Fluorescence and biological evaluation of the La(III) and Eu(III) complexes with 7-methoxychromone-3-carbaldehyde benzoyl hydrazone Schiff base.

A novel Schiff base ligand (L = 7-methoxychromone-3-carbaldehyde benzoyl hydrazone) and its La(III) and Eu(III) complexes have been successfully prepared. The crystal structure of [LaL(2)(NO(3))(3)].H(2)O was characterized by X-ray crystallography. It crystallizes in monoclinic, space group C2/c with crystallographic data: a = 27.7173(17) A, b = 10.0002(6) A, c = 14.7884(9) A, beta = 102.6870(10) degrees and Z = 4. In the structure, the La(III) ion satisfies 12 coordination and three nitrate coordinate as bidentate ligand. The biological experiments show that the ligand and its two complexes can strongly bind to DNA through intercalation mode, and the three compounds also exhibit good antioxidant activities against OH(*) and O(2) (-*). Moreover, it is found that the Eu(III) complex exhibits characteristic fluorescence of europium ion in different organic solvent.

Crystal structures, DNA-binding studies and antioxidant activities of the Ln(III) complexes with 7-methoxychromone- 3-carbaldehyde-isonicotinoyl hydrazone.

The neutral mononuclear Ln(III) complexes (Ln = La, Sm) with 7-methoxychrom-one-3-carbaldehyde-isonicotinoyl hydrazone ligand (L) have been synthesized, characterized and investigated their interactions with calf-thymus DNA. The results show that the binding affinity of the La(III) complex is stronger than that of the Sm(III) complex and that of the ligand (L). Furthermore, the antioxidant activities of the ligand (L) and its Ln(III) complexes (Ln = La, Sm) were studied in detail.

Synthesis, characterization and DNA-binding properties of the Cu(II) complex with 7-methoxychromone-3-carbaldehyde-benzoylhydrazone.

A new chromone derivative (7-methoxychromone-3-carbaldehyde-benzoylhydrazone) ligand (HL) and its novel Cu(II) complex have been synthesized and characterized on the basis of elemental analyses, molar conductivities, proton nuclear magnetic resonance, infrared spectra and mass spectra analyses. The general formula of the Cu(II) complex is [CuL(HB2BO)]Cl x 2H2O. In addition, the interaction of the Cu(II) complex and its free ligand with calf-thymus DNA was investigated by electronic absorption spectroscopy, fluorescence spectroscopy and viscosity measurement. Results suggest that both the two compounds can bind with calf-thymus DNA via an intercalation mechanism. Furthermore, the Cu(II) complex can bind to DNA more strongly than the free ligand due to the chelating effect of copper(II) ion to the free ligand.

Synthesis, crystal structure, antioxidant activities and DNA-binding studies of the Ln(III) complexes with 7-methoxychromone-3-carbaldehyde-(4'-hydroxy) benzoyl hydrazone.

A novel chromone Schiff base, 7-methoxychromone-3-carbaldehyde-(4'-hydroxy) benzoyl hydrazone (L) and its Ln(III) complexes (Ln = La, Eu) were synthesized and characterized. The crystal structure of the La(III) complex was determined by single-crystal X-ray diffraction: crystallized in the orthorhombic system, space group Pbcn, Z = 8, a = 14.595(2)A, b = 20.055(3)A, c = 30.078(5)A, R(1) = 0.0657. Fluorescence titration spectra, electronic absorption titration spectra, EB displacement and viscosity measurement indicated that both the ligand and the complexes can bind to DNA via the intercalation mode, and that the binding affinity of the La(III) complex is higher than that of the Eu(III) complex and of the ligand (L). The antioxidant activity experiments show that these compounds also exhibit good antioxidant activities against (*)OH and O(2)(-). Moreover, the Eu(III) complex exhibits characteristic fluorescence of europium ion in different organic solvents.

Synthesis, fluorescence study and biological evaluation of three Zn(II) complexes with Paeonol Schiff base.

The synthesis of three Paeonol Schiff base ligand and their Zn(II) complexes are reported. The complexes were fully characterized by IR, (1)H NMR, elemental analysis and molar conductivity. The experiment results show the three Zn(II) complexes can emit bright fluorescence at room temperature in DMF solution and solid state. The fluorescence quantum yields (Phi) of three Schiff base ligands and their Zn(II) complexes were calculated using quinine sulfate as the reference with a known Phi(R) of 0.546 in 1.0N sulfuric acid. Furthermore, in order to develop these Zn(II) complexes' biological value, the antioxidant activities against hydroxyl radicals (OH*) were evaluated. The results show the three complexes possess excellent ability to scavenge hydroxyl radicals.

DNA-binding properties studies and spectra of a novel Cu(II) complex with a new coumarin derivative.

A new coumarin derivative (8-methylcoumaro-4a,10a-pyrone-3-carbaldehyde benzoyl hydrazone) ligand and its novel Cu(II) complex have been synthesized and characterized on the basis of elemental analyses, molar conductivities, (1)H-NMR, IR spectra, UV-visible spectroscopy and thermal analyses. In addition, the interactions of the Cu(II) complex and the ligand with calf-thymus DNA were investigated by spectrometric titrations, ethidium bromide displacement experiments and viscosity measurements. It was found that both the two compounds, specially the Cu(II) complex, strongly bind with calf-thymus DNA, presumably via an intercalation mechanism.