卟啉酞菁模型化合物光致电子转移研究

本文采用时间相关单光子计数对卟啉酞菁ＴＴＰ－（ＣＨ２）ｎ－Ｐｃ模型化合物的光致电子转移进行了研究，发现激发Ｐｃ时，呈现单指数衰减，ｎ＝４时电子转移速率减小，活化能，重排能增加，电子转移效率下降，电子转移反应△ＧＣＳ与电荷分离活化络合物衰变速率ＫＣＴ，按以下规律：△Ｇ＾（５）ＣＳ〉△＾（３）ＣＳ〉△＾（４）ＣＳ〉△＾（２）ＣＳ，ｋ＾（２）ＣＳ〉ｋ＾（３）ＣＳ〉ｋ＾（４）ＣＳ〉ｋ＾（５）ｃｓ。其△Ｇ＾     

四磺化酞菁钴在微乳液、醇－水体系中的二聚现象研究

采用分光光度法研究了四磺化酞箐钴（ＣｏＴＳＰｃ），在微乳液（ＴｒｉｔｏｎＸ－１００－壬烷－正戊醇－水）、醇－水（甲醇、乙醇、丙醇）体系中的二聚现象，计算了ＣｏＴＳＰｃ的二聚常数ＫＤ。结果表明，ＣｏＴＳＰｃ的二聚常数ＫＤ值随着微乳液中表面活性剂的浓度及醇－水溶液的介电常数的增加而减小     

四磺化酞菁钴在微乳液、醇-水体系中的二聚现象研究

采用分光光度法研究了四磺化酞菁钴（ＣｏＴＳＰｃ），在微乳液（ＴｒｉｔｏｎＸ－１００－壬烷－正戊醇－水）、醇－水（甲醇、乙醇、丙醇）体系中的二聚现象，计算了ＣｏＴＳＰｃ的二聚常数ＫＤ。结果表明，ＣｏＴＳＰｃ的二聚常数ＫＤ值随着微乳液中表面活性的浓度及醇－水溶液的介电常数的增加而减小。     

修饰微带金电极上细胞色素C电极过程的热力学研究

研究了细胞色素Ｃ（Ｃｙｔ．Ｃ）在一种新的电子转移促进剂４，６－二甲基－２－巯基嘧啶修饰微带金电极（ＤＭＭＰ／Ａｕ）上的氧化还原热力学；求得Ｃｙｔ．Ｃ在ＤＭＭＰ／Ａｕ电极上反应的标准电极电位Ｅ＾ｏ，熵变△Ｓ＾ｏ，焓变△ＩＩ＾ｏ及Ｇｉｂｂｓ自由能的改变△Ｇ１０值分别为：０．２７２Ｖ（ｕｓ．ＮＨＥ），－１２３．７Ｊ．ｍｏｌ＾－＾１，－６３．１ｋＪ．ｍｏｌ．ｍｏｌ＾－＾１和－２６．２ｋＪ．ｍｏｌ＾－＾１（     

SPK势能面上Cl和H2反应的量子动力学计算

给出了在ＳＰＫ势能面上应用广义牛顿变分法（ＧＮＶＰ）和振幅密度衡量法（ＭＭＡＤ）对于反应系统Ｃｌ＋Ｈ２→ＨＣｌ＋Ｈ态－态之间反应几率的三维量子力学计算。总反应能量从９ｋｃａｌ．ｍｏｌ＾－１至１６ｋｃａｌ．ｍｏｌ＾－１。对于两种方法的计算结果进行了比较。为了同超球谐密耦合方法结果进行比较，还对总反应能量１９ｋｃａｌ．ｍｏｌ＾－１的情况进行了计算和分析。     

镓皂石的合成和交联及其催化性能

用水热法合成了Ｇａ取代皂石（ＧａＳ，并用羟基铝低聚物与其交换制得了ＰＧａＳ。用ＸＲＤ，＾２７Ａｌ、＾２９Ｓｉ ＭＡＳ ＮＭＲ和ＮＨ３－ＴＰＤ表征了ＧａＳ，ＰＧａＳ和ＣＰＧａＳ。在１，２，４－三甲苯歧化反应中观察了ＰＳ（交联皂石）和ＰＧａＳ的催化性能。结果表明ＧａＳ的结晶度很高，Ｇａ确实进入了皂石的骨架，与ＰＳ相比，ＰＧａＳ的活性和活性衰减低，歧化选择性高。这可能与ＰＧａＳ表面Ｌ酸所占表面酸份额高有     

苯酚氧化羰化合成碳酸二苯酯的新型PdCl2-Co(Pyca)2催化体系

研究了新型的Ｐｄ－Ｃｏ催化体系催化氧化碳化苯酚合成碳酸二苯酯。当ｎ（ＰｄＣｌ２）：ｎ「Ｃｏ（Ⅱ）」：ｎ（四丁基化铵）：ｎ（苯醌）＝１：１：１０：２５,Ｔ＝１２０,Ｐ＝２．５ＭＰａ（Ｐｃｏ／Ｐｏ２＝４：１）,反应时间８ｈ,ＰｄＣｌ２－Ｃｏ（Ｐｙｃａ）２比ＰｄＣｌ２－Ｃｏ（ＯＡｃ）２的催化活性高。当使用ＰｄＣｌ２－Ｃｏ（Ｐｙｃａ）２催化剂时,ＤＰＣ的产率为６．０３％。最佳的反应温度是１２０℃,ＤＰＣ的产率随着体系的总压增加而增大,当压力升到３．５ＭＰａ时,ＤＰＣ产率为８．５３％。     

Synthesis and Crystal Structure of Complex of Zinc（Ⅱ） with Schiff Base—{Zn［CH_3O（O）－C_6H_3CH_3＝NN＝C（S）NH_2］（DMF）}_2

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＣｏｍｐｌｅｘｏｆＺｉｎｃ（Ⅱ）ｗｉｔｈＳｃｈｉｆｆＢａｓｅ—{Ｚｎ［ＣＨ_３Ｏ（Ｏ）－Ｃ_６Ｈ_３ＣＨ_３＝ＮＮ＝Ｃ（Ｓ）ＮＨ_２］（ＤＭＦ）}_２ＣｕｉＸｕｅ－Ｇｕｉ；ＨｕＱｉｎｇ－Ｐｉｎｇ（Ｄ...     

聚环氧丙烷聚氨酯／聚（甲基丙烯酸甲酯—苯惭烯）IPN的研究

改变聚（甲基丙烯酸甲酯－苯乙烯（Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中 甲基丙烯酸甲酯的含量（ＷＭＭＡ），通过一步法合成出聚环氧氯丙烷聚氨酯（ＰＵ（ＰＥＣＨ）／Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）ＩＰＮ．ＤＳＣ、ＴＥＭ和动态粘弹谱研究结果表明：当Ｐ（ＭＭＡ＿ｃｏ－Ｓｔ）中ＷＭＭＡ大于０．６时，ＩＢＮ仅有一个Ｔｇ；当ＷＭＭＡ小于０．４时，ＩＰＮ有２个Ｔｇ，ＴＥＭ上出现相区，Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）深度参数（δ）及δ的氢键作     

聚环氧氯丙烷聚氨酯／聚（甲基丙烯酸甲酯－苯乙烯）IPN的研究

改变聚（甲基丙烯酸甲酯－苯乙烯）（Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中甲基丙烯酸甲酯的含量（Ｗ_（ＭＭＡ）），通过一步法合成出聚环氧氯丙烷聚氨酯（ＰＵ（ＰＥＣＨ）／Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）ＩＰＮ．ＤＳＣ、ＴＥＭ和动态粘弹谱研究结果表明：当Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中Ｗ_（ＭＭＡ）大于０．６时，ＩＰＮ仅有一个Ｔｇ；当Ｗ_（ＭＭＡ）小于０．４时，ＩＰＮ有２个Ｔ_ｇ，ＴＥＭ上出现相区，Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）溶度参数（δ）及δ的氢键作用分量（δｈ）与相态、力学性能有密切关系。     

磺化酞菁镓的二聚现象研究

采用分光光度法研究了磺化酞菁镓的二聚现象;测定了二聚常数k_d,讨论了PH值、离子强度、水、温度等因素对k_d的影响,研究结果表明:磺化酞菁镓的二聚反应可表示成:2SPcGaOH⇔(SPcGa)₂O+H₂O 且磺化酞菁镓的二聚常数随着离子强度、磺酸基数目、水的浓度的增加而增加。     

THE EFFECTS OF PORPHYRIN STRUCTURE AND AGGREGATION STATE ON PHOTOSENSITIZED PROCESSES IN AQUEOUS AND MICELLAR MEDIA

The efficiency of several porphyrins at 10 μM and 83 μM as sensitizers of the photooxidation of 0.1 mM tryptophan and histidine via a singlet oxygen-mechanism was studied in pH 7.4-buffered aqueous solutions and in aqueous dispersions of Triton X-100 micelles. The porphyrins were either solubilized in the bulk aqueous medium or associated with the micellar phase, whereas the amino acids were always located in the aqueous phase. With those porphyrins, such as uroporphyrin I, meso-tetra (4-sulfonatophenyl)porphine, meso-tetra(4-carboxyphenyl)porphine and meso-tetra)N,N,N-trimethylanilinium)porphine, which are > 98% monomeric in both media, the efficiency of histidine photooxidation was independent of the site of O₂(¹Δ_g) generation, as shown by the closely similar values for the photooxidation rate constant and oxygen-consumption quantum yield in the presence and absence of Triton micelles; the same indications were provided by photokinetic experiments with tryptophan. Actually, laser flash photolysis studies showed that the micelle-incorporation of the above mentioned porphyrins brought about only minor changes in their photophysical properties, including the relative yield of O₂(¹Δ_g) generation. On the other hand, hematoporphyrin IX, its Zn²⁺-complex, and coproporphyrin III are largely aggregated in homogeneous aqueous solution; their incorporation into Triton micelles caused an increase of the triplet quantum yield and an enhancement of the oxygen-consumption quantum yield and photooxidation rate constant for both histidine and tryptophan. The lower photosensitizing efficiency of aggregated porphyrin species in comparison with the corresponding monomeric porphyrin was confirmed by measuring the initial rate and quantum yield of oxygen consumption upon irradiation of 1 mM histidine and tryptophan in the presence of different hematoporphyrin concentrations within the 0.3-100μM range.     

Der geschwindigkeitsbestimmende Schritt bei der Decarboxy-lierung von 2,4-Dihydroxybenzoesäure in mässig konzentrierter wässeriger Salzsäure

The decarboxylation kinetics of 2,4-dihydroxybenzoic acid have been studied in 0.1–8 N aqueous HCl at 50°. At low HCl concentrations, the observed first order rate constant, k, increases with increasing acidity of the solution. In solutions with 3.5–6 N HCl, k remains constant. The D₂O solvent isotope effect decreases from ^kH₂O/^kD₂O = 2.0 in 1N HCl to 1.3 in 5 N HCl, and it remains unchanged at 1.3 if the HCl concentration is increased further to 8 N. It is concluded that an increase of the acidity of the solution causes a change of the rate determining step from slow proton transfer to rate limiting C? C bond cleavage.     

266 nm光照下水溶液中氯苯与H2O2的反应机理研究

利用瞬态吸收光谱技术研究了不同条件下C₆H₅Cl与H₂O₂水溶液的激光闪光光解情况, 初步考察了其瞬态物种的生长和衰减等行为. 研究表明, •OH自由基和C₆H₅Cl反应生成C₆H₅Cl-OH adduct, 其反应速率常数在近中性、酸性条件下约为(5.89±0.65)×10⁹和(7.07±0.61)×10⁹ L•mol^－1•s^－1; 其衰减则符合双分子二级反应, 速率常数2k/εl＝1.1×10⁶ s^－1, 而在碱性时则为(4.34±0.51)×10⁹ L•mol^－1•s^－1, 衰减呈准一级反应, 速率常数为2.11×10⁵ s^－1. 在有氧条件下, O₂与C₆H₅Cl-OH adduct反应生成C₆H₅Cl-OHO₂ adduct, 其反应速率常数为6.8×10⁸ L•mol^－1•s^－1.     

PHOTOPHYSICS OF THE FLUORESCENT Ca2+ INDICATOR QUIN-2

The photophysics of the complex forming reaction between Quin-2 and Ca²⁺ were investigated using steady-state and time-resolved fluorescence measurements. The fluorescence decay traces were analyzed with global compartmental analysis yielding the following values for the rate constants at room temperature in aqueous solution with EGTA as Ca²⁺ buffer: k₀₁= 8.6 times 10⁸ s^?1, k₂₁= 1 times 10¹¹M^?1 s^?1, k₀₂= 8.8 times 10⁷ s^?1, k₁₂= 4 times 10⁴ s^?1. k₀₁ and k₀₂ denote the respective deactivation rate constants of the Ca²⁺ free and bound forms of Quin-2 in the excited state. The constant k₂₁ represents the second-order rate constant of binding of Ca²⁺ and Quin-2 in the excited state while k₁₂ is the first-order rate constant of dissociation of the excited Ca²⁺:Quin-2 complex. From the estimated values of k₁₂ and k₂₁ the dissociation constant K_d* in the excited state was calculated. It was found that pK_d* (6.4) is slightly smaller than pK_d (7.2). There was no interference of the excited-state complex forming reaction with the determination of K_d. Intracellular Ca²⁺ concentrations can thus accurately be determined from fluorometric measurements using Quin-2 as Ca²⁺ indicator.     

Influence of pyridine oximate and quaternized pyridinium oximate ions on the hydrolysis of phosphate esters in cationic microemulsions

Kinetic studies have been performed to understand the hydrolytic potencies of oximate (2- and 4-pyridinealdoxime) and its functionalized oximate (4-(hydroxyiminomethyl)-1-alkylpyridinium bromide) ions (alkyl?=?C₁₀H₂₁ (4-C₁₀PyOx^-); alkyl?=?C₁₂H₂₅ (4-C₁₂PyOx^-)) in the cleavage of phosphate esters, diethyl p-nitrophenylphosphate (Paraoxon) and p-nitrophenyl diphenyl phosphate (PNPDPP) in a cationic (O/W) microemulsion system (ME) over a pH range 7.5 to 11.0 at 300?K. The k_obs values for the reaction of paraoxon with oximate and its functionalized oximate were determined in different microemulsion composition and the kinetic rate data shows that k_obs values increases with increasing water content. The specificity of different chain length of alcohols (n-butanol, n-pentanol, n-hexanol and n-octanol) was also investigated in hydrolytic reactions of paraoxon for different microemulsion composition.     

Product distribution in preparative scale electrolysis: Part VI. Competition between dimerization and first-order deactivation

The dependence of product distribution from the various experimental parameters (rates, concentration diffusion layer thickness, current density) is analyzed for a reaction scheme involving the competition between dimerization and first-order deactivation of the intermediate resulting from the first electron uptake (or removal). Two cases are considered, corresponding to the product of the first-order deactivation being either electroinactive or undergoing a further electron transfer at the electrode or in the solution. It is shown that the dimer yield is not very sensitive to the further fate of the deactivation product. It is in all cases a function of the competition parameter σ=k₁k₂^?3/2D^1/2 c⁰ δ^?1 in potentiostatic conditions and σ^Δ=k₁k₂^?3/2D^?1/2(i⁰/FS) in galvanostatic conditions (k₁, k₂ rate constants of the dimerization and deactivation reactions respectively; D diffusion coefficient; c⁰ concentration of substrate; δ diffusion layer thickness; (i⁰/S) current density). The reduction of CO₂ in DMF with competitive formation of oxalate and formate is taken as an example illustrating the theoretical analysis.     

Electrochemically Polymerized N,N-Dimethylaniline Films Containing Tris-(Bathophenanthroline Disulfonato)Iron(II/III) Complexes

The electropolymerization of N, N-dimethylaniline (DMA) was carried out in an aqueous CF₃COONa solution (pH 1.0) containing DMA in the presence of tris(bathophenanthroline disulfonato)iron(II), Fe(bphen)₃ ^4-. Poly(N, N-dimethylanilinium trifluoroacetate) (PDMA) film was formed on electrode surfaces and, at the same time, Fe(bphen)₃ ^4- ions were stably confined in the formed PDMA film by electrostatic interaction between them and the positively charged quaternary ammonium sites of the PDMA film. The PDMA-Fe(bphen)₃ ^4-/3- film thus prepared displayed well-defined reversible electroactivity and electrochromic properties ascribable to those of the Fe(bphen)₃ ^4-/3- couple confined in the film. The PDMA-Fe(bphen)₃ ^4- film is red, and the PDMA-Fe(bphen)₃ ^3- film is colorless. The response rate of the color change to a potential pulse was found to be correlated with the kinetic parameters characterizing the rate of the overall charge-transfer reaction at the PDMA-Fe(bphen)₃ ^4-/3- film-coated electrode, that is, the apparent diffusion coefficient (D _app) for the homogeneous charge-transport process within the film and the standard rate constant (k) of the heterogeneous electron-transfer reaction at the electrode/film interface. For the PDMA-Fe(bphen)₃ ^4-/3- film with larger k° and D _app values, the response rate of the color change was larger, Further, k°, D _app, and response rate depended on the concentration (C°) of the Fe(bphen)₃ ^4- (or Fe(bphen)₃ ^3-) confined in the PDMA film; and at a given film thickness, the lower C°, the higher were k°, D _app, and response rate. At a given C°, the thinner the film thickness, the greater was the response rate.     

Electrochemistry and electrocatalysis of binuclear cobalt phthalocyaninehexasulfonate-surfactant film modified electrode

Electrochemistry and electrocatalysis of binuclear cobalt phthalocyaninehexasulfonate sodium salt (bi-CoPc) were investigated successfully in liquid crystal films of didodecyldimethylammonium bromide (DDAB) on pyrolytic graphite (PG) electrodes in aqueous solution. This new bi-CoPc-surfactant film modified electrode could reduce aggregation of bi-CoPc in aqueous solution, which was confirmed by the electronic absorption spectra in the visible region and images of transmission electron microscopy (TEM). The charge transport diffusion coefficient (D_ct) and apparent heterogeneous electrode reaction rate constant (k_s) for this modified electrode were estimated. The reduction of bi-CoPc ligand showed excellent electrocatalytic ability for the reduction of trichloroacetic acid (TCA) and catalytic current had a linear relationship with the concentration of TCA in the range of 3×10⁻⁵-7.5×10⁻³ M. The reduction of bi-Co(III)Pc/bi-Co(II)Pc couple exhibited new pattern of catalytic reactivity in the reduction of oxygen. Peak current for the cathodic reduction of oxygen is proportion to the square root of the scan rate in the range of 5-1000 mV s⁻¹ in oxygen-saturated solution.     

Kinetics of the Oxidation of Phenylhydrazine by [Fe(CN)6]3− in Water‐in‐Oil Microemulsions

The oxidation reaction of phenyl hydrazine (Phh) by hexacyanoferrate ([Fe(CN)₆]^3?) has been studied in water‐in‐oil (w/o) microemulsion media. The kinetic profile of the reaction was investigated as a function of [Phh], droplet size, and droplet concentration. Comparison of the kinetic profiles of the reaction in microemulsion, water‐urea, and water‐AOT‐urea media indicates that the kinetic profile of the reaction in microemulsion shows a behavior similar to that of the reaction in water‐AOT‐urea medium at 4 M urea. An initial increase and then a decrease in k_obs is observed with increasing molar ratio, W_o(=[H₂O]/[AOT]) at constant [AOT] (=0.4 M), whereas k_obs decreases upon increasing the AOT concentration at constant molar ratio.