Many health claims have been made about the medicinal benefits of drinking green tea, including neuroprotection. This study mainly focuses on Epigallocatechin 3-gallate (EGCG), a potent antioxidant, which is abundantly found in tea. Cadmium [Cd(2+)] toxic pollutant that leads to neurotoxicity both animals and humans. Although entrance Cd(2+) adult central nervous system limited, developmental has evidenced as result blood-brain barrier (BBB) immaturity. Moreover, high levels are known impair...

Phosphate diester hydrolysis is strongly accelerated, by a factor of 104, in the presence artificial enzymes especially designed light spatiotemporal concepts, anchoring imidazoles pillar[5]arene matrix. Host:guest complexes cleave aryl phosphodiesters via nucleophilic attack properly placed imidazole moieties with release 2,4-dinitrophenolate and formation unstable phosphoroamidates that regenerate catalyst 2,4-dinitrophenyl phosphate. Comparison reactivity P5IMD shows 270-fold increase....

Synthesis of a new zwitterionic surfactant containing the imidazolium ring 3-(1-tetradecyl-3-imidazolio)propanesulfonate (ImS3-14) is described. The solubility ImS3-14 very low but increases on addition salt which helps to stabilize micellized surfactant. Fluorescence quenching and electrophoretic evidence for shows that micellar aggregation number only slightly sensitive added salts, as critical micelle concentration, NaClO(4) markedly zeta potentials in similar way...

The reaction between the benzohydroxamate anion (BHO−) and bis(2,4-dinitrophenyl)phosphate (BDNPP) has been examined kinetically, products were characterized by mass NMR spectroscopy. nucleophilic attack of BHO− follows two paths: (i) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement to phenyl isocyanate, aniline, diphenylurea, O-phenylcarbamyl benzohydroxamate; (ii) on aromatic carbon, was detected but slowly decomposes aniline 2,4-dinitrophenol. Thus, can...

Abstract Macromolecular chelating agents possessing high selectivity for rare metal ions have been synthetized. One of these, with the complexing group glyoxal bis‐2‐mercaptoanil, is suitable selective enrichment gold from sea‐water, while another copper and uranium. – The metallic in nature discussed, taking hemocyanin as an example. Both stereochemistry isomerism, well cyclic conjugation during chelate formation, may influence agents. quasi‐aromatic properties chelates are discussed.

Palladium nanoparticles (NPs) stabilized by a zwitterionic surfactant are revealed here to be good catalysts for the reductive amination of benzaldehydes using formate salts as hydrogen donors in aqueous isopropanol. In terms environmental impact and economy, metallic NPs offer several advantages over homogeneous traditional heterogeneous catalysts. usually display greater activity due increased metal surface area sometimes exhibit enhanced selectivity. Thus, it is possible use very low...

Cucurbit[7]uril (CB7) catalyzes the acid hydrolysis of alkoxyphenyldioxolanes bearing both neutral and cationic alkoxy groups. The magnitude catalytic effect depends on dioxolane structure, as reflected by CB7 binding constants catalysis rate constants. However, there is no clear relationship in such a way that increasing affinity (cationic dioxolanes or large groups) does not enhance effect. A-1 mechanism for involves protonation formation carbocation protonated ring opening. Supramolecular...

The rate of specific hydrogen ion-catalyzed hydrolysis 2-( p-heptoxyphenyl)-1,3-dioxolane and acid-base equilibrium 4-carboxy-1-n-dodecylpyridinium in zwitterionic micelles SB3-14, C14H29NMe2+(CH2)3SO3(-) are controlled by NaClO4, which induces anionic character uptake H3O+ the micelles. Other salts, e.g., NaF, NaCl, NaBr, NaNO3, NaI, NaBF4, have similar, but smaller, effects on H3O+. Salt upon zeta potentials SB3-14 micelles, estimated capillary electrophoresis, anion specific, order is...

Addition of salts, especially perchlorates, to zwitterionic micelles SB3-14, C(14)H(29)NMe(2)(+)(CH(2))(3)SO(3)(-), induces anionic character and uptake H(3)O(+) by SB3-14 micelles. Thus, the addition alkali metal perchlorates accelerates acid hydrolysis 2-(p-heptoxyphenyl)-1,3-dioxolane, HPD, in presence micelles, which depends on local proton concentration at micelle surface. The chlorides solutions such perchlorate-modified decreases both negative zeta potential observed rate constant for...

A polyhydroxamicalkanoate (PHA) polymer containing the functional groups hydroxamic acid and carboxylic with ability to accelerate dephosphorylation reactions is proposed. The methodology used prepare this favored position of two next each other, which allows for cooperativity between these groups. This cooperative effect has an important role when one wants mimic enzymes. catalytic promoted by was evaluated on cleavage bis(2,4-dinitrophenyl) phosphate (BDNPP) diethyl 2,4-dinitrophenyl...

Designing artificial enzymes with tailored molecular interactions between the substrate and active site is of major intellectual practical significance. We report improved catalytic efficiency a supramolecular polymer/surfactant complex comprised PAIM–, poly(acrylic acid) derivative imidazole groups attached to polymer by amide bonds, cationic surfactant cetyltrimethylammonium bromide (CTAB). Supramolecular formation, at concentrations below respective CMC values, provides convenient...

This paper presents the physicochemical properties of micellar aggregates formed from a series zwitterionic surfactants type 3-(1-alkyl-3-imidazolio)propane-sulfonate (ImS3-n), with n = 10, 12, 14, and 16. The ImS3-n dipolar ionic represent versatile class compounds, which form normal reverse micelles. Furthermore, they are able to stabilize nanoparticles in water organic media. Aqueous solubility is too low at room temperature allow characterization but increases addition salts, allowing...

A selective method is proposed for the determination of palladium, gold, and sulfur in catalytic systems, by direct liquid analysis using energy dispersive X-ray fluorescence (EDXRF), under an atmosphere helium or air. This allows a nondestructive rhodium, platinum, gold nanoparticulate catalysts stabilized imidazolium propane sulfonate based zwitterionic surfactants, allowing samples to be reused studies. The signals from presence sulfonate-based surfactants obtained EDXRF before (Pd(2+),...

Hexadecyl phosphorylcholine (HPC) micelles incorporate anions rather than cations in the interfacial region, giving an anionoid micelle with a negative zeta potential. Hydronium ion incorporation micellar pseudophase parallels increase potential, and salts rate of A1 hydrolysis 2-(p-heptyloxyphenyl)-1,3-dioxolane micellized HPC inhibit reaction OH(-) naphthoic anhydride. The kinetic effects are larger NaClO(4) NaCl. increased charge added increases repulsion between headgroups decreases...

Al3+-Mg2+ mixed oxides were prepared by coprecipitation and characterized with scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXRF), temperature programmed desorption of CO2 (CO2-TPD), N2 adsorption/desorption isotherms (BET BJH methods). By increasing the MgO concentration up to 31.8% (w/w), diffraction (XRD) measurements suggested an incipient magnesium aluminate spinel (MgAl2O4) phase. However, crystalline structure was obtained only after calcination at 950...

Abstract Aspartic proteinases, which include HIV‐1 proteinase, function with two aspartate carboxy groups at the active site. This relationship has been modeled in a system possessing an otherwise unactivated amide positioned between groups. The model is cleaved enzyme‐like rate that renders nonisolable 35 °C and pH 4 owing to joint presence of carboxylate A currently advanced theory attributing almost entire catalytic power enzymes electrostatic reorganization shown be superfluous when...

Mixed micelles of cetyltrimethylammonium bromide (CTABr) or dodecyltrimethylammonium (DTABr) and the α-nucleophile, lauryl hydroxamic acid (LHA) accelerate dephosphorylation bis(2,4-dinitrophenyl)phosphate (BDNPP) over pH range 4−10. With a 0.1 mole fraction LHA in DTABr CTABr, BDNPP is approximately 104-fold faster than its spontaneous hydrolysis, monoanionic LHA− reactive species. The results are consistent with mechanism involving concurrent nucleophilic attack by hydroxamate ion (i) on...

A polymer ( PAIM ) containing the functional groups imidazole and carboxylic acid acts as a nanoreactor to accelerate deacylation dephosphorylation reactions. The synthesis was designed position two next each other, allowing cooperativity. catalytic efficiency of evaluated for hydrolytic cleavage p‐nitrophenyl acetate PNPA diethyl 2,4‐dinitrophenyl phosphate DEDNPP ). both efficient promiscuous, increasing rates all reactions up 10 7 ‐fold. Copyright © 2014 John Wiley & Sons, Ltd.

This work describes the effect of a variety metal ions as quenchers fluorescence naphthalene, in aqueous micellar solutions sodium dodecyl sulfate (SDS). The quenching by can be adequately described Stern-Volmer equation and best signal to noise ratios are obtained with low micellized detergent concentrations. Apparent constants decrease order: Fe3+ > Cu2+ Pb2+ Cr3+ Ni2+ directly reflect relative sensitivity method for these ions. Detection limits (defined three times standard deviation...