四氮大环-金属配合物与DNA作用的电化学及谱学研究

Mononuclear copper（Ⅱ）, nickel（Ⅱ） and cobalt（Ⅲ） tetracoordinate macrocyclic complexes were synthesized and spectroscopically characterized. The crystal structure of the three compounds were determined by X-ray crystallography. The electrochemical experimental results indicate that the three complexes could interact with DNA mainly by electrostatic interaction. The interaction of tetracoordinate macrocyclic cobalt（Ⅲ） complex with DNA was studied by cyclic voltammetry and UV-vis spectroscopy. The experimental results reveal that tetracoordinate macrocyc- lic cobalt（Ⅲ） complex could interact with DNA by electrostatic interaction to form a 1 ： 1 DNA association complex with a binding constant of 7.50 ×10^3 L·mol^-1.     

Synthesis of a New Cobalt （Ⅱ） Complex and its Interaction with DNA

A new complex of bis(N-benzyl benzotriazole-N^3) dichloro Co(Ⅱ) (Co(Ⅱ)L2Cl2) was synthesized and its crystal was characterized. The interaction of this new complex with fs-DNA was studied by electrochemical and UV spectrophotometric method. In 0.01 mol/L pH 4.2 Tris-HCl buffer solution Co(Ⅱ)L2Cl2 has two reductive peaks with peak potentials at 0.38 V and 0.27 V, respectively, and an oxidative peak at 1.05 V. After the addition of DNA, the peak currents decrease and the peak potential at 0.27 V shifts negatively. The UV spectrophotometric experiment indicates that the maximum absorbance of Co(Ⅱ)L2Cl2 at 204 nm decreases and exhibits bathochromic shift after the addition of DNA. All the results reveal that Co(Ⅱ)L2Cl2binds with DNA by intercalation as well as electrostatic interaction.     

Synthesis of a New Cobalt (II) Complex and its Interaction with DNA

The interaction of metal complexes with DNA has been widely studied by differentmethods such as spectrophotometry, light scattering technique, fluorometry1-3. Manycomplexes such as Co(phen)2 ,Co(en)2 ,Fe(EDTA)2- etc.4,5 have been synthesized and 3+ 3+their effect on DNA has been studied in order to further explain the mechanism of genemutation, anti-cancer or cancer-induced reason and DNA targeted drugs. In this paper,a new cobalt complex was synth…     

Studies on the Interaction of Dinitratobis（phen） Cadmium Complex with DNA

DNA-binding properties of the dinitratobis（phen） cadmium complex [Cd（phen）2（NO3）2] （where phen = 1,10-phenanthroline） have been investigated with absorption titration, fluorescence spectroscopy, viscosity measurement, molecular modeling and density functional theory （DFT） calculations. The results indictate DNA-binding mode of the complex to be weak groove binding rather than partial intercalative interaction expected of the extended planar aromatic phen ring. In addition, the DNA cleavage study was carried out by gel electrophoresis experiment. The results showed that the complex both hardly cleaves pBR322 DNA in the absence and present ascorbate. So it is suggested that the formation of cadmium complex can decrease cadmium toxicity to some extents.     

Studies on the Interaction of Cobalt Mixed-Ligand Coordination Compound Containing Tetrapyrido [3,2-a:2′,3′-c:3″, 2″-h:2■,3■-j] phenazine with DNA

A new monometallic complex [Co(phen)_2tpphz]~(3+) (where tpphz is tetrapyrido [3,2-a:2′,3′-c:3″,2″-h:2′″,3′″-j] phenazine) was synthesized by the reaction of 5, 6-diamino-1,10-phenanthroline with [Co(phen)_2(phendione)]~(3+). It was characterized by elemental analysis, molar conductivity, IR, ~1H NMR, ultraviolet and fluorescence spectroscopy. The interaction of the complex with DNA was also investigated. The complex shows the absorption hypochromicity, fluorescence enhancement, the specific viscosity increased when bound to calf thymus DNA. The cyclic voltammetry (CV) measurement showed a change in peak current with the addition of DNA. All the results provide the support for the intercalative binding mode of the mononuclear complex.     

手性配合物Λ, Δ-[Ru(phen)2hpip]2+的两种结构对含G:T错配DNA识别的分子力学研究

In this work, the recognition of DNA including G：T mismatched pairs by the two different structures of [Ru（phen）2hpip]^2＋ was firstly studied with molecular modeling respectively. The results revealed that all of the four chiral isomers of the two structures could recognize the mismatched DNA from the minor groove orientation especially and the interaction was enantioselective and sitespecific. The two left isomers were more preferential than the right ones. Especially, the structure Ⅱ which had much lower energy after interacting with DNA was the advantaged structure. Detailed energy analysis indicated that the steric interaction in the process of the complex inserting base stack determined the recognition results and the electrostatic interaction made an effect to some extent.     

Spectroscopic study on the interaction between[Hg（SCN）4]2- and hemoglobin

The interaction between[Hg（SCN）₄]^2- and hemoglobin（Hb） under conditions that simulate a physiological environment was investigated by UV-vis spectroscopy,fluorescence spectroscopy,resonance Rayleigh scattering（RRS） spectroscopy and circular dichroism（CD） spectroscopy.The results obtained from the change of UV-vis and CD spectra,the quenching of Hb fluorescence and the enhancement of RRS intensity proved that a 10:1 type complex was formed between[Hg（SCN）₄]^2- and Hb.The possible mechanism suggested for the interaction was that ten Hg（SCN）₄]^2- anions entered the four subunits of a Hb molecule to react with some residues to form an adduct by coordination and electrostatic forces.The coordination of[Hg（SCN）₄]^2- with Trp was the major cause of the fluorescence quenching of Hb.     

Specific hydrolysis of DNA by Ce~(4+) -ODN hybrid

The cerium complex bound to the derivative of oligoDNA has been synthesized successfully that can hydrolyze DNA with sequence-specificity. The synthesized derivative of oligoDNA, 5'-EDTA-P-10 mers ODN, was demonstrated by HPLC. The fluorescence spectrum of Tb3+ was detected after its interaction with the hybrid of 10-mers ODN and 26-mers ODN and the results show that the artificial endo-enzyme can recognize and combine firmly with the substrate DNA. The electrophorogram shows that the cerium-oligoDNA hybrid can specifically hydrolyze its substrate DNA and the cleavage site of this hydrolysis reaction is also discussed. This artificial nuclease can be widely used in molecular biology and genetic engineering as one kind of endo-enzyme.     

三元配合物钯（Ⅱ）-2,2''-联吡啶-L-天冬氨酸与DNA作用研究

The ternary complex Pd(Ⅱ)-2,2‘-bipyridine-L-asparagic acid was synthesized and characterized by elemental analysis, IR-spectra and molar conductance. The formula of the complex is Pd(bipy)(L-asp). The interaction of the complex with DNA has been studied by UV-spectra, fluorescence spectra, CD-spectra and gel electrophoresis. The results showed that the interaction of the complex with DNA performed mainly in intercalative mode and the extent of interaction was dependent on the concentration of the complex.     

Synthesis,Characterization and Application of Methyl 3,5-Disulfo-benzoate Dipotassium Dihydrate as Nucleating Agent for Poly（L-lactide）

A newly synthesized aromatic sulfonate compound,complex 2 with formula of K2[H3COOC-C6H3（SO3）2]·2H2O（methyl 3,5-disulfo-benzoate dipotassium dihydrate） was synthesized and characterized by elemental analysis,infrared（IR） spectrometry,nuclear magnetic resonance（NMR） and crystal structure measurement.Single-crystal X-ray diffraction（XRD） revealed that complex 2 crystallized in the triclinic system with space group P（i）.Complex 2 was used as nucleating agent for poly（L-lactide）（PLLA）.The crystallization of PLLA with powder of complex 2 was investigated by means of differential scanning calorimetry（DSC） and polarized optical microscopy （POM）.The results prove that complex 2 was effective as nucleating agent for PLLA.It could accelerate crystallization by reducing the induction time and increasing the density of nuclei in the crystallization process.The half-time of crystallization（t0.5） for pure PLLA was about 8 times longer than that of PLLA sample with 1.0％（mass fraction） of complex 2.     

多吡啶锌配合物键合与切割DNA研究

The complex of Zn[(phen)(dione)Cl]ClO_4·H_2O(where phen is 1,10-phenanthroline and dione is 1,10-phenan-throline-5,6-dione)has been synthesized and characterized.The interaction of the complex with DNA was investi-gated using UV absorption,fluorescence spectroscopy and electrophoresis measurements.The results show that thecomplex mainly binds to the double helix of DNA with intercalation mode and the binding constant K is 2.4×10~4mol~(-1)·L.Moreover,the complex can efficiently cleave plasmid DNA at physiological pH and temperature.Thecleavage occurs via a hydrolysis mechanism,which is showed by adding radical scavengers,rigorously anaerobicexperiments,analysis for malondialdehyde-like products,and the hydrolysis experiment of BDNPP with a rate con-stant k_(obs)of 5.3×10~(-6)s~(-1).     

Spectrophotometric and Voltammetric Studies on the Interaction of Heparin with Phenosafranine

The interaction of phenosafranine （PSF） with a glycosaminoglycans of heparin （Hep） in aqueous solution has been characterized by UV-Vis absorption spectrophotometry and cyclic voltammetry in pH 1.5 Britton-Robinson （B-R） buffer solution. The addition of Hep caused decrease of the absorbance of PSF at 532 nm and the redox peak current of PSF. The study showed that an supramolecular complex of PSF-Hep was formed because of the electrostatic attraction of negatively charged Hep with the positively charged PSF, which resulted in the decrease of the equilibrium concentration of PSF in solutions, and the decrease of the absorbance or the peak current of PSF. The stoichiometry of the Hep/PSF complex was further calculated by voltammetric data with the result of 1：1 complex.     

Microwave Synthesis, Characterization and DNA-binding Properties of a New Cobalt（ Ⅱ ） Complex with 2,6-Bis（benzimidazol-2-yl）pyridine

A new cobalt(Ⅱ) complex with tridentate ligand 2, 6-bis (benzimidazol-2-yl)pyridine has been synthesized by microwave irradiation method and characterized by elemental analysis,electrochemical and spectral methods. The binding of the complex with calf thymus DNA has also been investigated by absorption and fluorescence spectra.     

Synthesis,DNA-binding,and Photocleavage of 2,3-Di-2-pyridylquinoxaline-silver（I） Complex

A new dinuclear complex, [Ag（L）（CH3CN）]2（ClO4）2·2H2O（L=2,3-di-2-pyridylquinoxaline）, was prepared and characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. The interaction of the complex with calf thymus DNA（CT-DNA） was investigated by absorption, fluorescence spectroscopies, and viscosity measurement. The results suggested that the complex was bound to DNA via an intercalative mode. The intrinsic binding constant value Kb was found to be approximately 1.48×10^3 L·mol^-1. Moreover, the Ag（I） complex could cleave the plasmid pUC19 DNA from the supercoiled Form Ⅰto the nicked FormⅡ under irradiation at 365 nm.     

Supramolecular assembly of 2,4,5-trifluorobenzoate complex based on weak interactions involving fluorine atoms

The complex[Cd（tfbz）₂（phen）]₂（1）（tfbz = 2,4.5-trifluorobenzoate,phen = 1,10-phenanthro-line） was synthesized using trifluorobenzoic acid ligand.The single-crystal structure of 1 has been determined by X-ray crystallography.The packing structure is characterized by the formation of an intricate threedimensional supramolecular network that depends on the C-H…F,F…F,F（lp）…π（1p = lone pair） interactions.     

The preparation of terephthalic acid by solvent-free oxidation of p-xylene with air over T（p-C1）PPMnC1 and Co（OAc）2

An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）₂ has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）₂ were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）₂ significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.     

Synthesis, Characterization and Properties of Tri-substitute Potassium Salt of Trinitrophloroglucinol

The title complex [K3（TNPG）·（H2O）2]n was synthesized by the reaction of the aqueous solutions of trinitrophlomglucinol （TNPG） with KHCO3. The complex was characterized by elemental analysis and FTIR spectroscopy, and its single crystal structure was determined by X-ray diffraction analysis. The structural analysis demonstrates that two different coordination modes of K cations [K（1） and K（2）] are around TNPG^3- anions in complex [Ka（TNPG）·（H2O）2]n, where the coordination numbers are eight. All K atoms coordinate with O atoms of phenolic hydroxyl group and nitro-group simultaneously. The thermolysis of the [Ka（TNPG） · （H2O）2]n has been investigated by using differential scanning calorimetry （DSC） and thermogravimetry-derivative thermogravimetry （TG-DTG） at a heating rate of 10 ℃/min. The thermal decomposition processes of the title complex were comprised of one endothermic dehydration stage and one exothermic decomposition stage in 270-320℃, and the final decomposition residue contained KNC. Impact and friction sensitivity results of the complex revealed its sensitive nature towards mechanical stimuli. The experiments verified that the complex has some characteristics of explosive.     

DNA Binding and Oxidative Cleavage by a Water-soluble Carboxyl Manganese（Ⅲ） Corrole

The interaction of calf thymus DNA （CT DNA） and water-soluble manganese corrole, 5,10,15-tris（4-carboxyphenyl）corrolatomanganese（Ⅲ） （MnuTCPC） has been studied by absorption spectra, fluorescence spectra and CD spectra, as well as by viscosity measurements. Results revealed that this manganese corrole binds to CT DNA via an outside groove binding mode with intrinsic binding constant Ku of 4.67 × 104 Lomol L DNA cleavage activities of MnmTCPC in the presence of various oxidants were also investigated, MnmTCPC can cleave the supercoiled plas- mid pBR322 DNA to both nicked and linear form in the presence of hydrogen peroxide or tert-BuOOH, while no nuclease activity was observed by using KHSO5 as oxidant. Inhibitor tests revealed that hydroxyl radicals or singlet oxygen was not involved in MnTCPC mediated DNA oxidative cleavage. It is suggested that （oxo）manganese（V） corrole is the possibly active intermediate in this oxidative cleavage reactions.     

Synthesis,Crystal Structure and Interaction with DNA of a Novel Chromium（Ⅲ） Complex Containing Salicylaldehyde Semicarbazone

The novel chromium（Ⅲ） complex with salicylaldehyde semicarbazone was synthesized and characterized by IR spectra and single-crystal X-ray diffraction analysis. The crystal belongs to the orthorhombic system, space group Pbca with a = 8.9849（13）, b = 12.0475（16）, c = 34.522（5）A, V = 3736.9（9）A3, Z = 8, C16H18C1CrN6O5, Mr= 461.81, De= 1.642 g/cm^3, F（000） = 1896,A（MoKα） = 0.799 mm^-1, the final R = 0.0370 and wR = 0.0827 for 2908 observed reflections with I 〉 2σ（I）. The interaction between the chromium（Ⅲ） complex with calf thymus DNA （Ct-DNA） has been investigated by absorption spectroscopy, fluorescence spectroscopy and viscosity measurements. The results indicated that the complex was bonded to Ct-DNA through a non-classical intercalative mode.     

Synthesis,Structure and Properties of an Iron Complex with Formally Zero Oxidation State

An unusual iron complex with formally zero oxidation state, iron bis（6,6’-dimethyl-2,2’-bipyridine）, was synthesized and its crystal structure was determined. Combination of experimental and theoretical studies reveals that the electronic structure of the complex is best described as Fe（II）(Mebipy^-)₂ with anionic Mebipy-ligands and high-spin Fe（II） center.