桂皮酸-邻菲啰啉稀土配合物的合成及其与DNA作用研究

分别以轻、中和重稀土Pr、Eu、Gd、Dy、Lu为中心离子,以桂皮酸(Hcin)和邻菲啰啉(phen)为配体,合成了五种三元稀土配合物。经C、H、N元素分析和稀土络合滴定推测三元配合物的组成为REphen(cin)3(RE3+=Pr3+、Eu3+、Gd3+、Dy3+、Lu3+);红外光谱和紫外吸收光谱测试表明配合物中RE3+与桂皮酸的羧基氧原子及邻菲啰啉的两个氮原子配位成键。采用紫外吸收光谱法及粘度法研究了三元稀土配合物与小牛胸腺DNA(CT-DNA)的作用,结果表明配合物是以插入方式与DNA结合,配合物中的平面分子phen在一定程度上插入到了DNA的碱基对中,与DNA的键合常数随稀土原子序数增大而增大,表明离子半径小的重稀土配合物更容易插入到DNA的碱基对中。     

含氮杂环铂(Ⅳ)配合物的合成、抑菌性及其与DNA作用研究

分别以咪唑(imidazole)、2,2'-联咪唑(2,2'-biimidazole)和邻菲咯啉(phenanthroline)为配体与氯铂酸钾作用合成了三种铂(Ⅳ)二元配合物并进行了表征,确定其化学组成分别为Pt(im)2Cl4·H2O(Ⅰ),PtH2biimCl4·H2O(Ⅱ)和PtPhenCl4·H2O(Ⅲ)(im=imidazole,H2biim=2,2'-biimidazole,Phen=phenanthroline).抑菌实验结果表明这3种配合物都具有一定的抑菌作用,并以溴化乙锭为荧光探针,研究了配合物与小牛胸腺ct-DNA的相互作用;采用电子吸收光谱法、荧光光谱法、热变性及盐效应等手段探讨了其作用机制并求出了结合常数K、结合位点数n以及热力学参数.实验结果表明:3种配合物均可以嵌插的方式与DNA发生强而稳定的作用,导致DNA双螺旋结构的破坏,使其具有一定的抑菌活性.     

三(2-苯甲酰胺乙基)胺及其Eu3+配合物的合成、表征及与DNA作用研究

合成了新型三脚架结构配体E(2-苯甲酰胺乙基)胺及其稀土Eu(3+)配合物.通过元素分析、IR、1H-NMR、TG-DTA和摩尔电导对此化合物进行组成和结构推测,结果显示配合物[EuL(NO3)2]·NO3是1:1型配位,3个硝酸根中有两个处于配位内界与Eu(3+)配位,总配位数为8.通过紫外吸收光谱、荧光发射光谱、粘度法及其与溴化乙啶(EB)的竞争实验研究了配合物与ct-DNA的作用情况,结果显示,配合物与ct-DNA作用时,其紫外吸收产生明显增色效应,荧光强度增强;EB-DNA体系的荧光强度随配合物的加入迅速减弱;配合物的加入使ct-DNA的粘度增加;实验结果证明,配合物与ct-DNA以插入方式结合,其键合常数Kq=8.86×10(3)L·mol(-1).凝胶电泳实验表明配合物[EuL(NO3)2]·NO3不能将pUC19 DNA选择性的断裂成线型和开环型DNA,并分析讨论了其原因.     

稀土金属有机电致发光器件研究进展

介绍了近年来国内外关于镧系稀有金属有机配合物及器件的研究进展，包括稀土金属薄膜器件传统制备技术和新型成膜技术——LB技术，稀土金属配合物材料选取配体的影响因素分析，制备稀土金属配合物材料新型技术——以溶胶-凝胶法为基础的OI技术，优化稀土金属有机电致发光器件性能的方法，以及稀土金属发光层材料的光伏特性研究等，同时提出目前器件存在问题和解决对策。     

[RE(pic)L](pic)_2·6H_2O的合成、荧光性质及与DNA作用方式初探

合成了四种N,N’-二(2-氨基吡啶)-1,1’-联萘-2,2’-二(氧杂乙酰胺)(L)稀土配合物。通过元素分析、红外光谱、紫外光谱、热重分析和摩尔电导率的分析,确定配合物的组成为[RE(pic)L](pic)2.6H2O[RE=La(Ⅲ)、Eu(Ⅲ)、Tb(Ⅲ)、Sm(Ⅲ),pic为苦味酸根],稀土离子的配位数为8,在CH3OH溶液中属于2∶1型电解质,该系列配合物的荧光光谱表明,Eu(Ⅲ)配合物的荧光强度远大于Tb(Ⅲ)配合物,说明配体L的三重态能级与Eu3+的激发态能级匹配较好。通过电子吸收光谱、荧光光谱和粘度法对配合物和DNA之间的作用方式进行了初步研究,结果表明,配合物与DNA之间存在着插入作用。     

手性Eu(Ⅲ)配合物的合成和作为ct-DNA荧光探针的研究

通过制备拆分剂氯化(8S,9R)-(-)-N-苄基辛可尼定,拆分了外消旋联萘酚得到其两种对映异构体,以手性联萘酚为原料分别合成了配体(R)-L和(S)-L及其相应的Eu(Ⅲ)配合物(R or S)-L-Eu(NO3)3,并测定了旋光度。分别研究了配合物(R or S)-L-Eu(NO3)3与ct-DNA的作用方式及键合常数,发现配合物与小牛胸腺DNA(ct-DNA)存在插入作用,且(R)-L-Eu3+配合物与ct-DNA的键合能力较强。由于ct-DNA对(R)-L-Eu3+配合物荧光的增敏作用,选择(R)-L-Eu3+配合物作为ct-DNA的手性荧光探针,在最佳实验条件下,其线性范围为0.11×10-5～0.55×10-5 mol·L-1,0.55×10-5～7.8×10-5 mol·L-1,检出限为5.85×10-7 mol·L-1。     

新型铈苦味酸配合物的合成、表征及其与白蛋白相互作用

合成了一种新的配体2,7-二(二苯胺酰乙氧基)萘及其铈苦味酸盐的配合物,采用1HNMR、红外光谱、元素分析、摩尔电导及热分析对其结构进行了表征,推测配合物的组成为[Ce(pic)3L2]。在pH=7.30的TrisHCl缓冲溶液中采用荧光光谱法分别研究了配合物与HSA、BSA、VOA的作用方式。结果表明,配合物对3种白蛋白的荧光猝灭属于静态猝灭,且猝灭程度为HSABSAVOA。计算了不同温度下配合物与3种白蛋白间的结合常数(KA)、结合位点(n≈1)及相关热力学参数(ΔH0,ΔS0,ΔG0),确定配合物与3种白蛋白之间主要靠静电作用力结合。并且采用同步荧光光谱及三维荧光光谱法研究了配合物对HSA、BSA和VOA构象的影响。     

1-萘甲酸稀土配合物的低温固相合成与表征

利用低温固相法合成了3种1-萘甲酸稀土配合物,经元素分析、稀土络合滴定及热重分析确定了配合物的组成为RE(L)3·nH2O [n＝0～1;RE＝La,Nd,Eu;L=C10H7COO-],红外光谱、核磁共振氢谱表明,1-萘甲酸稀土配合物中配体通过羧基以不对称桥式双齿的方式与稀土离子(Ⅲ)配位成键.二甲亚砜溶液中测定的摩尔电导率表明,所有配合物均为非电解质.铕(Ⅲ)配合物的荧光光谱和配体的磷光光谱表明,配体对铕(Ⅲ)的荧光具有一定的敏化作用.     

Tb1-xLaxA3(A＝邻氨基苯甲酸根,x＝0～0.9)固体配合物的光致发光

合成了一系列组成为Tb1-xLaxA3(A＝邻氨基苯甲酸根，x=0-0.9)的固体配合物。利用红外光谱，X射线衍射和荧光光谱研究了配合物的结构和荧光性质。红外光谱的结果表明，掺杂配合物的结构与未掺杂的邻氨基苯甲酸铽相似。X射线衍射的结果表明，掺杂配合物的晶体结构发生了改变。荧光光谱的结果显示，La^3 和Tb^3 的发光有显著的增敏作用。对荧光增敏的机理进行了探讨，荧光增强效应可以解释为配合物中异核多聚结构的分子内能量转移和掺杂离子配合物与中心离子配合物之间的分子间能量转移。     

均苯三甲酸邻菲罗啉稀土配合物的合成、表征及荧光性质

分别合成了以均苯三甲酸(H3BTC)和邻菲罗啉(phen)为配体,以Sm、Eu、Tb和Dy为中心的4种稀土三元配合物,通过元素分析及稀土络合滴定确定了配合物的组成为RELL'1.5 ·2H20(L=BTC,L'= phen);配合物的红外光谱、紫外光谱和荧光光谱测定结果表明,配合物中均苯三甲酸根的羧基氧原子和邻菲罗啉的氮原子均与稀土离子配位成键;四种配合物均可发出稀土离子的特征荧光,铕、铽配合物具有良好的荧光性能,钐、镝配合物也发出较强的特征荧光.     

Synthesis,crystal structures of novel complexes of rare earth with norfloxacin,interaction with DNA and BSA

Three novel rare earth complexes [N(CH 3) 4 ][Ln(NF) 4 ]·6H 2 O(Ln=Nd(III)(1),Sm(III)(2),Ho(III)(3)) were synthesized using hydrothermal method from norfloxacin HNF=1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid,C 16 H 18 FN 3 O 3),imidazole and rare earth nitrates.The complexes were characterized by elemental analysis,FT-IR,TG-DTG and X-ray single crystal diffraction.Each rare earth ion was eight-coordinated with carboxyl-O atoms and keto-O atoms from norfloxacin.Four of the norfloxacin ions acted as bidentate chelate group took part in the coordination with rare earth ion.The structures of complexes were tetragonal system with space group I4 1 /acd,which were allomerism.The interaction between complex 1 and DNA was studied by electronic absorption spectra and fluorescence spectroscopy.The binding interaction between the complex 1 and bovine serum albumin(BSA) was studied by fluorescence spectroscopy.The complex 1 bound to DNA by the mode of partial intercalation.Complex 1 had a strong ability to quench the fluorescence from BSA.The complex interaction was mainly a static quenching process with BSA together with formation of two binding sites.     

Coralyne has a preference for intercalation between TA.T triples in intramolecular DNA triple helices

Intercalating ligands may improve both the stability and sequence specificity of triple helices. Numerous intercalating drugs have been described, including coralyne, which preferentially binds triple helices, though its sequence specificity has been reported to be low [Lee,J.S., Latimer,L.J.P. and Hampel,K.J. (1993) Biochemistry , 32, 5591-5597]. In order to analyse the sequence preferences of coralyne we have used a combination of DNase I footprinting, UV melting, UV-visible spectrophotometry, circular dichroism and NMR spectroscopy to examine defined intermolecular triplexes and intramolecular triplexes linked either by hexaethylene glycol chains or by octandiol chains. DNase I footprinting demonstrated that coralyne has a moderate preference for triplexes over duplexes, but a substantial preference for TA.T triplets compared with CG. C+triplets. The drug was found to have essentially no effect on the melting temperatures of duplexes of the kind d(A)n.d(T)n or d(GA)n.d(TC)n. In contrast, it increased the T m for triplexes of the kind d(T)nd(A)n.dTn, but had little effect on the stability of d(TC)nd(GA).d(CT)n at either low or high pH. On binding to DNA triplexes, there is a large change in the absorption spectrum of coralyne and also a substantial fluorescence quenching that can be attributed to intercalation. The changes in the optical spectra have been used for direct titration with DNA. For triplexes d(T)6d(A)6.d(T)6, the Kd at 298 K was 0.5-0.8 microM. In contrast, the affinity for d(TC) nd(GA)n.d(CT)n triplexes was 6- to 10-fold lower and was characterized by smaller changes in the absorption and CD spectra. This indicates a preference for intercalation between TAT triples over CG.C+/TA.T triples. NMR studies confirmed interaction by intercalation. However, a single, secondary binding was observed at high concentrations of ligand to the triplex d(AGAAGA-L-TCTTCT-L-TCTTCT), presumably owing to the relatively low difference in affinity between the TA.T site and the competing, neighbouring sites.     

稀土配合物Eu(pic)_3L·2H_2O的合成、荧光性质及与DNA作用方式研究

合成了苦味酸铕与N,N-二苄基-N′-苯基-1,1′-联萘-2,2′-二(氧杂乙酰胺)(L)的稀土配合物。经元素分析,IR,TG-DTA和摩尔电导率的表征,确定其组成为Eu(pic)3L.2H2O。测定了配合物在不同溶剂中的荧光强度,发现其荧光强度随溶剂配位能力增强而减弱。通过紫外吸收光谱、荧光发射光谱、粘度法,稳态荧光猝灭方法及其与溴化乙啶(EB)的竞争实验研究了配合物与ct-DNA的作用情况,结果显示,配合物与ct-DNA作用时,其紫外吸收产生明显增色效应,荧光强度增强;EB-DNA体系的荧光强度随配合物的加入迅速减弱;在ct-DNA存在下,配合物被猝灭剂K4[Fe(CN)6]的发光猝灭程度减小;配合物的加入使ct-DNA的粘度增加;实验结果证明,配合物与ct-DNA以插入方式结合,其结合常数Kq=2.665×104L.mol-1。     

Photoaddition to DNA by nonintercalated chlorpromazine molecules

Chlorpromazine (CPZ) forms photoadducts with DNA and photosensitizes DNA strand breaks. These reactions may be responsible for the reported photomutagenicity of CPZ and for the well-known cutaneous and ocular phototoxicity associated with this drug. We have investigated whether CPZ molecules that are intercalated between base pairs in double-stranded (ds) DNA are the absorbing species for the photoaddition reaction. Quenching of CPZ fluorescence by ds-DNA gave nonlinear Stern-Volmer plots, indicating that more than one type of complex is formed. Linear dichroism spectra of CPZ in the presence of ds-DNA showed a minimum at 345 nm, indicating that the absorption maxima of intercalation complex(es) are red-shifted compared to the absorption maximum of free CPZ at 307 nm. The sum of the absorption of all CPZ complexes with ds-DNA, obtained from dialysis experiments, was broadened and maximized at about 315 nm, indicating that complexes not involving intercalation dominate the absorption spectrum at lambda < 350 nm. The wavelength dependence for covalent binding of CPZ to DNA was determined by irradiating 3H-CPZ in the presence of ds-DNA at 310, 322, 334, 346, 358 and 370 nm. The resulting spectrum correlated closely with the absorption spectrum of nonintercalated CPZ rather than with the spectrum of intercalated CPZ, indicating that the latter species is not the chromophore for the photoaddition reaction.     

Spectroscopy Study on Crystal Structure of Ce（NO3）3 （phen）2 and Interactions of Ce（NO3）3 （phen）2 with DNA

Inrecentyears ,Komiyaetal.[1] havefoundthatrareearthsionsmaybeoneofthestrongestcutre agentsofnucleicacids .Theexperimentalresults ,thatrareearthsrepresscancersonwholeanimalbodiesandonhumanbodies(invitro) ,indicatedthatrareearthselementsactuallyhavestrongf…     

Interaction of Complex of Europium and Hbbimp with DNA

TheartificialnucleasesforcleavingDNAhavebecomemoreimportant.Theenzymesystemmimicing theenzymaticsiteisthedicopperenzymehemocyanin thathasattractedmoreinterest[1～5].Somestudiesre portedthatmanynaturalenzymeswiththegoodactivi tiesalwayscontaintwoorthreeint…     

Aromatic stacking and bending of the DNA helix by the individual repeat units of the carboxy-terminal domain of RNA polymerase II

The carboxy-terminal domain (CTD) of RNA polymerase II consists of multiple repeats of the unique heptad sequence -(Ser-Pro-Thr-Ser-Pro-Ser-Tyr)- which may interact with DNA through the intercalation of adjacent tyrosine aromatic rings. We have examined details of the interaction of this motif with calf thymus DNA through analysis of peptide analogues that contain (1) an amino-terminal tyrosine which mimics the presence of an adjacent heptad repeat and (2) positively-charged lysine residues which facilitate the initial contact between peptide and DNA. Results of fluorescence experiments, NMR titrations, and viscometric analyses indicate that these peptides bind to the DNA helix through a non-classical intercalation mode involving partial aromatic stacking of the tyrosine rings with the Watson-Crick base pairs.     

Antitumour polycyclic acridines. Part 4. Physico-chemical studies on the interactions between DNA and novel tetracyclic acridine derivatives

The non-covalent interactions between a series of new tetracyclic acridine derivatives (5-11) and DNA have been studied by spectrophotometric analysis, fluorescences quenching, thermal denaturation, and circular and linear dichroism. In order to compare the extent of the DNA binding by compounds 5-11 in their neutral and cationic forms, all experiments were conducted at pH 7.4 (physiological pH) and 5.0. The results indicated that compounds 5-11 are strong DNA-binding ligands with DNA affinities comparable to that of m-AMSA (1) or even higher. They showed a stronger DNA binding activity at pH 5.0 as a result of the N-protonation of the pyridoacridine aromatic chromophore. Ethidium-DNA fluorescence assays showed an A-T base pair preference of the binding distinguishing these novel compounds from simple acridines which show a slight G-C base pair preference. Circular and linear dichroism studies indicated that the drugs bind to DNA by undergoing intercalation inside the duplex macromolecule at high DNA:drug ratios and revealed alternative binding modes at low DNA:drug ratios.     

The binding of echinomycin to deoxyribonucleic acid

Echinomycin is a peptide antibiotic which binds strongly to double-helical DNA up to a limit of approximately one molecule per five base-pairs. There is no detectable interaction with rRNA and only extremely feeble non-specific interaction with poly(rA)-poly(rU). Heat denaturation of DNA greatly decreases the binding, and similarly limited interaction is observed with naturally occurring single-stranded DNA. Association constants for binding to nine double-helical DNA species from different sources are presented; they vary by a factor of approximately 10, but are not simply related to the gross base composition. The interaction with DNA is ionic-strength-dependent, the binding constant falling by a factor of 4 when the ionic strength is raised from 0.01 to 0.10mol/litre. From the effect of temperature on the association constant for calf thymus DNA, the enthalpy of interaction is calculated to be about -13kJ/mol (-3kcal/mol). Binding of echinomycin persists in CsCl gradients and the buoyant density of nicked bacteriophage PM2 DNA is decreased by 25 mg/ml. Echinomycin interacts strongly with certain synthetic poly-deoxynucleotides, the binding constant decreasing in the order poly(dG)-poly(dC) greater than poly(dG-dC) greater than poly(dA-dT). For the latter two polymers the number of base-pairs occluded per bound antibiotic molecule is calculated to be three, whereas for poly(dG)-poly(dC) it is estimated to be four to five. Poly(dA)-poly(dT) and poly(dI)-poly(dC) interact only very weakly with the antibiotic. Poly(dI-dC) interacts to a slightly greater extent, but the binding curve is quite unlike that seen with the three strongly binding synthetic polynucleotides. Echinomycin affects the supercoiling of closed circular duplex bacteriophage PM2 DNA in the characteristic fashion of intercalating drugs. At low ionic strength the unwinding angle is almost twice that of ethidium. Likewise the extension of the helix, determined from changes in the viscosity of rod-like sonicated DNA fragments, is nearly double that expected for a simple (monofunctional) intercalation process. On this basis the interaction process is characterized as bifunctional intercalation. At higher ionic strength the unwinding angle relative to that of ethidium and the helix extension per bound echinomycin molecule fall, indicating a smooth progression towards more nearly monofunctional intercalation. Two simpler compounds which act as analogues of the quinoxaline chromophores of echinomycin, quinoxaline-2-carboxamide and the trypanocidal drug Bayer 7602, interact with DNA very much more weakly than does echinomycin, showing that the peptide portion of the antibiotic plays an essential role in determining the strength and specificity of the interaction.     

DNA receptor sites for the intercalation of nogalamycin

The intercalation of the planar chromophoric moiety of nogalamycin between two base pairs of duplex DNA has been evidenced by means of low-dichroism measurements. The possible presence of specific binding sites for mogalamycin on DNA has been suggested by studies on the denaturation and renaturation of DNA complexed with nogalamycin. A clear evidence was obtained by investigating the interaction of nogalamycin with polydeoxyribonucleotides containing known, regularly repeating sequences, used as model compounds. The results obtained with these polymers and the DNA suggest that the segment containing both purine (A,G) anf pyrimidine (T,C) bases in alternate sequences is the preferential receptor site on the DNA. A decreasing affinity is exhibited by poly d(A--T)-poly d(A--T), poly d(G--C)-poly d(G--C) and poly dG-poly dC segments, in the order. The poly dA-poly dT sequence appears to be closed to the interaction of nogalamycin.