Reactions in Supramolecular Systems

Zakharova, L. Ya.; Mirgorodskaya, A. B.; Zhil’tsova, E. P.; Kudryavtseva, L. A.; Коновалов, А. И.

doi:10.1002/9780470664872.ch15

Cited by 25 publications

(13 citation statements)

References 58 publications

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“…Our sphere of interest is also in the precipitation of small but closely situated catalytic particles for membrane electrode assemblies of fuel cells and design of supramolecular systems based on amphiphilic compounds with various functionality, i.e., nanoscale reactors and containers as well as the examination of their structural behavior by a complex of methods such as tensiometry, dynamic light scattering, AFM, EPR, etc. − The self-organization of surfactants in bulk solution and at the interface is the key feature determining the function of a majority of nanotechnological soft products. Therefore, understanding the factors controlling the surfactant interfacial behavior still remains a challenging task.…”

Section: Introductionmentioning

confidence: 99%

Platinum Nanoscale Lattice on a Graphite Surface Using Cetyltrimethylammonium Bromide Hemi- and Precylindrical Micelle Templates

2012

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One-dimentional (1-D) thin-layer (2−5 nm) parallel strips of Pt on a graphite surface have been synthesized via a template-directed chemical deposition of Pt. The templates are a surface micellar strip of cetyltrimethylammonium bromide (CTAB) at highly ordered pyrolytic graphite (HOPG). The concentration-and temperature-dependent morphology of surface micellar strips of CTAB at the graphite/aqueous solution is elucidated by using the atomic force microscopy (AFM) softcontacting techniques. The dimentions and repeat period of the Pt strips can be widely controlled by the temperature: the width is from 47 to 169 nm and the period from 134 to 233 nm in the temperature range 25−33 °C. The morphological characteristics of the Pt strips depend on those of the original surface micellar strips. The fact that the strips are composed of metallic platinum was confirmed by testing the membrane electrode assembly with the strips in a special fuel cell. This approach could be extended to fabricate a wide range of 1-D self-assembling metallic nanostructures on surfaces using micelle-like self-assemblies carrying metal ions at interfaces.

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Section: Introductionmentioning

confidence: 99%

Platinum Nanoscale Lattice on a Graphite Surface Using Cetyltrimethylammonium Bromide Hemi- and Precylindrical Micelle Templates

2012

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“…Decrease in the observed reaction rates after maxima is due to the dilution of catalysts in the Stern layer of micelles [39]. The rate enhancement in the phosponium-and pyridinium-based cationic surfactants is greater than in alkyl ammonium head groups due to their bulky head group [22,40]. The effect would correspond to a general decrease in the polarity of the head group region that would therefore increase the rate of the nucleophilic substitution [16,41].…”

Section: Kinetic Rate Constants Above the Cmcmentioning

confidence: 76%

Hydrolysis of carboxylate and phosphate esters using monopyridinium oximes in cationic micellar media

Singh

Ghosh

Marek

et al. 2011

Int J of Chemical Kinetics

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The reactions of p-nitrophenyl acetate (PNPA) with a series of monopyridinium oximes, viz. 2-PAM (2-hydroxyiminomethyl-1-methylpyridinium iodide), 3-PAM (3-hydroxyiminomethyl-1-methylpyridinium iodide), and 4-PAM (4-hydroxyiminomethyl-1-methylpyridinium iodide) have been studied in the presence of cationic surfactants of same hydrophobic chain length (C 16 ) within the concentration range of 0.5-6.0 mM at pH 8.0 under the pseudo-first-order condition. The observed rate constant (k obs ) increases with increasing surfactant concentration culminating into a maximum, and this has been analyzed in detail following the concepts of micellar catalysis. The structure-activity relationship of the investigated oximes has been discussed, and 2-PAM was found to be the most reactive among all the three investigated oximes for the cleavage of PNPA. Esterolytic decomposition of pnitrophenyldiphenyl phosphate with oximate ions ( CH NO − ) was followed in cetyltrimethylammonium bromide micelles at pH 9.0, and 4-PAM was the most reactive oxime for the micellar hydrolysis of phosphate ester. The apparent acid dissociation constants (pK a ) of the investigated oximes have been determined spectrophotometrically. C

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“…Second, the data in Table 1(nos. [20][21][22] show that both oxidative and nucleophilic processes in microemulsions are characterized by lower rates relative to analogous reactions in aqueous, aqueous-alcoholic, and micellar systems, the K S values being comparable for both substrates ( Table 2, cf. nos.…”

Section: Nomentioning

confidence: 99%

“…Therefore, organized nanosize systems such as micellar solutions and microemulsions are promising from the viewpoint of development of ecologically safe decontaminating compositions [11,12,[15][16][17][18][19][20][21]; these systems provide increased reagent concentration at the phase boundary between micelles (oil drop) and water and create favorable conditions for nucleophilic attack on electrophilic centers of toxic substrates [21,22].…”

mentioning

confidence: 99%

Nucleophilic oxidizing systems based on hydrogen peroxide for decomposition of ecotoxicants

et al. 2011

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The kinetics of oxidation of methylsulfanylbenzene and nucleophilic decomposition of diethyl 4-nitrophenyl phosphate with hydrogen peroxide in the presence of ammonium hydrogen carbonate or boric acid in aqueous, aqueous-alcoholic, micellar, and microemulsion media were studied. Quantitative parameters of the examined processes were determined, and the possibility of using hydrogen peroxide for the design of oxidative nucleophilic decontaminating systems was demonstrated.Taking into account huge worldwide stocks of chemical weapons [1-6], the problem implying utilization of highly toxic chemical agents has recently become especially important. The most common chemical weapons may be divided into three main groups: (1) phosphorus acid esters (neurotoxins and structurally similar pesticides, e.g., GB, GD, and Metaphos); (2) organosulfur compounds (blister agents, e.g., Yperite or HD); and (3) compounds with combined (neuroparalytic) action (VX).The optimal system for decontamination of toxic chemical agents should ensure their solubilization and simultaneously high rate of decomposition. Therefore, organized nanosize systems such as micellar solutions and microemulsions are promising from the viewpoint of development of ecologically safe decontaminating compositions [11,12,[15][16][17][18][19][20][21]; these systems provide increased reagent concentration at the phase boundary between micelles (oil drop) and water and create favorable conditions for nucleophilic attack on electrophilic centers of toxic substrates [21,22].While searching for chemically active components capable of rapidly and irreversibly decomposing toxic chemicals, specific attention is now given to the design of universal oxidative nucleophilic systems for degradation of chemical agents of different natures. For example, nucleophilic reagents are efficient toward phosphorus acid esters and halides (GB) [23,24], dialkyl sulfides like HD are decomposed by the action of oxidants [16,25,26], whereas oxidative nucleophilic systems containing an HOX-OX -couple (X = OH, Hlg, etc.) are preferred for decontamination of chemical agents like VX or mixtures of compounds belonging to the above three types (GB, HD, VX) [20,27]. In this respect, hydrogen peroxide due to its dual nature (it is an effective oxidant toward HD analogs [15,25] and reactive α-nucleophile toward phosphorus acid esters [1,24,28]) may be regarded as universal agent in the design of mild and ecologically safe decontami-

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Reactions in Supramolecular Systems

Cited by 25 publications

References 58 publications

Platinum Nanoscale Lattice on a Graphite Surface Using Cetyltrimethylammonium Bromide Hemi- and Precylindrical Micelle Templates

Platinum Nanoscale Lattice on a Graphite Surface Using Cetyltrimethylammonium Bromide Hemi- and Precylindrical Micelle Templates

Hydrolysis of carboxylate and phosphate esters using monopyridinium oximes in cationic micellar media

Nucleophilic oxidizing systems based on hydrogen peroxide for decomposition of ecotoxicants

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