Cu(II), Co(II), Ni(II), Mn(II), and Fe(II) metal complexes containing N,N '-(3,4-diaminobenzophenon)-3,5-Bu-2(t)-salicylaldimine ligand: Synthesis, structural characterization, thermal properties, electrochemistry, and spectroelectrochemistry

Department of Chemistry, University of Siirt, 56100 Siirt, Turkey.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (Impact Factor: 2.35). 02/2010; 75(2):811-8. DOI: 10.1016/j.saa.2009.12.002
Source: PubMed


The synthesis, structure, spectroscopic and electro-spectrochemical properties of steric hindered Schiff-base ligand [N,N'-(3,4-benzophenon)-3,5-Bu(t)(2)-salicylaldimine (LH(2))] and its mononuclear Cu(II), Co(II), Ni(II), Mn(II) and Fe(II) complexes are described in this work. The new dissymmetric steric hindered Schiff-base ligand containing a donor set of NONO was prepared through reaction of 3,4-diaminobenzophenon with 3,5-Bu(t)(2)-salicylaldehyde. Certain metal complexes of this ligand were synthesized by treating an ethanolic solution of the ligand with an equimolar amount of metal salts. The ligand and its complexes were characterized by FT-IR, UV-vis, (1)H NMR, elemental analysis, molar conductivity and thermal analysis methods in addition to magnetic susceptibility, electrochemistry and spectroelectrochemistry techniques. The tetradentate and mononuclear metal complexes were obtained by reacting N,N'-(3,4-benzophenon)-3,5-Bu(t)(2)-salicylaldimine (LH(2)) with some metal acetate in a 1:1 mole ratio. The molar conductance data suggest metal complexes to be non-electrolytes.

69 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Starting from 5-bromo-N,N′-bis-(salicylidene)-o-tolidine (H2L) new complexes with Co(II), Ni(II) and Cu(II) were synthesised and characterised. The features of complexes have been assigned from microanalytical, IR, UV–Vis–NIR and EPR spectra, magnetic data at room temperature as well as thermal analysis. IR data are in accordance with bischelate nature of the deprotonated ligand that coordinates through azomethinic nitrogen and phenolic oxygen. The electronic spectra display the characteristic pattern of tetrahedral stereochemistry for [CoL]·H2O complex and octahedral one for [NiL(OH2)2]·H2O complex. The electronic spectra correlated with magnetic susceptibility measurements indicate a square-planar surrounding for [ML] (M:Ni, Cu) species, while the EPR spectrum of copper complex sustains the proposed stereochemistry. The thermal analysis evidenced that thermal transformations are complex processes according to TG, DTA and DTG curves including (crystallization or coordination) water elimination, thermolyses and oxidative degradation of Schiff base. All these processes lead to the most stable metallic oxides as final product.
    Journal of Thermal Analysis and Calorimetry 02/2012; 111(2). DOI:10.1007/s10973-012-2273-y · 2.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Using the Schiff base ligand, dbdppo (4-(3′,4′-dimethoxybenzaldehydene)2-3-dimethyl-1-phenyl-3-pyrazolin-5-one or hnbdppo (4-(3′-hydroxy-4′-nitrobenzaldehydene)2-3-dimethyl-1-phenyl-3-pyrazolin-5-one with polypyridyl ligand(s) as co-ligand(s), Cu(II) and VO(IV) complexes have been synthesized and characterized by the physicochemical properties. The electrochemical properties, DNA binding affinities, as well as photonuclease activities of the complexes, were examined in detail. The DNA binding characteristics of the Cu(II) and VO(IV) complexes was investigated by spectroscopic, electrochemical and viscosity measurements. The UV–Vis, and magnetic moment data revealed an octahedral geometry around Cu(II) ion and square-pyramidal geometry around VO(IV) ion and conductivity data conveyed the electrolytic nature of the complexes. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that both of the complexes bound to CT DNA by partial intercalation into the base pairs of DNA. Moreover, these complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm. Further, the synthesized ligands, in comparison to their metal complexes were screened for their antimicrobial activity against bacterial and fungal species. The activity data show that the metal complexes have more antimicrobial potent than the parent Schiff base ligands.
    Journal of Molecular Structure 01/2011; 985(s 2–3):173–183. DOI:10.1016/j.molstruc.2010.10.038 · 1.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel chelating agent (Sqtsc; H4L) bearing both hard and soft donor atoms was synthesized by the condensation of squaric acid with thiosemicarbazide. The ligand has two symmetrical sets of donor atoms (SNO), therefore, it was allowed to react with the metal ions at the mole ratio 2:1 (M:L). Mono- and bi-nuclear chelates were obtained in which the ligand showed a variety of modes of bonding viz. (OO)2−, (SNNS)2− and (SNO)2− per each metal ion supporting the ambidentate and flexidentate characters of the ligand. The mode of bonding and basicity of the ligand depend mainly on the type of the metal cation and its counter anion. All the obtained complexes have the preferable Oh-geometry except the VOII-complex (7) which has also the preferable square pyramid geometry. Structural elucidation was achieved via elemental and spectral data.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2011; 78(3):1097-1104. DOI:10.1016/j.saa.2010.12.058 · 2.35 Impact Factor
Show more