title: Synthesis, structural investigation, DNA and protein binding study of some 3d-metal complexes with N'-(phenyl-pyridin-2-yl-methylene)-thiophene-2-carboxylic acid hydrazide.
abstract: The ligand, N'-(phenyl-pyridin-2-yl-methylene)-thiophene-2-carboxylic acid hydrazide (Hpmtc) derived from thiophene-2-carboxylic acid hydrazide and 2-benzoyl pyridine, and its metal complexes with Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized. These compounds are characterized by elemental analyses, magnetic susceptibility measurements, IR, NMR and UV-Vis spectral studies. The molecular structures of Hpmtc and its Co(II) (1), Ni(II) (2), Cu(II) (3) and Zn(II) (4) complexes are finally determined by X-ray crystallography. Various spectral and single-crystal X-ray diffraction studies suggest that Hpmtc coordinates with metal ions as a monobasic tridentate ligand forming mononuclear distorted octahedral complexes of the type [M(pmtc)2]. The molecular structures of the complexes are stabilized by CH⋯N, CH⋯O intermolecular H-bonding, and CH⋯π and π⋯π interactions. The DNA binding experiment of the complexes 1, 3 and 4 by UV-Vis absorption, and EB-DNA displacement by fluorescence spectroscopy, reveal an intercalative mode of binding between CT-DNA (calf-thymus DNA) and the metal complexes. These complexes exhibit a moderate ability to cleave pBR322 plasmid DNA. A comparative bovine serum albumin (BSA) protein binding activity of the complexes 1, 3 and 4 has also been determined by UV-Vis absorption and fluorescence spectroscopy. The DNA binding and protein binding studies suggest that the complex 3 exhibits more effective binding activity (Kb=5.54×10(5) and Kq=1.26×10(6) M(-1), respectively) than complexes 1 and 4. However, the complex 1 shows better hydrolytic DNA cleavage activity compared to 3 and 4 complexes.
authors.affiliation: Department of Chemistry, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Monika
authors.initials: M
authors.lastname: Mishra
authors.affiliation: Department of Chemistry, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Karishma
authors.initials: K
authors.lastname: Tiwari
authors.affiliation: Department of Zoology, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Sachin
authors.initials: S
authors.lastname: Shukla
authors.affiliation: Department of Zoology, Banaras Hindu University, Varanasi 221005, India.
authors.forename: R
authors.initials: R
authors.lastname: Mishra
authors.affiliation: Department of Chemistry, Banaras Hindu University, Varanasi 221005, India. Electronic address: singvp@yahoo.co.in.
authors.forename: Vinod P
authors.initials: VP
authors.lastname: Singh
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D002417:Cattle; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism*; D053837:DNA Cleavage; D004583:Electrons; D004996:Ethidium / Q000378:metabolism; D006834:Hydrazines / Q000737:chemistry / Q000378:metabolism*; D006860:Hydrogen Bonding; D008024:Ligands; D060328:Magnetic Phenomena; D008968:Molecular Conformation; D011485:Protein Binding; D066244:Proton Magnetic Resonance Spectroscopy; D011725:Pyridines / Q000737:chemistry / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D056831:Coordination Complexes; D006834:Hydrazines; D008024:Ligands; C000595755:N'-(phenyl-pyridin-2-yl-methylene)-thiophene-2-carboxylic acid hydrazide; D011725:Pyridines; D013876:Thiophenes; D012710:Serum Albumin, Bovine; D004247:DNA; C427203:calf thymus DNA; D004996:Ethidium
keywords: DNA binding; Hydrazones; Protein binding; Single crystal X-ray diffraction study; Transition metal complexes