四-(4-羧基苯基)卟啉在SDS胶束体系中的光谱研究

本文采用紫外-可见光谱法,研究了四-(4-羧基苯基)卟啉(TCPP)在阴离子表面活性剂十二烷基硫酸钠(SDS)胶束中的光谱行为。结果表明,由于TCPP的诱导作用,使SDS临界胶束浓度(CMC)值降低了。体相pH值由中性变化到酸性,TCPP在SDS胶束溶液中伴随着明显的质子化现象及跨膜转移过程。     

对微环境敏感的系列双亲卟啉的光谱研究

研究了系列双亲卟啉(四苯酚基卟啉P₀及其烷氧基衍生物P₁,P₂,P₃)在不同微环境下的电子吸收光谱和荧光发射及荧光激发光谱.研究发现,卟啉在THF溶液中以单体形式存在,并且其侧链取代基对卟啉电子态的影响很小;然而卟啉在CTAB胶束溶液中的光谱特性却表现出很大差异,由此分析了不同侧链取代基对卟啉分子聚集行为和定位性质的影响,初步解释了卟啉在CTAB胶束溶液中随体系pH值改变而发生的荧光猝灭现象.     

十二烷基磺酸钠对大豆过氧化物酶活性和构象的影响

在不同的pH值体系中, 利用酶活测量、圆二色谱、荧光谱和电子吸收谱研究了十二烷基磺酸钠(SDS)对大豆过氧化物酶(SBP)活性与构象的影响情况. 在pH 2.6和4.2 的体系中, 少量的SDS分子可通过静电作用与SBP结合, 进而与SBP分子中的His169残基结合, 降低其与铁卟啉的配位能力, 使其Soret吸收带蓝移, 二级结构发生轻微的变动, 活性永久丧失. 在pH 5.2体系中, SDS和SBP分子都带负电, 由于静电排斥作用, SDS无法进入SBP的分子内部, 失去与SBP分子中His169残基结合的能力, 对SBP分子的二级结构没有影响, 仅对SBP分子的三级结构有所影响. 当SDS的浓度大于临界胶束浓度时, 由于胶束与SBP的静电排斥作用增强, 限制了铁卟啉中乙烯基的运动, 乙烯基与卟啉环的共轭程度增大, Soret 吸收带红移. 由于SBP活性可完全恢复, 此变化是可逆的.     

含染料分子黑皂膜的共振Raman光谱

以染料分子BY为酸、碱性探针,研究了含BY的BSF,BY的CTAB胶束溶液和BY水溶液三种微环境,在不同pH条件下的共振Raman光谱。结果表明,束缚于BSF夹心界面和胶束界面的BY,具有类似的光谱变化,但BSF在很大的pH范围内(中-碱性),以酸式和碱式结构共存为特点。进一步研究发现,BSF夹心水核相的pH,对体相pH的变化,表现出相对稳定的新功能。     

单链四苯酚基卟啉在CTAB胶束微环境中的去质子化现象

叶绿素分子的光能转化功能的实现与其聚集状态、所处微环境性质及条件密切相关[1,2]．如何设计控制叶琳类分子在膜介质中的增溶位置，对于研究叶琳在膜体系中的跨膜电子传递、光能转化过程具有重要意义．本文研究了长链双亲卟啉──单链四苯酚基叶琳THPPH2在CTAB胶束中的去质子化，该过程能控制叶琳环在胶束中的增溶位置，使其由内核转移到胶束表面．1实验部分1·1仪器和测试条件岛津UV－240型紫外可见光谱仪（带有恒温夹套），狭缝宽2nm，石英池厚1cm，所用试剂皆为分析纯．UV光谱测试均在恒温条件下进行．1．2溶液的配制含一个十六…     

正离子型疏水改性聚氧乙烯单成相组分双水相系统的相行为

对正离子型疏水改性聚氧乙烯(HM-EO)单成相组分双水相系统的相行为进行了考察,并分析其电荷特性.HM-EO在水溶液中呈现两亲性,可以形成胶束,进而形成带电的胶束簇集体.通过改变溶液的pH值、盐浓度及添加带相反电荷的表面活性剂SDS,可改变胶束簇集体的带电状态,从而影响系统的相行为.增大pH值,有利于系统的分相.盐的添加也可以增大双水相两相区域,正离子影响次序为K+>Na+,负离子次序为SO42->F->Cl->Br->I-.进一步考察了HM-EO和SDS之间的相互作用,结果表明SDS能与HM-EO形成混合胶束簇集体,改变HM-EO双水相系统的带电特性.     

芘荧光探针法研究海藻酸钠与SDS的作用

采用芘荧光法研究了海藻酸钠(NaAlg)与十二烷基硫酸钠(SDS)在不同pH水溶液中的相互作用.以芘单体的荧光光谱第一峰与第三峰的荧光强度之比(I1/I3)及激基缔合物与单体荧光强度之比(IE/IM)来探测芘分子所处环境的极性.结果表明:NaAlg水溶液随pH值降低,出现了聚合物的疏水微区;pH从7降到5,NaAlg类似简单盐,对SDS的临界胶束浓度(CMC)有明显的影响;在pH 3时,海藻酸主链上有足够的疏水片段,使得SDS与海藻酸通过疏水性作用而聚集.NaCl对NaAlg /SDS体系的影响亦较明显.     

Ni(Ⅱ)与吡啶偶氮染料络合物形成的胶束催化

本文用停止流动法研究了水溶液中十二烷基硫酸钠(Sodium dodecyl sulfate,缩写SDS)胶束对Ni(Ⅱ)与吡啶偶氮染料(5-Bromopyridylazo diethylaminophenol and 3.5-dibromopyridylazo diethylaminophenol缩写为5-BrPADAP和3,5-2BrPADAP)络合物形成的动力学和胶束催化效应。动力学分析表明,胶束对于金属—配体络合物形成的催化作用主要是由于反应物在胶束表面区域的浓集效应;胶束的微环境既没有改变此络合反应的活化能,也没有改变反应途径。应用假相模型和的胶束催化概念,引入了配体有效反应浓度系数,从理论上定量地解释了SDS腔束对此络合反应的催化作用。     

四环己烷并卟啉的光谱性质及质子化反应常数的测定

本文测定了5,10,15,20-四(4-甲苯基)四环己烷并卟啉(1)、5,10,15,20-四苯基四环己烷并卟啉(2)和5,10,15,20-四(4-氯苯基)四环己烷并卟啉(3)在二甲基亚砜(DMSO)中的紫外-可见光谱,与相应的无环己烷并取代基的卟啉相比,所测定化合物的光谱吸收峰红移了19~33nm。同时测定了这三个四环己烷并卟啉在三氟乙酸(TFA)-DMSO和氢氧化四丁基铵(TBAOH)-DMSO介质中的吸收光谱,并与化合物在纯DMSO溶剂中的光谱进行了比较。在含有TFA或TBAOH的溶液中,化合物的Soret吸收峰均发生红移,而Q吸收峰数目则相应减少,表明化合物与酸发生了质子化反应,与碱则发生了去质子化反应。采用微量光谱法测定了每种四环己烷并卟啉在DMSO中与TFA反应的质子化常数,并讨论了取代基对质子化反应的影响。结果表明,上述三种四环己烷并卟啉在与TFA反应时均一步得到两个质子,质子化反应常数(logβ2)分别为12.4(1)、12.0(2)和11.5(3)。     

咖啡因及其9种类似物的胶束电动毛细管分析研究

 以十二烷基硫酸钠 (SDS)胶束为准固定相 ,考察了咖啡因及其 9种类似物在胶束电动毛细管 (MECC)分离模式下的分离行为。研究了运行缓冲液的 pH值、磷酸盐浓度、SDS浓度、甲醇体积分数、分离电压、分离温度等因素对这 10种化合物的迁移时间和分离效果的影响。结果发现 ,这些因素对上述 10种化合物的分离有显著的影响 ,尤以pH值为最。它不仅影响化合物的迁移时间和分离效率 ,还改变其出峰顺序 ,这与碱性条件下化合物仲胺基上氢的电离有关。优化后的分离条件 :运行缓冲液为 2 0mmol/L磷酸盐 2 0mmol/LSDS(pH 11 0 ) ,分离电压为2 5kV。     

Protonation of 5, 10, 15, 20-Tetra（4-hydroxyphenyl）-porphyrin in SDS Micellar Solution

An arnphiphilic porphyrin, 5, 10, 15, 20-tetra(4-hydroxyphenyl)-porphyrin (P) was solubilized in SDS micellar solutions. By taking advantage of protonation property of pyridine groups of amphiphilic porphyrin and the UV-Vis spectral sensitivity of Soret band and Q bands to the microenvironment of the porphyrin moiety, two-step protonation was studied in detail by means of UV-Vis spectroscopy. The free base, monocation and dication were described in detail in SDS micellar solution. The possibility of microphase transition was proposed to relate to the observation of two isosbestic points.     

Structural Multiplicity of Monomers of an Amphiphilic Porphyrin at the Outer Surface of CTAB Micelle

AggregationofporPhyrinsindifferentmedia,suchasinsolventswithvariouspolarity"'.insurfactantsolutionsofdifferentconcentrations'-',inmembranemedia',etc.,hasattTactedanincreasedinterestinthepastyears.ltiswellacceptedthattheSoretbandsaresensitivetosolventmicroenvironmentandaggregationformsofporphyrins.Thusspectra1characteristics,suchasfullwidthathalfheight(FWHH),peakposition,arecommonparameterstounderstandthesolubiIizationsiteandaggregationbehaviorsofporphyrinicmoleculesinmembranemedia'-'.Broade…     

A Study on the Location and Aggregation of Tetrahydrophenylporphyrin with a Single Hexadecyl Chain in Triton X-100 Micelle

The location and aggregation of 5,10,15-tris(4-hydroxyphenyl)-20-(hexadecyloxyphenyl)porphyrin (P) in nonionic polyoxyethylene (9.5) octylphenol (Triton X-100) micelle solutions were studied by means of UV–Vis and fluorescence spectra. P forms premicelle surfactant–porphyrin aggregates when the surfactant concentration is below and approaching the CMC. In Triton X-100 micelle solutions, different types of H-aggregates of P were formed when the concentration of P is higher than 3.9×10^-6?mol?dm^-3. As the bulk pH is changed, a transfer process for the porphyrin moiety in Triton X-100 micelle occurs. In neutral Triton X-100 micelle solutions, P may be located at the inner layer of the micelle; in basic conditions, the porphyrin moiety may transfer to the outer surface of the micelle. The kinetic study of porphyrin complexed with Cu(II) in Triton X-100 micelle solutions shows that the metalation rate could be controlled by changing the pH.     

Electronic and fluorescence spectral studies of a novel porphyrin-polypyridyl ruthenium(II) hybrid linked by a butyl chain

The electronic and fluorescence spectroscopic properties of a novel porphyrin-polypyridyl ruthenium(II) hybrid, [C(4)-TPP-(ip)Ru(phen)(2)](ClO(4))(2) (TPP=5,10,15,20-tetraphenylporphyrin, ip=imidazo[4,5-f][1,10]phenanthroline and phen=1,10-Phenanthroline), in which a polypyridyl ruthenium(II) moiety is linked to a porphyrin moiety by a butyl chain have been investigated and compared to its corresponding reference compounds. The studies of electronic absorption spectra have shown that there is an electronic interaction between the porphyrin moiety and the polypyridyl ruthenium(II) moiety in the hybrid. It can be found that intramolecular photoinduced electron and energy transfer processes may occur in the hybrid from the fluorescence spectra. When exciting in Soret band and Q band of porphyrin, the fluorescence quenching of the porphyrin moiety of the hybrid takes place due to electron transfer from the lowest singlet excited state (S(1)) to the appended polypyridyl rutherium(II) moiety, while the decay of S(2) (the second-excited singlet state) of the porphyrin moiety is mainly contributed to internal conversion to S(1). When exciting in MLCT band of the polypyridyl ruthenium(II) moiety, fluorescence corresponding to the polypyridyl ruthenium(II) moiety is quenched by intramolecular energy transfer from (3)MLCT of the ruthenium moiety to the lowest-energy triplet state localized on the porphyrin moiety.     

Light induced photoreactions with plasmid DNA by Cu/Ru and Cu/Ru/Pt multi-metallic porphyrins

Coordination of two [Ru(bipy)(2)Cl](+) moieties (where bipy = 2,2'-bipyridine) to the pyridyl nitrogens in the 5,10-positions of meso-5,10,15-(4-Pyridyl)-20-(pentafluorophenyl)porphyrin gives the diruthenium porphyrin complex II. Insertion of copper(II) into the porphyrin center allows for the third pyridyl nitrogen to coordinate to Pt(dmso)Cl(2). Electronic transitions associated with the ruthenium porphyrin include an intense Soret band and four less intense Q-bands in the visible region of the spectrum. An intense π-π* transition in the UV region associated with the bipyridyl groups and a metal to ligand charge transfer (MLCT) band appearing as a shoulder to the Soret band are also observed. A slight blue shift of the Soret band and collapse of the Q-bands into one band is observed upon insertion of Cu(II) into the porphyrin center. No change in the electronic spectrum is observed upon coordination of the Pt(dmso)Cl(2) moiety. Electrochemical properties associated with the complexes include a redox couple in the cathodic region attributed to the porphyrin and a redox couple in the anodic region due to the Ru(III/II) couple. DNA titrations of the Cu/Ru and Cu/Ru/Pt porphyrins indicate that both complexes interact strongly with DNA potentially through a partial intercalation mechanism. Gel electrophoresis studies indicate that the Cu/Ru/Pt porphyrin has a greater effect on DNA migration through the gel than the well known DNA binding agent cis-platin. Irradiation of aqueous solutions of the Cu/Ru porphyrin and supercoiled DNA at a 5:1 base pair to complex ratio (in the absence of oxygen) with visible light above 400 nm shows a nicking of the DNA. Repeat experiments in the presence of oxygen show that the Cu/Ru porphyrin photocleaves the DNA, giving the linear form, as evidenced by gel electrophoresis.     

UV-visible and fluorescence spectral study on a pH controlled transfer process of an amphiphilic porphyrin in nonionic micelle

5,15-di(4-hydroxyphenyl)-10,20-di(hexadecyloxyphenyl) porphyrin P was solubilized in nonionic polyoxyethylene(9.5) octylphenol (Triton X-100 or TX-100) micelle solutions. By means of analyzing the UV-visible and fluorescence spectra of the synthesized amphiphilic porphyrin P in different solvent environments, and the relationship between the solubilizing location of the porphyrins in TX-100 micelle and the microenvironment polarity, P is shown to involve in a transfer process for the porphyrin moiety from inner to the outer surface of TX-100 micelle as the pH is increased. The kinetic study of porphyrin incorporate with Cu(II) shows that metalation rate of porphyrin increases with the pH increasing, indicating that metalation rate could be controlled by changing pH.     

四甲基-四乙基钯卟啉的表面光伏特性研究

合成了1,3,5,7-四甲基-2,4,6,8-四乙基卟啉(TMTEP)及其钯络合物(PdTMTEP),并利用表面光电压谱(SPS)和场诱导表面光电压谱(FISPS)技术对它们的表面光伏特性进行了研究.TMTEP有较强的荧光发射,而PdTMTEP以磷光辐射为主,其光伏响应强度比TMTEP的强得多;在外电场诱导下,PdTMTEP的Soret带与Q带的光伏响应强度随外加正电场光伏响应强度的增加而增强,随外加负电场光伏响应强度的增加而减弱,并且在680,750nm处出现两个新的光伏响应带,这两个光伏响应带与极化子跃迁有关.