title: Studies on some metal complexes of quinoxaline based unsymmetric ligand: Synthesis, spectral characterization, in vitro biological and molecular modeling studies.
abstract: Mononuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes of an unsymmetric Schiff base ligand, 3-(-(3-(-3,5-dichloro-2-hydroxybenzylideneamino)propylimino)methyl)quinoxalin-2(1H) -one (L) were synthesized and characterized by various analytical and spectral techniques. The molar conductance values of metal complexes indicate non-electrolytic behavior of the metal complexes. The Schiff base act as tetra dentate ONNO donor ligand in Co(II), Ni(II), Zn(II) complexes and tridentate NNO donor in Cu(II) complex. Thermal stabilities of the newly synthesized compounds were determined by thermal analysis. Crystallinity, average grain size and unit cell parameters were determined from powder X-ray diffraction study. Electrochemical behaviors of the compounds were examined by cyclic voltammetry technique. The Schiff base and its complexes have been screened for their in vitro antimicrobial activities against some bacterial and fungal strains by disc diffusion method. The interaction of the compounds with calf thymus DNA (CT DNA) has been investigated by electronic absorption spectral titration and viscosity measurement (hydrodynamic) methods. Furthermore, the pUC18 DNA cleavage activities of the complexes have been explored. The compounds were also subjected to in vitro antioxidant, anticancer activity screening, druglikeness and bioactivity predictions using Molinspiration software. Molecular docking studies of the present compounds were carried out against B-DNA dodecamer d(CGCGAATTCGCG)2 and vascular endothelial growth factor receptor (VEGFR-2) kinase. Quantum chemical calculations were done with DFT method to determine the optimum geometry of the ligand and its metal complexes. From the quantum chemical parameters, the reactivity parameters of the compounds were established.
authors.affiliation: Department of Chemistry, University College of Engineering, Nagercoil (Anna University Constituent College), Konam, Nagercoil 629004, Tamil Nadu, India. Electronic address: c.justindhanaraj@gmail.com.
authors.forename: Chellaian Justin
authors.initials: CJ
authors.lastname: Dhanaraj
authors.affiliation: Department of Chemistry, University College of Engineering, Nagercoil (Anna University Constituent College), Konam, Nagercoil 629004, Tamil Nadu, India.
authors.forename: Jijo
authors.initials: J
authors.lastname: Johnson
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry; D001665:Binding Sites; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D053837:DNA Cleavage / Q000187:drug effects; D055664:Electrochemical Techniques; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000737:chemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry; D062105:Molecular Docking Simulation; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011789:Quantum Theory; D011810:Quinoxalines / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D000970:Antineoplastic Agents; D000975:Antioxidants; D056831:Coordination Complexes; D008024:Ligands; D008670:Metals; D011810:Quinoxalines; D012545:Schiff Bases; D042461:Vascular Endothelial Growth Factor A; D004247:DNA; C427203:calf thymus DNA; D006861:Hydrogen Peroxide
keywords: Anticancer; Antioxidant; Bioactivity; DNA; Molecular docking