新型阴离子表面活性剂的合成及其反胶束体系的酶催化性能

合成了未见文献报道的新型阴离子表面活性剂磷酸二[(2-乙基己氧基)乙基]酯钠(sodium di-[(2-ethylhexyloxy)ethyl] phosphate，DEEPA)；以核磁共振氢谱和红外光谱表征了它的结构；在DEEPK/异辛烷反胶束体系中进行了脂肪酶催化橄榄油水解反应实验.结果表明，该反胶束体系的催化活性优于AOT反胶束体系，更优于油-水双相中的酶催化反应，最大活性是油-水双相体系的1.86倍.     

Preparation and antibacterial activity of copper and cobalt complexes of 4-chloro-3-nitrobenzoate with a nitrogen donor ligand

Copper and cobalt complexes with 4-chloro-3-nitrobenzoate (ClNBz) and the nitrogen ligands 1,3-diaminopropane (1,3-DAP) or o-phenylenediamine (o-PDA), were prepared and characterized. The complexes [Cu(ClNBz)2(1,3-DAP)] (1), [Cu(ClNBz)(o-PDA)]Cl (2), [Co(ClNBz)2(1,3-DAP)] (3) and [Co(ClNBz)2(o-PDA)2] (4) were characterized by FTIR, UV-Visible absorption, elemental analysis and thermal analysis. Complex [Cu(ClNBz)(o-PDA)]Cl (2) shows high antibacterial activity as indicated by its ability to inhibit the growth of Staphylococcus aureus, Enterococcus faecalis.     

邻苯二胺及其金属配位型含氟聚酰胺磺酰胺的合成与荧光性能

采用溶解聚合法使β-四氟乙烷磺内酯分别与邻苯二胺、二氯-邻苯二胺合锌(Ⅱ)和二氯-邻苯二胺合镉(Ⅱ)开环缩聚,制备出邻苯二胺型和金属配位邻苯二胺型含氟聚酰胺磺酰胺聚合物。通过红外光谱、核磁共振氢谱、电感耦合等离子体发射光谱仪、凝胶渗透色谱等手段,确定其分子链为同时含有酰胺、磺酰胺、氟碳基团、芳环和金属离子的特殊结构;采用紫外-可见分光光度计和荧光分光光度计分析表明:邻苯二胺型含氟聚酰胺磺酰胺具有高荧光量子产率0.65,Cd2+配位后荧光量子产率保持0.65,而络合Zn2+的邻苯二胺型含氟聚酰胺磺酰胺的荧光量子产率降低为0.39,Zn2+对该类聚合物的荧光性能具有选择性。     

聚甲基丙烯酸甲酯接枝聚氧乙烯在甲苯中的聚集态结构

两亲接枝共聚物;胶束;聚甲基丙烯酸甲酯接枝聚氧乙烯在甲苯中的聚集态结构     

Catalytic performance of lignin peroxidase in a novel reverse micelle

To enhance the catalytic activity of lignin peroxidase (LiP) in a reverse micelle, a synthesized two-tail nonionic surfactant N-gluconyl glutamic acid didecyl ester (GGDE) was used to formulate a novel reverse micelle. Based on the LiP catalyzed oxidation of veratryl alcohol (VA) in this novel GGDE/TritonX-100-cyclohexane-H(2)O reverse micelle, the effects of the size of the reverse micelle, the buffer pH, and the concentration of H(2)O(2) on the catalytic activity of LiP were investigated. Under the optimized conditions, the catalytic efficiency of LiP in the GGDE/TritonX-100 reverse micelle was 40 times higher than that in the AOT reverse micelle. The full expression of catalytic activity of LiP in this medium was mainly due to the lack of electrostatic interaction between LiP and the head group of GGDE and TritonX-100 and to the size fit between LiP and the inner water cavity of the reverse micelle.     

The inverted micellar catalysis of the reaction of 2-aminomethylphenols with 4-nitrophenyl bis(chloromethyl)phosphinate

The parameters of the reaction ofpara-substituted 2-aminomethylphenols with 4-nitrophenyl bis(chloromethyl)phosphinate in toluene catalyzed by reversed micelles of polyethylene glycol-600 monolaurate depend on the nucleophile structure. The efficiency of the catalytic action increases in the series of substitutes C₉H₁₉ ⁱ<H<Cl. An increase in the catalytic activity of micelles in the region of structural rearrangement of micelle aggregates was observed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 275–278, February, 1999.     

Synthesis of poly(dipeptide)s on the surface of functional micelle and reversed micelle

Amphiphilic active 4-dodecanoyl-2-nitrophenyl esters of dipeptide containing β-alanine ( 1 – 5 ) were prepared and their polycondensation was studied in detail. The critical micelle concentrations of the active esters 1 – 5 were determined in water by the dye method and the apparent mean aggregation number of reversed micelles formed by model compound 6 was determined by the osmotic method. The results of polycondensation can be explained by assuming that aggregations such as micelle and reversed micelle play an important role in polycondensation. The obtained new poly(dipeptide)s were examined by IR, ¹H NMR, x-ray diffraction, and circular dichroism spectra.     

Micellar catalysis on the electron transfer reactions of iron(III)-polypyridyl complexes with organic sulfides-importance of hydrophobic interactions

The oxidation of organic sulfides with iron(III)-polypyridyl complexes [Fe(NN)3]3+ proceeds through an electron transfer mechanism and an increase in the methanol content in the methanol-water mixture favors the reaction. The reaction is catalyzed by both the anionic surfactant, sodium dodecyl sulfate (SDS) and the cationic surfactant, cetyltrimethylammonium bromide (CTAB). The micellar catalysis in the presence of SDS is accounted for in terms of strong binding of the cationic oxidant with the anionic surfactant and the development of positive charge on sulfur center of substrate in the transition state. The micellar catalysis observed on the reaction involving a trication, [Fe(NN)3]3+, in the presence of CTAB indicates the importance of hydrophobic interaction between the micelle and hydrophobic ligand of [Fe(NN)3]3+. The micellar catalysis is explained in terms of a pseudophase ion exchange model.     

萃取过程的量热研究(Ⅳ)——皂化P507萃取有机相中反向胶束和微乳状液的形成

利用量热滴定法研究皂化P507萃取有机相中反向胶束的形成和滴水过程中微乳状液的形成.求得临界胶束浓度、胶束形成常数K、聚集数n以及热力学函数,并用激光动态光散射仪测定胶团和微乳颗粒的流体力学半径。     

Effects of the water content on the growth rate of AgCl nanoparticles in a reversed micelle system

The effects of water content on the growth rate and the final particle size of AgCl nanoparticles in a reversed micelle (RM) system of polyoxyethylene (6) nonylphenyl ether (NP-6)/water/cyclohexane were investigated using a double-jet technique, in which RM solutions of AgNO(3) and KCl were added concurrently to a RM solution containing the excess concentration of chloride ion. As a result, the particle growth rate and the final particle size at a constant Rw ( identical with[water]/[surfactant]) below 5 were found to be in excellent agreement with our theoretical prediction based on a dynamic Ostwald ripening mechanism governed by the overall solubility of the solid and the diffusivity of the reversed micelles, whereas the final particle size was far beyond the size of the water pool of a reversed micelle. Thus, the dramatic reduction of the particle size in the RM system can be explained by the drastic reduction of the overall solubility of the solid and the small diffusivity of the bulky reversed micelles as a carrier of silver ion, and not by the size of the water pool of a reversed micelle as conventionally explained. Some additional contribution of a coagulation process was also suggested in a high Rw range above 5. Significant coagulation of AgCl particles was observed in a RM system with AOT in place of NP-6 even under the standard conditions for the NP-6 system.     

Decomposition of di-tert-butyl nitroxide in aqueous solutions

Di-tert-butyl nitroxide (DTBN) decomposes in aqueous solutions producing 2-methyl-2-nitroso propane (MNP) and tert-butanol. The process is acid catalyzed, it is of second order in DTBN, and takes place with a rate constant of (1.0 ± 0.1) M^?2 s^?1. The reaction is also catalyzed by the anionic surfactant sodium dodecyl sulfate and by Fe(II) and Fe(III) ions. The catalysis by Fe(III) involves a very fast reduction of Fe(III) ions with concomitant formation of 2-methyl-2-nitroso propane. The reaction catalyzed by Fe(II) also produces 2-methyl-2-nitroso propane with a formation rate given by: d[MNP]/dt = (0.25 ± 0.10) [Fe(II)] [DTBN]. This reaction rate is nearly pH independent.     

POLARIZATION STUDY OF 5(E)-STYRYL-1,3-DIMETHYL URACIL IN DIISOOCTYL SULFOSUCCINATE (AEROSOL-OT) REVERSED MICELLE SOLUTIONS

The degree of polarization around the water pool generated in aerosol- OT/hexane/water reversed micelle solutions was studied by monitoring the depolarization of solubilized probe fluorescence. The 5(E)-styryI-1, 3-dimethyl uracil (SDU) used in this study was moderately polar and proved to be solubilized between the interface and hydrocarbon phases in reversed micelle solution by a fluorescence quenching study with hydrophilic and hydrophobic quenchers. The degree of polarization monitored by SDU was parallel with that obtained from the fluorescence depolarization study of hydrophylic probes solubilized in the water pool and interface. A dramatic increase in microviscosity was observed when ω value became small.     

维生素C对菲醌三重激发态的淬灭机理及动力学研究

Time-resolved electron spin resonance has been used to study quenching reactions between the antioxidant Vitamin C (VC) and the triplet excited states of 9,10-phenanthrenequinone (PAQ) in ethylene glycol-water (EG-H₂O) homogeneous and inhomogeneous reversed micelle solutions. Reversed micelle solutions were used to be the models of physiological environment of biological cell and tissue. In PAQ/EG-H₂O homogeneous solution, the excited triplet of PAQ (³PAQ*) abstracts hydrogen atom from solvent EG. In PAQ/VC/EG-H₂O solution, ³PAQ* abstracts hydrogen atom not only from solvent EG but also from VC. The quenching rate constant of ³PAQ* by VC is close to the diffusion-controlled value of 1.41×10⁸ L/(mol·s). In hexadecyltrimethylammonium bromide (CTAB)/EG-H₂O and aerosol OT (AOT)/EG-H₂O reversed micelle solutions, ³PAQ* and VC react around the water-oil interface of the reversed micelle. Exit of ³PAQ* from the lipid phase slows down the quenching reaction. For Triton X-100 (TX-100)/EG-H₂O reversed micelle solution, PAQ and VC coexist inside the hydrophilic polyethylene glycol core, and the quenching rate constant of ³PAQ* by VC is larger than those in AOT/EG-H₂O and CTAB/EG-H₂O reversed micelle solutions, even a little larger than that in EG-H₂O homogeneous solution. The strong emissive chemically in-duced dynamic electron polarization of As^- resulted from the effective TM spin polarization transfer in hydrogen abstraction of ³PAQ* from VC.     

Size-dependent carrier dynamics in CdS nanoparticles by femtosecond visible-pump/IR-probe measurements

Ultrafast photoexcited carrier dynamics in CdS nanoparticles prepared by an AOT/n-heptane reversed micelle system were investigated by a femtosecond visible-pump/mid-IR probe technique. A mid-IR probe beam was found to mainly probe the ultrafast dynamics of photoexcited electrons in the conduction band. Dispersions of CdS nanoparticles with 8 different mean diameters from 2.9 to 4.1 nm were prepared by tuning the mole ratio between water and AOT (W = [H(2)O]/[AOT]) in the reversed micelle systems. The excited state lifetime strongly depended on the mean size of CdS nanoparticles with a maximum around a mean diameter of 3.5 nm. This result was explained by considering the balance between the carrier recombination rates via surface states and those via interior states. The relationship between the excited state lifetime and the size of CdS nanoparticles was drastically changed when the surface was terminated by thiol molecules.     

Time-resolved EPR investigation on the photoreactions of vitamin K with antioxidant vitamins in micelle systems

The photochemical reactions of vitamin K (VK) with antioxidant vitamins (vitamin E (VE) and vitamin C (VC)) in aqueous hexadecyltrimethylammonium chloride (CTAC), sodium dodecyl sulfate (SDS), and Triton X-100 micelle systems, and in an aerosol OT (AOT) reversed micelle system were investigated by a time-resolved EPR (TR-EPR). The photolysis of VK with VE in the aqueous micelle solutions gave the TR-EPR spectra having strong intensity and net emissive polarization, suggesting that the excited triplet state of VK (³VK^*) was rapidly quenched by VE coexisting inside the micelle. On the other hand, the photolysis of VK with VC in the aqueous SDS and CTAC micelle systems gave the spectra having weak intensity, showing that the reaction between ³VK^* and VC was inefficient in these micelle systems, probably because ³VK^* scarcely diffused out from the micelle. The photolysis of VK with VC in the AOT reversed micelle solution gave the spin-correlated radical pair CIDEP spectrum. The result suggests that the long-lived radical pair was generated from the reaction between ³VK^* and VC in the water/oil interface region of the AOT micelle, although one of the reactants dissolved in the oil phase and another did in the separated water phase.     

萃取过程的量热研究(Ⅰ)——有机相中反向胶束的形成及对萃取的影响

用滴定量热法研究萃取有机相中反向胶束的形成,分别测定P204(钠)-仲辛醇-煤油体系和季铵盐-仲辛醇-煤油体系的临界胶束浓度、聚集数和胶束形成常数等,并讨论了胶束的形成对萃取分配比的影响。     

Pathway from N‐Alkylglycine to Alkylisonitrile Catalyzed by Iron(II) and 2‐Oxoglutarate‐Dependent Oxygenases

N‐alkylisonitrile, a precursor to isonitrile‐containing lipopeptides, is biosynthesized by decarboxylation‐assisted ‐N≡C group (isonitrile) formation by using N‐alkylglycine as the substrate. This reaction is catalyzed by iron(II) and 2‐oxoglutarate (Fe/2OG) dependent enzymes. Distinct from typical oxygenation or halogenation reactions catalyzed by this class of enzymes, installation of the isonitrile group represents a novel reaction type for Fe/2OG enzymes that involves a four‐electron oxidative process. Reported here is a plausible mechanism of three Fe/2OG enzymes, Sav607, ScoE and SfaA, which catalyze isonitrile formation. The X‐ray structures of iron‐loaded ScoE in complex with its substrate and the intermediate, along with biochemical and biophysical data reveal that ‐N≡C bond formation involves two cycles of Fe/2OG enzyme catalysis. The reaction starts with an Fe^IV‐oxo‐catalyzed hydroxylation. It is likely followed by decarboxylation‐assisted desaturation to complete isonitrile installation.     

Pathway from N-Alkylglycine to Alkylisonitrile Catalyzed by Iron(II) and 2-Oxoglutarate-Dependent Oxygenases

N-alkylisonitrile, a precursor to isonitrile-containing lipopeptides, is biosynthesized by decarboxylation-assisted -N≡C group (isonitrile) formation by using N-alkylglycine as the substrate. This reaction is catalyzed by iron(II) and 2-oxoglutarate (Fe/2OG) dependent enzymes. Distinct from typical oxygenation or halogenation reactions catalyzed by this class of enzymes, installation of the isonitrile group represents a novel reaction type for Fe/2OG enzymes that involves a four-electron oxidative process. Reported here is a plausible mechanism of three Fe/2OG enzymes, Sav607, ScoE and SfaA, which catalyze isonitrile formation. The X-ray structures of iron-loaded ScoE in complex with its substrate and the intermediate, along with biochemical and biophysical data reveal that -N≡C bond formation involves two cycles of Fe/2OG enzyme catalysis. The reaction starts with an Fe^IV-oxo-catalyzed hydroxylation. It is likely followed by decarboxylation-assisted desaturation to complete isonitrile installation.     

丙烯酸接枝邻苯二酚衍生物的二次聚合

合成了2种聚合前驱体邻苯二丙烯酸酯(o-PDA)和2-甲氧基苯丙烯酸酯(2-MOPA), 分别通过与丙烯酸(AA)自由基共聚得到邻苯二丙烯酸酯-丙烯酸共聚物(O1)和2-甲氧基苯丙烯酸酯-丙烯酸共聚物(O2). 产物邻苯二酚(o-DHB)-O1(质量比1∶1)和1-羟基-2-甲氧基苯(HMOB)-O2(质量比1∶1)分别在乙腈/二氯甲烷-三氟化硼乙醚体系中直接阳极氧化聚合获得交联网状共聚物P1和P2. P1和P2均可溶于DMSO, 而难溶于ACN, DCM和THF等有机溶剂. 通过UV-Vis, FTIR和 ¹H NMR对交联共聚物膜的结构进行了表征. AA的引入不仅可以增加链的柔韧性, 而且提高了共聚物的力学性能. 而o-DHB/ HMOB的引入极大地减弱了单体的聚合位阻, 实现了单体的二次聚合, 同时也增强了单体及聚合物的电化学活性. 荧光光谱显示, 得到的2种交联共聚物膜分别在415和487 nm处有较强的发射峰, 表明共聚物仍具有良好的蓝色发光性能, 且聚丙烯酸结构的引入并没有对聚邻苯二酚(Po-DHB)和聚(1-羟基-2-甲氧基苯)(PHMOB)产生较大的荧光猝灭作用. 热重分析曲线(TGA)表明2种交联共聚物膜均具有较高的热稳定性.     

Synthesis of unimolecular reversed micelle consisting of a poly(L‐lactide) shell and hyperbranched D‐mannan core

A novel biodegradable unimolecular reversed micelle consisting of a poly(L ‐lactide) (PLA) shell and a hyperbranched D ‐mannan (HBM) core, that is, a chestnut‐shaped polymer (PLA–HBM), was synthesized by the polymerization of L ‐lactide on HBM with 4‐(dimethylamino)pyridine (DMAP) as the catalyst. The obtained polymers were soluble in dimethyl sulfoxide, tetrahydrofuran, and chloroform but insoluble in H₂O. The molecular weights of the PLA chain on PLA–HBM tended to increase with increasing polymerization time. The number of PLA chains on PLA–HBM could be controlled by the ratio of DMAP to the sugar unit in HBM. The obtained copolymer, PLA–HBM, acted as a unimolecular reversed micelle with an encapsulation ability toward the hydrophilic molecule. In addition, the entrapped hydrophilic molecules were slowly released from the core of PLA–HBM, and the release rate was accelerated by the breaking of the PLA chains of the shell when proteinase K as a hydrolase of PLA was used. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 406–413, 2006