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The present work describes the development of sustainable bio-benzoxazines for oil water separation and its composites for applications where a low dielectric constant is required. In addition, cardanol benzoxazine monomers (C-ida and C-pyta) with low curing temperature were designed with inbuilt catalytic core using two different heterocyclic amines, namely tetra aryl imidazole diamine (ida) and pyridine core triamine (pyta). Cotton fabric coated with poly(C-ida) and poly(C-pyta) show water contact angle values of 160o and 164[degrees], respectively. The oil-water separation efficiency of the polybenzoxazines coated cotton fabrics was 95%. Further, the poly(C-ida) and poly(C-pyta) matrices were reinforced with varying weight percentages (1, 3, 5, 7, and 10 wt%) of glycidylpropoxytrimethylsilane-functionalized biosilica. The benzoxazine matrices and composites obtained were characterized using different analytical techniques in order to assess their molecular structure, cure behavior, thermal stability, morphology, surface, and dielectric behavior. Data obtained from different studies suggest that these matrices and composites can be used as coatings for oil-water separation and high-performance micro-electronics insulation applications under adverse environmental conditions. KEYWORDS bio-benzoxazines, biocomposites, contact angle, dielectric constant, heterocyclic core amine, oilwater separation efficiency, 1 | INTRODUCTION Polybenzoxazines have been received great attention from both academic and industrial research in the recent past. [1-3] Benzoxazine resins have been used widely for different industrial and [...]

Non-aqueous buffer solutions are successfully used to check acidity in determinations of easily hydrolyzed elements by extraction-photometry [1, 2]. For the time being, a number of solvents is screened to [...], Non-aqueous (ethanol-toluene) standard buffer solutions are proposed on the basis of amines of various structures. The general trends in the change of acidity with the amine structure are revealed, which allow the prediction of the acidic properties of such buffer solutions and also the linearity range of the dependence of the activity index of hydrogen ions ([pa.sub.H]) on the amine concentration. This makes possible the precise selection of a buffer solution of the desired acidity. Keywords: acidity of non-aqueous solutions, buffer solutions, circuits without transfer, electromotive force (EMF) of a circuit, electrodes, electrical conductivity, degree of dissociation, dissociation constant, ion activity DOI: 10.1134/S1061934811020122

Mass transport through an interracial area at nanometer scale is a key process to be addressed in research and applications employing nanostructured electrodes, nanofluidic devices, and high surface area materials. Ionic transport through single glass nanopores is investigated by multifrequency impedance techniques. The conical glass nanopores display current rectification under controlled experimental conditions in voltammetric studies. Being inaccessible by conductivity and DC voltammetry, phase sensitive capacitive and 'inductive' components in the two-dimensional impedance spectrum reveal dynamic ionic transport information. The nanopore impedance responses are strongly influenced by the concentration of electrolytes and are correlated with current rectification. Multitime-constant impedance loops are detected in different frequency ranges. The multitime-constant features are attributed to the negative charges at the glass--solution interface. The impedance data are interpreted by designed equivalent circuit models. With the correlation of experimental and modeling results established, current signals can be differentiated into two categories: those originated from ionic transport affected by the immobilized charges at the solid--solution interface and those resulted from the applied waveform with ionic transport governed by geometric factors such as the radius of the nanopore. 10.1021/ac100440z

The nanosecond equilibrium method is employed to describe the determination of the standard potential of alkyl primary amines. The versatility and accuracy of the method shows that while it is an alternative to the classical and modern electrochemical approaches, it is also a powerful tool for quantifying inductive and/or solvation effects in related family of compounds.

Semiconductor CdS and CdSe nanostructures with complex form such as urchin-like nanoflowers, branched nanowires and fractal nanotrees were synthesized via a facile solvothermal approach in a mixed solution made of diethylnetriamine (DETA) and deionized water (DIW). The results showed that the morphologies of CdS and CdSe nanocrystals can be controlled via tuning the volume ratio of DETA and DIW suggesting that the photocatalytic property of CdS nanostructures is related to its unique structural feature.

Capillary electrophoresis was coupled successfully and reliably to potentiometric sensors, which are based on an ionically conductive rubber phase coating, applied on a 250 [micro]m diameter metal substrate. The membrane components included potassium tetrakis(p-chlorophenyl)borate (TCPB), bis(2-ethylhexyl)sebacate (DOS), and high molecular mass poly(vinyl chloride) (PVC). Potentiometry reveals a very sensitive CE detection mode, with submicromolar detection limits for amines and the randomly chosen drugs quinine, clozapine, cocaine, heroine, noscapine, papaverine, and ritodrine. The lowest detection limit, 1 x [10.sup.-8] M injected concentration, was obtained for the quaternary ammonium compound tetrahexylammonium chloride. The more polar lower aliphatic amines and the biogenic amines dopamine, adrenaline, and cadaverine have much higher detection limits. The detection limits are log P dependent. Addition of a commercially available calixarene molecule or a synthetic macrocyclic amphiphilic receptor molecule to the electrode coatings enhanced the sensitivity respectively for the lower aliphatic amines and for the biogenic amines. A transpose of the Nikolskii-Eisenman-type function was suggested and used to convert the signal of the detector to a concentration-dependent signal.

Nonclassical cations are found to be competent C-H hydrogen bond donors. Interaction between nonclassical cations and amines are energetically favourable and their interaction energies are in the range of those for more traditional hydrogen bonds.

Dielectric and acid-base bifunctional effects are examined in heterogeneous aminocatalysis by using a synthetic strategy based on bulk silica imprinting. The results show that reaction mechanism and product selectivity in heterogeneous aminocatalysts are critically dependent on the outer-sphere environment.

The electrochemical oxidation of tris(4-bromophenyl)amine (TBPA) in the presence of 2,6-lutidine is examined in acetonitrile. Voltammetric and spectroscopic studies show that the electrogenerated triaryl aminium radical cation oxidizes 2,6-lutidine in an electrochemical mechanism and a homogeneous electron transfer equilibrium exists between electrogenerated species TBPA and 2,6-lutidine.

The energetic ionic formed by the 1,2,4-trizolium cation family and dinitramide anion are investigated by ab initio quantum chemistry calculations, to assess charge delocalization in triazolium ions is discussed. The results address several different aspects of energetic ionic liquids, one of them revealing that triazolium dinitramide systems are rich in structure.

Electrophoretic resolution of 14 biogenic amines and metabolites with similar mobilities is addressed by employing micellar electrokinetic capillary chromatography coupled to amperometric electrochemical detection. The present study describes the optimization of separation conditions to achieve resolution of analytes of biological significance within 20 min in a single separation. They include dopamine, epinephrine, norepinephrine, octopamine (OA), L-3, 4-dihydroxyphenylalanine, tyramine (TA), and serotonin as well as metabolites 5-hydroxyindolacetic acid, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 3-methoxytyramine in addition to N-acetylated metabolites including N-acetyldopamine, N-acetyloctopamine (naOA), and N-acetylserotonin. The optimized conditions used result in excellent reproducibility and predictable peak shifting, thus enabling identification of several metabolites along with their biogenic amine precursors in biological samples, specifically from the fruit fly Drosophila melanogaster. The separation method is sensitive, selective, and quantitative as demonstrated by its capacity to detect changes in TA, OA, and naOA present in the head homogenates of the Canton-S and mutant inactive Drosophila lines. Quantitative analysis of metabolites in conjunction with their biogenic amine precursors in a single separation offers tremendous potential to understand the physiological processes and underlying mechanisms mediated by various biogenic amines in Drosophila and other animals.

We describe here in detail the first reversible electrochemical sensors for the polyion protamine. Potentiometric sensors were proposed in recent years, mainly for the determination of the polyions heparin and protamine. Such potentiometric polyion sensors functioned on the nonequilibrium extraction of polyions into a hydrophobic membrane phase via ion pairing with lipophilic ion exchangers. This made it difficult to design sensors that operate in a truly reversible fashion. The reversible sensors described here utilize the same basic response mechanism as their potentiometric counterparts, but the processes of extraction and ion stripping are now fully controlled electrochemically. Spontaneous polyion extraction is avoided by using membranes containing highly lipophilic electrolytes that possess no ion-exchange properties. Reversible extraction of polyions is induced if a constant current pulse of fixed duration is applied across the membrane, followed by a baseline potential pulse. The key theoretical response principles of this new class of polyion sensors are discussed here and compared to those of its classical potentiometric counterpart. The electrochemical sensing system is characterized in terms of optimal working conditions, membrane composition, selectivity, and influence of sample stirring and organic-phase diffusion coefficient on the response characteristics. Excellent potential stability and reversibility of the sensors are observed, and measurements of heparin concentration in whole blood samples via protamine titration are demonstrated.

Ensembles of silver nanowires (AgNEs) with diameters ranging from 200 nm to 1.0 [micro]m have been prepared by electrochemical step edge decoration. These AgNEs showed a rapid ( |-50%|) irreversible decrease in resistance was seen upon exposures to acids including HCl, HN[O.sub.3], and [H.sub.2]S[O.sub.4]. Based on these and other data, we propose a model in which oxidized constrictions in silver nanowires limit the conductivity of the wire and provide a means for 'gating' conduction based on the protonation state of the oxide surface.

CpRu(P-P) H carries out a study on the scope and mechanism of the catalysis of the ionic hydrogenation of an iminium cation (where P-P is a chelating diphosphine). This catalysis reaction involves the transfer of H(super -) to form an amine, the coordination of H(sub 2) to the resulting Ru cation, and the transfer of H(super +) from the coordinated dihyrodgen to the amine formed.

Microwave-assisted synthesis of solid-supported reagents for acylation of amines was developed. This methodology can be used to acylate both primary and secondary amines and enantiomerically pure amines without any racemization.

A synthetic path for the preparation of methacrylic homo- and copolymers containing secondary amine groups that can be converted into nitric oxide (No) releasing N-diazeniumdiolates is described. The study shows that polymethacrylates and polyacrylates can be covalently bonded to a variety of metal and silica surfaces using metacrylate silanes.

A photoinduced effect on the rate of reverse inter system crossing in single sulforhodamine molecules were studied using a novel two-color, multipurpose, double resonance technique. Results from single color, pulsed experiments showed no evidence of photoindused reverse for two dyes DiI and SRIoI.

Aminoalkynes and related heterocyclic systems react with CF3SO3H for generating dicationic electrophiles that can react with benzene and other arenes. These novel species are composed of vinyl cations with adjacent positive charge centers that can be used to prepare products with good yields from inter and intramolecular reactions.

A 'safety-catch' linker strategy is used to site-selectively cleave and characterize molecules from a microelectrode array. The linker which is attached to the array by means of an ester and contain either a protected amine or protected alcohol nucleophile that could be released using acid generated at the microelectrodes.

Wolff rearrangement is used to perform two step syntheses of cyclic enaminones from amino acids. The cyclization represents a rare 6-exo-dig cyclization involving a ketene as an electrophile without any racemization observed during the reaction process.

The enantioselective ring-opening reactions of azabicyclic alkenes with primary and secondary aromatic amine nucleophiles are described by using an iridium catalyst generated in situ from [[Ir(COD)Cl].sub.2] and (S)-BINAP. The reaction has produced the corresponding trans-1,2-diamine derivatives and trans-configuration of the 1,2-diamino product is conformed by X-ray crystallography.

Mechanistic studies were conducted to establish the resting state of the gold catalyst, the kinetic order of the reaction, the effect of ligand electronics on the overall rate, and the reversibility of the last steps in the catalytic cycle for the intermolecular hydroamination of allenes which occurs readily with hydrazide nucleophiles, in the presence of 3-12% [Ph.sub.3]PAuNT[f.sub.2]. The results suggested that the rate-limiting transition state for the reaction does not involve the nucleophile and the reaction could be accelerated with the use of more electron-deficient phosphine ligands on the gold(I) catalyst.

A family of discrete chalcogenide T4 clusters ([[[M.sub.x][Ga.sub.18-x][Sn.sub.2][Q.sub.35]].sup.21-], x = 2 or 4, M = Mn, Cu, Zn, Q = S, Se) are described whose discovery has resulted from an unusual phase transformation from a 3-D T4 covalent framework into 0-D T4 molecular clusters. The T4 clusters are the largest molecular supertetrahedral Tn clusters and can be made in various compositions showing tunable band structures in both solution and solid state.

A new one-pot electrophilic aminoalkylation reaction is developed by using olefin, cyclic ether, amine and N-bromosuccinimide. The olefinic substrates and the cyclic ether partners are flexibly varied to produce a range of amino ether derivatives and the protocol is applied in the synthesis of biologically active morpholine compounds.

A new chiral organic catalyst was developed based on a carboxylate-ammonium salt prepared from a thiourea-amine and a carboxylic acid. The new catalyst facilitated the development of an efficient asymmetric vinylogous aldol reaction of unprecedented scope with respect to both 2-trimethylsilyloxy furans and aldehydes.

The fragmentation of protonated molecules (M[H.sup.+]) in mass spectrometry has resulted in even-electron product ions, but the M[H.sup.+] ions of sulfonamides are different as they have produced dominant radical cations of the constituent amines. The studies have shown that for a series of benzenesulfonamides of anilines that bear various substituents the sulfonamides are protonated at the nitrogen, which is different from the carboxylic amides.

A colorimetric detection method is used to develop amine-functionalized polymer films doped with a pH indicator for the rapid, sensitive, and quantitative detection of gaseous formaldehyde at concentrations well below the immediately dangerous to life or health (IDLH) limit. The developed sensor is not affected by changes in humidity or temperature and is not sensitive to common interferents.

Large-scale molecular dynamics simulations are used for analyzing the propagation of shock waves normal to (111) in the energetic molecular crystal cyclotrimethylene trinitramine (RDX). The onset of homogeneous dislocation nucleation has accounted for the abrupt change in the elastic-plastic response of macroscopic (111)-oriented RDX single crystals observed in experiments by giving rise to an anomalous plastic hardening.

A strategy to prepare fully air stable, amorphous semiconducting polymers which could achieve charge carrier mobilities in the range of 0.04 [cm.sup.2]/(V s), remaining over a period of over 3 months in ambient conditions is reported. The results showed that the electrical performance of organic semiconducting polymers in the field-effect transistor devices could be increased through operation in an inert atmosphere or a hydrophobic surface treatment and annealing step.

Charge switching and detection are achieved by ambient atomic force microscopy (AFM) on small domains of polyarylamines, down to the single molecule limit. The studies have allowed charge switching of individual redox molecules and subsequent direct study of single ions in different environments relevant to molecular function in devices.

A one-step palladium-catalyzed aminocarbonylation of simple o-halobenzoate ester as starting material is used to obtain a range of isoindole-1,3-diones. The results provide a very convenient one-step approach to important class of heterocycles such as alcohol, ketone, methoxy, and nitro groups that also works for aliphatic and aromatic primary amines.

The relationship of line edge roughness (LER) in positive-tone chemically amplified (CA) resist after development with amine concentration and exposure dose is analyzed by using Monte Carlo simulation and dissolution model. The dependence of amine concentration on the LER after development is shown to be sensitive to the dissolution characteristics.

The structural, optical and electrical properties of films of spin-cast, oleate-capped PbSe nanocrystals, which are treated thermally or chemically in solutions of hydrazine, methylamine or pyridine to produce electronically coupled nanocrystal solids, are described. These chemically treated films have oxidized rapidly in air to yield highly conductive p-type nanocrystal solids.