title: Synthesis, spectroscopic studies and crystal structure of the Schiff base ligand L derived from condensation of 2-thiophenecarboxaldehyde and 3,3'-diaminobenzidine and its complexes with Co(II), Ni(II), Cu(II), Cd(II) and Hg(II): Comparative DNA binding studies of L and its Co(II), Ni(II) and Cu(II) complexes.
abstract: The Schiff base ligand, N,N'-bis-(2-thiophenecarboxaldimine)-3,3'-diaminobenzidine (L) obtained from condensation of 2-thiophenecarboxaldehyde and 3,3'-diaminobenzidine, was used to synthesize the complexes of type, [M2L2]Cl4 [M=Co(II), Ni(II), Cu(II), Cd(II) and Hg(II)]. The newly synthesized ligand (L) was characterized on the basis of the results of elemental analysis, FT-IR, 1H NMR, 13C NMR, mass spectroscopic studies and single crystal X-ray crystallography. The characteristic resonance signals in 1H NMR and 13C NMR spectra indicated the presence of azomethine group as a result of condensation reaction. The stoichiometry, bonding and stereochemistries of complexes were ascertained on the basis of results of elemental analysis, magnetic susceptibility measurements, molar conductance and spectroscopic studies viz., FT-IR, 1H and 13C NMR, UV-vis and EPR. EPR, UV-vis and magnetic moment data revealed an octahedral geometry for complexes with distortion in Cu(II) complex and conductivity data show 1:2 electrolytic nature of complexes. Absoption and fluorescence spectroscopic studies supported that Schiff base ligand L and its Co(II), Ni(II) and Cu(II) complexes exhibited significant binding to calf thymus DNA. The complexes exhibited higher affinity to calf thymus DNA than the free Schiff base ligand L.
authors.affiliation: Division of Inorganic Chemistry, Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India. shakir078@yahoo.com
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shakir
authors.forename: Ambreen
authors.initials: A
authors.lastname: Abbasi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Azam
authors.forename: Asad U
authors.initials: AU
authors.lastname: Khan
mesh_terms: D015100:3,3'-Diaminobenzidine / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000378:metabolism; D003300:Copper / Q000737:chemistry; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008628:Mercury / Q000737:chemistry; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry; D012545:Schiff Bases / Q000138:chemical synthesis* / Q000378:metabolism*; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013876:Thiophenes / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
chemical_list: C508885:2-thiophene carboxaldehyde; D000447:Aldehydes; D056831:Coordination Complexes; D012545:Schiff Bases; D013876:Thiophenes; D028561:Transition Elements; D002104:Cadmium; D015100:3,3'-Diaminobenzidine; D003035:Cobalt; D003300:Copper; D009532:Nickel; D004247:DNA; C427203:calf thymus DNA; D008628:Mercury; D015032:Zinc