血卟啉及金属血卟啉与甲氧卞氨嘧啶相互作用的荧光光谱研究

荧光光谱法研究了甲氧卞氨嘧啶与血卟啉及金属血卟啉的作用情况 ,考察了酸度对甲氧卞氨嘧啶荧光强度的影响。在 p H=11.0的 KH2 PO4- Na2 HPO4缓冲液中 ,甲氧卞氨嘧啶有较强的荧光峰 ,血卟啉及金属血卟啉对甲氧卞氨嘧啶有明显的识别作用 ,结合常数大于 10 5,结合比均为 1∶ 1。金属血卟啉与甲氧卞氨嘧啶的结合常数小于血卟啉与甲氧卞氨嘧啶的结合常数 ,并对识别机理进行了探讨。     

血卟啉衍生物与血红蛋白相互作用的光谱特性研究

采用荧光光谱法和紫外-可见吸收光谱法研究了在不同温度下,血卟啉衍生物(HPD)与血红蛋白(Hb)结合反应的荧光猝灭光谱行为。证实由于非辐射能量转换机制,HPD对Hb有较强的荧光猝灭能力。根据Stern-Volmer方程和Lineweaver-Burk双倒数函数曲线,计算其结合常数在高温时要比低温时大,并获得相关结合常量和热力学参数。根据Fster能量传递原理计算出临界结合位点R₀＝3.22 nm。     

血卟啉与左旋多巴相互作用的研究

文章采用荧光光谱法研究了卟啉类化合物血卟啉与左旋多巴之间的相互作用,研究发现： 在模拟人体生理条件下(pH 7.4),随着体系中血卟啉浓度的增大,左旋多巴的荧光强度逐渐猝灭,荧光发射峰发生轻微蓝移,并有等发射点出现,表明卟啉与左旋多巴发生了作用,且形成了新的配合物。根据Stern-Volmer方程,求得了不同温度时两者的结合常数、相关系数及热力学常数,实验结果表明血卟啉HP对左旋多巴荧光猝灭速率常数Kq值均大于2.0×1010 L·mol-1·s-1,证实了血卟啉与左旋多巴的结合反应为静态猝灭反应,且随着温度的升高,结合反应常数有不同程度的减小。在25 ℃时,ΔG＝-26.58 kJ·mol-1;ΔS＝138.7 J·K-1;ΔH=14.71 kJ·mol-1。     

Mn(Ⅱ)与EHPG结合的光谱研究

在pH 7.4,0.05 mol·L-1 N-2-羟乙基哌嗪-N’-2-乙磺酸(Hepes)及室温条件下,用荧光光谱和紫外吸收差光谱进行了Mn(Ⅱ)与N,N’-乙烯-二[2-(2-羟基苯基)甘氨酸](EHPG)相互作用的研究。结果表明, Mn(Ⅱ)对EHPG荧光的猝灭为静态猝灭,Mn(Ⅱ)与EHPG形成1∶1的配合物,条件解离常数K_D为1.43×10-5。紫外吸收差光谱表明,随着Mn(Ⅱ)的不断滴加其紫外差光谱在238和291 nm处吸收峰逐渐增强。经计算配合物的ε_{238 nm}为(1.31±0.02)×104 cm-1·mol-1·L,条件解离常数K_D为(1.36±0.21)×10-5。与荧光光谱结果一致且均表明Mn(Ⅱ)与EHPG结合比较弱。     

光谱法考察对称四甲基六元瓜环与二氯化-二(2-苯并咪唑)丁烷的分子识别

以对称四甲基六元瓜环为主体,二氯化-二(2,2’-苯并咪唑)丁烷为客体,采用荧光光谱法和紫外吸收光谱法研究了主客体的相互作用。实验结果表明,主体对客体具有较强的包结识别能力,主客体之间可形成1∶1及2∶1的包结配合物,紫外吸收光谱法测得配合物的包结常数为K_(1∶1)=4.79±0.01×104 L·mol-1, K_(2∶1)=8.51±0.01×1010 L2·mol-2; 荧光光谱法测得配合物的包结常数为K_(1∶1)=7.02±0.01×104 L·mol-1, K_(2∶1)=2.88±0.01×1010 L2·mol-2,两种方法结果一致。     

碱性介质中茜素黄R与牛血清白蛋白作用的荧光法研究

在碱性条件下,采用荧光光谱法研究了茜素黄R(alizarin yellow R, AYR)与牛血清白蛋白(BSA)结合反应的光谱特征。研究表明,pH 11.00,激发波长为393 nm时,BSA的发射峰位于641 nm,且AYR对BSA有较强的荧光猝灭作用,AYR在BSA分子上荧光敏感部位有五个结合位点;由温度对AYR-BSA体系荧光猝灭速率的影响和动态猝灭常数K_SV以及静态猝灭结合常数K_LB的计算得出,AYR对BSA内源荧光的猝灭机制属于形成BSA-AYR复合物的静态猝灭,荧光猝灭常数为1.6×104 L·mol-1;由反应前后热力学函数ΔHθ＜0,ΔSθ＜0以及AYR对BSA-CBBG(CBBG-考马斯亮蓝G)体系具有荧光猝灭作用推出,茜素黄R与牛血清白蛋白之间的作用力主要是氢键和范德华力。     

马钱子碱与牛血清白蛋白相互作用的研究

应用荧光光谱和紫外光谱法研究了马钱子碱与牛血清白蛋白(BSA)的结合反应,求得它们之间的结合常数K_A和结合位点数n分别为K_A=6.3×103,n=0.94(27 ℃);K_A=7.7×103,n=0.97(37 ℃)。根据Frster非辐射能量转移理论求出了马钱子碱与BSA之间的结合距离为3.99 nm(27 ℃)和4.21 nm(37 ℃)。探讨了马钱子碱的荧光猝灭机理,结果表明马钱子碱能够插入BSA内部形成基态复合物导致内源荧光猝灭,猝灭机理主要是静态猝灭和非辐射能量转移。根据热力学参数确定马钱子碱与BSA之间的作用力类型主要为疏水性相互作用。     

光谱学研究血卟啉与鲱鱼精DNA的相互作用

以中性红(NR)作探针研究了血卟啉(HD)与DNA的相互作用.光谱学研究表明,血卟啉与DNA发生作用生成了超分子复合物.其结合比nHD:nDNA=3:1,血卟啉与DNA的结合常数K=1.84×104L/mol.同时运用Scatchart方程研究了血卟啉与DNA的作用方式,确定了血卟啉与鲱鱼精DNA之间的作用方式为混合作用方式.其作用机理可能是血卟啉以部分插入方式同时伴随共价和静电方式与DNA作用,影响其基因调控与表达,进而抑制肿瘤细胞的生长.     

人血清血卟啉荧光光谱的双正交样条小波识别

人血清中血卟啉含量很低,其荧光光谱强度很弱,往往呈肩峰形态,难以识别其位置和荧光强度。双正交样条小波可实现对其弱信号的分辨。在血清背景荧光光谱上叠加血卟啉荧光信号,并改变其荧光强度,得到一系列强度改变的 血清血卟啉荧光光谱。用双正交样条小波bior5.5对获取的荧光光谱通过7次小波分解,将背景与卟啉荧光信号分离,得到了离散逼近信号(a₁～a₇)和离散细节信号(d₁～d₇)。结果 表明,信号频率随着分解次数的增加逐步降低。当分解到第7次时,出现了血卟啉荧光特征峰。信号峰的位置随着信号强度的下降蓝移约2.5 nm,而通过小波滤波器提取的信号峰的位置不变。随着信号的强度降低,信号峰的位置逐渐消失 ,因而其荧光强度与荧光峰的位置无法确定,而通过小波滤波器提取的信号则不受影响,且灵敏度高,从而实现了用双正交样条小波对人血清血卟啉荧光光谱的识别。由于小波变换是线性变换,离散细节信号保持信号原有的线性关系,可 以用来对血清中所含血卟啉的准确成份和定量信息,从而进行定性和定量分析,为血清荧光光谱用于肿瘤的早期诊断提供了一种方法。     

原儿茶酸和藜芦酸与生物大分子相互作用的光谱学研究

原儿茶酸(P)和藜芦酸(V)属于酚酸类化合物, 具有广泛的生理和药理活性。应用荧光光谱,紫外光谱等方法研究了P和V与鱼精DNA(fsDNA)的相互作用机理。紫外光谱显示P和V在190～230 nm(K吸收带)、230～270 nm(B吸收带)和270～310 nm(R吸收带)有3个较强的吸收带。在280 nm激发光波长时,位于338和334 nm处有强的荧光发射峰,其荧光发射峰在与fsDNA结合后发生明显的猝灭现象。P和V的stern-volmer猝灭速率常数分别1.03×1012和0.61×1012 L·mol-1·s-1,为静态猝灭机理。药物与DNA之间形成了复合物,结合常数分别为K_fsDNA/P=6.22×106 L·mol-1、K_fsDNA/V=1.57×104 L·mol-1。研究表明,V与DNA之间的结合比为1∶1,而P可以与DNA分子中的两个碱基发生结合,这与P分子中的两个酚羟基有关。P和V的结构对它们与DNA的结合方式有较大的影响。     

Inert and stable erbium(III)-cored complexes based on metalloporphyrins bearing aryl-ether dendron for optical amplification: synthesis and emission enhancement

We have developed novel inert and stable erbium (Er)(III)-cored complexes based on metalloporphyrins for optical amplification. The functionalized metalloporphyrin ligands have been designed and synthesized to provide enough coordination sites for the formation of inert and stable 9-coordinated Er(III)-cored complexes. Er³⁺ ions were encapsulated by the metalloporphyrin ligands, such as Zn(II)- and Pt(II)-porphyrins. The near-infrared (IR) emission intensity of Er³⁺ ion is much stronger in the Er(III)-cored complex based on Pt(II)-porphyrin than Er(III)-cored complex based on Zn(II)-porphyrin. Furthermore, we have incorporated a G2-aryl-ether functionalized dendron into the Er(III)-cored complex, yielding an Er(III)-cored dendrimer complex bearing the Pt(II)-porphyrin. The Er(III)-cored dendrimer complex shows the stronger near-IR emission intensity than the corresponding complex based on Pt(II)-porphyrin by seven times in solid state. The lifetimes of the emission band of Pt(II)-porphyrin ligands in the visible region were found to be 30 and 40 μs for the Er(III)-cored complex and the Er(III)-cored dendrimer complex based on Pt(II)-porphyrin in deoxygenated THF solution samples, respectively. Also, in both cases, the sensitized luminescence intensity is increased in deoxygenated solution. Therefore, it indicates that the energy transfer from the metalloporphyrins to Er³⁺ ions takes places through the triplet state. In this paper, the synthesis and photophysical properties of novel Er(III)-cored complexes based on metalloporphyrins and Er(III)-cored dendrimer complex based on metalloporphyrin will be discussed.     

Cu(II) recognition materials: Fluorophores grafted on mesoporous silica supports

There were designed and synthesized naphthalene and pyrene derivatives consisting of fluorophore group and of receptor fragment with donor N and O atoms. These fluorosensors were covalently attached by grafting carboxyl group to surfaces of silica xerogel or mesoporous silicas (MCM-41 and MCM-48) functionalized either with 3-aminopropyl or 3-glycidoxypropyl groups. The pyrene derivatives 2 and 3 covalently grafted on MCM-48 silica functionalized with 3-aminopropyl groups are potential recognition elements of a fluorescence chemical sensor.Fluorescence emission of the prepared recognition materials is quenched specifically owing to photoinduced electron transfer (PET) effect after coordination reactions with Cu(II) ions. Moreover, both the materials exhibit selectivity for Cu(II) ions in aqueous solutions in presence of such metal ions as: alkali, alkaline earth and transition. During UV irradiation the studied recognition elements undergo slowly photochemical degradation.     

Optical spectra of Cu porphin and VO porphin in single crystal triphenylene

Polarized optical absorption spectra of copper porphin and vanadyl porphin in single crystals of triphenylene have been obtained at room temperature, 77°K and 4.2°K. Luminescence spectra of these samples are also reported. The gross features of the spectra of these two metalloporphins are similar but the spectral lines in vanadyl porphin are much sharper than those in copper porphin, revealing much more satellite structure. It is shown that the central metal can substantially affect metalloporphyrin absorption spectra, contrary to the case of broad band solution spectra. The data is consistent with porphin molecules in substitutional sites of triphenylene and a crystal field reduction of the usual D_4h metalloporphyrin symmetry to D_2h.     

Thea 1 mass from τ→a 1ν decay

The three recent experiments of the MARK II, DELCO, and ARGUS groups are reanalysed using an analytically correct Breit-Wigner form including apart from the ρπ also (i) the \(K*\bar K + \bar K*K\) thresholds, and (ii) an energy dependent real part (a “running” mass shift function involving Chew-Mandelstam functions) to thea ₁ mass parameter. It is found that all three experiments can be fitted with ana ₁ mass of (1250±40) MeV in agreement with the Particle Data Group value (1275±28) MeV, but in contrast to results presented by the experimental groups. However, the width ofa ₁ determined from the τ→a ₁ν→3πν decay data is considerably larger than the conventional value.     

取代基对卟啉类化合物三阶非线性光学特性的影响

主要采用吸收光谱、荧光光谱和皮秒Z-扫描等实验方法研究了三种不同取代基的卟啉化合物5,10,15,20-四对羟基苯基卟啉[T(4-HP)P]、5,10,15,20-四对酯基苯基卟啉[T(4-EP)P]和5,10,15,20-四对溴苯基卟啉[T(4-BrP)P]的光学及非线性光学性质,并从离域电子共轭结构理论和共振、非共振增强理论进行了分析。结果表明,强给电子基团取代的T(4-HP)P的吸收和荧光发射带比弱给电子基团取代的T(4-EP)P及吸电子基团取代的T(4-BrP)P有明显红移;三种样品均具有正的三阶非线性极化率χ(3),强的给电子能力和共振增强使得T(4-HP)P的三阶极化率比T(4-BrP)P增强了近两个量级,并在532 nm光激发时,χ(3)具有最大值6.81×10-10esu。     

Catalysis of nucleophilic aromatic substitutions in the 2,6,8-trisubstituted purines and application in the synthesis of combinatorial libraries

The following paper summarizes our work on compound libraries of 2,6,8-trisubstituted purines. This synthesis route on a polystyrene support begins with 2,6-dichloro purine making extensive use of catalysis. During the synthesis the polymer bound purines were brominated selectively on C8. The substitution reaction of C6-Cl by amines was found to be acid catalyzed. The substitution of C2-Cl by amines and aryls, as well as the substitution of a C8-Br by aryls, alkenyl and alkynyl groups can be catalyzed by transition metals. Under some bromination conditions novel selective oxidative transformations of 2-amino groups in 2,6-diamino purines have been found.     

四-(二甲氨基苯基)卟啉及其金属配合物的合成及光谱性能研究

以丙酸、乙酸、硝基苯为溶剂一步法合成了四-(二甲氨基苯基)卟啉(T(DMAP)P),并采用氯仿-N,N二甲基甲酰胺为溶剂合成了其与Zn2+,Mn2+,Tb3+三种离子的配合物,考察了溶剂种类、温度、时间对反应的影响,探讨了卟啉与金属盐反应两者用量的最佳比例,在较温和条件下合成了卟啉金属配合物,避免了高温合成金属卟啉不稳定现象。利用元素分析,IR,UV-Vis等方法确定了目标化合物的组成和结构。考察了不同浓度及温度下卟啉配合物的电导率并计算了其摩尔电导率。实验结果发现,卟啉与铽离子配合物摩尔电导率远大于锌、锰配合物。实验研究了不同金属离子对反应的影响,重点考察了卟啉及其金属配合物的分子光谱性能的差异。与四苯基卟啉相比,T(DMAP)P及其金属配合物UV-Vis光谱均发生红移,探讨了该现象产生的原因。     

Structural and Interaction Properties of Porphyrin Layers — A Quantum Chemical Study

This paper is proposed to understand the interaction of porphyrin layers with diatomic molecules interacting at their interior regions by applying ab initio and density functional theory(DFT) methods. We have used NO, CO, and O2 diatomic molecules to interact with the porphyrin layers. The most common Fe-centered metalloporphyrin structure with tetra-pyrrlic rings having N4 core is chosen for the study. The optimization of Porphyrin-Porphyrin(P I-P II)and Porphyrin-Diatomic molecule-Porphyrin(P I-AB-P II)(AB = NO, CO, and O2) complexes are performed using HF method. In order to understand the planarity and appropriate stacking size of porphyrins and also to infer the separation of diatomic molecules between porphyrin layers the behavior of P I-AB-P II complexes(where AB = NO, CO, and O2)are analyzed using structural properties and molecular electrostatic potentials(MEP). The MEPs are calculated using hybrid exchange correlation functional B3PW91 of DFT along with 6-31+G* basis set for the P I-P II and P I-AB-P II complexes obtained from HF method.     

Coordination and Oxidation States of Iron Incorporated in Mesoporous MCM41

Mesoporous Fe–MCM41 samples (Si/Fe=25) were synthesized and characterized under evacuation and reducing/oxidizing treatments by in situ FTIR and Mössbauer spectroscopies. Both Fe(II) and Fe(III) located in low coordination states in top layers of pore walls exhibit Lewis acidity and may participate in Fe(III) Fe(II) processes at low temperatures (570 K). Furthermore, Fe(III) Fe(II) cycles can be achieved and repeated with participation of the full amount of iron at higher temperatures (670 K). The accompanying formation of oxygen vacancies and restoration of the structure in the reverse process does not result in extended damages; the MCM41 structure retains its stability under the conditions applied.