Role of ligand backbone of tridentate Schiff-base on complex nuclearity and bio-relevant catalytic activities of zinc(II) complexes: Experimental and theoretical investigations

摘要: Abstract Reaction of ZnII-acetate with two N, O-donor Schiff-base ligands, HL1 {4-Chloro-2-[(2-morpholin-4-yl-ethylimino)-methyl]-phenol} and HL2 {4-Chloro-2-[(3-morpholin-4-yl-propylimino)-methyl]-phenol}, which are formed in situ via condensation 5-chlorosalicylaldehyde N-(2-aminoethyl/propyl)morpholine, produce one tri- mononuclear species, Zn3L1(OAc)4 (1) ZnL2(OAc) (2). The hypothetical ZnL1(OAc) Zn3L2(OAc)4 energetically unfavorable by 9.2 5.1 kcal/mol, compare their respective real counterparts 1 2 evidenced from DFT calculations. Both catalyze the hydrolytic cleavage phosphoester bond (4-nitrophenyl) phosphate where shows higher activity than that 2. proposed mechanistic pathways phosphatase efficiency latter have been rationalized study. DNA activities investigated using supercoiled pET28a plasmid both complexes show dose dependent varying degree. Complex excellent breakage even at a concentration 20 μM. However, cases hydroxyl radical pathway is most probably operative activity.