[Synthesis, characterization and interaction with ct-DNA of four novel secondary amine complexes].

A novel ligand(L), (N, N'-bis (4-methylbenzyl) ethane-1, 2-diamine), and its transition metal(II) complex, [ML2 (H2O)2]2+ x 2NO3- (M = Cu(II), Co(II, Ni(II), Zn(II)), have been synthesized and characterized by elemental analysis, IR and 1H NMR. The crystal structure of the Cu-L complex was characterized by X-ray single crystal diffraction, and the results showed a regular octahedral structure in which each metal ion is six--coordinated with four nitrogen atoms from two ligands and two oxygen atoms from two water molecules. The interaction of the complex with calf thymus DNA was investigated by UV spectroscopy and fluorescence spectroscopy, and the results suggest that the complex binds to DNA by electrostatic interaction mode. The binding constant(Cu-L, Co-L, Ni-L, Zn-L) was 1.67 x 10(3), 2.5 x 10(3), 1.35 x 10(3) and 9.85 x 10(2), respectively.

Bis(µ-N-benzyl-N-tetra-decyl-dithio-carbamato-κS:S')bis-[(N-benzyl-N-tetra-decyl-dithio-carbamato-κS,S')zinc(II)].

In the title compound, [Zn(2)(C(22)H(36)NS(2))(4)], two bidentate dithio-carbamate groups chelate directly to the Zn(II) atoms, whereas the two remaining dithio-carbamate ligands bridge the Zn atoms via a crystallographic inversion centre. The Zn atoms show a strongly distorted tetra-hedral geometry. Adding the long S⋯S distance with the inversion centre being in the middle, the resulting five-coordinate geometry around the Zn atoms can be considered to be between distorted recta-ngular pyramidal and trigonal bipyramidal, with a calculated τ value of 0.31. In this dimer complex, two inversion-related tetra-decyl carbon chains exhibit all-trans conformations, and the other two chains show a cis conformation at the end of the chains.

Synthesis, crystal structure and interaction with DNA and HSA of (N,N'-dibenzylethane-1,2-diamine) transition metal complexes.

A new ligand, N,N'-dibenzylethane-1,2-diamine (L) and its four transition metal(II) complexes, ML(2)(OAc)(2).2H(2)O (M=Cu, Ni, Zn, Co), have been synthesized and characterized by elemental analysis, mass spectra, molar conductivity, NMR and IR. Moreover, the crystals structure of Cu(II) and Ni(II) complexes characterized by single crystal X-ray diffraction showed that the complexes have a similar molecular structure. Ni(II) has an regular octahedral coordination environment complexes, but typical Jahn Teller effect influenced Cu(II) in an elongated octahedral environment. The interaction between complexes and calf thymus DNA were studied by UV and fluorescence spectra measure, which showed that the binding mode of complexes with DNA is intercalation. Under physiological pH condition, the effects of Cu(OAc)(2)L(2).2H(2)O and Ni(OAc)(2)L(2).2H(2)O on human serum albumin were examined by fluorescence. The results of spectroscopic measurements suggested that the hydrophobic interaction is the predominant intermolecular force. The enthalpy change DeltaH(0) and the entropy change DeltaS(0) of Cu(OAc)(2)L(2).2H(2)O and Ni(OAc)(2)L(2).2H(2)O were calculated to be -11.533 kJ mol(-1) and 46.339 J mol(-1)K(-1), -11.026 kJ mol(-1) and 46.396 J mol(-1)K(-1), respectively, according to the Scatchard's equation. The quenching mechanism and the number of binding site (n approximately 1) were also obtained from fluorescence titration data.

[Synthesis of sulfur-contained D(+)-glucosamine metal complexes and interaction with DNA and serum albumin].

Four sulfur-contained D(+)-glucosamine metal complexes were synthesized (M-GLUS, M = Co, Cu, Ni and Zn)and characterized by elementary analysis, molar conductance, and proton nuclear magnetic resonance. The yield of the complex was about 70%, and it dissolved easily in water. The ligand coordinates with metalions mainly between sulphur and metalions, the coordination molar ratio of the ligand to metalion was 2 : 1, and the molar conductivity indicated that all the complexes are nonelectrolyte. The mechanism of the interaction between metal complexes and calf thymus (ct) DNA in Tris buffer (pH = 7. 08), was studied by ultraviolet absorption and fluorescence spectroscopy. The results from varied experiments showed that the intensity of the maximal absorption peaks increased with gradual addition of metal complexes, but the metalions can decrease the maximal absorption and the ligand has no effect on it. Meanwhile, metal complexes could remarkably quench the emission intensity of the DNA-EB system, and the metal complexes could be bound to ct DNA. The quenching mechanism was discussed by Stern-Volmer's equation, the figure showed that it is influenced by static quenching and dynamic quenching, so the partial interaction of the complexes and ct DNA was the major mode. Under physiological pH condition, this study was designed to examine the effect of complexes on human serum albumin and bovine serum albumin by fluorescence. The binding constants and sites of the interaction with SA were analyzed by the Scatchard's equation, the results indicated that there was a strong interaction between the four metal complexes and serum albumin and the binding force was Co-GLUS > Zn-GLUS > Cu-GLUS > Cu-GLUS, and the binding site is only one.

Synthesis, characterization and DNA interaction studies of complexes of lanthanide nitrates with tris(2-[(3,4-dihydroxybenzylidene)imino]ethyl)amine.

A new tripodal, hydroxyl-rich ligand, tris(2-[(3,4-dihydroxybenzylidene)imino]ethyl)amine (L), and its complexes with lanthanide nitrates were synthesized. These complexes which are stable in air with the general formula of [LnL(NO3)2]NO3.H2O (Ln=La, Sm, Eu, Gd, Y) were characterized by molar conductivity, elemental analysis, IR spectra and thermal analysis. The NO3(-) groups coordinated to lanthanide mono-dentately, and the coordination number in these complexes may be 8. The interaction of complexes with DNA were investigated by ultraviolet and fluorescent spectra, which showed that the binding mode of complexes with DNA was intercalation, and the binding affinity with DNA were La(III) complex>Sm(III) complex>Eu(III) complex>Gd(III) complex>Y(III) complex. Based on these results, it can be shown that the La(III)complex is promising candidate for therapeutic reagents and DNA probes.

[Study on the interaction between Fe3(CO)12 and DNA by electronic and fluorescence spectrophotometry].

The interaction between Fe3(CO)12 and DNA was investigated by absorption and spectra, fluorescence spectra. The absorption of EB-DNA system in the presence of Fe3 (CO)12 showed that Fe3(CO)12 could partly sustain the place of EB. The result of fluorescence spectra suggested that Fe3(CO)12 could enhance the fluorescence intensity of DNA sharply. All the experimental results indicated that the intercalative binding mode was the major model for the interaction of Fe3(CO)12 cluster complex with DNA.

[Studies on the mechanism of the interaction between hydrazide-podophyllic Ni(II), Co(II), Zn(II) metal complexes and DNA].

The mechanism of the interaction between hydrazide-podophyllic (HDPP) metal (Me) complexes and calf thymus (ct) DNA in Tris buffer (pH 7.08) was studied by viscosity measurements, electronic absorption, gel electrophoresis, and ethidium bromide (EB) fluorescence spectroscopy. The results from varied experiments show that the intensity of the maximal absorption peaks from absorption spectra is weakened in the presence of DNA compared with that in the absence of DNA. Meanwhile, DNA can remarkably quench the emission intensity of the complex Me-HDPP system. The Me-HDPP complexes can increase the viscosity of ct DNA slightly and catalyze the cleavage of super coiled pBR322 DNA to the nicked form. The complexes of Ni-HDPP and Co-HDPP can be bound to ct DNA mainly by interaction, while the partial interaction of Zn-HDPP and ct DNA is the major modes. The binding constant of Me-HDPP complexes with ct DNA was determined.

Synthesis, characterizations and luminescent properties of three novel aryl amide type ligands and their lanthanide complexes.

Three new aryl amide type ligands, N-(phenyl)-2-(quinolin-8-yloxy)acetamide (L(1)), N-(benzyl)-2-(quinolin-8-yloxy)acetamide (L(2)) and N-(naphthalene-1-yl)-2-(quinolin-8-yloxy)acetamide (L(3)) were synthesized. With these ligands, three series of lanthanide(III) complexes were prepared: [Ln(L(1))(2)(NO(3))(2)]NO(3), [Ln(L(2))(2)(NO(3))(2)(H(2)O)(2)]NO(3).H(2)O and [Ln(L(3))(2)(NO(3))(2)(H(2)O)(2)]NO(3).H(2)O (Ln=La, Sm, Eu, Gd). The complexes were characterized by the elemental analyses, molar conductivity, (1)H NMR spectra, IR spectra and TG-DTA. The fluorescence properties of complexes in the solid state and the triplet state energies of the ligands were studied in detail, respectively. It was found that the Eu(III) complexes have bright red fluorescence in solid state. The energies of excited triplet state for the three ligands are 20325 cm(-1) (L(3)), 21053 cm(-1) (L(2)) and 22831 cm(-1) (L(1)), respectively. All the three ligands sensitize Eu(III) strongly and the order of the emission intensity for the Eu(III) complexes with the three ligands is L(3)>L(2)>L(1). It can be explained by the relative energy gap between the lowest triplet energy level of the ligand (T) and (5)D(1) of Eu(III). This means that the triplet energy level of the ligand is the chief factor, which dominates Eu(III) complexes luminescence.