Gentamicin as the standard antibiotic. Schi bases revealed good antioxidant activity by
the DPPH method, and the IC50 values were compared to the Trolox standard. Pancreatic porcine
lipase inhibition assay of the synthesized compounds revealed promising activity as compared to the
Orlistat reference.