四苯基卟啉质子化结构变化的理论研究(Ⅱ)——五氟苯基及吡咯环上氟的取代基效应

卟啉的衍生物在DNA螺旋中的嵌入并堆积具有高选择性.为考察5,10,15,20-四(五氟苯基)卟啉(TF₅-PPH₂)和2,3,7,8,12,13,17,18-八氟-5,10,15,20-四(五氟苯基)卟啉(F₂₈TPPH₂)中F取代基对质子化卟啉结构的影响,在四苯基卟啉研究的基础上,用半经验的AM₁MO方法,并进行合理的对称性限制,计算了TF₅-PPH₂和F₂₈TPPH₂及其质子化二酸(TF₅-PPH₄²⁺)和(F₂₈TPPH₄²⁺)的几种可能的构型.结果表明,由于F取代基的影响,质子化过程中的结构、键电荷布居和前线分子轨道均有明显的变化,二者的质子化二酸与溶液质子的快速交换作用也都变得更加困难.     

影响间位取代四苯基卟啉锌轴向配合物稳定因素的研究

用光度滴定法研究了间位取代四苯基卟啉锌[ZnT(m-X)PP,X=NO₂,Cl,OCH₃,H,CH₃]与3种新型空间不对称金属席夫碱和4种取代咪唑的轴向配位反应动力学.采用Rose-Drago数据处理方法确定了各反应体系的平衡常数,探讨了温度、轴向配体、卟啉环上的取代基对轴向配合物稳定性的影响,发现在5种间位取代四苯基卟啉锌与7种轴向配体的配位反应中均存在线性自由能关系和等平衡关系,对所研究体系采用不同的方法求取等平衡温度β及温度T→∞时的反应对电子效应的敏感系数ρ_∞,得到吻合的结果.     

侧链取代的芴苯共聚物的光电性质及其溶剂化效应研究

采用Suzuki偶联聚合的方法合成了一系列化学结构明确、侧基性质(长度、体积、给/吸电子性质)不同的Hairy-Rod型芴苯共聚物. 通过光谱、电化学和模拟计算等手段研究了苯环上不同性质的侧基取代芴苯聚合物的发光性质、电化学性质和溶剂化效应等, 同时研究了侧基性质的变化对这些物理性质的影响规律. 苯环上烷基侧链长度的改变对取代共聚物的光谱、电化学和发光效率等影响很小|而随着苯环上烷氧基侧链长度的增加, 聚合物的光谱稳定性逐渐增强, 荧光发射光谱中的0-1转变逐渐被抑制, 荧光发射半峰宽减小. 苯环上取代侧基的给/吸电子性质变化对聚合物的光电性能具有全面的影响, 改变取代侧基的给/吸电子性质可调节芴苯共聚物的发光颜色和HOMO, LUMO能级以及HOMO-LUMO能隙等, 因此, 通过引入不同性质的侧基可实现对此类聚合物光物理性能的调控. 溶剂的极性对聚合物溶液的光谱性质具有显著影响, 溶液光谱随溶剂极性的增大逐渐向长波移动. 当聚合物本身带有强极性基团时, 在强极性溶剂中将发生聚合物分子链与溶剂分子间的强极性相互作用, 从而会引起更复杂的结果.     

meso,β-和β,β-全氟醚基磺酸酯桥连双卟啉的合成

β-氟砜基全氟醚基取代四芳基卟啉与5-(4-羟苯基)-10,15,20-三苯基卟啉、BINOL反应分别生成meso,β-和β,β-全氟醚基磺酸酯桥连双卟啉,双卟啉与醋酸锌在CHCl₃/CH₃OH中回流可高产率获得双锌卟啉,测定并讨论了meso,β-和β,β-全氟醚基磺酸酯连接双卟啉的紫外可见和荧光光谱.     

NMR研究溶液中正十四烷基硫酸钠/正十四烷基聚氧乙烯醚(3)表面活性剂之间的相互作用

采用¹HNMR弛豫、自扩散系数和二维相敏(2DNOESY)实验研究了正十四烷基硫酸钠[n-CH₃(CH₂)₁₃OSO₃Na(STS)]和正十四烷基聚氧乙烯醚(3)[n-CH₃(CH₂)₁₃O(C₂H₄O)₃H(C₁₄E₃)]在溶液中的自聚集以及二者混合后的相互作用.结果表明,STS与C₁₄E₃混合后存在相互作用,并形成混合胶束;弛豫实验表明,混合胶束中STS疏水链质子运动更加受阻,C₁₄E₃的α-(4″)和β-CH₂(3″)处链堆积紧密.C₁₄E₃的亲水端(CH₂CH₂0)₃链卷曲紧贴在疏水壳表面外链堆积较紧密处.自扩散系数测量表明,混合胶束比单一阴离子表面活性剂形成的胶束大.单一非离子型胶束和混合胶束的亲水端(CH₂CH₂0)₃(5″)链构成相应较软和松散的外壳.单一C₁₄E₃在极性溶剂氯仿溶液中,质子运动比在水中自由度大,但2DNOESY谱中出现了少量分子间的交叉峰,也可能形成了一些小的聚集体.     

卟啉多枝分子合成与分子内能量转移、双光子吸收性能研究

以三苯胺或硝基苯为端基, 合成了三个卟啉多枝分子: 5-(4-硝基苯甲酰氧基)苯基-10,15,20-三-(4-溴苯基)卟啉(TPP-NO₂)、5-(4-硝基苯甲酰氧基)苯基-10,15,20-三-(4-二苯胺基-1-苯乙烯基)苯基卟啉(TPP-X₃)和5,10,15,20-四-(4-二苯胺基-1-苯乙烯基)苯基卟啉(TPP-X₄), 进行了红外光谱、核磁共振光谱和质谱表征. 比较研究了分子“枝”、“核”不同键合方式与不同对称结构对分子的线性光谱、非线性光谱以及分子内能量转移行为的影响. 在钛宝石激光器(800 nm)和Nd∶YAG倍频光(532 nm)泵浦下, 样品溶液均发出卟啉环特有的红色荧光——前者系双光子吸收机制“上转换”荧光, 后者则为双光子吸收与分子内能量转移机制“下转换”荧光. 飞秒Z-scan技术测得样品双光子吸收截面最大可达130 GM, 与四苯基卟啉(TPP)同等测试条件下的双光子吸收截面相比增大了两个数量级.     

克拉霉素的电化学反应机理研究与应用

应用线性扫描伏安法、循环伏安法、常规脉冲伏安法等电化学手段并结合紫外吸收光谱研究了药物克拉霉素(clarithromycin, CAM)在pH 1.8～9.2 Britton-Robinson缓冲溶液和0.05 mol•L^－1 NaOH溶液中的电化学行为. 在所研究的pH范围, CAM分别产生P₁, P₂, P₃, P₄四个还原波, 其中P₁, P₂, P₄三个波均为其药效活性基团C-9位羰基的还原所产生. 实验结果表明: 在pH 1.8～5.7的B-R缓冲溶液条件下所获得的P₁波为两电子不可逆弱吸附还原波; 在6.0＜pH＜9.2的B-R缓冲溶液中, CAM产生P₂和P₃两个波, 其中P₂为两电子不可逆还原波, P₃为催化氢波. 在0.05 mol• L^－1 NaOH溶液中, CAM产生的P₄波是一个单电子的不可逆吸附还原波. 根据P₄波的峰电流i_P与CAM浓度的线性关系, 建立了CAM含量测定的新方法.     

利培酮的电化学行为及应用研究

采用循环伏安法、线性扫描伏安法、常规脉冲伏安法和恒电位电解法等电化学手段, 详细研究了利培酮在pH 7.07～10.32 B-R缓冲溶液和0.2 mol•L^－1 NaOH溶液中的电化学行为. 研究表明: 在pH 7.07～10.07 B-R缓冲溶液中, 利培酮产生的P₁波为催化氢波. 在pH＝10.32 B-R缓冲溶液中, 利培酮可以产生P₂和P₃两个波. 其中, P₂波为不可逆的单电子还原波, P₃波可以分裂成两个波P_3a和P_3b. P_3a波为P₂波的进一步单电子还原, 而P_3b波则属于催化氢波. 在0.2 mol•L^－1 NaOH溶液中, 利培酮产生的P₄波是一个两电子的不可逆还原波. 另外, 根据P₁波的一阶导数峰电流与利培酮浓度在1.6×10^－5～2.0×10^－6 mol•L^－1 (r＝0.9950)间的线性关系, 建立了利培酮片剂中利培酮含量的测定新方法. 新方法的检出限为1.0×10^－6 mol•L^－1, 回收率在105%～102%之间, 相对标准偏差为0.84%.     

长链卟啉金属配合物的合成与性质研究

通过带有12条长链的卟啉配体Meso-5, 10, 15, 20-四[3, 4, 5-三（辛酰氧基）苯基]卟啉（P）,与金属氯化盐（ZnCl₂, CuCl₂, CoCl₂, NiCl₂, CdCl₂, MnCl₂, PdCl₂, PtCl₂）发生配位反应,合成出长链卟啉的8种金属配合物：Zn-P, Cu-P, Co-P, Ni-P, Cd-P, Mn-P, Pd-P, Pt-P,通过UV – Vis, ¹H NMR, IR,HR-MS进行了表征,研究了不同金属卟啉配合物合成的反应条件,并通过荧光光谱、荧光寿命等方法研究了卟啉化合物的发光性质。      

胶束催化作用下实现聚苯乙烯的氯甲基化

用紫外分光光度法测定了离子型表面活性剂胶束溶液对聚苯乙烯四氯化碳溶液的增溶性能; 用胶束催化法实现了聚苯乙烯的氯甲基化, 用红外光谱法和佛尔哈德法表征了氯甲基化聚苯乙烯的化学结构与组成; 通过比较阴、 阳离子表面活性剂及结构不同的阳离子表面活性剂的催化效果, 探索了胶束催化的作用机理, 考察了表面活性剂结构对催化作用的影响规律. 结果表明, 表面活性剂胶束溶液可增溶聚苯乙烯的四氯化碳溶液, 随着四氯化碳在胶束中的增溶, 聚苯乙烯可转移至表面活性剂的胶束中; 胶束催化是实现聚苯乙烯的氯甲基化的有效途经, 仅用3.35 g/L的十六甲基三甲基溴化铵(CTAB),  于65 ℃， 5 h内即可使聚苯乙烯大分子链中的苯环氯甲基化程度达到37%; 聚苯乙烯与甲醛、 氯化氢的反应过程由亲电取代和亲核取代串联而成, 阳离子表面活性剂比阴离子表面活性剂的催化作用更加有效, 说明亲核取代是慢步骤; 阳离子表面活性剂疏水链越长, 对聚苯乙烯的增溶效果越好, 催化作用越强.     

Side-chain-controlled H- and J-aggregation of amphiphilic porphyrins in CTAB micelles

The aggregation behavior of a series of amphiphilic 4-hydroxyphenyl porphyrins with one (P1), two (P2) and three (P3) hexadecyl side chains in cetyltrimethylammonium bromide (CTAB) micelles has been studied by means of UV-vis and fluorescence spectra. It was found that the number of hexadecyl side chains not only controls the H- and J-aggregation of the porphyrins in CTAB micelles, but also influences the aggregation concentration and tendency. With increasing porphyrin concentration, P1 and P2 form H-aggregates in CTAB micelles, while P3 forms J-aggregates. Porphyrins with more hexadecyl side chains tend to form aggregates more easily and at lower concentrations in CTAB micellar solutions.     

系列双亲卟啉在水溶液及盐溶液中的不同聚集行为

分析了中性条件下在水溶液及盐溶液中系列双亲卟啉随其浓度连续变化的紫外-可见吸收光谱。结果表明,在中性条件下不同侧链取代基对双亲卟啉的聚集行为有很大影响,盐的加入导致卟啉的聚集形态发生改变,初步解释了影响卟啉聚集的原因。     

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…     

A novel pH-controlled transfer process of 5,10,15-tri(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl) porphyrin in CTAB micelles

By analysis of the UV-visible and fluorescence spectra of 5,10,15-tri(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl)porphyrin (P) in different microenvironments of micelle and solvent solutions, a novel pH-controlled transfer process of P in CTAB micelle was reported. In neutral CTAB micelles, porphyrins may locate at the inner layers of micelles. With pH increases to 11.19, the porphyrin can be completely deprotonated and transfers to the outer surface of CTAB micelle. The investigation of kinetics of porphyrin complexing with Cu(II) indicates that the metallation rate of porphyrins in CTAB micelles could also be controlled by changing pH.     

Studies on the antioxidant effect of rutin in the microenvironment of cationic micelles

UV-vis spectra, fluorescence emission spectra, cyclic voltammetric and electron spin resonance are employed to study the location of rutin in cetyltrimethylammonium bromide (CTAB) micelles with different microstructures and microenvironments, and to gain information about the antioxidant capacity (hydroxyl radical scavenge activity) of rutin in CTAB micelles. Rutin molecules can be partly solubilized in CTAB spherical micelles through electrostatic attraction and hydrophobic force, which leads to the bathochromic shift of absorption spectra, decrease of the microenvironment polarity of pyrene and the hydroxyl radical scavenge activity. However, CTAB rod-like micelles congregate rutin molecules on their surfaces, which results in the hypochromic shift of absorption spectra compared to the spectrum in CTAB spherical micelles and also heightens the antioxidant capacity of rutin. Correspondence: Rong Guo, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, P.R. China     

界面微环境中双亲卟啉的光谱研究

用敏感于微环境变化的UV-Vis光谱,研究了在SDS胶束微环境中,双亲原卟啉P1对体相pH值的依赖关系。体相pH值由弱碱性到强酸性改变的过程中,P1在SDS胶束内存在明显等色点,为一典型的双组分平衡,同时其质子化峰吸收强度逐渐增强,表明P1在胶束内发生了质子化;体相pH值从弱碱到强碱变化时,P1的Soret带红移,吸光度变小,半峰宽加大,这是卟啉从SDS胶束内核转移到胶束表面的结果,由此证明改变pH值可以实现卟啉跨膜转移的控制。     

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.     

ON THE NATURE OF CHLOROPHYLL a IN AQUEOUS MICELLAR SYSTEMS

Abstract— Absorption and fluorescence spectra of chlorophyll a in aqueous micellar solutions were studied. Solutions in anionic micelles gave an absorption band at 740 nm, attributable to microcrystal- line chlorophyll a. Solutions in cationic and nonionic micelles do not show this band. The positions of the spectral bands in anionic micelles and the possible structure of microcrystalline form are discussed. A comparison is made of the behaviour of microcrystalline form in hydrocarbon solvents and in micellar solutions.     

Fluorescence behaviour of 4-[5-(2-phenyloxazolyl)] benzenesulfonic acid and N-hexyl-4-[5-(2-phenyloxazolyl)] benzenesulfonamide in homogeneous micellar and microemulsion systems

The fluorescence and excitation spectra of 4-[5-(2-phenyloxazolyl)]benzenesulfonic acid (PPOS) and N-hexyl-4-[5-(2-phenyloxazolyl)] benzenesulfonamide (PPOSA) were investigated in homogeneous solutions of varying polarities (hexane, heptane, butanol and water) and in aqueous micellar systems of anionic surfactants (bis(2-ethylhexyl)sulfosuccinate, sodium salt (AOT), sodium dodecyl sulfate (SDS)) and cationic surfactants (benzyldimethylhexadecylammonium chloride (CDBA), hexadecyltrimethylammonium chloride (CTAB)). These compounds were also investigated in different oil-in-water (o/w) and water-in-oil (w/o) microemulsions of the system composed of SDS, n-butanol, cyclohexane and water. The results revealed that the two probes exhibit pronounced spectral changes in response to the changes in the polarity of the medium, and in hydrophobic—hydrophilic interactions. The spectral behaviour of PPOS and PPOSA in micellar systems indicates that these two probes are incorporated at the interface of the cationic micelles. In microemulsions, however, the probes exhibit different Stokes shifts compared with those found for homogeneous solutions, indicating different salvation processes of both the ground and the excited states.     

Synthesis,Photophysics, and Self‐Assembly of Furan‐Embedded Heteroarenes

A series of pyrene/phenanthrene‐fused furan derivatives ( 1 – 8 ) were synthesized by a simple condensation reaction between pyrene‐4,5‐diketone/phenanthrenequinone and substituted phenol/naphthol in the presence of trifluoromethanesulfonic acid in 1,2‐dichlorobenzene heated at reflux. The formed compounds can emit strong blue light in organic solvents. Additionally, the self‐assembly behaviors of two of the compounds ( 3 and 5 ) were studied through re‐precipitation method and the resulting nanostructures were characterized by UV/Vis, fluorescence spectra, and field‐emission scanning electron microscopy (FESEM). The findings showed that the shape and size of compounds 3 and 5 could be tuned by the ratio of THF and hexadecyl trimethyl ammonium bromide (CTAB) solution in water.