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Some divalent metal(II) complexes of novel potentially tetradentate Schiff base N , N ′‐bis(2‐carboxyphenylimine)‐2,5‐thiophenedicarboxaldhyde: Synthesis, spectroscopic characterization and bioactivities
Author(s) -
Abdel Aziz Ayman A.,
ElSayed Ibrahim S.A.,
Khalil Mostafa M.H.
Publication year - 2017
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.3730
Subject(s) - chemistry , schiff base , chelation , ligand (biochemistry) , deprotonation , metal , imine , stereochemistry , nuclear chemistry , medicinal chemistry , polymer chemistry , inorganic chemistry , organic chemistry , ion , biochemistry , receptor , catalysis
A novel tetradentate dianionic Schiff base ligand, N , N ′‐bis(2‐carboxyphenylimine)‐2,5‐thiophenedicarboxaldhyde (H 2 L) and some first row d‐transition metal chelates (Co(II), Cu(II), Ni(II) and Zn(II)) were synthesized and characterized using various physicochemical and spectroscopic methods. The spectroscopic data suggested that the parent Schiff base ligand coordinates through both deprotonated carboxylic oxygen and imine nitrogen atoms. The free Schiff base and its metal chelates were screened for their antimicrobial activities for various pathogenic bacteria and fungi using the agar well diffusion method. The antibacterial and antifungal activities of all the newly synthesized compounds are significant compared to the standard drugs ciprofloxacin and nystatin. The antioxidant activities of the compounds were determined by reduction of 1,1‐diphenyl‐2‐picrylhydrazyl and compared with that of vitamin C as a standard. DNA binding ability of the novel Schiff base and its complexes was investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation. The obtained results clearly demonstrate that the binding affinity with calf thymus DNA follows the order: Cu(II) complex > Ni(II) complex > Zn(II) complex > Co(II) complex >H 2 L. Furthermore, the DNA cleavage activity of the newly synthesized ligand and its metal complexes was investigated using supercoiled plasmid DNA (pUC18) gel electrophoresis.