吡啶-2-羧酸的Dy(Ⅲ)和Tm(Ⅲ)配合物及其与牛血清白蛋白结合性能

以5-(三氟甲基)吡啶-2-羧酸(Htpc)与DyCl₃·6H₂O、TmCl₃·3H₂O构筑了2种异质同晶的单核配合物[M(tpc)₃(H₂O)₃]·H₂O,其中 M=Dy (1)、Tm (2)。配合物 1 和 2 均为单斜晶系,P2₁/c 空间群,中心金属离子为八配位且形成了轻微扭曲的十二面体构型。温度梯度下的荧光和紫外测试表明,2 种配合物均能与牛血清白蛋白(BSA)发生静态猝灭作用,猝灭常数(K_sv)为 10⁵~10⁶ L·mol^-1。配合物与BSA结合过程的ΔH和ΔS均为正值,说明疏水作用在其中扮演重要的角色。25℃时,2种配合物与BSA结合常数约为10⁴ L·mol^-1,表明二者与BSA的具有中等强度的结合力。     

吡啶-2-羧酸的Dy（Ⅲ）和Tm（Ⅲ）配合物及其与牛血清白蛋白结合性能

以5-(三氟甲基)吡啶-2-羧酸(Htpc)与DyCl₃·6H₂O、TmCl₃·3H₂O构筑了2种异质同晶的单核配合物[M(tpc)₃(H₂O)₃]·H₂O,其中M=Dy(1)、Tm(2)。配合物1和2均为单斜晶系,P2₁/c空间群,中心金属离子为八配位且形成了轻微扭曲的十二面体构型。温度梯度下的荧光和紫外测试表明,2种配合物均能与牛血清白蛋白(BSA)发生静态猝灭作用,猝灭常数(K_sv)为105~10⁶ L·mol^-1。配合物与BSA结合过程的ΔH和ΔS均为正值,说明疏水作用在其中扮演重要的角色。25℃时,2种配合物与BSA结合常数约为10⁴ L·mol^-1,表明二者与BSA的具有中等强度的结合力。     

苯并咪唑衍生的单核钴（Ⅱ）和单核镍（Ⅱ）配合物与DNA和蛋白质的结合反应性及细胞毒活性研究

利用紫外吸收光谱、荧光光谱、圆二色光谱（CD）等各种光谱手段对比地研究了由苯并咪唑衍生的单核钴配合物[Co（EDTB）]²⁺（1）和单核镍配合物[Ni（EDTB）]²⁺（2）（这里EDTB为N,N,N’,N’-四（2-苯并咪唑甲基）-1,2-乙二胺）与小牛胸腺DNA（CT-DNA）和牛血清白蛋白（BSA）的相互作用。结果表明,在生理条件下,配合物1和2均能通过插入方式较强的与CT-DNA结合,诱导DNA构象的改变;且配合物1对DNA的结合能力略强于2,其结合常数分别为K_b（1）=3.23×10⁴L·mol^-1和K_b（2）=2.40×10⁴L·mol^-1。配合物与BSA相互作用的研究表明,1和2均能与BSA发生较强的相互作用,结合常数均处在10⁴~10⁵L·mol^-1;该结合引起了BSA微环境和构象发生变化,且使BSA内源荧光被淬灭,淬灭机理为静态淬灭。利用MTT法研究了配合物1和2对小鼠白血病细胞株P388和人非小细胞肺癌细胞株A-549的体外细胞毒活性,实验结果表明,配合物1和2对P388不敏感,对A-549在高浓度（10^-4~10^-5mol·L^-1）下表现出与顺铂相当的细胞毒活性。     

重金属Cr(Ⅵ)与血清蛋白质组的结合反应性能研究

利用亲和毛细管电泳(Affinity capillary electrophoresis, ACE)方法,基于位点结合模型,构建配体(Cr(Ⅵ))-血清蛋白质组受体(Fetal bovine serum, FBS)结合反应方程,研究重金属离子Cr(Ⅵ)和血清蛋白质组的结合反应性能。结果表明,组学条件下,Cr(Ⅵ)与FBS中高丰度组分白蛋白(Bovine serum albumin, BSA)、转铁蛋白(Bovine apo transferrin, bATF)、免疫球蛋白(Bovine IgG, IgG)之间形成Cr(Ⅵ)-蛋白质络合物;结合反应均为快平衡反应;依据有效淌度的变化,通过结合方程测得结合反应的表观结合常数K_Cr(Ⅵ)-bATF=1.27×10⁴ L·mol^-1、K_Cr(Ⅵ)-IgG=4.91×10⁴ L·mol^-1、K_Cr(Ⅵ)-BSA=8.98×10⁴ L·mol^-1;同时根据实验数据非线性模拟结果表明,Cr(Ⅵ)与FBS中高丰度组分发生相互作用的强度与Cr(Ⅵ)浓度之间存在明显的量效关系。本文有关工作可为重金属离子-蛋白质络合物结合性能等生物无机化学研究内容提供参考。     

一个对2,4,6-三硝基苯酚和Fe3+离子具有双重荧光传感行为的层状镉(Ⅱ)-有机配位聚合物

通过水热法合成了一个由三连接的2,3-喹啉二甲酸桥联扭曲的Cd²⁺八面体形成的二维层状配位聚合物[Cd（QDA）]_n（1）。该配合物发射出较强的蓝色荧光并具有很高的热稳定性和化学稳定性。更为重要的是,该配合物在乙醇分散体系中可快速识别痕量的2,4,6-三硝基苯酚和Fe³⁺离子,其对2,4,6-三硝基苯酚的淬灭常数（K_sv）和检测限（LOD）分别为6.61×10⁴ L·mol^-1和0.83 μmol·L^-1,对Fe³⁺离子的淬灭常数和检测限分别为1.74×10⁴ L·mol^-1和2.70 μmol·L^-1。     

镍(Ⅱ)、镉(Ⅱ)与去甲基斑蝥酸钠和咪唑配合物的结构、与DNA/BSA的作用及抗增殖活性

以2种配体去甲基斑蝥酸钠(Na₂DCA=7-氧杂二环[2.2.1]庚烷-2,3-二甲酸钠)和咪唑(IM),分别与镍(Ⅱ)和镉(Ⅱ)的醋酸盐通过溶液法合成了2种配合物[Ni(IM)(DCA)(H₂O)₂]·2H₂O(1),[Cd₂(IM)₄(DCA)₂]·2H₂O(2)。应用元素分析、热重分析、红外光谱及X-射线单晶衍射法对配合物的组成和结构进行了表征。配合物1与2的中心离子分别与咪唑的亚胺氮原子、去甲基斑蝥酸根的羧基氧原子和醚键氧原子配位,配位数均为6,分别为单核(1)和双核(2)配合物。通过紫外光谱法、荧光光谱法和粘度法研究了配合物与DNA的相互作用。结果表明,配合物能通过部分插入模式与DNA发生较强的结合作用(K_b:5.51×10³(1)、1.01×10³(2)L·mol^-1)。同时,利用荧光光谱法研究了配合物与牛血清白蛋白(BSA)的相互作用。配合物能与BSA发生强烈的相互作用(K_AM:1.91×10⁵(1)和6.17×10⁵(2)L·mol^-1),结合位点数均为1。测试了配合物对人肝癌细胞(SMMC₇₇₂₁)和人乳腺癌(MCF-7)的体外抗增殖活性。结果显示,配合物对不同癌细胞具有选择性抑制作用。镍配合物(1)对SMMC₇₇₂₁的抗癌活性较去甲基斑蝥酸钠有明显提高。     

两个线形三核配合物的晶体结构及性质

合成并表征了2个新的线性三核配合物[Co₂^ⅢCo^ⅡL₂（μ-OAc）₄]（1）和[Ni₃L₂（μ-OAc）₂（CH₃OH）₂]·2H₂O（2）,其配体L为2-羟基-1,3-丙二胺和5-氟水杨醛缩合的产物。配合物1与DNA的作用通过紫外-可见光谱、荧光光谱、粘度实验和电化学方法进行了研究。紫外-可见光谱的结果表明配合物1与DNA的结合常数为2.43×10⁵ L·mol^-1。荧光光谱的研究结果表明配合物1能取代溴化乙锭和DNA结合,其淬灭常数为4.92×10³ L·mol^-1。配合物1和2的变温磁学性质研究表明在2个配合物的三金属中心之间均存在反铁磁性耦合。     

钌(Ⅱ)配合物[Ru(dpq)2L]4+的合成、晶体结构及与G-四链体DNA的相互作用

以cis-[Ru(dpq)₂Cl₂]·2H₂O(dpq=二吡啶[3,2-d:2',3'-f]二氮萘)为原料与5,5'-二(1-(三乙胺)甲基)-2,2'-联吡啶阳离子(L)合成钌(Ⅱ)配合物[Ru(dpq)₂L](PF₆)₄,并研究了该配合物与G-四链体DNA的作用:FRET实验表明,配合物对人端粒DNAh-telo具有选择性,其作用能力要强于同癌基因启动子区域的四链DNA,如c-myc和bcl2;CD光谱表明,在Na⁺和K⁺都不存在的情况下,配合物能诱导h-telo形成平行结构;此外,紫外和发射光谱都显示,配合物在K⁺溶液中与h-telo的作用力要大于在Na⁺溶液中的。     

4-氯-2-(1H-咪唑并[4,5-f][1,10]菲咯啉)苯酚铜(Ⅱ)配合物的晶体结构及其与DNA的相互作用

利用菲咯啉酮衍生物4-氯-2-(1H-咪唑并[4,5-f][1,10]菲咯啉)苯酚(HL)设计合成了一种新的单核铜配合物[Cu (L)(5-Cl-sal)(DMF)]ClO₄·DMF (5-Cl-Hsal=5-氯-水杨醛),用元素分析和X射线单晶衍射等手段对配合物进行了表征。该配合物晶体属三斜晶系,P1空间群。用紫外吸收光谱、荧光光谱和凝胶电泳等方法研究了配合物与DNA的相互作用。结果表明,配合物以插入方式与CT-DNA结合,结合常数为1.02×10³ L·mol^-1。同时配合物也能较大程度淬灭EB-DNA复合物的荧光,表观键合常数为4.37×10⁵ L·mol^-1,略小于经典键合常数10⁷ L·mol^-1。淬灭机理为动态淬灭。凝胶电泳实验研究表明配合物在H₂O₂存在下可将pBR322质粒DNA切割为开环缺口型DNA和线型DNA,配合物浓度越大,切割效果越好。机理研究显示,配合物切割DNA的反应是由羟基自由基(·OH)和单线态氧(¹O₂)作为活性物种的氧化切割过程。     

[Me3NC2H4OH]Zn2Cl5水溶液的激光光解研究

利用时间分辨激光光解技术研究了季铵盐型离子液体[Me₃NC₂H₄OH]Zn₂Cl₅(简写R-Zn₂Cl₅)的光解行为, 研究发现离子液体能被266 nm激光单光子电离, 生成阳离子自由基、[Zn₂Cl₅]^•中性自由基和水合电子, 观察到胆碱激发三线态的存在, 并测定了离子液体光电离的量子产额为0.04. 利用266 nm激光对离子液体、胆碱、氯化锌、氯化钠的光解行为比较, 发现胆碱阳离子的贡献很小, [Zn₂Cl₅]^－阴离子起主要作用. 采用氧化性自由基SO₄^•－引发离子自由基, 揭示其光电离机理, 测定离子液体的动力学反应速率常数, SO₄^•－ 460 nm的衰减速率常数为1.3×10⁹ L•mol^－1•s^－1, 320 nm离子自由基瞬态产物的生成速率常数为1.5×10⁹ L•mol^－1•s^－1, 两者很接近, 说明SO₄^•－自由基的衰减与瞬态自由基的生成是同步的.     

金属元素组与血清白蛋白的竞争结合反应性能研究

利用亲和毛细管电泳(Affinity capillary electrophoresis,ACE)法研究金属元素组和血清白蛋白(Bovine serum albumin,BSA)的竞争结合反应性能。基于位点结合模型,构建双金属组[Zn2+,Cu2+]与血清白蛋白结合反应模型,建立多元金属组与生物大分子竞争结合的理论方程,测定结合参数并解析动力学机制。结果表明,金属元素组[Zn2+,Cu2+]与BSA发生竞争结合反应形成配合物Zn2+-BSA和Cu2+-BSA。依据有效淌度变化,通过建立的理论方程非线性拟合竞争结合反应的平均表观结合常数KZn2+-BSA=4.01×104L·mol-1、KCu2+-BSA=7.75×104L·mol-1。结合反应均为快平衡反应,Cu2+对Zn2+离子的结合作用有明显拮抗作用。分析ACE谱显示配合物的峰高与配体结合能力大小、配合物稳定性之间存在量效关系。     

Effects of Temperature and Common Ions on Binding of Puerarin to BSA

The effects of temperature and common ions on binding of puerarin to bovine serum albumin (BSA) are investigated. The binding constants (K _a) between puerarin and BSA are 1.13×10⁴ L⋅mol⁻¹ (20 °C) and 1.54×10⁴ L⋅mol⁻¹ (30 °C), and the number of binding sites (n) is (0.95±0.02). However, at a higher temperature (40 °C) the stability of the puerarin–BSA system decreases, which results in a lower binding constant (1.58×10³ L⋅mol⁻¹) and number of binding sites (n=0.73) of the puerarin–BSA system. However, the presence of Cu²⁺ and Fe³⁺ ions increases the binding constants and the number of binding sites in the puerarin–BSA complex.     

Study on Interactions of Phenolic Acid-Like Drug Candidates with Bovine Serum Albumin by Capillary Electrophoresis and Fluorescence Spectroscopy

The interactions of the phenolic acids cinnamic acid (CNA), ferulic acid (FA), caffeic acid (CA) and chlorogenic acid (CLA) with bovine serum albumin (BSA) were investigated and compared using affinity capillary electrophoresis (ACE) and the fluorescence quenching methods. ACE gives binding constants (K _b) and thermodynamic parameters. The thermodynamic parameters show that each of four phenolic acids bind to BSA mainly by hydrogen bonds, electrostatic and hydrophobic interactions. The fluorescence quenching method provided quenching constant K _sv, binding site number n and K _b. The fluorescence results indicate that BSA fluorescence quenching is mainly a static quenching process. The binding constants (K _b) of CNA, FA, CA and CLA were from 2.52×10⁴ to 7.90×10⁴ L⋅mol⁻¹ from ACE experiments and 1.19×10⁴ to 5.21×10⁴ L⋅mol⁻¹ from fluorescence, their increase corresponded to the increase in the number of hydroxyl groups. These results imply that molecular structure and the number of hydroxyl groups of phenolic acids play act key roles in the affinity of natural phenolic acids towards BSA.     

苯乙烯三嗪衍生物的合成及在重金属离子识别中的应用

合成了2,4-二(2-噻吩乙烯基)-6-(4′-N,N-二甲氨基苯乙烯基)-1,3,5-均三嗪(2)并鉴定了其结构。在乙腈-水混合介质中,化合物2在355和416 nm处呈现双吸收峰,加入Cu2+,Hg2+和Fe3+后,均在520 nm附近形成新的吸收峰。化合物2与Cu2+、Hg2+和Fe3+均形成1∶1型配合物,其结合常数分别为1.9×105L·mol-1,6.6×103L·mol-1,2.7×103L·mol-1。对照化合物4与金属离子的光谱响应与化合物2相似,仅吸收峰的位置不同。因此,可认为化合物2和4中三嗪环中的N和噻吩环中的S与Cu2+、Hg2+和Fe3+共同配位形成了稳定的金属配合物。     

苯并咪唑衍生的单核钴(Ⅱ)和单核镍(Ⅱ)配合物与DNA和蛋白质的结合反应性及细胞毒活性研究

利用紫外吸收光谱、荧光光谱、圆二色光谱(CD)等各种光谱手段对比地研究了由苯并咪唑衍生的单核钴配合物[Co(EDTB)]2+(1)和单核镍配合物[Ni(EDTB)]2+(2)(这里EDTB为N,N,N′,N′-四(2′-苯并咪唑甲基)-1,2-乙二胺)与小牛胸腺DNA(CTDNA)和牛血清白蛋白(BSA)的相互作用。结果表明,在生理条件下,配合物1和2均能通过插入方式较强的与CT-DNA结合,诱导DNA构象的改变;且配合物1对DNA的结合能力略强于2,其结合常数分别为Kb(1)=3.23×104L·mol-1和Kb(2)=2.40×104L·mol-1。配合物与BSA相互作用的研究表明,1和2均能与BSA发生较强的相互作用,结合常数均处在104~105 L·mol-1;该结合引起了BSA微环境和构象发生变化,且使BSA内源荧光被淬灭,淬灭机理为静态淬灭。利用MTT法研究了配合物1和2对小鼠白血病细胞株P388和人非小细胞肺癌细胞株A-549的体外细胞毒活性,实验结果表明,配合物1和2对P388不敏感,对A-549在高浓度(10-4~10-5 mol·L-1)下表现出与顺铂相当的细胞毒活性。     

Effect of Hydrogenation on Ring C of Flavonols on Their Affinity for Bovine Serum Albumin

In this paper, the effect of hydrogenation on ring C of flavonols on the affinity for bovine serum albumin was investigated. Two differently substituted B-ring hydroxylation flavonols (myricetin and quercetin) and their dihydrides (dihydromyricetin and dihydroquercetin) were used to study their affinities for BSA by quenching the intrinsic BSA fluorescence in solution. From the spectra, the bimolecular quenching constants, the binding constants, the number of binding sites and the binding distances were calculated. The hydroxylation on ring B and hydrogenation on ring C of flavonols significantly affected the binding/quenching process; in general, the hydroxylation increased the affinity and the hydrogenation decreased the affinity. For myricetin and quercetin, the binding constants (K _a) for BSA were 1.84×10⁸ L⋅mol⁻¹ and 3.83×10⁷ L⋅mol⁻¹. For dihydromyricetin, the binding constant was 1.36×10⁴ L⋅mol⁻¹, while dihydroquercetin hardly quenched the BSA intrinsic fluorescence. These results showed that hydrogen bonding and conjugative effects may play an important role in binding of flavonols to BSA. These results also showed that the properties of flavonols are related to their chemical structure.     

Study on the Interaction of Raloxifene and Bovine Serum Albumin by the Tachiya Model

The interaction of bovine serum albumin (BSA) with raloxifene was assessed via fluorescence spectroscopy. The number of binding sites and the apparent binding constants between raloxifene and BSA were analyzed using the Tachiya model and Stern-Volmer equation, respectively. The apparent binding constant and the number of binding sites at 298 K were 2.33×10⁵ L?mol^?1 and 1.0688 as obtained from the Stern-Volmer equation and 2.00×10⁵ L?mol^?1 and 2.6667 from the Tachiya model. The thermodynamic parameters ΔH and ΔS were calculated to be 69.46 kJ?mol^?1 and 121.12 J?K^?1?mol^?1, respectively, suggesting that the force acting between raloxifene and BSA was mainly a hydrophobic interaction. The binding distance between the donor (BSA) and acceptor (raloxifene) was 4.77 nm according to Förster’s nonradiational energy transfer theory. It was also found that common metal ions such as K⁺, Cu²⁺, Zn²⁺, Mg²⁺ and Ca²⁺ decreased the apparent association constant and the number of binding sites between raloxifene and BSA.     

Probing the Interaction Between a Surfactant–Cobalt(III) Complex and Bovine Serum Albumin

The mechanism of binding of the surfactant–cobalt(III) complex, cis-[Co(phen)₂(C₁₄H₂₉NH₂)Cl](ClO₄)₂⋅3H₂O (phen = 1,10-phenanthroline, C₁₄H₂₉NH₂ = tetradecylamine) with bovine serum albumin (BSA) was investigated by UV–vis absorption, circular dichroism (CD) and fluorescence spectroscopic techniques. The results of fluorescence titration revealed that the surfactant–cobalt(III) complex quenched the intrinsic fluorescence of BSA through a combination of static and dynamic quenching. The apparent binding constant (K _a) and number of binding sites (n) were calculated below and above the critical micelle concentration (CMC). The thermodynamic parameters determined by the van’t Hoff analysis of the constants (ΔH ^∘=14.87 kJ⋅mol⁻¹; ΔS ^∘=152.88 J⋅mol⁻¹⋅K⁻¹ below the CMC and 25.70 kJ⋅mol⁻¹ and 243.14 J⋅mol⁻¹⋅K⁻¹, respectively, above the CMC) clearly indicate that the binding is entropy-driven and enthalpically disfavored. Based on F?rster’s theory of non-radiation energy transfer, the binding distance, r, between donor (BSA) and the acceptor (surfactant–cobalt(III) complex) was evaluated. UV–vis, CD and synchronous fluorescence spectral results showed that the binding of the surfactant–cobalt(III) complex to BSA induced conformational changes in BSA.     

Studies of the interaction between apigenin and bovine serum albumin by spectroscopic methods

The interaction between apigenin (Ap) and bovine serum albumin (BSA) in physiological buffer (pH = 7.4) is investigated by fluorescence quenching technique and UV-vis absorption spectra. The results reveal that Ap could strongly quench the intrinsic fluorescence of BSA. The quenching mechanism of Ap for BSA varies with the change of Ap concentration. when Ap concentration is lower, it is a static quenching procedure, when Ap concentration is higher, a combined quenching (both static and dynamic) would operate. The apparent binding constants Ka and number of binding sites n of Ap with BSA are obtained by fluorescence quenching method. The thermodynamic parameters, enthalpy change (Δ_r H ^m and entropy change (Δ_r S ^m ), are calculated to be −15.382 kJ mol⁻¹ K⁻¹ < 0 and 104.888 J mol⁻¹ K⁻¹ > 0, respectively, which indicate that the interaction of Ap with BSA is driven mainly by hydrogen bonding and hydrophobic interactions. The distance r between BSA and Ap is calculated to be 1.89 nm based on F?rster’s non-radiative energy transfer theory. The results of synchronous fluorescence spectra show that binding of Ap with BSA cannot induce conformational changes in BSA.