Synthesis, spectral characterization, antioxidant and antidiabetic activities of transition metal complexes of 4-aminoantipyrine: experimental and theoretical studies

• A new series of metal complexes (1–12) were synthesized with 43–79 % yield using HL1 and HL2 ligands. • The synthesized compounds were evaluated for antioxidant and antidiabetic activities. • Complexes 3, 6, 9 , and 11 exhibited strong antidiabetic activity with IC 50 values of 12.52–43.89 μg/mL. • Iron and copper complexes showed enhanced antioxidant activity compared to their parent ligands. • Molecular docking and DFT studies confirmed the biological potential and reactivity trends of the synthesized complexes. A novel series of chelates with considered transition metals such as manganese (II), iron (II) cobalt (II), nickel (II), copper (II) and zinc (II) have been synthesized from the schiff base ligands. The newly synthesized 4-aminoantipyrine ligands ( HL 1 and HL 2 ) and their metal complexes ( 1–12 ) were characterized by UV–visible, FT-IR, 1 H-NMR, 13 C-NMR and mass spectrum analyses. Then these compounds ( HL 1 , HL 2 and 1–12 ) were examined for antioxidant and antidiabetic activities. The binding potential of the synthesized compounds to human alpha amylase was explored through docking study. The activities of ligands and their metal complexes against antidiabetic alpha amylase (PDB ID: 4GQR ) were compared with theoretical calculations. Then, the ADME/T properties of most active synthesized compounds were also examined to interpret and correlate the experimental results. Geometry optimization, global reactivity parameters, frontier molecular orbital, natural bond orbital and molecular electrostatic potential analyses of all the synthesized compounds were performed at DFT/B3LYP/6–31 G (d,p) theory level.