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We have recently reported the synthesis and application of boron-nitrogen dihydroindeno[1,2-b]fluorene derivatives as acceptors in organic photovoltaic devices. Their modest observed efficiencies may be related to the properties of their reduced congeners. In this work, we report two new members of this family of compounds prepared via the electrophilic borylation of 2,5-di-p-tolylpyrazine followed by an arylation of the boron center with [ZnAr.sub.2] reagents. Two derivatives, 1 (Ar = 2,4,6-[F.sub.3][C.sub.6][H.sub.2]) and 2 (Ar = [C.sub.6][F.sub.5]) were synthesized, and their radical anions, [1*.sup.-] and [2*.sup.-], were formed via chemical reductions with [CoCp*.sub.2] and [CoCp.sub.2], respectively. Through comparison of structural parameters, as well as spectroscopic and computational data, the unpaired electron in the radical anions is localized in the planar core of the molecule, and dimerization is disfavored as a result. However, unlike the neutral starting materials, [1*.sup.-] and [2*.sup.-] are reactive toward ambient atmosphere. These observations suggest that the reduced compounds are stable toward intrinsic degradation pathways but subject to extrinsic degradation in device operation. Key words: radical anions, boron, heterocycles Nous avons récemment décrit la synthèse et l'application de dérivés de dihydro-indéno[10,2 b]fluorène à base de bore et d'azote comme accepteurs d'électrons dans des cellules photovoltaïques organiques (PVO). La piètre efficacité observée de ces dérivés pourrait être liée aux propriétés de leurs congénères réduits. Dans le cadre des présents travaux, nous faisons état de deux nouveaux membres de cette famille de composés que nous avons préparés par borylation électrophile de la 2,5 di p tolylpyrazine suivie d'une arylation de l'atome central de bore par des réactifs de type ZnAr2. Les deux dérivés que nous avons synthétisés, 1 (Ar = 2,4,6 F3C6H2) et 2 (Ar = C6F5), ont formé les anions radicalaires correspondants 1*- et 2*- par réduction chimique sous l'action du CoCp*2 et du CoCp2, respectivement. La comparaison des paramètres structuraux, ainsi que des données spectroscopiques et computationnelles, révèle que l'électron non apparié dans les anions radicalaires est localisé dans le noyau planaire de la molécule, ce qui défavorise la dimérisation. Toutefois, contrairement aux produits de départ neutres, les anions radicalaires 1*- et 2*- sont réactifs à l'air libre. Ces observations laissent donc supposer que les composés réduits sont stables aux processus de dégradation intrinsèques, mais qu'ils sont susceptibles de subir une dégradation extrinsèque lors du fonctionnement du dispositif. [Traduit par la Rédaction] Mots-clés : anions radicaux, bore, hétérocycles, Introduction Polycyclic aromatic molecules and polymers are well-studied materials for use in organic photovoltaic (OPV) or light-emitting devices. A subset of these materials consists of molecules and materials having one [...]

The ability of the beta-La2Mo2O9 cationic sublattice to distort as a semirigid framework of tilting [OLa3Mo) antitetrahedral units is studied through a mathematical analysis. It is proposed that the extra volume expansion, observed at the postulated Arthenius/Vogel-Tamman-Fulcher (VTF) transition, originates from such a tilting mechanism.

A study on the behavior of isolated AsO4(super 3--), PO4(super 3--), SO4(super 2--) and SeO4 (super 2--) in the gas phase and in solution is conducted. It is indicated that to calculate the repulsive Coulomb barrier (RCB) values, the electrostatic and point charge model are applied together with the Conceptual Density Functional Theory (DFT) based approach.

The highly twisted tetrakis(di-tert-butylmethylsilyl)disilene 4 was prepared and reacted with BuLi in THF, producing disilene anion radical 5 upon one-electron reduction. The anion radical 5 was isolated in the form of its lithium salt as extremely air- and moisture-sensitive red crystals.

Reaction of peroxynitrite with oxyMb and oxyHb in the presence of 1.2mM CO2 was investigated. Results reveal that this reaction can lead to Tyr, which might react with NO2 to generate 3-nitrotyrosine.

Two new neutral receptors (1 and 2) containing thiourea and amide groups were synthesized by simple steps in good yields. The binding properties of 1 and 2 with anions were examined by UV-vis, fluorescence, and [sup.1]H NMR spectroscopy. Receptor 1 had a better Ac[O.sup.-]: [H.sub.2]P[O.sub.4.sup.-] selectivity in comparison with that for receptor 2. The association constants of 1 x Ac[O.sup.-], 2 x Ac[O.sup.-], and 2 x [H.sub.2]P[O.sub.4.sup.-] were higher in comparison with those of other anions ([Cl.sup.-], [Br.sup.-], [I.sup.-], p-N[O.sub.2]Ph[O.sup.-], and p-N[O.sub.2]PhOP[O.sub.3.sup.2-]). In particular, a clear color change was observed, from pale yellow to red-brown, upon addition of Ac[O.sup.-] to the solution of 1 in DMSO. The UV-vis and fluorescence data indicate that a 1:1 stoichiometry complex is formed between compound 1 or 2 and anions through hydrogen-bonding interactions. Key words: neutral receptors, anion recognition, synthesis, hydrogen bonds.

The theoretical construction and calculation of the reaction paths and the constant rates for the dissociation of the radical anions in solution, which is a ground electronic state conical intersection reaction, the aspects of which are analyzed. It is concluded with such extension in hand, the reaction path and rate-constant issues of the present work is examined in a molecular solvent context via available methods.

Byline: G. Benzal (1), A. Kumar (2), A.M. Sastre (3), A. Delshams (4) Abstract: A mathematical model is developed for the carrier facilitated transport of metal ions through a flat sheet support liquid membrane (FSSLM) in transition state from Fick's second law. From this model, and from Fick's first law, the flow density is derived as a non-linear concentration gradient. Both expressions, concentration and flow density, depend on the thickness of the membrane and on time. Since the rate constant plays an important role in the model, it is considered as the parameter that controls the system and an equation for it is obtained. This equation explains the velocity of the co-transport process. The proposed model takes into account the species co-transported together with the metal ions. An equation for the number of moles of this species is obtained as a function of the metal species. The concentration gradient of this species explains the behaviour of pH in the feed phase during the process. The model is tested against experimental data corresponding to the transport of metal anions in acidic solution and it is shown that the co-transport process is reproduced with high accuracy. Author Affiliation: (1) Department of Mathematics, School of Chemistry, Universidad Nacional de Tucuman, Tucuman, Argentina, Ayacucho 490, 4000 (2) PREFRE, Bhabha Atomic Research Centre, Tarapur, India (3) Department of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB, Barcelona, Diagonal 647, E-08028, Spain (4) Department of Applied Mathematics I, Universitat Politecnica de Catalunya, ETSEIB, Barcelona, Diagonal 647, E-08028, Spain Article History: Registration Date: 08/10/2004

We describe a method, based on pressure-assisted capillary electrophoresis coupled to electrospray ionization mass spectrometry (PACE/ESI-MS), that allows the simultaneous and quantitative analysis of multivalent anions, such as citrate isomers, nucleotides, nicotinamide-adenine dinucleotides, and flavin adenine dinucleotide, and coenzyme A (CoA) compounds. Key to the analysis was using a noncharged polymer, poly(dimethylsiloxane), coated to the inner surface of the capillary to prevent anionic species from adsorbing onto the capillary wall. It was also necessary to drive a constant liquid flow toward the MS by applying air pressure to the inlet capillary during electrophoresis to maintain a conductive liquid junction between the capillary and the electrospray needle. Although theoretical plates were inferior to those obtained by CE/ESI-MS using a cationic polymer-coated capillary, the PACE/ESI-MS method improved reproducibility and sensitivity of these anions. Eighteen anions were separated by PACE and selectively detected by a quadrupole mass spectrometer with a sheath-flow electrospray ionization interface. The relative standard deviations (n = 6) of the method were better than 0.6% for migration times and between 1.4% and 6.2% for peak areas. The detection limits for these species were between 0.4 and 3.7 [micro]mol/L with pressure injection of 50 mbar for 30 s (30 nL), that is, mass detection limits calculated in the range from 12 to 110 fmol at a signal-to-noise ratio of 3. The utility of the method was demonstrated by analysis of citrate isomers, nucleotides, dinucleotides, and CoA compounds extracted from Bacillus subtilis cells.

DFT calculations were carried out on a series of mixed Keggin and Wells-Dawson(W-D) anions so that their redox and basicity properties could be analyzed. Mixed tungstoniobates behave differently since niobium orbitals are inserted into the tungsten band and the reduction of SiW(sub 9)Nb(sub 3+) for example, yields the blue species SiW(sub 9)Nb(sub 3) 1e and not the cluster SiW(sub 9)Nb(super V)2Nb(sub IV).

A method for sorption preconcentration of Cr(VI) from aqueous samples was developed using a polymer inclusion sorbent (PIS). The PIS used in this method was prepared by physical inclusion of Aliquat-336 in the matrix formed by cellulose triacetate and 2-nitrophenyl octyl ether. This sorbent was found to be stable, cost-effective, efficient for preconcentration of Cr(VI) present in the aqueous samples, and amenable to direct quantitative analysis of Cr(VI) held in it by neutron activation analysis and spectrophotometry. The quantifying of Cr(VI) in PIS by spectrophotometry was carried out by developing color directly on the PIS after reacting it with 1,5-diphenylcarbazide. The distinct color developed on the PIS even at very low concentrations of Cr(VI) suggests its possible use for field determination of Cr(VI). The composition of PIS was optimized to obtain maximum uptake of Cr(VI) without sacrificing uniformity in terms of thickness and distribution of ion-exchange sites, stability, and time required for quantitative sorption of Cr(VI) from aqueous samples. The Cr(VI) species held in the PIS, mainly HCr[O.sub.[4.sup.-]] and Cr[O.sub.[4.sup.2-]], were found to vary as a function of pH of the aqueous samples from which Cr(VI) was preconcentrated. A close agreement was found in the abundances of Cr(VI) species held in the PIS with those reported in the literature for aqueous solutions at different pH. The variation of Cr(VI) species as a function of pH was found to have a significant impact on the tolerance to anions on the uptake of Cr(VI) in the PIS. The high selectivity of PIS toward Cr(VI) from aqueous solution at pH = 2 was explained on the basis of hydration of anions. The uptake of Cr(VI) was found to be fairly constant (88 [+ or -] 3%) up to nearly complete exchange of counterions present in the PIS. The method developed in the present work was successfully used for the preconcentration of Cr(VI) from tap water and seawater samples containing low levels of Cr(VI).

Byline: R. Cusack (1), A. Rhodes (1), P. Lochhead (1), B. Jordan (1), S. Perry (1), J. Ball (1), R. Grounds (1), E. Bennett (1) Keywords: Strong ion gap Standard base excess Prognostic indicators Acid-base disturbance Abstract: Abstract Objective. To examine whether the strong ion gap (SIG) or standard base excess corrected for abnormalities of serum chloride and albumin (BE.sub.UA) can predict outcome and to compare the prognostic abilities of these variables with standard base excess (SBE), anion gap (AG), pH, and lactate, the more traditional markers of acid-base disturbance. Design. Prospective, observational study. Setting. University teaching hospital, general adult ICU. Patients. One hundred consecutive patients on admission to the ICU. Measurements and results. The anion gap (AG) was calculated and corrected for abnormal serum albumin (AG.sub.corrected). Serum lactate was measured and SBE, BE.sub.UA, SIG, and APACHE II scores calculated for each patient. 28-day survival was recorded. There was a significant difference between the mean APACHE II (P Conclusion. Traditional indices of SBE, BE.sub.UA, lactate, pH, AG, and APACHE II all discriminated well between survivors and non-survivors. In this group of patients the SIG, SIDeff, and SIGapp appear to offer no advantage in prediction of outcome and their use as prognostic markers can therefore not be advocated. Author Affiliation: (1) Department of Intensive Care Medicine, St George's Hospital, Blackshaw Road, London SW17 OQT, UK Article History: Received Date: 18/07/2001 Accepted Date: 29/03/2002 Article note: Electronic Publication

Research describes the free energy profiles of the dissociative pathway of methyl phosphate monoanion species both in the gas and aqueous phases. Data suggest that the dissociative phosphoryl transfer takes place from the hydrated tautomeric form of the anion species.

Aerosol mass spectrometers can be used to classify individual airborne particles on the basis of chemical composition. While positive ion mass spectra are normally used to characterize ultrafine particles (defined here as particles smaller than 200 nm in diameter), negative ion mass spectra can provide complementary information. To effectively utilize the negative ion mass spectra of ultrafine particles, it is important to understand biases in the formation and detection of negative ions. It is found that the intensity of negative ions is generally less than that of positive ions, due to the creation of electrons in the ablation process that must react to form negative ions. The ablation efficiency, defined as the probability that an ablated particle produces a detectable ion signal, exhibits both size and composition dependencies. The ablation efficiency for detection of negative ions follows the same trends as the ablation efficiency for the detection of positive ions: sodium chloride and ammonium nitrate have higher ablation efficiencies than oleic acid, and the ablation efficiency decreases with the particle diameter. The ablation efficiency of negative ions is less than or equal to the ablation efficiency of positive ions, and the relative difference increases as the particle diameter decreases. Pure ammonium suffate particles exhibit an ablation efficiency too low to be measured in the present experiments. However, trace amounts of sulfate in mixed-composition particles can be readily detected in the negative ion mass spectra.

A series of podands based on two or three hydrogen bonding 'arms' situated in mutually ortho, meta, or para relationships about an aryl core have been prepared, and their affinities for simple inorganic anions were measured. Of the two-arm hosts the meta compound and to a lesser extent the ortho host exhibit a cooperative anion binding effect. The two arms function essentially independently in the para derivative. The mutually meta three-arm host shows dramatically enhanced cooperative binding. Conformational changes within the meta two-arm host result in significantly enhanced electrochemical anion sensing compared with the more conformationally rigid three-arm host.

Two thread-shaped cations, pyridinium nicotinamide and imidazolium, as their chloride and hexafluorophosphate salts, were studied with regards to complexation with hydrogen-bond-donating acyclic and macrocyclic ligands. In the latter case, the cations form pseudorotaxanes templated by the chloride anion but not hexafluorophosphate. This formation is a function of the coupling of ion-pairing between the cation and chloride anion and subsequent recognition of the anion by the macrocyclic diamide, which provides the driving force for interpenetration. We propose that this anion template principle is a general method for the construction of pseudorotaxanes and could be applied to other cationic threads, anions, and macrocyclic species.

In situ production of thiolate anion is described. The thiolate anions are deprotecting agnets for alkyl and aryl esters as well as aryl sulfonates in the order of aryl ester to alkyl ester to aryl sulfonates. Data indicate that an aryl acetate/benzoate is selectively deprotected.

Excitatory amino acid transporters (EAATs) buffer and remove synaptically released L-glutamate and maintain its concentrations below neurotoxic levels. EAATs also mediate a thermodynamically uncoupled substrate-gated anion conductance that may modulate cell excitability. Here, we demonstrate that modification of a cysteine substituted within a C-terminal domain of EAAT1 abolishes transport in both the forward and reverse directions without affecting activation of the anion conductance. E[C.sub.50]s for L-glutamate and sodium are significantly lower after modification, consistent with kinetic models of the transport cycle that link anion channel gating to an early step in substrate translocation. Also, decreasing the pH from 7.5 to 6.5 decreases the E[C.sub.50] for L-glutamate to activate the anion conductance, without affecting the E[C.sub.50] for the entire transport cycle. These findings demonstrate for the first time a structural separation of transport and the uncoupled anion flux. Moreover, they shed light on some controversial aspects of the EAAT transport cycle, including the kinetics of proton binding and anion conductance activation.

For a low-pressure (1-100 mtorr) oxygen RF discharge plasma, the scaling laws for the densities of charged species such as positive ion, negative ion, and electron are estimated in terms of external and internal plasma parameters for the ion-flux-loss-dominated region based on the global balance equations. The scaling formulas are compared with Langmuir probe measurement results performed on a planar inductively coupled oxygen plasma. The transition point from the ion-flux-loss-dominated region to the recombination-loss-dominated region moves to a lower pressure region as the absorbed power increases. Index Terms--Low-pressure oxygen RF discharge, negative-ion density, scaling formula.

Research has been conducted on the smallest symmetrical bowl-shaped fragments of C (sub)60 and its tetra-tert-butyl derivative. The reduction of these compounds with lithium metal has been carried out to yield dianions and tetraanions.

Research has been conducted on the dialkyl sulfoxides. The enentiospecific displacement or enantioselective oxidation of a carbanionic leaving group which allows an access to these dialkyl sulfoxides has been investigated and discussed.

The temperature dependence of the absorption spectrum of the formation and decay of dimer anion (SCN)(sub 2)(super dot-) is analysed in the temperature range of 25 to 400 degree Celsius. Analysis showed that the absorption peak shift to longer wavelength (red shift) with increase in temperature.

Research has been conducted on the micellar systems. Results indicate that the contribution of the general catalysis in these systems is different due to the different sensitivity of their rate constants to the polarity change of the reaction medium.

Research suggests that the 'anions' such as carbenoids, nitrenoids, and oxenoids share common chemical properties like electrophilic nature, reactions with nucleophiles, and organometallic compounds. Data indicate that a metal and a group leaving the chemical reaction simultaneously bond to form a C, N, or O atom, which give rise to unique properties of these anions.

Results demonstrate that the structural framework of hexamethylenebis(acetamide) (HMBA) involves transfer of anions facilitating octahedrally coordinated 'node' points of HMBA-linked cations and the highly charged counteranions of suitable size and shape in the framework 'voids'.

The cyclopropenyl anions with 3-aryl substitutions are unstable in the gas phase during their transition to 6-substituted 3-indenyl anions. The acidity of 3-(4-methylphenyl)cyclopropene is determined by the DePuy method and the pH value agrees with that ab initio value.

Results show that the three lithium amidohydridoaluminate compounds exhibit their anions in a distorted tetrahedral coordination spheres as deduced from the crystal structure and elemental analyses.

Research discusses the isolation and characterization of one- and two-electron reduced anions of tetraalkylammonium salts. Data indicate that one-electron reduced anion is a simple paramagent and stable in dry solvents whereas the two-electron species is less paramagnetic and its solutions do not exhibit EPR signals.

Results show that alpha-phosphonovinyl anion reacts with aldehydes and ketones or with isocyanate to form alpha-(hydroxymethyl)vinylphosphonates or uracils with the former's role in the preparation of beta-substituted alpha-formylvinylphosphonates. Furthermore, synthesis of phosphono-functionalized heterocyclic compounds from alpha-formylvinylphosphonates is demonstrated.

A multicomponent mobile phase utilizing ion-exchange, ion-exclusion, and ion-pairing principles for the rapid isocratic separation of anions in low explosives residue by ion chromatography (IC) has been developed. The notable feature of this system is that an ion-pairing reagent and an ion-exclusion reagent are combined in the same mobile phase. Contrary to expectation, these reagents act independently of each other in solution. The stock mobile-phase composition consisted of boric acid, D-glueonic acid, lithium hydroxide, and glycerol. Tetrapropylammonium hydroxide, an ion-interaction reagent was used to achieve pH 8.5. Acetonitrile (ACN) was added to enhance resolution and oetanesuffonie acid, an ion-exclusion reagem, was added to adjust the retention time of perchlorate. Separation of a mixture of anions common to low explosives residue was achieved in less than 16 min using a Waters IC-Pak Anion HR column. Optimization studies were performed by changing the concentration of the ACN and by altering the pH or the type of ioninteraction or-exclusion agents. Simulated case studies were performed using postblast residues from pipe bombs. The results show this method to be a valid and reproducible procedure for forensic casework analysis. The practical significance of this system is that a reduction in the analysis time and an improvement in efficiency of late-eluting peaks can be achieved without resorting to gradient elution techniques. For the analysis of anions detected in explosives residue, the Waters IC-Pak Anion HR column has proven to be a suitable replacement for the Vydac 300IC405 column, which has been discontinued by the manufacturer.

Results suggest that the n-sigma type chloranil dianion interaction plays a role in the hydrogen bond formation in p-quinone dianion complexes with methyl alcohol as indicated by the blue-shift of the p-quinone dianion spectra.

Quantitative analysis of the complex problem of coupled electron- and proton-transfer steps during reduction of the polyoxo anions [Alpha]-[[[P.sub.2][W.sub.18][O.sub.62]].sup.6-] and [Alpha]-[[[H.sub.2][W.sub.12][O.sub.40]].sup.6-] in aqueous NaCl (0.5 M) has been achieved by simulation of cyclic voltammograms (Rudolph, M.; Reddy, D. P.; Feldberg, S. W. Anal. Chem. 1994, 66, 589A) over wide ranges of anion concentration, pH, and scan rate. Since there are too many unknown parameters to attempt a one-step global form of simulation, a systematic, stepwise approach has been adopted by progressively accessing regimes of increasing voltammetric complexity. This protocol allows experimental behavior in each system over 5 orders of magnitude in proton concentration to be simulated by estimation of three protonation constants combined with experimentally determined reversible half-wave potentials for the two one-electron processes involved. Fast electron transfer and protonation kinetics are assumed. The importance of the values chosen for the diffusion coefficients of the proton and polyoxo anion species is considered. The simulations account for the fact that pairs of one-electron processes coalesce to give an apparent two-electron process in the pH range 1-6 for reduction of both anions.

Ion-channel-mimetic sensors show potential for the analysis of very hydrophilic, relatively large analytes, where synthesis of hosts that encapsulate the analyte and do not permit it to be hydrated is difficult. This was concluded from the results of a study on the use of a hydrogen bond-forming bis(thiourea) compound for channel-mimetic sensing of inorganic anions. Selectivities of channel-mimetic sensing based on monolayers of these receptors were compared to selectivities of ion-selective electrodes based on membranes containing the same receptor.

This paper describes a straightforward approach for stacking extremely large volumes of sample solutions containing small organic and inorganic anions in capillary electrophoresis. The methodology involves the stacking of large sample volumes and the separation of the stacked anions in an acidic buffer (pH

Previously we demonstrated that the conductometric determination of anions of weak acids in chemically suppressed ion chromatography could be enhanced, by conversion of the acid to a conjugate salt, if the anion was present above what we termed the critical point concentration (CPC). In this paper we have developed a simple theoretical model for the calculation of CPCs for weak acid/conjugate salt pairs. The CPC was found to be dependent on the acid ionization constant [K.sub.a] and the molar ionic conductivities (MICs) of the ions present. For monovalent anions with a MIC in the common range 2575 S [cm.sup.2] [mol.sup.-1], with sodium or potassium as cations, the CPCs could be estimated from the expression pC [approximately equal to] p[K.sub.a] - 1, where pC = -log CPC. For formate, benzoate, and acetate, excellent agreement was found between the calculated and experimental CPCs, with a mean deviation of 0.05 mM. For fluoride, the calculated and experimental CPCs were 7.4 and 9.2 mM, respectively. Experimental CPCs could not be determined for other anions as their calculated CPCs were below the detection limits of the IC system. The simple theoretical model could also be used to estimate the expected conductivity enhancement for the conversion of weak acid to a particular conjugate salt. The effects of detector linearity and dispersion in the IC system on the use of CPCs are also discussed.

A study was conducted to test whether Cl/HCO3 and/or Cl/OH exchange correlates with vectorial chloride movement by examining the spatial distribution and influence of sodium depletion on anion-dependent 36Cl uptake by apical membrane vesicles in rat distal colon. Results indicated that Cl/HCO3 exchange is responsible for vectorial chloride absorption. Findings also showed that Cl/OH exchange supports a role in cell volume and/or cell pH homeostasis.

The structure and vibrational spectrum of the phenolate anions were computed using a number of quantum chemical techniques. Correlated techniques indicated a C-O bond length between 1.28 and 1.29 angstroms, which is much shorter than a previously reported value of 1.40 angstroms. This suggests a partial double bond feature for the C-O bond in the phenolate anion, which is explained in terms of resonance structures. Upon complexation of the phenolate anion with a positively charged counterion the C-O bond is elongated and has substantial bond character.

A fast flow reactor-quadrupole mass spectrometer coupled with a laser vaporization source was employed to investigate the gas-phase reaction of nickel and nickel oxide cluster anions with nitric oxide. Findings showed that three processes are happening in the presence of the nickel cluster anions. First, nickel and nickel oxide clusters are oxidized by the reaction with nitric oxide. Then, addition products with these oxides are also produced. Lastly, nitrogen dioxide and nitrogen trioxide are produced on nickel oxide clusters and later released as anions.

Gas-phase mutliply charged anions and their intramolecular Coulomb repulsion and solvation stabilization were investigated by photoelectron spectroscopy combined with an electrospray ionization method. An initial study on a series of linear dicarboxylate dianions (DC2-), -O2C(CH2)nCO2- (n = 3-6), solvated by one and two waters. Results showed that the dianion with n = 2 can be stabilized by one water, and in general the first water stabilizes the electron binding energy of DC2 by approximately 0.3 eV.

A study of the gas-phase thermochemistry of polyhalide anions used a flowing afterglow-tandem mass spectrometer to compute 0 K bond strengths in three hypervalent polyhalide ions. The bond strengths were found to be approximate to the values quantified previously. In addition, an inverse correlation was observed between solvation energies for the trihalides, obtained in this experiment and previous studies, and the size of the ion.

1,3-Bis(2-cyano-2-alpha-thienylethenyl)benzene, 1,4-bis(2-cyano-2-alpha-thienylethenyl)benzene and 2,7-bis(2-cyano-2-alpha-thienylethenyl)benzene were synthesized by electrogenerating polymeric thin films on electrode surfaces. The second compound can be reversibly reduced to produce the corresponding dianion, while the reduction of the other two compounds were either quasireversible or reversible. The diradicaloid properties were proposed to account for the high reactivity of the dianions of the two compounds.

Capillary electrophoresis with conductivity detection is evaluated for quantitative analysis of anions at low- to sub-ppb concentration levels in the presence and absence of a conductive sample matrix composed of 2 ppm ammonia and 50 ppb hydrazine. The low-level sensitivity is extended by a transient isotachophoretic stacking procedure. The linear range of the CE system and conductivity detector is graphically evaluated on the basis of absolute and corrected (normalized) chloride and sulfate peak profiles using an ASTM linearity criterion. The influence of random contamination bias from ubiquitous entities of nonsample chloride and sulfate levels introduced by liquid handling, laboratory atmosphere, and bulk chemical residues is quantitatively compared against an internal (contamination) reference ion.

A computation of the pi* orbital energies of 1,4,5,8-tetrahydronaphthalene or isotetralin employed the exponent-stabilized Koopmans' theorem (ESKT). Results provided a predicted pi* orbital ordering at 2b(sub 3g) < 2a(sub u) < 3b(sub 3g), which is identical to the ordering of ethylene trimer where only through-space interactions are observed. The through-bond interactions were cited for destabilizing all the pi* orbitals although they do not rearrange the order.