Metal saccharinate complexes with N-(2-aminoethyl)piperazine [M(sac)2(aeppz)2]: electrochemistry, antioxidant activity and DFT/TDDFT analysis

Previously synthesized [M II (sac) 2 (aeppz) 2 ] [M= Co ( 1 ), Ni ( 2 ), Cu ( 3 ), Zn ( 4 ), Cd ( 5 ); sac=saccharinate anion; aeppz=N-(2-aminoethyl)piperazine] type complexes which were structurally characterized have been further investigated electrochemically by cyclic voltammetry technique. Antioxidant activities of the complexes were evaluated using 1,1- Diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals scavenging, Fe 2+ chelating and superoxide dismutase activity methods and the results were compared with the uncoordinated aeppz ligand and the aeppz-free metal-saccharinate complexes. The molecules were also optimized using ORCA package program, molecular orbital diagrams were drawn, and highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) energy gap and electronic transitions of molecules were analyzed by Density Functional Theory (DFT)-Time Dependent DFT (TDDFT) calculations. Additionally, the reactivities of the molecules were evaluated for their Global Reactivity Descriptors according to Koopmans Theorem.