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A portable surface-enhanced Raman scattering (SERS) sensor is developed and applied to simultaneous detection of aniline and phenol derivatives in a label-free way with an electrostatic preconcentration technique to amplify the signals. A SERS-active substrate, silver-electrodeposited screen-printed electrodes (Ag-SPEs), is used for qualification and quantification of polar organic pollutants. Observation of SERS spectra at different potentials indicates that polar pollutants are selectively adsorbed on the Ag-SPEs at a given potential, suggesting that Ag-SPEs could selectively attract polar pollutants to an oppositely charged electrode at different potentials. Optimum SERS-active substrate was obtained when a potential of-0.15 V vs Ag/AgC1 was applied on the SPEs in 0.1 M AgN[O.sub.3] solution for 10 min. Moreover, the effects of experimental variables such as the electrodeposition time and potential of Ag and preconcentration time of polar molecules on the SERS signals are presented. Under optimum conditions and with a 785 nm laser, the method is effective over a wide range of concentration (1 nM to 1 [micro]M) for aniline and phenol derivatives. The novel method described herein presents a new detection regime for environmental pollutant analysis and also demonstrates simultaneous multiplexed detection of polar organic pollutants using convenient Ag-SPEs. 10.1021/ac101812x

The oxidation of 4-chloroaniline (4-CA) has been studied by electrochemistry (EC) coupled on-line with electrospray ionization mass spectrometry (ESI-MS) using two electrochemical flow cells of different design. The experimental results, which generally verify previously suggested oxidation pathways for 4-CA, also indicate the presence of an up to now unrecognized comproporfionation reaction. The oxidation of 4-CA (m/z 128.2) was found to give rise to the formation of both an oxidized dimer, 4-[(4-chlorophenyl)imino]-2,5-cyclohexadien-1-imine (m/z 217.2), and a reduced dimer, 4-amino-4'-chlorodiphenylamine (m/z 219.2), in addition to a dimer intermediate (m/z 253.2). The unexpected formation of the reduced dimer is shown to stem from a comproportionation reaction involving 4-CA and the oxidized dimer. The presence of the latter reaction was clearly seen by comparing results obtained with two thin-layer flow cells, both with conversion efficiencies of 50% under mass transport controlled conditions but of different design with respect to the influence of the counter electrode reaction on the reaction at the working electrode. The experimental results demonstrate that the formation of the reduced dimer is favored by a decrease in the local pH in the flow cell, and the influence of the pH on the oxidation of 4-CA was also investigated in the pH range between 2.0 and 6.0 using off-line voltammetry. It is concluded that EC/ESI-MS is a powerful tool for the study of the present type of reactions and that studies of the reaction pathways of these systems are best carried out under noncoulometric experimental conditions as the latter facilitates the detection of reaction intermediates. Comproportionation reactions, similar to the reaction present in the 4-CA system, can also be expected to be present during the formation of conducting polymers such as polyaniline and polypyrrole.

2-Amino-4-nitroaniline crystallizes in a noncentrosymmetric space group giving it significant potential for second-order nonlinear optical properties (NLO) in the bulk. The theoretically predicted NLO properties at the molecular level are confirmed using various methods like X-ray diffraction, conventional and polarized IR spectroscopy, thermal and elemental analysis.

The development of a new Lewis acid system based on a complex formed from niobium(V) methoxide and (R)-3,3'-bis(2-hydroxy-3-isopropylbenzyl)-1,1'-binaphthalene-2,2'-diol is described. The catalyst is able to distinguish between different meso-epoxides stemming from its sensitivity to steric bulk at the [beta]-carbon of epoxides and the synthetic utility is enhanced by its ability to promote the asymmetric ring opening of nonsymmetric cis-epoxides with anilines.

The comparison results of the standard molar enthalpies of formation of fluoromethylaniline in gaseous state with the Cox scheme and the G3MP2/B3LYP calculations are presented.

Ruthenium-catalyzed preparation of the conjugated enynes is carried out in reactions of 1-cyclopropyl-2-propyn-1-ols with nitrogen- and oxygen-centered nucleophiles like anilines and water in the presence of a catalytic amount of sulfur-bridged diruthenium complexes. These complexes are used as catalysts for realizing the completely stereoselective preparation of tri- and tetrasubstituted conjugated enynes where ruthenium-allenylidene complexes work as key intermediates.

The simultaneous in-situ ultraviolet-visible (UV-vis) and open-circuit potential (OCP) monitoring of the low-concentrated aniline (An) polymerization in the presence of camphorsulfonic acid (CSA) has shown that a transition state is formed during the induction period (IP) step. The results have shown that an addition of the SiC dispersion phase into the polymerization mixture has accelerated differently at all stages of the aniline polymerization.

A novel method for pH measurements between pH 7.5 and 10.4 is reported in this paper. The method combines Raman spectroscopy and the automated sequential injection analysis system (SIA) and makes use of the acid base properties of a commercially available water dispersion of polyaniline (PANI) nanoparticles with a mean particle size of 46 nm. The useful pH range of the PANI nanoparticles is broader than for conventional acid-base indicators, due to the 1:2 reaction stoichiometry of the proton-ligand complex of the nanoparticles. The pH measurements were conducted with the 633-nm laser excitation wavelength by calculating the difference between the Raman intensities of the primary and reference wavenumbers. In this study, the pH-sensitive CH=CH stretching band at 1422 [cm.sup.-1] and C-H in-plane bending band of the quinoid form at 1163 [cm.sup.-1] were chosen as the primary wavenumbers. The presented method is fast and allows pH to be measured with a precision of 0.2 pH unit. The advantage of the proposed method is that the hysteresis effect, which is usually observed for PANI films, can be overcome with the PANI nanoparticles, because a fresh nanoparticle solution is used in each measurement. It should be pointed out, that this work is a fundamental study showing the applicability of Raman spectroscopy in combination with the SIA technique for pH measurements in specific applications, where the conventional glass pH electrode cannot be used.

Three alternating poly(m-p-anilines) are synthesized via palladium-catalyzed amination reactions and polymers are oxidized to radical cations by the use of chemical and electrochemical methods. The presence of radical cations is demonstrated by the appearance of two bands in UV-vis spectra, the positions of which depend on chemical structure of polymers.

A very simple and effective method for the generation of aromatic amine radical cations, which involves mixing of the aromatic amine with a equiv of Cu[(Cl[O.sub.4]).sub.2] in acetonitrile solution is presented. The reaction could be used for synthetic application by taking N,N-dimethylaninline (DMA) and N,N-diethylaniline (DEA) as examples.

The infrared photodissociation (IRPD) spectra of size-selected clusters composed on protonated aniline ([C.sub.6][H.sub.8][N.sup.} = An[H.sup.}) and a variable number of neutral ligands (L = Ar, [N.sub.2]) are obtained in the N-H stretch range. The comparison with clusters of neutral aniline and the aniline radical cations has shown the drastic effect of protonation and ionization on the acidity of the N-H bonds and the topology of the intermolecular potential, in particular on the preferred aromatic substrate-nonpolar ligand recognition motif.

The components of the nitrogen chemical shift (CS) tensor of a series of para substituted N-N-dimethylaniline derivatives were examined through measurement of (Super 15)N NMR spectra of powdered samples and through quantum chemical calculations on the isolated molecules. The methodology has proved the feasibility of performing N cross-polarization experiments on nonspinning powder samples at natural isotopic abundance.

Acid doped polyaniline nanofibers are examined for use as room-temperature hydrogen sensors. Results reveal that polyaniline nanofibers have the potential of being a good room-temperature hydrogen sensor in a dry atmosphere, and that their response is not inhibited by oxygen unlike many hydrogen sensors.

The reactions of Single-walled carbon nanotubes (SWNTs) 'on water' in the presence of a substituted aniline and an oxidizing agent yield functionalized materials. The process is an example of an 'on water' reaction that leads to functionalized SWNTs, and represents a 'green', or environmentally friendly process.

Structural and electronic properties of pristine and lithium-intercalated, phenyl-capped aniline dimmers as a model for the lithium-polyaniline system were studied by photoelectron spectroscopy and quantum chemical calculations. It was found that the electronic structure of reduced and oxidized forms of oligoanilines is only weakly affected by isomerism.

The local field effects on the nonlinear optical properties of p-nitroaniline (pNA) in three solvents of different multipolar character, that is, cyclohexane (CH), 1,4-dioxane (DI) and tetrahydrofuran (THF), was elucidated by employing a discrete description of the solutions. A very good agreement between simulated and experimental linear optical properties was obtained for the pure solvents, together with a good to reasonable agreement in the much more difficult to simulate high-order process of third harmonic generation (THG).

The ruthenium complexes containing 2-anilinopyridiante anionic bridging ligands substituted on the pyridyl site of the molecule are described. Reaction of the metal-metal bonded complex [Ru.sub.2]([[O.sub.2]CC[H.sub.3]).sub.4]Cl with 2-anilino-4-methylpyridine leads to the (3,1) isomer of the diruthenium (III,II) complex [Ru.sub.2][(ap-4-Me).sub.4]Cl, while the same reaction with 2-anilino-6-methylpyridine gives the monoruthenium(III) derivative, [Ru.sub.2][(ap-6-Me).sub.3].

Neutron diffraction data and crystal Hartree-Fock calculations are utilized to complement the multiple modeling of X-ray diffraction data. The experimental and theoretical evidences prove that the dipole enhancement for NMR in crystal is not at all close to the one previously reported, but is only on the order of 30-40% (~2.5D).

The dependence of the activation parameters on both substituents and solvents in selected S(sub N)2 reactions is calculated by using the DFT method with a moderate basis set. The measured and calculated activation parameters show considerable deviations for reactions of ions and for any reaction in protic solvents.

Appending a stable radical to the bridge molecule in a donor--bridge--acceptor system (D-B-A) is potentially an important way to control charge- and spin-transfer dynamics through D-B-A. Using both time-resolved optical and EPR spectroscopy, it is shown that nitronyl nitroxide (NN*) influences the spin dynamics of the photogenerated triradical states (super 2,4)(MeOAn-6ANI-Ph(NN*)-(super 3*)NI), in which NN* is strongly spin-polarized.

The proline-catalyzed direct asymmetric Mannich reaction between cyclohexanone, formaldehyde, and various anilines is thermally accelerated. With only 0.5 mol % of catalyst, Mannich products with up to 98% ee are obtained after a short period of time in reactions performed under microwave irradiation.

Improved catalysts for additions of arylamines to vinylarines and dienes are developed and these catalysts can tolerate the types of functionality commonly found unnatural products and pharmaceutically active materials. It is also found that palladium complexes of Xantphos are much more reactive catalysts for the hydroamination of dienes and vinylarenes than known catalysts and that the concentration of active catalyst and identity of the counterion control reactivity.

The aggregation of nanoparticles during synthesis, particularly the effect of mechanical agitation, is investigated, using conjugated polymer, polyaniline, as an example. Homogeneous nucleation of polyaniline results in nanofibers, while heterogeneous nucleation leads to granular particulates.

Nafion membranes were first used in the chlor-alkali industry for electrodialysis process that was modified by chemical polymerization of aniline using ammonium peroxodisulfate as the oxidant. Their transport properties were evaluated by conductivity and electrodialysis measurements and were extensively characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), infrared (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) differential scanning calorimetry (DSC) and ion exchange capacity measurements.

The decomposition reaction mechanism of the anions generated by atmospheric pressure chemical ionization mass spectrometry, in the negative mode, of nitroanilines and 2,4-dinitroanilines is probed using quantum chemical calculations. The result show that the effects of the amino and nitro groups as well as that of the negative charge on the nitro-nitric interconversion are small and do not qualitatively modify the landscape of the pertinent energy surface and thereby the NO-loss mechanism.

The structure and properties of the triplet states of the unsubstituted aniline using quantum chemical methods is being studied to obtain results which will help in understanding the electronic transitions of related aniline derivatives. It was found that in contrast with the S(sub 0) state, the triplet aniline is no longer aromatic, and its protonation occurs preferentially at the ring metacarbon site, with a proton affinity PA = 243 plusmn 3 kal/mol.

Chiral nitroanilines containing 1,2- or 1,3-diol functionalities is synthesized by nucleophilic aromatic substitution of fluoronitroanilines with 1-aminopropane-2,3-diols and 2-aminopropane-1,3-diol in the melt. The results reveal that the functionalization of the amino nitrogen of p-nitroaniline derivatives with polar groups, which are not in direct n-pi conjugation with the aromatic system, also affects the solvatochromism of the pull-push system in a complex fashion.

Photoinduced intramolecular charge-separation and charge-recombination processes in covalently connected C60-(spacer)-bis(biphenyl)aniline (C60-sp-BBA) and (C60-(sp-BBA)2 is studied by time-resolved fluoreseence and transient absorption methods. The rates of charge separation and the charge recombination for one BBA are faster then the other suggesting that one of the BBA moieties approaches the C60 moiety by pushing another BBA moiety due to the flexible spacers.

The reaction of 2-(arylazo) aniline with RhCl(sub3) afforded new cyclometalated complexes of Rh(III), (L)(HL)Rh(super III)Cl(sub2) and (L)(ArNH(sub2)Rh(super III)Cl(sub2).The formation of (L)(HL)Rh(super III)Cl(sub2) and (L)(ArNH(sub2)Rh(super III)Cl(sub2) indicated azo (-N=N-) bond cleavage of 2-(arylazo) aniline.

The calculations with Gaussian orbitals and periodic boundary conditions were carried out using several density functionals, to study the proton-doping of polyaniline. It was found that the bipolaron structure was lower in energy and the structural and spectroscopic theoretical predictions for both polaron and bipolaron lattices agreed well with the experimental data.

A conjugated donor-acceptor-donor molecule incorporating a central moiety of naphthyridine and two terminal moieties of di(hydroxyethyl)aniline connected by ethynyl bridges shows two-stage color changes on binding with mercury(II) ion in Me2SO/H2O solution with a bathochromic shift from 450 to 498 nm, and then an extraordinarily large hypsochromic shift to 378 nm. The designed sensor shows high selectivity toward mercury(II) ion over other competing metal ions.

The reactivity of the phthalimide-N-oxyl radical (PINO) toward the NO-methyl C-H bond of a number of 4-X-substituted N,N-dimethylanilines is investigated. It is found that the PINO is very reactive toward the methyl C-H bond of N,N-dimethylanilines promoting the oxidative N-demethylation of the substrate.

A demonstration that Fe(super 3+) in one solution can be reduced to Fe(super 2+) by ascorbic acid in another solution when both aqueous solutions are separated by polyaniline membrane, is presented. This transmembrane redox process is possible due to electron/anion coupled counter transport through polyaniline membrane.

A facile parallel synthesis of polysubstituted 2,6-dicyanoanilines through microwave-promoted three-component reaction of aldehydes, ketones, and propanedinitrile in solution and also on polymer support is developed. The screening for optical properties identified two new compounds with high fluorescence quantum yields.

A study conducted shows how the presence of aromatic substituents OH, CH2OH, CO2H, and CONH2 modifies the relative methylation rate of amines, plausibly by altering the adsorption of these substrates within the pores of the zeolite used. The study demonstrates that several factors could account for the trend of reactivity shown by the amines in their mono-N-methylation with dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC).

The kinetics of the oxidative decarboxylation of a series of anilino carboxylates is measured. A quantitative study of the factors that control the rate constants for oxidative decarboxylation is conducted and the need for qualitative theoretical descriptions that would accommodate all of the important observations and factors that control the rates is discussed.

Solid-state dye-sensitized solar cells (DSSCs) were fabricated using 4-dodecylbenzenesulfonic acid-doped polyaniline (PANI-DBSA) blended with LiI and 4-tert-butylpyridine (tBP) as hole conductors. The introduction of LiI and tBP into the polymer improves the photovoltaic behavior of solid-state DSSCs significantly.

Aniline chemisorption at clean and partially oxidized Cu(110) surfaces at 293 K is compared with the reaction of a 300:1 aniline/dioxygen mixture at the same surface using STM and XPS. Limited dissociation occurs at the clean surface but in the presence of chemisorbed oxygen efficient oxy-dehydrogenation takes place with water desorption and the formation of chemisorbed phenyl imide [(C6H5N(a)] with a reaction stoichiometry that changes with coverage.

Photoinduced multistep electron transfer is studied in two symmetrical oligoaniline-oligo(p-phenylene vinylene)-perylene diimide-oligo(p-phenylene vinylene)-oligoaniline multichromophore arrays with fluorescence and transient absorption in the femtosecond and nanosecond time domains.

The two systems that form emissive states in electrogenertaed chemiluminescence (ECL) with different properties are described. The findings from these two simple systems demonstrate that ion annihilation pathway of ECL can generate different emissive states than those formed following photoexcitation.

A new procedure to decompose the solvent response to solute perturbation into electrostatic and nonelectrostatic components, to understand solvent reorganization process, is proposed. The ab initio reference interaction site model-self consistent field (RISM-SCF) method is applied to depict the solvent reorganization process and electronic structures of N,N-dimethylaniline (DMA) and 1,4-dimethoxybenzene (DMB) associated with a charging process in acetonitrile solutions.

The fabrication of conducting polymer nanowires on thermally oxidized Si surfaces by use of DNA templates is described. The conductivity of the nanowires is very sensitive to the proton doping-undoping process, suggesting that the nanowires hold great promise for sensitive chemical sensor applications.

A large high-quality zeolite MFI single crystal 3.0 x 1.5 x 1.5 mm(super 3) in size was synthesized by means of a nutrition supplemental method and a p-nitroaniline (PNA)/MFI single crystal was prepared via physical vapor deposition. The light yellow PNA/MFI single crystal changed to green when irradiated by 1062 nm fundamental wavelength from a Nd: YAG pulse laser.

The investigating is done to compile the existing pk(sub a) data (in water) and provide the missing data for 2-mono- and 2,6-disubstituted anilines containing Ch3, CH3O, Cl and NO2 substituents and their combinations are presented. The quantum-chemical approach has the advantage that its results implicitly involve all manifestations of substituents, inclusive of the formation of hydrogen bonds between molecular moieties, nonbonding interactions and so forth.

The photochemistry of 4-haloanilines and 4-halo-N,N-dimethylanilines is examined in apolar, polar aprotic, and protic solvents. Photophysical and flash photolysis experiments show that the reaction proceeds in any case from the triplet state.

The results of the research conducted on van der Waals complexes of aniline and 4-aminobenzonitrile with polar solvents formed in a supersonic jet is reported. It also reports the solvatochromism studies of all substituted benzenes and napthalenes.

A novel class of amphiphilic hemicyanine dyes is described where electron-pushing aniline and electron-pulling pyridinium are joined by anellated benzene rings. From the intramolecular charge shift that is induced by electronic excitation, the linear Stark effect that is expected when the Annine dyes are used as voltage-sensitive probes in a biomembrane is estimated.

The study observes NH stretching vibrations of jet-cooled aniline and its various derivatives in the neutral and cationic ground states. The results reveal that the intramolecular hydrogen bond formation was found for o-cyanoaniline in both the neutral and cationic ground states based on the infrared spectra of deuterated isotopomers resulting in hydrogen bond strength, which is remarkably enhanced upon ionization.

A study of diffusion processes of intermediate ion radicals created by photoexcited electron-transfer reaction of benzoquione (BQ) and aniline (AN) in sodium dodecyl sulfate (SDS; anionic micelle) and cetyltrimethyl-ammonium bromide(CTAB; cationic micelle) solutions is presented. The method described can be used to determine the equilibrium constants of the transient radicals in the micellar solutions.