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Sample records for acetonitrile

  1. (Methoxymethylidenedimethylazanium tetraphenylborate acetonitrile monosolvate

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    Ioannis Tiritiris

    2014-03-01

    Full Text Available In the cation of the title salt, C4H10NO+·C24H20B−·C2H3N, the C—N bond lengths are 1.2864 (16, 1.4651 (17 and 1.4686 (16 Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.2978 (15 Å shows double-bond character, pointing towards charge delocalization within the NCO plane of the iminium ion. C—H...π interactions are present between the methine H atom and two of the phenyl rings of the tetraphenylborate ion. The latter forms an aromatic pocket in which the cation is embedded. The iminium ion is further connected through a C—H...N hydrogen bond to the acetonitrile molecule. This leads to the formation of a two-dimensional supramolecular pattern along the bc plane.

  2. Urinary acetonitrile concentrations correlate with recent smoking behaviour

    NARCIS (Netherlands)

    Pinggera, Germar-Michael; Lirk, Philip; Bodogri, Florian; Herwig, Ralf; Steckel-Berger, Gabriele; Bartsch, Georg; Rieder, Josef

    2005-01-01

    To assess the concentration of acetonitrile (a saturated aliphatic nitrile) in the urine of habitual cigarette smokers and non-smokers, as exposure to smoke can be measured by monitoring ambient air or by in vivo tests, but acetonitrile measured in exhaled breath is reportedly a quantitative marker

  3. Microstructure and hydrogen bonding in water-acetonitrile mixtures.

    Science.gov (United States)

    Mountain, Raymond D

    2010-12-16

    The connection of hydrogen bonding between water and acetonitrile in determining the microheterogeneity of the liquid mixture is examined using NPT molecular dynamics simulations. Mixtures for six, rigid, three-site models for acetonitrile and one water model (SPC/E) were simulated to determine the amount of water-acetonitrile hydrogen bonding. Only one of the six acetonitrile models (TraPPE-UA) was able to reproduce both the liquid density and the experimental estimates of hydrogen bonding derived from Raman scattering of the CN stretch band or from NMR quadrupole relaxation measurements. A simple modification of the acetonitrile model parameters for the models that provided poor estimates produced hydrogen-bonding results consistent with experiments for two of the models. Of these, only one of the modified models also accurately determined the density of the mixtures. The self-diffusion coefficient of liquid acetonitrile provided a final winnowing of the modified model and the successful, unmodified model. The unmodified model is provisionally recommended for simulations of water-acetonitrile mixtures.

  4. Vibrational Energy Relaxation in Water-Acetonitrile Mixtures

    NARCIS (Netherlands)

    Cringus, Dan; Yeremenko, Sergey; Pshenichnikov, Maxim S.; Wiersma, Douwe A.; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

    2004-01-01

    IR pump-probe spectroscopy is used to study the effect of hydrogen bonding on the vibrational energy relaxation pathways. Hydrogen bonding accelerates the population relaxation from 12ps in diluted acetonitrile solution to 700fs in bulk water.

  5. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry

    Science.gov (United States)

    Colizza, Kevin; Mahoney, Keira E.; Yevdokimov, Alexander V.; Smith, James L.; Oxley, Jimmie C.

    2016-11-01

    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression.

  6. Nucleofugalities of Neutral Leaving Groups in 80 % Aqueous Acetonitrile

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    Sandra Jurić

    2016-06-01

    Full Text Available Nucleofugalites of tetrahydrothiophene, dimethyl sulfide and differently substituted pyridines in 80 % aqueous acetonitrile have been derived from the SN1 solvolysis rate constants of the corresponding X,Y-substituted benzhydryl derivatives (1–10. In sol-volysis of sulfonium ions in 80 % aqueous acetonitrile, where acetonitrile is a good cation solvator, the solvation of the reactant ground state is an important rate determining variable since the positive charge is almost entirely located on the leaving group. As a consequence, reaction rates of sulfonium ions are more sensitive to the substrate structure in 80 % aqueous acetonitrile than in pure and aqueous alcohols, which are less efficient as cation solvators. In solvolysis of pyridinium ions the solvation of the reactant ground state is less important, since the positive charge is considerably distributed between the carbon at the reaction center and the leaving group. In such cases the important rate determining variable is solvation of the transition state. Slower reactions of pyridinium sub-strates progress over later, carbocation-like transition states in which the solvation is more important, so those substrates solvolyze slightly faster in aqueous acetonitrile than in methanol (k80AN > kM. Faster reactions proceed over earlier TS in which the solvation is diminished, so those substrates solvolyze somewhat faster in methanol than in aqueous acetonitrile (k80AN kM. This work is licensed under a Creative Commons Attribution 4.0 International License.

  7. Inhalation developmental toxicology studies: Acetonitrile in rats. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mast, T.J.; Weigel, R.J.; Westerberg, R.B.; Boyd, P.J.; Hayden, B.K.; Evanoff, J.J.; Rommereim, R.L.

    1994-02-01

    The potential for acetonitrile to cause developmental toxicity was assessed in Sprague-Dawley rats exposed to 0, 100, 400, or 1200 ppM acetonitrile, 6 hours/day, 7 days/week. Exposure of rats to these concentrations of acetonitrile resulted in mortality in the 1200 ppM group (2/33 pregnant females; 1/10 non-pregnant females). However, there were no treatment-related effects upon body weights or reproduction indices at any exposure level, nor was there a significant increase in the incidence of fetal malformations or variations. The only effect observed in the fetuses was a slight, but not statiscally significant, exposure-correlated increase in the incidence of supernumerary ribs. Determination of acetonitrile and cyanide concentrations in maternal rat blood showed that acetonitrile concentration in the blood increased with exposure concentration for all exposed maternal rats. Detectable amounts of cyanide in the blood were found only in the rats exposed to 1200 ppM acetonitrile ({approximately}2 {mu}g cyanide/g of blood).

  8. (Acetonitrile[bis(2-pyridylmethylamine]bis(perchloratocopper(II

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    Ray J. Butcher

    2008-01-01

    Full Text Available In the title compound, [Cu(ClO42(C12H13N3(C2H3N], the CuII atom is six-coordinate in a Jahn–Teller distorted octahedral geometry, with coordination by the tridentate chelating ligand, an acetonitrile molecule, and two axial perchlorate anions. The tridentate ligand bis(2-pyridylmethylamine chelates meridionally and equatorially while an acetonitrile molecule is coordinated at the fourth equatorial site. The two perchlorate anions are disordered with site occupancy factors of 0.72/0.28. The amine H is involved in intramolecular hydrogen bonding to the perchlorate O atoms and there are extensive but weak intermolecular C—H...O interactions.

  9. Photochemical reduction of uranyl ion by acetonitrile and propionitrile

    International Nuclear Information System (INIS)

    Brar, A.S.; Chander, R.; Sandhu, S.S.

    1979-01-01

    The photochemical reduction of uranyl ion by acetonitrile, propionitrile, benzonitrile, phenylacetonitrile, cyanoacetic acid and malononitrile in aqueous or aq. acetone medium using radiations >= 400 nm from a medium pressure mercury vapour lamp has been investigated. Except acetonitrile and propionitrile all other nitriles fail to bring about the reduction of uranyl ion. The reduction with aceto- and propionitriles has been found to obey pseudo-first order kinetics. The magnitude of rate of reduction with propionitrile is higher than that with acetonitrile. The pseudo-first order rate constants and quenching constant have been calculated from the kinetic data. It has been found that physical and chemical quenching compete with each other. The plot of reciprocal of quantum yield versus reciprocal (nitrile) is linear with a small intercept on the ordinate axis. Absorption spectra of uranyl ion in pure water, in the presence of acid and in the presence of acid+nitrile reveal that there is no ground state interaction between uranyl ion and the nitrile. A mechanism of photochemical reduction of uranyl ion based on α-hydrogen abstraction from the nitrile has been proposed. (auth.)

  10. Antioxidant and antibacterial activities of acetonitrile and hexane extracts of Lentinus tigrinus and Pleurotus djamour

    Science.gov (United States)

    This paper highlighted the antioxidant and antibacterial activities of Lentinus tigrinus and Pleurotus djamour. Extracts of mushroom fruiting bodies were obtained using hexane and acetonitrile solvents. Acetonitrile extracts of both mushrooms exhibited higher biological activities than hexane extrac...

  11. Anodic dissolution of samarium in acetonitrile solution of acetylacetone

    International Nuclear Information System (INIS)

    Kostyuk, N.N.; Dik, T.A.; Trebnikov, A.G.; Shirokij, V.L.

    2003-01-01

    Electrochemical dissolution of metal samarium in acetonitrile medium in the presence of 0.1 M tetraethylammoniumbromide and 0.9 M acetylacetone (HAA) in argon atmosphere under a voltage of 3 V was considered for studying feasibility of electrochemical synthesis of samarium β-diketonates. Using IR and mass spectrometry, thermal and elementary analyses it was ascertained that, depending on cathode and anode areas ratio, anodic dissolution of samarium can give rise to formation of complexes of bi- and trivalent samarium featuring the composition Sm 4 (AA) 8 · 3HAA, Sm(AA) 3 · HAA and Sm(AA) 3 · 4HAA [ru

  12. Luminescence enhancement of uranyl ion by benzoic acid in acetonitrile

    International Nuclear Information System (INIS)

    Satendra Kumar; Maji, S.; Joseph, M.; Sankaran, K.

    2014-01-01

    Uranyl ion is known for its characteristic green luminescence and therefore luminescence spectroscopy is a suitable technique for characterizing different uranyl species. In aqueous medium, luminescence of uranyl ion is generally weak due to its quenching by water molecules and therefore in order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HCIO 4 have been widely used. The other method to enhance the uranyl luminescence is by ligand sensitized luminescence, a method well established for lanthanides. In this work, luminescence of uranyl ion is found to be enhanced by benzoic acid in acetonitrile medium. In aqueous medium benzoic acid does not enhance the uranyl luminescence although it forms 1:1 and 1:2 complexes with uranyl ion. Luminescence spectra of uranyl benzoate revealed that enhancement is due to sensitization of uranyl luminescence by benzoate ions. UV-Vis spectroscopy has been utilized to characterize the specie formed in the in acetonitrile medium. UV-Vis spectroscopy along with luminescence spectra revealed that the specie to be tribenzoate complex of uranyl (UO 2 (C 6 H 5 COO) 3 ) - having D 3 h symmetry. (author)

  13. Thermometric titrations of amines with nitrosyl perchlorate in acetonitrile solvent.

    Science.gov (United States)

    Gündüz, T; Kiliç, E; Cakirer, O

    1996-05-01

    Thirteen aliphatic and four aromatic amines, namely diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-butylamine, isopropylamine, di-isopropylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, aniline, N,N-dimethylaniline, 2-nitroaniline and 4-nitroaniline were titrated thermometrically with nitrosyl perchlorate in acetonitrile solvent. All the aliphatic amines gave very well-shaped thermometric titration curves. The calculated recovery values of the amines were very good. In comparison, the aromatic amines, aniline and N,N-dimethylaniline gave rather well-shaped titration curves, but the recovery values were fairly low. 2-Nitro- and 4-nitro anilines gave no thermometric response at all. The heats of reaction of the amines with nitrosyl perchlorate are rather high. However, the average heat of reaction of the aromatic amines is approximately two-thirds that of the average heat of the aliphatic amines. To support this method all the amines were also titrated potentiometrically and very similar results to those obtained with the thermometric method are seen. The nitrosyl ion is a Lewis acid, strong enough to titrate quantitatively aliphatic amines in acetonitrile solvent, but not strong enough to titrate aromatic amines at the required level in the same solvent.

  14. Rhodamine 6G hexachloridostannate(IV acetonitrile disolvate

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    Ramaiyer Venkatraman

    2008-01-01

    Full Text Available In the title compound, bis({6-ethylamino-10-[2-(methoxycarbonylphenyl]-2,7-dimethylxanthen-3-ylidene}ethanaminium hexachloridotin(IV acetonitrile disolvate, (C27H29N2O32[SnCl6]·2C2H3N, the octahedral SnCl62− anion lies on an inversion center. The xanthene ring system is essentially planar, with an average deviation of 0.020 Å, and the substituent benzene ring forms a dihedral angle of 85.89 (2° with it. The Sn—Cl distances are in the range 2.4237 (3–2.4454 (3 Å. There are N—H...Cl hydrogen bonds between SnCl62− ions and rhodamine 6G cations as well as π–π stacking interactions between rhodamine 6G cations (interplanar distance of 3.827 Å.

  15. Interaction of acetonitrile with thin films of solid water

    International Nuclear Information System (INIS)

    Bahr, S.; Kempter, V.

    2009-01-01

    Thin films of water were prepared on Ag at 124 K. Their properties were studied with metastable impact electron spectroscopy, reflection absorption infrared spectroscopy, and temperature programmed desorption. The interaction of acetonitrile (ACN) with these films was studied with the abovementioned techniques. From the absence of any infrared activity in the initial adsorption stage, it is concluded that ACN adsorbs linearly and that the C≡N axis is aligned parallel to the water surface (as also found on neat Ag). Initially, the interaction with water surface species involves their dangling OD groups. During the completion of the first adlayer the ACN-ACN lateral interaction becomes of importance as well, and the ACN molecules become tilted with respect to the water surface. ACN shows propensity to stay at the surface after surface adsorption even during annealing up to the onset of desorption. The present results for the ACN-water interaction are compared with available classical molecular dynamics calculations providing the orientation profile for ACN on water as well as the ACN bonding properties.

  16. Suicide attempt with acetonitrile ingestion in a nursing mother.

    Science.gov (United States)

    De Capitani, Eduardo Mello; Borrasca-Fernandes, Carla Fernanda; Branco Pimenta, Maíra; Prado, Camila Carbone; Soubhia, Paula Christiane; Lanaro, Rafael; Mello Moreira, Sueli; Linden, Rafael; Nóbrega, Helena Valle; Bucaretchi, Fábio; Costa, José Luiz

    2017-09-01

    Acetonitrile (ACN) is a solvent rapidly absorbed through lungs and intestinal tract, and is slowly metabolized to cyanide (CN) by enzymatic processes mediated by CYP2E1. To describe the clinical and laboratory evolution, ACN elimination half-life, and its presence in breast milk in a nursing mother who attempted suicide. A 25-year-old 2-month nursing mother ingested an estimated dose of 2.1 g/kg of ACN. Blood and urine samples were collected 24 h later for ACN, CN and thiocyanate analysis, and 12.5 g sodium thiosulfate i.v. in 1-h infusion was started and repeated every 24 h for 4 days. ACN results showed 200 mg/L in blood and 235 mg/L in urine. ACN analysis in the breast milk at Day 6 showed level of 21 mg/L compared to 27 mg/L in blood collected at the same time, suggesting a possible relationship of 1.3:1.0 ratio. An elimination half-life of 40.4 h was calculated, compared to 32 and 36 h showed in other studies. The clinical management must involve the use of CN antidotes for more than 24 h depending on the symptoms and blood levels of ACN. Furthermore, our data showed the possible existence of a close relationship between plasma and breast milk levels.

  17. Structure of human insulin monomer in water/acetonitrile solution

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    Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta [National Medicines Institute (Poland); Tarnowska, Anna; Kawecki, Robert [Institute of Organic Chemistry Polish Academy of Sciences (Poland); Kozerski, Lech [National Medicines Institute (Poland)], E-mail: lkoz@icho.edu.pl

    2008-01-15

    Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H{sub 2}O/CD{sub 3}CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER{sub V}C), or including a generalized Born solvent model (AMBER{sub G}B)

  18. Structure of human insulin monomer in water/acetonitrile solution

    International Nuclear Information System (INIS)

    Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta; Tarnowska, Anna; Kawecki, Robert; Kozerski, Lech

    2008-01-01

    Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H 2 O/CD 3 CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER V C), or including a generalized Born solvent model (AMBER G B)

  19. Sorbate-nitrite interactions: acetonitrile oxide as an alkylating agent.

    Science.gov (United States)

    Pérez-Prior, M Teresa; Gómez-Bombarelli, Rafael; González-Pérez, Marina; Manso, José A; García-Santos, M Pilar; Calle, Emilio; Casado, Julio

    2009-07-01

    Because chemical species with DNA-damaging and mutagenic activity are formed in sorbate-nitrite mixtures and because sorbic acid sometimes coexists with nitrite occurring naturally or incorporated as a food additive, the study of sorbate-nitrite interactions is important. Here, the alkylating potential of the products resulting from such interactions was investigated. Drawn were the following conclusions: (i) Acetonitrile oxide (ACNO) is the compound responsible for the alkylating capacity of sorbate-nitrite mixtures; (ii) ACNO alkylates 4-(p-nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to those of DNA bases, forming an adduct (AD; epsilon = 1.4 x 10(4) M(-1) cm(-1); lambda = 519 nm); (iii) the NBP alkylation reaction complies with the rate equation, r = d[AD]/dt = k(alk)(ACNO)[ACNO][NBP]-k(hyd)(AD)[AD], k(alk)(ACNO) being the NBP alkylation rate constant for ACNO and k(hyd)(AD) the rate constant for the adduct hydrolysis reaction; (iv) the small fraction of ACNO forming the adduct with NBP, as well as the small magnitude of the quotient (k(alk) (ACNO)/k(hyd)(ACNO)) as compared with those reported for other alkylating agents, such as some lactones and N-alkyl-N-nitrosoureas, reveals the ACNO effective alkylating capacity to be less significant; (v) the low value of the NBP-ACNO adduct life (defined as the total amount of adduct present along the progression of the NBP alkylation per unit of alkylating agent concentration) points to the high instability of this adduct; and (vi) the obtained results are in accordance with the low carcinogenicity of ACNO.

  20. Laboratory investigations of irradiated acetonitrile-containing ices on an interstellar dust analog

    International Nuclear Information System (INIS)

    Abdulgalil, Ali G. M.; Marchione, Demian; Rosu-Finsen, Alexander; Collings, Mark P.; McCoustra, Martin R. S.

    2012-01-01

    Reflection-absorption infrared spectroscopy is used to study the impact of low-energy electron irradiation of acetonitrile-containing ices, under conditions close to those in the dense star-forming regions in the interstellar medium. Both the incident electron energy and the surface coverage were varied. The experiments reveal that solid acetonitrile is desorbed from its ultrathin solid films with a cross section of the order of 10 −17 cm 2 . Evidence is presented for a significantly larger desorption cross section for acetonitrile molecules at the water–ice interface, similar to that previously observed for the benzene–water system.

  1. 78 FR 14241 - Acetonitrile; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2013-03-05

    ... dysfunctions, (II) neurological disorders, (III) heritable genetic mutations, or (IV) other chronic health... attributed to metabolism of acetonitrile to cyanide (Ref. 8). Several cases were reported in which children...

  2. Potentiometric pKa Determination of Piroxicam and Tenoxicam in Acetonitrile-Water Binary Mixtures

    OpenAIRE

    Çubuk Demiralay, Ebru; Yılmaz, Hülya

    2012-01-01

    Abstract: Ionization constant (pKa) is one among the parameter to be estimated with accuracy, irrespective of solubility constraints. In the present study, acid-base behaviour of the piroxicam and tenoxicam was studied. By using the potentiometric method, pKa values of piroxicam and tenoxicam have been determined in different percentage of acetonitrile-water binary mixtures (acetonitrile content between 30 and 45% in volume). Aqueous pKa values of these compounds were calculated by mole fract...

  3. Analysis of sorption into single ODS-silica gel microparticles in acetonitrile-water.

    Science.gov (United States)

    Nakatani, Kiyoharu; Kakizaki, Hiroshi

    2003-08-01

    Intraparticle mass transfer processes of Phenol Blue (PB) in single octadecylsilyl (ODS)-silica gel microparticles in acetonitrile-water were analyzed by microcapillary manipulation and microabsorption methods. An absorption maximum of PB, the sorption isotherm parameters, and the sorption rate in the microparticle system were highly dependent on the percentage of acetonitrile in solution. The results are discussed in terms of the microscopic polarity surrounding PB in the ODS phase and the relationship between the isotherm parameters and the sorption rate.

  4. Combined carbon and nitrogen removal from acetonitrile using algal-bacterial bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, R.; Jacinto, M.; Guieysse, B.; Mattiasson, B. [Dept. of Biotechnology, Center for Chemistry and Chemical Engineering, Lund Univ., Lund (Sweden)

    2005-06-01

    When compared with Chlorella vulgaris, Scenedesmus obliquus and Selenastrum capricornutum, C. sorokiniana presented the highest tolerance to acetonitrile and the highest O{sub 2} production capacity. It also supported the fastest acetonitrile biodegradation when mixed with a suitable acetonitrile-degrading bacterial consortium. Consequently, this microalga was tested in symbiosis with the bacterial culture for the continuous biodegradation of acetonitrile at 2 g l{sup -1} in a stirred tank photobioreactor and in a column photobioreactor under continuous illumination (250 {mu}E m{sup -2} s{sup -1}). Acetonitrile removal rates of up to 2.3 g l{sup -1} day{sup -1} and 1.9 g l{sup -1} day{sup -1} were achieved in the column photobioreactor and the stirred-tank photobioreactor, respectively, when operated at the shortest retention times tested (0.4 days, 0.6 days, respectively). In addition, when the stirred-tank photobioreactor was operated with a retention time of 3.5 days, the microbial culture was capable of assimilating up to 71% and nitrifying up to 12% of the NH{sub 4}{sup +} theoretically released through the biodegradation of acetonitrile, thus reducing the need for subsequent nitrogen removal. This study suggests that complete removal of N-organics can be combined with a significant removal of nitrogen by using algal-bacterial systems and that further residual biomass digestion could pay-back part of the operation costs of the treatment plant. (orig.)

  5. Crystal structure of cis-anti-cis-dicyclohexane-18-crown-6 acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Alexander Nazarenko

    2015-07-01

    Full Text Available The title compound (systematic name: cis-anti-cis-2,5,8,15,18,21-hexaoxatricyclo[20.4.0.09,14]hexacosane acetonitrile disolvate, C20H36O6·2CH3CN, crystallizes from an acetonitrile solution of dicyclohexane-18-crown-6 on evaporation. The molecule is arranged around a center of symmetry with half the crown ether molecule and one molecule of acetonitrile symmetry independent. All O—C—C—O torsion angles are gauche while all C—O—C—C angles are trans. The sequence of torsion angles is [(tg+t(tg−t]3; the geometry of oxygen atoms is close to pseudo-D3d with three atoms below and three atoms above the mean plane, with an average deviation of ±0.16 (1 Å from the mean plane. This geometry is identical to that observed in metal ion complexes of dicyclohexane-18-crown-6 but differs significantly from the conformation of a free unsolvated molecule. Each acetonitrile molecule connects to a crown ether molecule via two of its methyl group H atoms (C—H...O. Weaker interactions exist between the third H atom of the acetonitrile methyl group and an O atom of a neighbouring crown ether molecule (C—H...O; and between the N atom of the acetonitrile molecule and a H atom of another neighbouring crown ether molecule. All these intermolecular interactions create a three-dimensional network stabilizing the disolvate.

  6. Effect of the composition of a solution on the enthalpies of solvation of piperidine in methanol-acetonitrile and dimethylsulfoxide-acetonitrile mixed solvents

    Science.gov (United States)

    Kuz'mina, I. A.; Volkova, M. A.; Sitnikova, K. A.; Sharnin, V. A.

    2014-01-01

    Heat effects of dissolution of piperidine (ppd) are measured by calorimetry at 298.15 K over the range of composition of acetonitrile-methanol (AN-MeOH) mixed solvents. Based on the Δsol H ○(ppd)AN-MeOH values obtained using the literature data on Δsol H ○ (ppd) in acetonitrile-dimethylsulfoxide (AN-DMSO) mixed solvents and the vaporization enthalpy of ppd, the enthalpies of solvation of amine in AN-MeOH and AN-DMSO binary mixtures are calculated. A rise in the exothermicity of solvation of piperidine is observed upon the transition from AN to DMSO and MeOH, due mainly to the enhanced solvation of the amino group of ppd as a result of changes in the acid-base properties of the mixed solvent.

  7. Gadolinium-, Calcium-, copper- and zirc complexes with riboflavin in acetone and acetonitrile

    International Nuclear Information System (INIS)

    Lugina, L.N.; Romanenko, V.I.; Davidenko, N.K.

    1983-01-01

    Using the methods of solubility and spectrophotometry, stability copstants Of complexes RFMSSUp(n+) (RF=riboflavin, Mnsup(n+)=Cdsup(3+), Ca 2+ , Cu 2+ and Zn 2+ ) in acetone and acetonitrile against the background of 1 mol/l LiClO 4 x3H 2 O have been determined. It was found that stability of copper and zinc complexes with riboflavin in acetone is higher than in acetonitrile, whereas the stability of gadolinium and calcium complexes, on the contrary, is higher in acetonitrile than in acetone. It is shown that the character of the absorption spectrum change of riboflavin in complexing with metal ions depends on the nature of coordinating cation

  8. Study of cellulase enzymes self-assembly in aqueous-acetonitrile solvent: Viscosity measurements

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    Ghaouar, N., E-mail: naoufel-ghaouar@lycos.co [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia); Institut National des Sciences Appliquees et de Technologie, INSAT, Centre Urbain Nord, BP. 676, Tunis (Tunisia); Aschi, A. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia); Belbahri, L. [School of Engineering of Lullier, University of Applied Sciences of Western Switzerland, 150, Route de Presinge, 1254 Jussy (Switzerland); Trabelsi, S.; Gharbi, A. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia)

    2009-11-15

    The present study extends the viscosity measurements performed by Ghaouar et al. [Physica B, submitted for publication.] to study the conformational change of the cellulase enzymes in aqueous-acetonitrile mixture. We aim to investigate: (i) the denaturation process by measuring the specific viscosity for temperatures varying between 25 and 65 deg. C and acetonitrile concentrations between 0% and 50%, (ii) the enzyme-enzyme interaction by calculating the Huggins coefficient and (iii) the enzyme sizes by following the hydrodynamic radius for various temperatures. The precipitation of cellulases versus acetonitrile concentration is also considered. We show from all physical quantities measured in this work that the precipitation and the denaturation processes of cellulase enzymes exist together.

  9. High-yield acetonitrile | water triple phase boundary electrolysis at platinised Teflon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, John D.; MacDonald, Stuart M.; Fordred, Paul S.; Bull, Steven D. [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Gu, Yunfeng; Yunus, Kamran; Fisher, Adrian C. [Department of Chemical Engineering, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Bulman-Page, Philip C. [School of Chemistry, University of East Anglia, Norwich, Norfolk NR4 7TJ (United Kingdom); Marken, Frank [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)], E-mail: f.marken@bath.ac.uk

    2009-11-30

    A dynamic acetonitrile | aqueous electrolyte phase boundary in contact with platinised Teflon working electrodes is investigated. High concentrations of salt in the aqueous phase (2 M NaCl and 0.1 M NaClO{sub 4}) ensure immiscibility and the polar nature of acetonitrile aids the formation of a well-behaved triple phase boundary reaction zone. The one-electron oxidation of tert-butylferrocene in the organic phase without intentionally added electrolyte is studied. The limiting current for the flowing triple phase boundary process is shown to be essentially volume flow rate independent. The process is accompanied by the transfer of perchlorate from the aqueous into the organic phase and the flux of anions is shown to be approximately constant along the dynamic acetonitrile | aqueous electrolyte | platinum line interface. A high rate of conversion (close to 100%) is achieved at slow volume flow rates and at longer platinum electrodes.

  10. Study of cellulase enzymes self-assembly in aqueous-acetonitrile solvent: Viscosity measurements

    International Nuclear Information System (INIS)

    Ghaouar, N.; Aschi, A.; Belbahri, L.; Trabelsi, S.; Gharbi, A.

    2009-01-01

    The present study extends the viscosity measurements performed by Ghaouar et al. [Physica B, submitted for publication.] to study the conformational change of the cellulase enzymes in aqueous-acetonitrile mixture. We aim to investigate: (i) the denaturation process by measuring the specific viscosity for temperatures varying between 25 and 65 deg. C and acetonitrile concentrations between 0% and 50%, (ii) the enzyme-enzyme interaction by calculating the Huggins coefficient and (iii) the enzyme sizes by following the hydrodynamic radius for various temperatures. The precipitation of cellulases versus acetonitrile concentration is also considered. We show from all physical quantities measured in this work that the precipitation and the denaturation processes of cellulase enzymes exist together.

  11. Molecular dynamics simulation of the ionic liquid N-octylpyridinium tetrafluoroborate and acetonitrile: Thermodynamic and structural properties

    Science.gov (United States)

    Zhou, Siwen; Zhu, Guanglai; Kang, Xianqu; Li, Qiang; Sha, Maolin; Cui, Zhifeng; Xu, Xinsheng

    2018-06-01

    Using molecular dynamics simulation, the research obtained the thermodynamic properties and microstructures of the mixture of N-octylpyridinium tetrafluoroborate and acetonitrile, including density, self-diffusion coefficients, excess properties, radial distribution functions (RDFs) and spatial distribution functions (SDFs). Both RDFs and SDFs indicate that the local microstructure of the polar region is different from the nonpolar region with different mole fraction of ionic liquids. Acetonitrile could increase the order of the polar regions. While with acetonitrile increasing, the orderliness of the nonpolar region increases firstly and then decreases. In relatively dilute solution, ionic liquids were dispersed to form small aggregates wrapped by acetonitrile.

  12. Enhancement of the stimulated Raman scattering of benzene, acetonitrile and pyridine

    International Nuclear Information System (INIS)

    Munoz, L; Contreras, W A; Cabanzo, R; Aya-RamIrez, O; Mejia-Ospino, E

    2011-01-01

    In this work we used the second harmonic of Nd:YAG laser to observe stimulated Raman scattering (SRS). SRS was observed on benzene, acetonitrile and pyridine using a single shot laser. The SRS radiation is very intense due their laser characteristics, and it is possible to observe several harmonics of different vibrational modes to each molecule studied here.

  13. Liquid / liquid biphasic electrochemistry in ultra-turrax dispersed acetonitrile / aqueous electrolyte systems

    International Nuclear Information System (INIS)

    Watkins, John D.; Amemiya, Fumihiro; Atobe, Mahito; Bulman-Page, Philip C.; Marken, Frank

    2010-01-01

    Unstable acetonitrile | aqueous emulsions generated in situ with ultra-turrax agitation are investigated for applications in dual-phase electrochemistry. Three modes of operation for liquid / liquid aqueous-organic electrochemical processes are demonstrated with no intentionally added electrolyte in the organic phase based on (i) the formation of a water-soluble product in the aqueous phase in the presence of the organic phase, (ii) the formation of a product and ion transfer at the liquid / liquid-electrode triple phase boundary, and (iii) the formation of a water-insoluble product in the aqueous phase which then transfers into the organic phase. A three-electrode electrolysis cell with ultra-turrax agitator is employed and characterised for acetonitrile / aqueous 2 M NaCl two phase electrolyte. Three redox systems are employed in order to quantify the electrolysis cell performance. The one-electron reduction of Ru(NH 3 ) 6 3+ in the aqueous phase is employed to determine the rate of mass transport towards the electrode surface and the effect of the presence of the acetonitrile phase. The one-electron oxidation of n-butylferrocene in acetonitrile is employed to study triple phase boundary processes. Finally, the one-electron reduction of cobalticenium cations in the aqueous phase is employed to demonstrate the product transfer from the electrode surface into the organic phase. Potential applications in biphasic electrosynthesis are discussed.

  14. Why a diaminopyrrolic tripodal receptor binds mannosides in acetonitrile but not in water?

    Directory of Open Access Journals (Sweden)

    Diogo Vila-Viçosa

    2014-07-01

    Full Text Available Intermolecular interactions involving carbohydrates and their natural receptors play important roles in several biological processes. The development of synthetic receptors is very useful to study these recognition processes. Recently, it was synthetized a diaminopyrrolic tripodal receptor that is selective for mannosides, which are obtained from mannose, a sugar with significant relevance in living systems. However, this receptor is significantly more active in acetonitrile than in water. In this work, we performed several molecular dynamics and constant-pH molecular dynamics simulations in acetonitrile and water to evaluate the conformational space of the receptor and to understand the molecular detail of the receptor–mannoside interaction. The protonation states sampled by the receptor show that the positive charges are always as distant as possible in order to avoid large intramolecular repulsions. Moreover, the conformational space of the receptor is very similar in water above pH 4.0 and in acetonitrile. From the simulations with the mannoside, we observe that the interactions are more specific in acetonitrile (mainly hydrogen bonds than in water (mainly hydrophobic. Our results suggest that the readiness of the receptor to bind mannoside is not significantly affected in water (above pH 4.0. Probably, the hydrogen bond network that is formed in acetonitrile (which is weaker in water is the main reason for the higher activity in this solvent. This work also presents a new implementation of the stochastic titration constant-pH molecular dynamics method to a synthetic receptor of sugars and attests its ability to describe the protonation/conformation coupling in these molecules.

  15. The (water + acetonitrile) mixture revisited: A new approach for calculating partial molar volumes

    International Nuclear Information System (INIS)

    Carmen Grande, Maria del; Julia, Jorge Alvarez; Barrero, Carmen R.; Marschoff, Carlos M.; Bianchi, Hugo L.

    2006-01-01

    Density and viscosity of (water + acetonitrile) mixtures were measured over the whole composition range at the temperatures: (298.15, 303.15, 308.15, 313.15, and 318.15) K. A new mathematical approach was developed which allows the calculation of the derivatives of density with respect to composition avoiding the appearance of local discontinuities. Thus, reliable partial molar volumes and thermal expansion coefficients were obtained

  16. Evidence of three-body correlation functions in Rb+ and Sr2+ acetonitrile solutions

    Science.gov (United States)

    D'Angelo, P.; Pavel, N. V.

    1999-09-01

    The local structure of Sr2+ and Rb+ ions in acetonitrile has been investigated by x-ray absorption spectroscopy (XAS) and molecular dynamics simulations. The extended x-ray absorption fine structure above the Sr and Rb K edges has been interpreted in the framework of multiple scattering (MS) formalism and, for the first time, clear evidence of MS contributions has been found in noncomplexing ion solutions. Molecular dynamics has been used to generate the partial pair and triangular distribution functions from which model χ(k) signals have been constructed. The Sr2+ and Rb+ acetonitrile pair distribution functions show very sharp and well-defined first peaks indicating the presence of a well organized first solvation shell. Most of the linear acetonitrile molecules have been found to be distributed like hedgehog spines around the Sr2+ and Rb+ ions. The presence of three-body correlations has been singled out by the existence of well-defined peaks in the triangular configurations. Excellent agreement has been found between the theoretical and experimental data enforcing the reliability of the interatomic potentials used in the simulations. These results demonstrate the ability of the XAS technique in probing the higher-order correlation functions in solution.

  17. Phase separation of acetonitrile-water mixtures and minimizing of ice crystallites from there in confinement of MCM-41.

    Science.gov (United States)

    Kittaka, Shigeharu; Kuranishi, Miki; Ishimaru, Shinji; Umahara, Osamu

    2007-03-07

    The effect of confinement of an acetonitrile-water mixture, whose correlation length was comparable to the pore size of the mesopores of MCM-41 (d=2.4-3.6 nm), on the phase changes was studied. Used techniques were low temperature differential scanning calorimetry and Fourier transform infrared spectroscopy, where the phase separation, lowering of the freezing and melting temperatures, and phase transitions of the acetonitrile were detected. The latter occurred in the mesopores at temperatures similar to that of the pure liquid, while the melting temperature of the water in the mesopores<3.1 nm decreased markedly at higher acetonitrile contents, suggesting a marked lowering of ice crystallite size.

  18. Synthesis and tribological behaviors of diamond-like carbon films by electrodeposition from solution of acetonitrile and water

    International Nuclear Information System (INIS)

    Zhang Jisheng; Huang Lina; Yu Laigui; Zhang Pingyu

    2008-01-01

    Diamond-like carbon (DLC) films were prepared on silicon substrates by liquid phase electrodeposition from a mixture of acetonitrile and deionized water. The deposition voltage was clearly reduced owing to the presence of deionized water in the electrolyte by changing the basic properties (dielectric constant and dipole moment) of the electrolyte. Raman spectra reveal that the ratio of sp 3 /sp 2 in the DLC films is related to the concentration of acetonitrile. The surface roughness and grain morphology determined by atomic force microscopy are also influenced by the concentration of the acetonitrile. The UMT-2 universal micro-tribometer was used to test the friction properties of the DLC films obtained from electrolytes with different concentration. The results convey that the DLC film prepared from the electrolyte containing 10 vol.% acetonitrile has the better surface morphology and friction behavior comparing with the other. In addition the growth mechanism of the film was also discussed

  19. Photo-assisted cyanation of transition metal nitrates coupled with room temperature C-C bond cleavage of acetonitrile.

    Science.gov (United States)

    Zou, Shihui; Li, Renhong; Kobayashi, Hisayoshi; Liu, Juanjuan; Fan, Jie

    2013-03-07

    It is a challenge to use acetonitrile as a cyanating agent because of the difficulty in cleaving its C-CN bond. Herein, we report a mild photo-assisted route to conduct the cyanation of transition metal nitrates using acetonitrile as the cyanating agent coupled with room-temperature C-C bond cleavage. DFT calculations and experimental observations suggest a radical-involved reaction mechanism, which excludes toxicity from free cyanide ions.

  20. SYNTHESIS OF N- ACETONITRIL AND N- ETHYLAMINE- 3- HYDROXYPYRIDINONES AS IRON (III CHELATORS

    Directory of Open Access Journals (Sweden)

    L.A. SAGHAEI

    2000-12-01

    Full Text Available Background. The need of iron-chelating agents as orally active alternatives to desferal for the treatment of iron overload in thalassaemic patients, has stimulated considerable research efforts in the synthesis of new metal chelators. One of the member of hydroxypyridinones (2,3- dimethyl-3- hydroxypyridinones has so far received the most attention. This compound is rapidly glucuronidated into a non-chelating metabolite, which partly explains why high doses of the compound has to be used in order to achieve negative balance. This metabolic behavior has led the medicinal chemists to design compounds such as N-hydroxyalkyl derivatives which do not undergo extensive metabolism. The objective of the present work was to further synthesis and design new derivatives of hydroxypyridinones (N- acetonitril and N-ethylamine derivatives Methods. The synthesis route involves the benzylation of hydroxyl group of maltol (ethyl maltol using benzyl chloride conversion of the benazylated maltol (ethyl maltol to the N-acetonitril bezylated pyridinone derivatives by introducing the aminoacetonitril in pyridine solvent and cleavage of benzyl group by hydrogenation method or using the bromodimethyl borane to form the N-acetonitril or N- ethylamine- 3- hydroxypyridinones respectively.
    Results. In this work three final compounds such as 1- (2- aminoethyl- 2- methyl- 3-hydroxypyridin- 4- one, 1- (2- aminoethyl- 2- ethyl- 3- hydroxypyridin-4- one and 1- cyanomethyl -2- methyl- 3- hydroxypyridin- 4- one were synthesized.
    Discussion. Identification and structural elucidation of compounds were achieved by IH NMR and Mass spectra, elemental analysis and through physical constants. The biological effects of compounds will be studied in the near future.

  1. Reduction of a dimeric tantalum(III) compound in acetonitrile solution by pulse radiolysis

    International Nuclear Information System (INIS)

    Koulkes-Pujo, A.-M.; Le Motais, B.; Hubert-Pfalzgraf, L.G.

    1986-01-01

    The reduction of the compound [Ta 2 Cl 6 (4Me-py) 4 ] (4Me-py 4-methylpyridine), having a metal-metal double bond, has been achieved by pulse radiolysis in dry oxygen-free acetonitrile. The reduction occurs by CH 3 CN - which leads to a transient species assigned to a tantalum dimer in a 2.5 oxidation state. The spectrum of this species has been established. It decays by a first-order process to give a new transient species which in turn decays more slowly by a second-order reaction. (author)

  2. Ethynamine - Ketenimine - Acetonitrile - Rearrangements: A computational Study of Flash Vacuum Pyrolysis Processes

    OpenAIRE

    Wentrup, Curt; Begue, Didier; Leung-Toung, Regis

    2017-01-01

    The rearrangements of ethynamine 3 (H-CºC-NH2) to ketenimine 4 (CH2=C=NH) and acetonitrile 5 (CH3CN) were investigated computationally up to the MP4(SDTQ)/6-31G*//MP2(FU)/6-31G* level. The calculated barrier for a concerted reaction 3 -> 4 is very high, 74 kcal/mol, the structure of the transition state very unusual, and this path is discredited. A lower barrier of about 60 kcal/mol via aminovinylidene 2 and imidoylcarbene 15 has been found. The calculated barrier for ...

  3. Density Functional Studies on the Complexation and Spectroscopy of Uranyl Ligated with Acetonitrile and Acetone Derivatives

    International Nuclear Information System (INIS)

    Schoendorff, George E.; Windus, Theresa L.; De Jong, Wibe A.

    2009-01-01

    The coordination of nitrile (acetonitrile, propionitrile, and benzonitrile) and carbonyl (formaldehyde, ethanal, and acetone) ligands to the uranyl dication (UO22+) has been examined using density functional theory (DFT) utilizing relativistic effective core potentials (RECPs). Complexes containing up to six ligands have been modeled for all ligands except formaldehyde, for which no minimum could be found. A comparison of relative binding energies indicates that five coordinate complexes are predominant while a six coordinate complex involving propionitrile ligands might be possible. Additionally, the relative binding energy and the weakening of the uranyl bond is related to the size of the ligand and, in general, nitriles bind more strongly to uranyl than carbonyls.

  4. Chlorido(1,3-dimethylthiourea-κSbis(triphenylphosphine-κPcopper(I acetonitrile hemisolvate

    Directory of Open Access Journals (Sweden)

    Brian W. Skelton

    2009-08-01

    Full Text Available The title compound, [CuCl(C3H8N2S(C18H15P2]·0.5CH3CN, was prepared by the reaction of copper(I chloride with 1,3-dimethylthiourea (dmtu and triphenylphosphine (PPh3 in acetonitrile. The CuI atom has a distorted tetrahedral environment formed by two P atoms from triphenylphosphine, one S atom from the dmtu ligand and one Cl atom. In addition, the molecules exhibit intra- and intermolecular N—H...Cl interactions.

  5. An alternative pathway for production of acetonitrile: ruthenium catalysed aerobic dehydrogenation of ethylamine

    DEFF Research Database (Denmark)

    Corker, Emily; Mentzel, Uffe Vie; Mielby, Jerrik Jørgen

    2013-01-01

    The oxidative synthesis of acetonitrile from ethylamine was studied using a supported ruthenium catalyst. The reaction was conducted in both batch and flow processes and high conversions (over 85%) were achieved in both cases. Selectivity of both reactions was improved by optimisation of reaction...... conditions, achieving over 90% selectivity in the batch process and 80% selectivity in the continuous flow process. The use of a selective solid catalyst that utilises a feedstock that can be derived from biomass, dioxygen as the oxidant and water as the solvent represents a new, green route...

  6. Possible stabilization of the tetravalent oxidation state of berkelium and californium in acetonitrile with triphenylarsine oxide

    International Nuclear Information System (INIS)

    Payne, G.F.; Peterson, J.R.

    1987-01-01

    It appears that we may have prepared Bk(IV) nitrate.nTPAs0 and Bk(IV) perchlorate.nTPAs0 complexes which formed the corresponding Cf(IV) complexes through the beta decay of Bk-249. Definitive proof should come from similar experiments with quantities of Bk-249 large enough to allow spectrophotometric detection of the characteristic f→f transitions in these berkelium and californium species. It is clear, however, that TPAs0 and acetonitrile can play a pivotal role in the stabilization of lanact(IV) species

  7. Large scale exact quantum dynamics calculations: Ten thousand quantum states of acetonitrile

    Science.gov (United States)

    Halverson, Thomas; Poirier, Bill

    2015-03-01

    'Exact' quantum dynamics (EQD) calculations of the vibrational spectrum of acetonitrile (CH3CN) are performed, using two different methods: (1) phase-space-truncated momentum-symmetrized Gaussian basis and (2) correlated truncated harmonic oscillator basis. In both cases, a simple classical phase space picture is used to optimize the selection of individual basis functions-leading to drastic reductions in basis size, in comparison with existing methods. Massive parallelization is also employed. Together, these tools-implemented into a single, easy-to-use computer code-enable a calculation of tens of thousands of vibrational states of CH3CN to an accuracy of 0.001-10 cm-1.

  8. Photoinduced electron transfer and solvation in iodide-doped acetonitrile clusters.

    Science.gov (United States)

    Ehrler, Oli T; Griffin, Graham B; Young, Ryan M; Neumark, Daniel M

    2009-04-02

    We have used ultrafast time-resolved photoelectron imaging to measure charge transfer dynamics in iodide-doped acetonitrile clusters I(-)(CH(3)CN)(n) with n = 5-10. Strong modulations of vertical detachment energies were observed following charge transfer from the halide, allowing interpretation of the ongoing dynamics. We observe a sharp drop in the vertical detachment energy (VDE) within 300-400 fs, followed by a biexponential increase that is complete by approximately 10 ps. Comparison to theory suggests that the iodide is internally solvated and that photodetachment results in formation of a diffuse electron cloud in a confined cavity. We interpret the initial drop in VDE as a combination of expansion of the cavity and localization of the excess electron on one or two solvent molecules. The subsequent increase in VDE is attributed to a combination of the I atom leaving the cavity and rearrangement of the acetonitrile molecules to solvate the electron. The n = 5-8 clusters then show a drop in VDE of around 50 meV on a much longer time scale. The long-time VDEs are consistent with those of (CH(3)CN)(n)(-) clusters with internally solvated electrons. Although the excited-state created by the pump pulse decays by emission of a slow electron, no such decay is seen by 200 ps.

  9. The interhemispheric distribution and the budget of acetonitrile in the troposphere

    International Nuclear Information System (INIS)

    Hamm, S.; Warneck, P.

    1990-01-01

    Gas chromatography in conjunction with a thermionic nitrogen-specific detector was used to determine mixing ratios of acetonitrile in air samples collected in Europe and over the Atlantic Ocean. In the city of Mainz, values of the order of 340 pptv were observed with large variations indicating the vicinity of sources. In the rural community of Deuselbach the average mixing ratio was 147±28 pptv; over the North Sea the range was 65-196 pptv depending on wind direction. Over the open ocean, maximum mixing ratios were observed near 4 degree S with values of 175 pptv. At latitudes near 30 degree S the mixing ratio averaged 90.4 pptv, whereas at 30 degree N the average was 52.1 pptv. The lowest mixing ratios of 21 pptv were found near 50 degree N. The tropical maximum is attributed to the advection with the trade winds of continental air from Africa, enriched with acetonitrile form biomass burning. The mixing ratios north and south of the maximum correlate well with the surface temperature of seawater, indicating a gas-liquid equilibrium for CH 3 CN dissolved in seawater. From the observations and with the further assumption that CH 3 CN is vertically well mixed, its total mass content in the troposphere was estimated as 0.37-0.57 Tg. Global emission rates for various sources were estimated as follows: Automobiles 0.27 Tg/year, oil-fired power stations 0.0035 Tg/year, and biomass burning 0.80 Tg/year. The total estimated source strength is 1.1±0.5 Tg/year. The troposphere residence time of acetonitrile was calculated from these data as 0.23-0.90 year with a probable value of 0.45 year. Wet precipitation and reaction with OH radicals are known sinks for tropospheric CH 3 CN, but they can take up only 30% of the global emission rate. The authors suggest absorption in the ocean to be the major sink

  10. Determination of pesticides in fruits and vegetables using acetonitrile extraction and GC/MS technique

    International Nuclear Information System (INIS)

    Hussain, Z.

    2010-01-01

    A selection of oranges, guava and spinach were purchased from the local markets of Lahore, Pakistan. Extraction of the samples was carried out using an acetonitrile/toluene extraction procedure to determine the residual concentration of pesticides which may have been used during seasonal growth. Gas chromatography/mass spectrometry (GC/MS) was used for quantitative and confirmatory analysis of GC-amenable pesticides. The data obtained was compared with that of a referenced pesticide by matching molecular weight to a library of known pesticides. For comparison the same non-sprayed fruits/vegetable were extracted as a control reference. Factors studied were retention time, elution time, relative abundance and molecular weight. The results showed that low molecular weight pesticides were eluted before the high molecular weight pesticides. Pesticides identified included crotoxyphos, fenoxycarb and methoxyfenozide. (author)

  11. Competitive solvation of (bis)(trifluoromethanesulfonyl)imide anion by acetonitrile and water

    Science.gov (United States)

    Chaban, Vitaly

    2014-10-01

    Competitive solvation of an ion by two or more solvents is one of the key phenomena determining the identity of our world. Solvation in polar solvents frequently originates from non-additive non-covalent interactions. Pre-parametrized potentials poorly capture these interactions, unless the force field derivation is repeated for every new system. Development cost increases drastically as new chemical species are supplied. This work represents an alternative simulation approach, PM7-MD, by coupling the latest semiempirical parametrization, PM7, with equation-of-motion propagation scheme and temperature coupling. Using a competitive solvation of (bis)(trifluoromethanesulfonyl)imide anion in acetonitrile and water, the work demonstrates efficiency and robustness of PM7-MD.

  12. Determination of triazines in hemodialysis saline solutions by adsorptive stripping voltammetry after extraction in acetonitrile

    Directory of Open Access Journals (Sweden)

    Nascimento Paulo Cícero do

    2003-01-01

    Full Text Available A method for the voltammetric determination of 2-methylthio-4,6-dialkylamino-1,3,5-triazine (triazines herbicides in hemodialysis (HD saline solutions was developed. The herbicides were detected in the saline solutions at the hanging mercury drop electrode (HMDE with high sensitivities only after extraction of the analytes in acetonitrile (ACN. The salting out effect originated by the saline environment existing in the solutions enabled the extractions. The volume ratio between the saline and ACN phases was investigated in order to find the best sensitivity to detect the triazines. The speciation amongst them (ametryn, desmetryn, prometryn and terbutryn was not possible. Recoveries between 88 and 107% were calculated in spiked samples, and detection limits of 0.03 mumol L-1 were calculated for the triazines in the saline samples using this methodology.

  13. Studies on (acid + base) equilibria in substituted (phenol + n-butylamine) systems in acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, A. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Czaja, M. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, L. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chem.univ.gda.pl

    2005-08-15

    (Acid + base) equilibria, including molecular heteroconjugation ones, between n-butylamine and one of the following phenols: 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, 3-chlorophenol, 4-chlorophenol, 2,3,4,5,6-pentachlorophenol and 2,4,6-tribromophenol have been studied potentiometrically in a protophobic polar aprotic solvent, acetonitrile. Among the phenols studied, 2,5-dinitrophenol exhibited the strongest tendency towards formation of asymmetric hydrogen bonds with n-butylamine, whereas a weakest complex was formed with 2-nitrophenol. In the (n-butylamine + 2,3,4,5,6-pentachlorophenol) and (n-butylamine + 2,4-dinitrophenol) systems proton transfer reactions occurred.

  14. Tetraethylammonium (2,2′-bipyridinetetracyanidocobaltate(III sesquihydrate acetonitrile solvate

    Directory of Open Access Journals (Sweden)

    Ganna Lyubartseva

    2010-04-01

    Full Text Available The title complex, (C8H20N[Co(CN4(C10H8N2]·CH3CN·1.5H2O, consists of tetraethyl ammonium cations, mononuclear [CoIIIbpy(CN4]− anions and uncoordinated water and acetonitrile molecules. The CoIII atom is six-coordinated by two 2,2′-bipyridine (bpy N atoms and four cyanide C atoms in a distorted octahedral geometry. The acute bite angle of the chelating bpy [82.28 (8°] is the main factor accounting for this distortion. In addition, the tetraethylammonium cation is significantly disordered [occupancy ratio 0.611 (3:0.389 (3]. The presence of water molecules, one of which is disordered over two positions about an inversion center, results in the formation of a network of O—H...N hydrogen bonds involving the cyanide N atoms.

  15. Hydroxyl group as IR probe to detect the structure of ionic liquid-acetonitrile mixtures

    Science.gov (United States)

    Xu, Jing; Deng, Geng; Zhou, Yu; Ashraf, Hamad; Yu, Zhi-Wu

    2018-06-01

    Task-specific ionic liquids (ILs) are those with functional groups introduced in the cations or anions of ILs to bring about specific properties for various tasks. In this work, the hydrogen bonding interactions between a hydroxyl functionalized IL 1-(2-hydroxylethyl)-3-methylimidazolium tetrafluoroborate ([C2OHMIM][BF4]) and acetonitrile were investigated in detail by infrared spectroscopy, excess spectroscopy, two-dimensional correlation spectroscopy, combined with hydrogen nuclear magnetic resonance and density functional theory calculations (DFT). The hydroxyl group rather than C2sbnd H is found to be the main interaction site in the cation. And the ν(Osbnd H) is more sensitive than v(C-Hs) to the environment, which has been taken as an intrinsic probe to reflect the structural change of IL. Examining the region of ν(Osbnd H), by combining excess spectroscopy and DFT calculation, a number of species were identified in the mixtures. Other than the hydrogen bond between a cation and an anion, the hydroxyl group allows the formation of a hydrogen bond between two like-charged cations. The Osbnd H⋯O hydrogen bonding interactions in the hydroxyl-mediated cation-cation complexes are cooperative, while Osbnd H⋯F and C2sbnd H⋯F hydrogen bonding interactions in cation-anion complexes are anti-cooperative. These in-depth studies on the properties of the ionic liquid-acetonitrile mixtures may shed light on exploring their applications as mixed solvents and understanding the nature of doubly ionic hydrogen bonds.

  16. Solubility of nicotinic acid in water, ethanol, acetone, diethyl ether, acetonitrile, and dimethyl sulfoxide

    International Nuclear Information System (INIS)

    Gonçalves, Elsa M.; Minas da Piedade, Manuel E.

    2012-01-01

    Highlights: ► We determined the solubility of nicotinic acid in six solvents by the gravimetric method. ► We found that, regardless of the solvent, the same monoclinic solid phase was in equilibrium with the solution. ► We determined the activity coefficients of nicotinic acid in the six solvents. ► We found that the solubility trends seem to be determined by the polarity and polarizability of the solvent. - Abstract: The mole fraction equilibrium solubility of nicotinic acid in six solvents (water, ethanol, dimethyl sulfoxide, acetone, acetonitrile and diethyl ether) differing in polarity, polarizability, and hydrogen-bonding ability, was determined over the temperature range (283 to 333) K, using the gravimetric method. The results obtained led to the solubility order dimethyl sulfoxide (DMSO) ≫ ethanol > water > acetone > diethyl ether > acetonitrile. An analysis based on various solvent descriptors, indicated that this trend seems to be mainly determined by the polarity and polarizability of the solvent. The activity coefficients of nicotinic acid in the different solvents, under saturation conditions, were determined as a function of the temperature and it was found that DMSO exhibits enhanced solubility relative to an ideal solution while the opposite is observed for all other solvents. Both the solvent and the fact that nicotinic acid is primarily zwitterionic in aqueous solution and non-zwitterionic in non-aqueous media, did not affect the nature of the solid phases in equilibrium with the different solutions. Indeed, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry analysis indicated that, despite some differences in particle size and morphology, the starting material and the solid products obtained at the end of the solubility studies in the six solvents used in this work were all crystalline and corresponded to the same monoclinic phase.

  17. Physicochemical properties of binary solutions of propylene carbonate-acetonitrile in the range of 253.15-313.15 K

    Science.gov (United States)

    Tyunina, E. Yu.; Chekunova, M. D.

    2017-05-01

    The density, dynamic viscosity, and dielectric constant of propylene carbonate solutions with acetonitrile are measured over the composition of a mixed solvent at temperatures of 253.15, 273.15, 293.15, and 313.15 K. The molar volume, molar viscosity, and molar capacity of a mixture of propylene carbonate-acetonitrile and an excess amount of it are calculated. The effect the temperature and composition of the mixture have on the excess molar properties is discussed. A linear correlation is observed between the values of the molar fluidity, capacity, polarization, and molar volume of the studied system.

  18. Tetrakis(acetonitrilecopper(I hydrogen oxalate–oxalic acid–acetonitrile (1/0.5/0.5

    Directory of Open Access Journals (Sweden)

    A. Timothy Royappa

    2013-10-01

    Full Text Available In the title compound, [Cu(CH3CN4](C2HO4·0.5C2H2O4·0.5CH3CN, the CuI ion is coordinated by the N atoms of four acetonitrile ligands in a slightly distorted tetrahedral environment. The oxalic acid molecule lies across an inversion center. The acetonitrile solvent molecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid molecules are linked via O—H...O hydrogen bonds, forming chains along [010].

  19. Calorimetric and FTIR Studies of Acetonitrile on H-[Fe]ZSM-5 and H-[Al]ZSM-5

    Czech Academy of Sciences Publication Activity Database

    Kotrla, Josef; Kubelková, Ludmila; Lee, C. C.; Gorte, R. J.

    1998-01-01

    Roč. 102, č. 8 (1998), s. 1437-1443 ISSN 1089-5647 R&D Projects: GA MŠk OC D5.10 Institutional research plan: CEZ:A54/98:Z4-040-9-ii Keywords : adsorption of acetonitrile * neutral surface complex Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.385, year: 1998

  20. Effect of the physicochemical parameters of benzimidazole molecules on their retention by a nonpolar sorbent from an aqueous acetonitrile solution

    Science.gov (United States)

    Shafigulin, R. V.; Safonova, I. A.; Bulanova, A. V.

    2015-09-01

    The effect of the structure of benzimidazoles on their chromatographic retention on octadecyl silica gel from an aqueous acetonitrile eluent was studied. One- and many-parameter correlation equations were obtained by linear regression analysis, and their prognostic potential in determining the retention factors of benzimidazoles under study was analyzed.

  1. On the Origin of Microheterogeneity : Mass Spectrometric Studies of Acetonitrile-Water and Dimethyl Sulfoxide-Water Binary Mixtures (Part 2)

    NARCIS (Netherlands)

    Shin, Dong Nam; Wijnen, Jan W.; Engberts, Jan B.F.N.; Wakisaka, Akihiro

    2002-01-01

    The microscopic structures of acetonitrile-water and DMSO-water binary mixed solvents and their influence on the solvation for solutes (some alcohols and phenol) have been studied on the basis of the cluster structures observed through a specially designed mass spectrometer. In acetonitrile-water

  2. Nanosolvation by acetonitrile and 18-crown-6 ether induce strongly different effects on the electron-capture induced dissociation of aromatic tripeptide cations in the gas phase

    DEFF Research Database (Denmark)

    MacLot, S.; Rangama, J.; Nielsen, Steen Brøndsted

    2013-01-01

    for acetonitrile. One or two acetonitrile molecules have also been found to induce little effect on the fragmentation patterns of the charge-reduced peptide ions. By contrast, one or two CE decreases the NH3-loss probability, which is accounted for by the inhibition of this channel upon CE binding to the N...

  3. ALMA Spectroscopy of Titan's Atmosphere: First Detections of Vinyl Cyanide and Acetonitrile Isotopologues

    Science.gov (United States)

    Cordiner, Martin; Y Palmer, Maureen; Nixon, Conor A.; Charnley, Steven B.; Mumma, Michael J.; Irwin, Pat G. J.; Teanby, Nick A.; Kisiel, Zbigniew; Serigano, Joseph

    2015-11-01

    Studies of Titan's atmospheric chemistry provide a unique opportunity to explore the origin and evolution of complex organic matter in primitive planetary atmospheres. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new telescope, well suited to the study of molecular emission from Titan's stratosphere and mesosphere. Here we present early results from our ongoing study to exploit the large volume of Titan data taken using ALMA in Early Science Mode (during the period 2012-2014). Combining data from multiple ALMA Band 6 observations, we obtained high-resolution mm-wave spectra with unprecedented sensitivity, enabling the first detection of vinyl cyanide (C2H3CN) in Titan's atmosphere. Initial estimates indicate a mesospheric abundance ratio with respect to ethyl cyanide (C2H5CN) of [C2H3CN]/[C2H5CN] = 0.31. In addition, we report the first detections on Titan of the 13C and 15N-substituted isotopologues of acetonitrile (13CH3CN and CH3C15N). Radiative transfer models and possible chemical formation pathways for these molecules will be discussed.

  4. Polymerization of Acetonitrile via a Hydrogen Transfer Reaction from CH3 to CN under Extreme Conditions.

    Science.gov (United States)

    Zheng, Haiyan; Li, Kuo; Cody, George D; Tulk, Christopher A; Dong, Xiao; Gao, Guoying; Molaison, Jamie J; Liu, Zhenxian; Feygenson, Mikhail; Yang, Wenge; Ivanov, Ilia N; Basile, Leonardo; Idrobo, Juan-Carlos; Guthrie, Malcolm; Mao, Ho-Kwang

    2016-09-19

    Acetonitrile (CH3 CN) is the simplest and one of the most stable nitriles. Reactions usually occur on the C≡N triple bond, while the C-H bond is very inert and can only be activated by a very strong base or a metal catalyst. It is demonstrated that C-H bonds can be activated by the cyano group under high pressure, but at room temperature. The hydrogen atom transfers from the CH3 to CN along the CH⋅⋅⋅N hydrogen bond, which produces an amino group and initiates polymerization to form a dimer, 1D chain, and 2D nanoribbon with mixed sp(2) and sp(3) bonded carbon. Finally, it transforms into a graphitic polymer by eliminating ammonia. This study shows that applying pressure can induce a distinctive reaction which is guided by the structure of the molecular crystal. It highlights the fact that very inert C-H can be activated by high pressure, even at room temperature and without a catalyst. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Aging of electrochemical double layer capacitors with acetonitrile-based electrolyte at elevated voltages

    International Nuclear Information System (INIS)

    Ruch, P.W.; Cericola, D.; Foelske-Schmitz, A.; Koetz, R.; Wokaun, A.

    2010-01-01

    Laboratory-scale electrochemical capacitor cells with bound activated carbon electrodes and acetonitrile-based electrolyte were aged at various elevated constant cell voltages between 2.75 V and 4.0 V. During the constant voltage tests, the cell capacitance as well as the capacitance and resistance of each electrode was determined. Following each aging experiment, the cells were analyzed by means of electrochemical impedance spectroscopy, and the individual electrodes were characterized by gas adsorption and X-ray photoelectron spectroscopy. At cell voltages above 3.0 V, the positive electrode ages much faster than the negative. Both the capacitance loss and resistance increase of the cell could be totally attributed to the positive electrode. At cell voltages above 3.5 V also the negative electrode aged significantly. X-ray photoelectron spectroscopy indicated the presence of degradation products on the electrode surface with a much thicker layer on the positive electrode. Simultaneously, a significant decrease in electrode porosity could be detected by gas adsorption.

  6. Density functional simulation of resonant inelastic X-ray scattering experiments in liquids: acetonitrile.

    Science.gov (United States)

    Niskanen, Johannes; Kooser, Kuno; Koskelo, Jaakko; Käämbre, Tanel; Kunnus, Kristjan; Pietzsch, Annette; Quevedo, Wilson; Hakala, Mikko; Föhlisch, Alexander; Huotari, Simo; Kukk, Edwin

    2016-09-21

    In this paper we report an experimental and computational study of liquid acetonitrile (H 3 C-C[triple bond, length as m-dash]N) by resonant inelastic X-ray scattering (RIXS) at the N K-edge. The experimental spectra exhibit clear signatures of the electronic structure of the valence states at the N site and incident-beam-polarization dependence is observed as well. Moreover, we find fine structure in the quasielastic line that is assigned to finite scattering duration and nuclear relaxation. We present a simple and light-to-evaluate model for the RIXS maps and analyze the experimental data using this model combined with ab initio molecular dynamics simulations. In addition to polarization-dependence and scattering-duration effects, we pinpoint the effects of different types of chemical bonding to the RIXS spectrum and conclude that the H 2 C-C[double bond, length as m-dash]NH isomer, suggested in the literature, does not exist in detectable quantities. We study solution effects on the scattering spectra with simulations in liquid and in vacuum. The presented model for RIXS proved to be light enough to allow phase-space-sampling and still accurate enough for identification of transition lines in physical chemistry research by RIXS.

  7. Kinetics and mechanism of the pyridinolysis of phenacyl bromides in acetonitrile

    Science.gov (United States)

    Koh; Han; Lee; Lee

    2000-07-28

    Kinetic studies of the reactions of substituted phenacyl bromides (YC6H4COCH2Br) with pyridines (XC5H4N) are carried out in acetonitrile at 45.0 degrees C. A biphasic Bronsted plot is obtained with a change in slope from a large (betaX approximately equals 0.65-0.80) to a small (betaX approximately 0.36-0.40) value at pKa = 3.2-3.6, which can be attributed to a change in the rate-determining step from breakdown to formation of a tetrahedral intermediate in the reaction path as the basicity of the pyridine nucleophile increases. This mechanism is supported by the faster rates with pyridines than with anilines and the change of cross-interaction constant rhoXY from a large positive (rhoXY = +1.4) to a small positive (rhoXY approximately +0.1) value. The large magnitude of Hammett rhoX (= -5.5 to -6.9) values for the pyridines with electron-withdrawing substituents and positive deviations of the pi-acceptors, p-CH3CO and p-CN, are quite similar to those for the pyridinium ion formation equilibria. The activation parameters are also in line with the proposed mechanism.

  8. Pulse radiolyses of anthraquinone and anthraquinone-triethylamine in acetonitrile and toluene at room temperature

    International Nuclear Information System (INIS)

    Nakayama, Toshihiro; Ushida, Kiminori; Hamanoue, Kumao; Washio, Masakazu; Tagawa, Seiichi; Tabata, Yoneho

    1990-01-01

    Nanosecond pulse radiolysis of anthraquinone (AQ) in several solvents has been performed at room temperature, and the following results are obtained: (1) in acetonitrile (CH 3 CN), the formation of triplet AQ and a free-radical anion (AQ .- ) of AQ is observed. The former is produced by energy transfer from an excited neutral of CH 3 CN which may be produced via the geminate recombination of a radical cation and a radical anion of CH 3 CN in a spur, while the latter is produced by electron transfer from anionic species such as a solvated electron, a monomeric and/or a dimeric radical anion of CH 3 CN. In CH 3 CN-triethylamine (TEA), both free AQ .- and triplet AQ mentioned above are also produced; however, the latter reacts with TEA, giving rise to the formation of free AQ .- (from the second triplet state of AQ) and an exciplex of the lowest triplet state of AQ with ground-state TEA. This exciplex decomposes to free AQ .- and the radical cation of TEA. (2) In toluene, only triplet AQ is produced by energy transfer from triplet toluene to AQ, and, in the presence of TEA, the formation of the triplet exciplex of AQ-TEA is observed. On a microsecond timescale, however, this exciplex changes to a contact ion pair followed by proton transfer, generating anthrasemiquinone radical and triethylamine radical in accordance with the result of photolysis. (author)

  9. Hydrolysis mechanism of BH4- in moist acetonitrile. III. Kinetic isotope effects

    International Nuclear Information System (INIS)

    Meeks, B.S. Jr.; Kreevoy, M.M.

    1979-01-01

    The present work and a concurrent paper show that, in the presence of acetic acid, BH 4 - in acetonitrile is rapidly converted to BH 3 OCOCH 3 - and that previous kinetic studies of the hydrolysis of BH 4 - in such solutions actually referred to the hydrolysis of BH 3 OCOCH 3 - . As previously shown, the substrate (now shown to be BH 3 OCOCH 3 - ) complexes with acetic acid, with a complexing constant of about 160. That complex hydrolyzes by spontaneous and water-catalyzed paths. The present paper shows that the latter reaction is accelerated 15 to 40% by the substitution of D for H on boron. The rate is reduced, by a factor of approx. 1.75, by replacing all the hydroxylic hydrogen with deuterium. These results are consistent with BH 3 OC(CH 3 )O . HOCOCH 3 as the acetic acid-substrate complex. The displacement of the incipient biacetate ion by water is rate determining in this process. Isotopic substitution at either position reduces the rate of the spontaneous process. Its mechanism is uncertain. 2 figures, 3 tables

  10. Ionic association and solvation in solutions of magnesium and nickel perchlorates in acetonitrile

    Science.gov (United States)

    Kalugin, O. N.; Agieienko, V. N.; Otroshko, N. A.; Moroz, V. V.

    2009-02-01

    The paper presents the conductometric data on solutions of Mg(ClO4)2 and Ni(ClO4)2 in acetonitrile over the temperature ranges 5-55°C for Mg(ClO4)2 and 25-75°C for Ni(ClO4)2. The extended Lee-Wheaton equation for unsymmetrical electrolytes was used to determine the limiting equivalent conductivities of the Mg2+, Ni2+, and ClO{4/-} ions and first-step ionic association constants with the formation of [KtClO4]+ ion pairs. Lower ionic association constants for Ni(ClO4)2 compared with Mg(ClO4)2 were a consequence of stronger non-Coulomb repulsion in the formation of [KtClO4]+ ion pairs because of the formation of a firmer solvation shell by the nickel compared with magnesium cation. The structure-dynamic parameter of ionic solvation was estimated. It was found that spatial-time correlations in the nearest environment of ions increased in the series ClO{4/-} > Mg2+ > Ni2+.

  11. Full characterization of polypyrrole thin films electrosynthesized in room temperature ionic liquids, water or acetonitrile

    International Nuclear Information System (INIS)

    Viau, L.; Hihn, J.Y.; Lakard, S.; Moutarlier, V.; Flaud, V.; Lakard, B.

    2014-01-01

    Highlights: • Polypyrrole films were electrodeposited from three room temperature ionic liquids. • Polymer films were characterized using many surface analysis techniques. • The incorporation of anions and/or cations inside the polymer films was evidenced. • The influence of the ionic liquid on the polymer properties was deeply studied. - Abstract: Pyrrole was electrochemically oxidized in two conventional media (water and acetonitrile) and in three room temperature ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Infrared and Raman Spectroscopies confirmed the formation of polypyrrole by electropolymerization but were unable to demonstrate the presence of anions in the polymer films. The use of ionic liquids as growth media resulted in polymer films having a good electrochemical activity. The difference of activity from one polymer film to the other was mainly attributed to the difference of viscosity between the solvents used. The morphological features of the polypyrrole films were also fully studied. Profilometric measurements demonstrated that polymer films grown, at the same potential, in ionic liquids were thinner and had a smaller roughness than those grown in other solvents. Atomic Force Microscopy showed that polypyrrole films had nearly similar micrometric nodular structure whatever the growth medium even if some differences of porosity and homogeneity were observed using Scanning Electron Microscopy. The incorporation of counter-anions at the top surface of the films was finally evidenced by X-ray Photoelectron Spectroscopy. These anions were also incorporated inside the polymer film with a uniform distribution as shown by Glow Discharge Optical Emission Spectroscopy

  12. Singlet versus Triplet Excited State Mediated Photoinduced Dehalogenation Reactions of Itraconazole in Acetonitrile and Aqueous Solutions.

    Science.gov (United States)

    Zhu, Ruixue; Li, Ming-de; Du, Lili; Phillips, David Lee

    2017-04-06

    Photoinduced dehalogenation of the antifungal drug itraconazole (ITR) in acetonitrile (ACN) and ACN/water mixed solutions was investigated using femtosecond and nanosecond time-resolved transient absorption (fs-TA and ns-TA, respectively) and nanosecond time-resolved resonance Raman spectroscopy (ns-TR 3 ) experiments. An excited resonance energy transfer is found to take place from the 4-phenyl-4,5-dihydro-3H-1,2,4-triazol-3-one part of the molecule to the 1,3-dichlorobenzene part of the molecule when ITR is excited by ultraviolet light. This photoexcitation is followed by a fast carbon-halogen bond cleavage that leads to the generation of radical intermediates via either triplet and/or singlet excited states. It is found that the singlet excited state-mediated carbon-halogen cleavage is the predominant dehalogenation process in ACN solvent, whereas a triplet state-mediated carbon-halogen cleavage prefers to occur in the ACN/water mixed solutions. The singlet-to-triplet energy gap is decreased in the ACN/water mixed solvents and this helps facilitate an intersystem crossing process, and thus, the carbon-halogen bond cleavage happens mostly through an excited triplet state in the aqueous solutions examined. The ns-TA and ns-TR 3 results also provide some evidence that radical intermediates are generated through a homolytic carbon-halogen bond cleavage via predominantly the singlet excited state pathway in ACN but via mainly the triplet state pathway in the aqueous solutions. In strong acidic solutions, protonation at the oxygen and/or nitrogen atoms of the 1,2,4-triazole-3-one group appears to hinder the dehalogenation reactions. This may offer the possibility that the phototoxicity of ITR due to the generation of aryl or halogen radicals can be reduced by protonation of certain moieties in suitably designed ITR halogen-containing derivatives.

  13. Biodegradation of cyanide by acetonitrile-induced cells of Rhodococcus sp. UKMP-5M.

    Science.gov (United States)

    Nallapan Maniyam, Maegala; Sjahrir, Fridelina; Ibrahim, Abdul Latif; Cass, Anthony E G

    2013-01-01

    A Rhodococcus sp. UKMP-5M isolate was shown to detoxify cyanide successfully, suggesting the presence of an intrinsic property in the bacterium which required no prior cyanide exposure for induction of this property. However, in order to promote growth, Rhodococcus sp. UKMP-5M was fully acclimatized to cyanide after 7 successive subcultures in 0.1 mM KCN for 30 days. To further shorten the lag phase and simultaneously increase the tolerance towards higher cyanide concentrations, the bacterium was induced with various nitrile compounds sharing a similar degradatory pathway to cyanide. Acetonitrile emerged as the most favored inducer and the induced cells were able to degrade 0.1 mM KCN almost completely within 18 h. With the addition of subsequent aliquots of 0.1 mM KCN a shorter period for complete removal of cyanide was required, which proved to be advantageous economically. Both resting cells and crude enzyme of Rhodococcus sp. UKMP-5M were able to biodegrade cyanide to ammonia and formate without the formation of formamide, implying the identification of a simple hydrolytic cyanide degradation pathway involving the enzyme cyanidase. Further verification with SDS-PAGE revealed that the molecular weight of the active enzyme was estimated to be 38 kDa, which is consistent with previously reported cyanidases. Since the recent advancement in the application of biological methods in treating cyanide-bearing wastewater has been promising, the discovery of this new bacterium will add value by diversifying the existing microbial populations capable of cyanide detoxification.

  14. DFT simulation, quantum chemical electronic structure, spectroscopic and structure-activity investigations of 2-benzothiazole acetonitrile.

    Science.gov (United States)

    Arjunan, V; Thillai Govindaraja, S; Jose, Sujin P; Mohan, S

    2014-07-15

    The Fourier transform infrared and FT-Raman spectra of 2-benzothiazole acetonitrile (BTAN) have been recorded in the range 4000-450 and 4000-100 cm(-1) respectively. The conformational analysis of the compound has been carried out to obtain the stable geometry of the compound. The complete vibrational assignment and analysis of the fundamental modes of the compound are carried out using the experimental FTIR and FT-Raman data and quantum chemical studies. The experimental vibrational frequencies are compared with the wavenumbers derived theoretically by B3LYP gradient calculations employing the standard 6-31G(**), high level 6-311++G(**) and cc-pVTZ basis sets. The structural parameters, thermodynamic properties and vibrational frequencies of the normal modes obtained from the B3LYP methods are in good agreement with the experimental data. The (1)H (400 MHz; CDCl3) and (13)C (100 MHz;CDCl3) nuclear magnetic resonance (NMR) spectra are also recorded. The electronic properties, the energies of the highest occupied and lowest unoccupied molecular orbitals are measured by DFT approach. The kinetic stability of the molecule has been determined from the frontier molecular orbital energy gap. The charges of the atoms and the structure-chemical reactivity relations of the compound are determined by its chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors by conceptual DFT methods. The non-linear optical properties of the compound have been discussed by measuring the polarisability and hyperpolarisability tensors. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Electrochemical oxidation of cholesterol in acetonitrile leads to the formation of cholesta-4,6-dien-3-one

    International Nuclear Information System (INIS)

    Hosokawa, Yu-Ya; Hakamata, Hideki; Murakami, Tomonori; Aoyagi, Sakae; Kuroda, Minpei; Mimaki, Yoshihiro; Ito, Ayumi; Morosawa, Sayaka; Kusu, Fumiyo

    2009-01-01

    Cholesterol was shown to be oxidized at the glassy carbon electrode in an acetonitrile-2-propanol mixture and this oxidation reaction was applied to the determination of serum total cholesterol by high-performance liquid chromatography with electrochemical detection (K. Hojo, H. Hakamata, A. Ito, A. Kotani, C. Furukawa, Y.Y. Hosokawa, F. Kusu, J. Chromatogr. A 1166 (2007) 135-141). To gain insight into the detection mechanisms of cholesterol, an electrolytic product of cholesterol was collected and characterized by infrared spectroscopy, one- and two-dimensional nuclear magnetic resonance, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The three techniques, together with comparisons of literature spectral data, confirmed the formation of cholesta-4,6-dien-3-one. The conversion of cholesterol to cholesta-4,6-dien-3-one, a four-electron, four-proton electrochemical process, has been proposed as an electrochemical oxidation mechanism of cholesterol in acetonitrile.

  16. A PPy-B15C5 modified lanthanum (III electrode in acetonitrile and its thermodynamic application

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Arbab Zavar

    2017-02-01

    Full Text Available Polypyrrole modified electrode prepared by electropolymerization of pyrrole in the presence of a complexing ligand, benzo-15-crown-5 (B15C5, was prepared and investigated as a La3+-selective electrode in acetonitrile. The potentiometric response of the electrode was linear within the La3+ concentration range 1 × 10−4 to 1 × 10−1 M with a Nernstian slope of 19.5 mV decade−1 in AN. The electrode was applied to study the complexation of the lanthanum (III ion in acetonitrile with other basic solvent molecules (D such as dimethyl sulfoxide, N,N-dimethylformamide, propylene carbonate, N,N,Diethylaniline and methanol. The successive complex formation constant (βi and Gibbs energies of transfer (ΔGtr of La3+ in AN in relation to such D were obtained.

  17. (Acetonitrile-κNchloridobis[2-(pyridin-2-ylphenyl-κ2C1,N]iridium(III

    Directory of Open Access Journals (Sweden)

    Florian Blasberg

    2011-12-01

    Full Text Available The IrIII atom of the title compound, [Ir(C11H8N2Cl(CH3CN], displays a distorted octahedral coordination. The pyridyl groups are in trans positions [N—Ir—N = 173.07 (10°], while the phenyl groups are trans with respect to the acetonitrile and chloride groups [C—Ir—N = 178.13 (11 and C—Ir—Cl = 176.22 (9°]. The pyridylphenyl groups only show a small deviation from planarity, with the dihedral angle between the planes of the two six-membered rings in each pyridylphenyl group being 5.6 (2 and 5.8 (1°. The crystal packing shows intermolecular C—H...Cl, C—H...π(acetonitrile and C—H...π(pyridylphenyl contacts.

  18. Cold-induced aqueous acetonitrile phase separation: A salt-free way to begin quick, easy, cheap, effective, rugged, safe.

    Science.gov (United States)

    Shao, Gang; Agar, Jeffrey; Giese, Roger W

    2017-07-14

    Cooling a 1:1 (v/v) solution of acetonitrile and water at -16° C is known to result in two clear phases. We will refer to this event as "cold-induced aqueous acetonitrile phase separation (CIPS)". On a molar basis, acetonitrile is 71.7% and 13.6% in the upper and lower phases, respectively, in our study. The phase separation proceeds as a descending cloud of microdroplets. At the convenient temperature (typical freezer) employed here the lower phase is rather resistant to solidification, although it emerges from the freezer as a solid if various insoluble matter is present at the outset. In a preliminary way, we replaced the initial (salting-out) step of a representative QuEChERS procedure with CIPS, applying this modified procedure ("CIPS-QuEChERS") to a homogenate of salmon (and partly to beef). Three phases resulted, where only the upper, acetonitrile-rich phase is a liquid (that is completely clear). The middle phase comprises ice and precipitated lipids, while the lower phase is the residual matrix of undissolved salmon or meat. Treating the upper phase from salmon, after isolation, with anhydrous MgSO 4 and C18-Si (typical QuEChERS dispersive solid phase extraction sorbents), and injecting into a GC-MS in a nontargeted mode, gives two-fold more preliminary hits for chemicals, and also number of spiked pesticides recovered, relative to that from a comparable QuEChERS method. In part, this is because of much higher background signals in the latter case. Further study of CIPS-QuEChERS is encouraged, including taking advantage of other QuERChERS conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Determination of thermodynamic affinities of various polar olefins as hydride, hydrogen atom, and electron acceptors in acetonitrile.

    Science.gov (United States)

    Cao, Ying; Zhang, Song-Chen; Zhang, Min; Shen, Guang-Bin; Zhu, Xiao-Qing

    2013-07-19

    A series of 69 polar olefins with various typical structures (X) were synthesized and the thermodynamic affinities (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the polar olefins obtaining hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the polar olefins (X(•-)) obtaining protons and hydrogen atoms, and the thermodynamic affinities of the hydrogen adducts of the polar olefins (XH(•)) obtaining electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The pure C═C π-bond heterolytic and homolytic dissociation energies of the polar olefins (X) in acetonitrile and the pure C═C π-bond homolytic dissociation energies of the radical anions of the polar olefins (X(•-)) in acetonitrile were estimated. The remote substituent effects on the six thermodynamic affinities of the polar olefins and their related reaction intermediates were examined using the Hammett linear free-energy relationships; the results show that the Hammett linear free-energy relationships all hold in the six chemical and electrochemical processes. The information disclosed in this work could not only supply a gap of the chemical thermodynamics of olefins as one class of very important organic unsaturated compounds but also strongly promote the fast development of the chemistry and applications of olefins.

  20. Spectroscopic and quantum-chemical investigation of association of ions in acetonitrile - LiX (X=I, ClO4, NCS) systems

    International Nuclear Information System (INIS)

    Semenov, S.G.; Solov'eva, L.A.; Akopyan, S.Kh.

    1995-01-01

    Data on association constants of ions in acetonitrile-salt binary systems, obtained from the data on intensity of IR absorption bands of acetonitrile (Acn) molecules contained in solvate shells of Li + cations, have been analyzed. Using the CCP MO LCAO semiempirical method in the PPDP approximation, electronic structure of acetonitrile molecule and Acn k Li + and Acn m Li + X - complexes has been studied. It is ascertained that relative stability of ionic pairs Acn 3 Li + X - , estimated by the squares of their dipole momenta (characterizing solvation energy) increases in the series X=I, ClO 4 , NCS in agreement with data of spectroscopic experiment, according to which the constant of ion association for LiNCS solution in acetonitrile is much higher than for the systems CH 3 CN-LiI and CH 3 CN-LiClO 4 . 13 refs.,2 figs., 2 tabs.64

  1. The influence of Methanol and Acetonitrile in the Borate-Gluconate eluent the separation of Nitrate, Phosphate and Sulfate Anions by IC A column

    International Nuclear Information System (INIS)

    Djokowidodo; Bambang-Edi HB; Budi-Setiawan

    1996-01-01

    The modified of Borate-Gluconate solution has been used for the separation of nitrate, phosphate, sulfate anions with methanol and acetonitrile additions. The addition of acetonitrile increased the resolution of nitrate-phosphate, meanwhile the resolution of phosphate-sulfate decreased. The addition of methanol increased the resolutions of nitrate-phosphate, and phosphate-sulfate. The best separation of nitrate, phosphate and sulfate anions with IC. A column were done at the mixture of eluent Natrium Borate Gluconate:Butanol:Acetonitril:water = 1: 1: 10: 38. The best resolution of nitrate-phosphate was 2.4 with the eluent mixture at the ratio of 1 part of borate-gluconate, 1 part of butanol, and 10 part of acetonitrile, and the best resolution of the phosphate-sulfate, was done by the eluent mixture at the with of 1 part of borate-gluconate, 1 part of butanol, and 10 parts of methanol

  2. Structural investigation of water-acetonitrile mixtures: An ab initio, molecular dynamics and X-ray diffraction study

    International Nuclear Information System (INIS)

    Bako, Imre; Megyes, Tuende; Palinkas, Gabor

    2005-01-01

    In this work, we present a study on water-acetonitrile (AN) mixtures by molecular dynamics ab initio and X-ray diffraction techniques. Comparison of the experimental total G(r) functions of the mixtures with the results of molecular dynamics simulation shows an overall good agreement. The properties of hydrogen bonded clusters (water clusters, and water-AN clusters) in these mixtures have been determined. Two different types of AN-water dimers were identified by ab initio quantum chemical calculation. One of these structures proved to be a true H-bonded dimer and the other a dipole bound dimer

  3. Composite films of poly-(ester-sulphonated) and poly-(3-methylthiophene) for ion-exchange voltammetry in acetonitrile solutions

    International Nuclear Information System (INIS)

    Scopece, Paolo; Moretto, Ligia M.; Polizzi, Stefano; Ugo, Paolo

    2006-01-01

    This paper describes the preparation and characterisation of a polymeric electrode coating based on a composite of the poly-(ester-sulphonated) Eastman AQ55[reg] (AQ55) and poly-(3-methylthiophene) (PMeT), which is used for the controlled uptake and partial release of electroactive cations in acetonitrile solutions. The film is prepared by electrochemical oxidation in acetonitrile of 3-methylthiophene on glassy carbon disks or Pt-quartz crystal electrodes pre-coated with a thin film of AQ55. The electropolymerisation process is controlled so that the overall number of positive charges of oxidised PMeT is equal to the number of negative charges of the sulphonate groups of AQ55. Cyclic voltammetry and quartz crystal microbalance measurements indicate that the AQ55/PMeT mixed film is stable in acetonitrile and that its cation-exchange properties depend on the applied potential. When the PMeT moieties are reduced, the film incorporate cations; following electrochemical oxidation of the coating causes a release of the incorporated cations which, however, is only partial. Scanning electron microscopy (SEM) examination of cross sections of the composite polymer layer indicate that it is really a bi-layer, made by an inner compact layer of AQ55 on which a thicker and porous PMeT layer is grown. The outer PMeT layer acts as a barrier whose ionic charges can be changed electrochemically from positive (oxidation) to neutral (reduction). These ionic charges hinder or allow, respectively, the permeation of redox cations which tend to interact with the negatively charged sulphonic sites of the AQ55 layer. Direct self-neutralization of part of the positive charges of oxidized PMeT by the AQ55 sulphonic groups allows the release of part of the redox cations incorporated previously in the mixed film when PMeT is in the reduced state. By operating in acetonitrile solutions without added electrolyte it is possible to increase the fraction of redox cations which are released in

  4. Stacking and Analysis of Melamine in Milk Products with Acetonitrile-Salt Stacking Technique in Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Yu Kong

    2014-01-01

    Full Text Available Melamine was measured in real milk products with capillary electrophoresis (CE based on acetonitrile-salt stacking (ASS method. Real milk samples were deproteinized with acetonitrile at a final concentration of 60% (v/v and then injected hydrodynamically at 50 mBar for 40.0 s. The optimized buffer contains 80.0 mmol/L pH 2.8 phosphates. Melamine could be detected within 20.0 min at +10 kV with a low limit of detection (LOD of 0.03 μmol/L. Satisfactory reproducibility (inter- and intraday RSD% both for migration time and peak area was lower than 5.0% and a wide linearity range of 0.05 μmol/L ~ 10.0 μmol/L were achieved. The proposed method was suitable for routine assay of MEL in real milk samples that was subjected to a simple treatment step.

  5. On-column nitrosation of amines observed in liquid chromatography impurity separations employing ammonium hydroxide and acetonitrile as mobile phase.

    Science.gov (United States)

    Myers, David P; Hetrick, Evan M; Liang, Zhongming; Hadden, Chad E; Bandy, Steven; Kemp, Craig A; Harris, Thomas M; Baertschi, Steven W

    2013-12-06

    The availability of high performance liquid chromatography (HPLC) columns capable of operation at pH values up to 12 has allowed a greater selectivity space to be explored for method development in pharmaceutical analysis. Ammonium hydroxide is of particular value in the mobile phase because it is compatible with direct interfacing to electrospray mass spectrometers. This paper reports an unexpected N-nitrosation reaction that occurs with analytes containing primary and secondary amines when ammonium hydroxide is used to achieve the high pH and acetonitrile is used as the organic modifier. The nitrosation reaction has generality. It has been observed on multiple columns from different vendors and with multiple amine-containing analytes. Ammonia was established to be the source of the nitroso nitrogen. The stainless steel column frit and metal ablated from the frit have been shown to be the sites of the reactions. The process is initiated by removal of the chromium oxide protective film from the stainless steel by acetonitrile. It is hypothesized that the highly active, freshly exposed metals catalyze room temperature oxidation of ammonia to NO but that the actual nitrosating agent is likely N(2)O(3). Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Isotopic and chemical dilution effects on the vibrational relaxation rate of some totally symmetric motions of liquid acetonitrile

    International Nuclear Information System (INIS)

    Marri, E.; Morresi, A.; Paliani, G.; Cataliotti, R.S.; Giorgini, M.G.

    1999-01-01

    The vibrational dephasing of the ν 1 (C-H, C-D stretching) and ν 3 (C-H, C-D bending) symmetric motions of liquid acetonitrile in its light and fully deuterated forms has been studied in the frame of the vibrational time correlation functions obtained as Fourier transforms of the isotropic Raman spectral distributions and interpreted within the Kubo theory. In addition, the experimental isotropic profiles have been analysed within the bandshape approach formulated by analytical Fourier transformation of the Kubo vibrational time correlation functions in order to derive the relaxation parameters in the frequency domain. The effects of the isotopic (CH 3 CN/CD 3 CN and vice versa) and chemical (CCl 4 ) dilution on the bandshapes and on the vibrational relaxation parameters have been studied. It was observed that the decay rate of ν 1 mode is insensitive to the isotopic dilution but varies appreciably with chemical (CCl 4 ) dilution. The vibrational dephasing of ν 3 mode is qualitatively, but not quantitatively, affected in the same way by chemical dilution and shows a slower modulation regime than that exhibited by the stretching mode. Unlikely from the latter, the ν 3 mode results are slightly affected by the isotopic dilution. Phase relaxation mechanisms of these two motions of acetonitrile in the liquid state are proposed on the basis of these data, and a comparison is made with the results earlier published. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  7. Spectrophotometric determination of pKa's of 1-hydroxybenzotriazole and oxime derivatives in 95% acetonitrile-water

    International Nuclear Information System (INIS)

    Fathallah, M.F.; Khattab, S.N.

    2011-01-01

    1-hydroxybenzotriazole derivatives are used with carbodiimide as additives to generate active esters during peptide bond formation. They are also used as additives during the peptide bond formation. Dissociation constants of the 1-hydroxybenzotriazole (HOBt) and its derivatives, 1-hydroxy-6-chloro benzotriazole, 1-hydroxy-6-trifluoro methylbenzotriazole, 1-hydroxy-6-nitrobenzo-triazole were determined spectrophotometrically in 95% acetonitrile-water. In addition, 7-aza-1-hydroxybenzotriazole (7-HOAt) and 4-aza-1-hydroxybenzotriazole (4-HOAt) were also studied. Recently, oxyma was reported as a good replacement for the benzotriazole derivatives. As alcoholic components of active esters, the oximes seem to be good leaving groups. Therefore it was expected, that the strongly acidic and nucleophilic oximes, which possess electron-withdrawing groups in the molecule, are suitable as additives during the peptide bond formation. The dissociation constant of some oximes, such as diethyl 2-(hydroxyimino)malonate, ethyl 2-cyano-2-(hydroxyimino)acetate (oxyma), hydroxycarbonimidoyl dicyanide and N-hydroxypicolinimidoyl cyanide in 95% acetonitrile-water are reported. (author)

  8. μ-Hexathiometadiphosphato-bis[(1,4,7,10,13,16-hexaoxacyclooctadecane-κ6Orubidium] acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Flora Qarri

    2013-12-01

    Full Text Available The asymmetric unit of the title compound, [Rb2(P2S6(C12H24O62]·2CH3CN, contains one half of an [Rb(18-crown-62]2[P2S6] unit and one acetonitrile solvent molecule. The [Rb(18-crown-6]2[P2S6] unit is completed by inversion symmetry. Its Rb+ ion is situated near the centre of the macrocyclic cavity, but is displaced by 0.8972 (1 Å from the O atoms of the crown in the direction of the [P2S6]2− moiety. The overall coordination number of the cation is eight, defined by the six crown ether O atoms and by two terminal S atoms of the [P2S6]2− anion. The hexathiometadiphosphate anion is built up from two tetrahedral PS4 units joined together by a common edge. The crystal structure is characterized by alternating layers of [Rb(18-crown-6]2[P2S6] and acetonitrile solvent molecules stacked along [010].

  9. A Study of Acid-Base Equilibria in Acetonitrile Systems of 2-Halo(Cl,Br,I-4-nitropicoline(3,5,6 N-oxides

    Directory of Open Access Journals (Sweden)

    Lech Chmurzynski

    1999-03-01

    Full Text Available An attempt has been made to determine potentiometrically (1 acid dissociation constants of cations obtained by protonation of nine trisubstituted pyridine N-oxides, namely 2-halo(Cl, Br and I-4-nitropicoline N-oxides with the methyl group at positions 3, 5, and 6, as well as (2 the cationic homoconjugation constants of these cationic acids with conjugated N-oxides in acetonitrile. On the basis of the substitution effect, variations of the acid dissociation constants of the trisubstituted pyridine N-oxide cations are discussed. The determined pKa values of the protonated 2-halo-4-nitropicoline N-oxides are compared with the previously determined equilibrium constants of the cationic acids conjugated with the mono- and disubstituted pyridine N-oxides in acetonitrile. Further, based on the pKa values of the protonated 2-halo-4-nitropicoline N-oxides in acetonitrile, supplemented with correlations between pKa’s of the protonated mono- and disubstituted pyridine N-oxides in acetonitrile and water, the pKa's of the acids conjugated with the trisubstituted N-oxides studied in aqueous solutions have been estimated. Moreover, it has been concluded that the cationic homoconjugation constants cannot be determined by potentiometric titration in acetonitrile solutions of the 2-halo-4-nitropicoline N-oxide systems.

  10. Vapor pressures, osmotic and activity coefficients for (LiBr + acetonitrile) between the temperatures (298.15 and 343.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Nasirzadeh, Karamat E-mail: karamat.nasirzadeh@chemie.uni-regensburg.de; Neueder, Roland; Kunz, Werner

    2004-06-01

    Precise vapor pressure data for pure acetonitrile and (LiBr + acetonitrile) are given for temperatures ranging from T=(298.15 to 343.15) K. The molality range is from m=(0.0579 to 0.8298) mol {center_dot} kg{sup -1}. The osmotic coefficients are calculated by taking into account the second virial coefficient of acetonitrile. The parameters of the extended Pitzer ion interaction model of Archer and the mole fraction-based thermodynamic model of Clegg-Pitzer are evaluated. These models accurately reproduce the available osmotic coefficients. The parameters of the extended Pitzer ion interaction model of Archer are used to calculate the mean molal activity coefficients.

  11. Crystal structure of chlorido(dimethyl sulfoxide-κSbis[4-(pyridin-2-ylbenzaldehyde-κ3C2,N]iridium(III acetonitrile monosolvate

    Directory of Open Access Journals (Sweden)

    Andrew J. Peloquin

    2017-09-01

    Full Text Available The title compound, [IrCl(C12H8NO2{(CH32SO}]·H3CCN or [IrCl(fppy2(DMSO]·H3CCN [where fppy is 4-(pyridin-2-ylbenzaldehyde and DMSO is dimethyl sulfoxide], is a mononuclear iridium(III complex including two fppy ligands, a sulfur-coordinating DMSO ligand, and one terminal chloride ligand that define a distorted octahedral coordination sphere. The complex crystallizes from 1:1 DMSO–acetonitrile as an acetonitrile solvate. In the crystal, weak C—H...O and C—H...N hydrogen-bonding interactions between adjacent complexes and between the acetonitrile solvent and the complex consolidate the packing.

  12. 2-{[2-Methyl-3-(2-methylphenyl-4-oxo-3,4-dihydroquinazolin-8-yl]oxy}acetonitrile

    Directory of Open Access Journals (Sweden)

    Adel S. El-Azab

    2012-07-01

    Full Text Available In the title compound, C18H15N3O2, the fused ring system is almost planar [the dihedral angle between the six-membered rings is 1.81 (6°]. The 2-tolyl ring is approximately orthogonal to this plane [dihedral angle = 83.03 (7°] as is the acetonitrile group [C—O—C—C torsion angle = 79.24 (14°] which is also syn to the methyl substituent of the tolyl group. In the crystal, supramolecular layers are formed in the bc plane mediated by C—H...O, C—H...N and C—H...π interactions. The tolyl group is disordered over two positions in a 0.852 (3:0.148 (3 ratio.

  13. On the complexing of phosphoric acid vinyl esters with praseodymium (3) and europium (3) nitrates in acetonitrile

    International Nuclear Information System (INIS)

    Goryushko, A.G.; Gololobov, Yu.G.; Boldeskul, A.E.; Oganesyan, A.S.; Yartsev, V.G.

    1990-01-01

    By the methods of electron, IR and PMR spectroscopy interaction of vinyl esters of phosphoric acid with praseodymium (3) and europium (3) nitrates in acetonitrile solutions has been studied. It is shown that the character of metal-ligand interaction is determined by chemical nature of the ligands: for a compound of ionic structure partially covalent bond is formed, and for a compound of betaine structure the interaction has mainly dipole character. Addition of molecule with betaine structure to praseodymium nitrate causes a change in geometry of Pr 3+ close surrounding and increase in its coordination number. The possibility of formation of the complex with metal-ligand ratio equal to 1:3 is shown

  14. μ-Peroxido-bis­[acetonitrile­bis­(ethyl­enediamine)­cobalt(III)] tetrakis(per­chlorate)

    Science.gov (United States)

    Regeta, Khrystyna O.; Odarich, Iryna; Pavlova, Svetlana V.; Kalibabchuk, Valentina A.; Haukka, Matti

    2010-01-01

    The title compound, [Co2(O2)(CH3CN)2(C2H8N2)4](ClO4)4, consists of centrosymmetric binuclear cations and perchlorate anions. Two CoIII atoms, which have a slightly distorted octa­hedral coordination, are connected through a peroxido bridge; the O—O distance is 1.476 (3) Å. Both acetonitrile ligands are situated in a trans position with respect to the O—O bridge. In the crystal, the complex cations are connected by N—H⋯O hydrogen bonds between ethyl­endiamine NH groups and O atoms from the perchlorate anions and peroxide O atoms. PMID:21589305

  15. A quantum mechanical strategy to investigate the structure of liquids: the cases of acetonitrile, formamide, and their mixture.

    Science.gov (United States)

    Mennucci, Benedetta; da Silva, Clarissa O

    2008-06-05

    A computational strategy based on quantum mechanical (QM) calculations and continuum solvation models is used to investigate the structure of liquids (either neat liquids or mixtures). The strategy is based on the comparison of calculated and experimental spectroscopic properties (IR-Raman vibrational frequencies and Raman intensities). In particular, neat formamide, neat acetonitrile, and their equimolar mixture are studied comparing isolated and solvated clusters of different nature and size. In all cases, the study seems to indicate that liquids, even when strongly associated, can be effectively modeled in terms of a shell-like system in which clusters of strongly interacting molecules (the microenvironments) are solvated by a polarizable macroenvironment represented by the rest of the molecules. Only taking into proper account both these effects can a correct picture of the liquid structure be achieved.

  16. Study of the mechanism of acetonitrile stacking and its application for directly combining liquid-phase microextraction with micellar electrokinetic chromatography.

    Science.gov (United States)

    Sun, Jingru; Feng, Jing; Shi, Ludi; Liu, Laping; He, Hui; Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2016-08-26

    Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260-791. Limits of qualification ranged from 5.5 to 16.0ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl(-) ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Automatized sspKa measurements of dihydrogen phosphate and Tris(hydroxymethyl) aminomethane in acetonitrile/water mixtures from 20 to 60°C.

    Science.gov (United States)

    Acquaviva, A; Tascon, M; Padró, J M; Gagliardi, L G; Castells, C B

    2014-09-01

    We measured pKa values of Tris(hydroxymethyl)aminomethane and dihydrogen phosphate; both are commonly used to prepare buffers for reverse-phase liquid chromatography (RPLC), in acetonitrile/water mixtures from 0% to 70% (v/v) (64.6% (w/w)) acetonitrile and at 20, 30, 40, 50, and 60°C. The procedure is based on potentiometric measurements of pH of buffer solutions of variable solvent compositions using a glass electrode and a novel automated system. The method consists in the controlled additions of small volumes of a thermostated solution from an automatic buret into another isothermal solution containing exactly the same buffer-component concentrations, but a different solvent composition. The continuous changes in the solvent composition induce changes in the potentials. Thus, only two sequences of additions are needed: increasing the amount of acetonitrile from pure water and decreasing the content of acetonitrile from 70% (v/v) (64.6% (w/w)). In the procedure with homemade apparatus, times for additions, stirring, homogenization, and data acquisition are entirely controlled by software programmed for this specific routine. This rapid, fully automated method was applied to acquire more than 40 potential data covering the whole composition range (at each temperature) in about two hours and allowed a systematic study of the effect of temperature and acetonitrile composition on acid-base equilibria of two widely used substances to control pH close to 7. The experimental pKa results were fitted to empirical functions between pKa and temperature and acetonitrile composition. These equations allowed predictions of pKa to estimate the pH of mixtures at any composition and temperature, which would be very useful, for instance, during chromatographic method development. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Thermodynamics of various F420 coenzyme models as sources of electrons, hydride ions, hydrogen atoms and protons in acetonitrile.

    Science.gov (United States)

    Xia, Ke; Shen, Guang-Bin; Zhu, Xiao-Qing

    2015-06-14

    32 F420 coenzyme models with alkylation of the three different N atoms (N1, N3 and N10) in the core structure (XFH(-)) were designed and synthesized and the thermodynamic driving forces (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the 32 XFH(-) releasing hydride ions, hydrogen atoms and electrons, the thermodynamic driving forces of the 32 XFH˙ releasing protons and hydrogen atoms and the thermodynamic driving forces of XF(-)˙ releasing electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The effects of the methyl group at N1, N3 and N10 and a negative charge on N1 and N10 atoms on the six thermodynamic driving forces of the F420 coenzyme models and their related reaction intermediates were examined; the results show that seating arrangements of the methyl group and the negative charge have remarkably different effects on the thermodynamic properties of the F420 coenzyme models and their related reaction intermediates. The effects of the substituents at C7 and C8 on the six thermodynamic driving forces of the F420 coenzyme models and their related reaction intermediates were also examined; the results show that the substituents at C7 and C8 have good Hammett linear free energy relationships with the six thermodynamic parameters. Meanwhile, a reasonable determination of possible reactions between members of the F420 family and NADH family in vivo was given according to a thermodynamic analysis platform constructed using the elementary step thermodynamic parameter of F420 coenzyme model 2FH(-) and NADH model MNAH releasing hydride ions in acetonitrile. The information disclosed in this work can not only fill a gap in the chemical thermodynamics of F420 coenzyme models as a class of very important organic sources of electrons, hydride ions, hydrogen atoms and protons, but also strongly promote the fast development of the chemistry and applications of F420 coenzyme.

  19. Surface Collisions of the Acetonitrile Molecular Ion: Evidence for Isomerization of CD3CN center dot+ to the Ketenimine Cation CD2=C=ND center dot+

    Czech Academy of Sciences Publication Activity Database

    Mair, C.; Roithová, Jana; Fedor, J.; Lezius, M.; Herman, Zdeněk; Märk, T. D.

    223-224, 1/3 (2003), s. 279-290 ISSN 1387-3806 R&D Projects: GA ČR GA203/00/0632 Institutional research plan: CEZ:AV0Z4040901 Keywords : acetonitrile cation * surface reactions * isomerization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.361, year: 2003

  20. (Vapour + liquid) equilibria in the ternary system (acetonitrile + n-propanol + ethylene glycol) and corresponding binary systems at 101.3 kPa

    International Nuclear Information System (INIS)

    Qian, Guo-fei; Liu, Wen; Wang, Li-tao; Wang, Dao-cai; Song, Hang

    2013-01-01

    Highlights: • We adopted a new extractive solvent “ethylene glycol” to separate the mixture. • We measured the VLE data of binary system n-propanol + ethylene glycol. • We reinforce the VLE data of binary system acetonitrile + ethylene glycol. • We predicted the VLE data for the ternary system successfully. -- Abstract: Experimental isobaric (Vapour + liquid) equilibrium (VLE) data at 101.3 kPa were determined for three binary systems, viz. {acetonitrile (1) + n-propanol (2)}, {acetonitrile (1) + ethylene glycol (3)} and {n-propanol (2) + ethylene glycol (3)} and for one ternary system {acetonitrile (1) + n-propanol (2) + ethylene glycol (3)}. The measurements were performed using an improved Rose equilibrium still. The VLE data of the binary systems passed thermodynamic consistency tests and were correlated by Wilson and NRTL models. Good results were achieved. The phase behaviour of the ternary system was predicted directly by the parameters of two models obtained from the experimental binary results. The results showed an excellent agreement with experimental values

  1. Performance of the SMD and SM8 models for predicting solvation free energy of neutral solutes in methanol, dimethyl sulfoxide and acetonitrile

    Science.gov (United States)

    Zanith, Caroline C.; Pliego, Josefredo R.

    2015-03-01

    The continuum solvation models SMD and SM8 were developed using 2,346 solvation free energy values for 318 neutral molecules in 91 solvents as reference. However, no solvation data of neutral solutes in methanol was used in the parametrization, while only few solvation free energy values of solutes in dimethyl sulfoxide and acetonitrile were used. In this report, we have tested the performance of the models for these important solvents. Taking data from literature, we have generated solvation free energy, enthalpy and entropy values for 37 solutes in methanol, 21 solutes in dimethyl sulfoxide and 19 solutes in acetonitrile. Both SMD and SM8 models have presented a good performance in methanol and acetonitrile, with mean unsigned error equal or less than 0.66 and 0.55 kcal mol-1 in methanol and acetonitrile, respectively. However, the correlation is worse in dimethyl sulfoxide, where the SMD and SM8 methods present mean unsigned error of 1.02 and 0.95 kcal mol-1, respectively. Our results point out the SMx family of models need be improved for dimethyl sulfoxide solvent.

  2. Study of the hydrolysis of acetonitrile using different brønsted acid models : zeolite-type and HCl(H2O)x clusters

    NARCIS (Netherlands)

    Barbosa, Louis; Santen, van R.A.

    2000-01-01

    The hydrolysis of acetonitrile has been studied theoretically by different ab initio methods (RHF, DFT, and MP2). Two Brønsted acid catalysts have been compared: zeolite and HCl(H2O)x=2,1 clusters. Some interesting analogies have been found for the reaction path catalyzed by these different acids,

  3. Synthesis of Poly pyrrole Inverse Opal in [bmim] Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

    International Nuclear Information System (INIS)

    Yan, W.; Dong, Q.Q.; Sun, L.N.; Deng, W.; Wu, Sh.

    2013-01-01

    Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered poly pyrrole (PPy) inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF 6 . PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS) were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF 6 - anions kept de doping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF 6 - anions also kept de doping from the PPy inverse opals, the PO 4 3- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours

  4. Partial molar volumes of (acetonitrile + water) mixtures over the temperature range (273.15 to 318.15) K

    International Nuclear Information System (INIS)

    Yeow, Y. Leong; Leong, Yee-Kwong

    2007-01-01

    Isothermal molar volume data of (acetonitrile + water) mixtures, between T = 273.15 K and T = 318.15 K, extracted from different sources are combined and treated as a single set to even out minor differences between sources and to increase the number of data points for each temperature. Tikhonov regularization is applied to compute the isothermal first and second derivatives of these data with respect to molar composition. For the reference temperature of 298.15 K, this computation is extended to the third derivative. Generalized Cross Validation is used to guide the selection of the regularization parameter that keeps noise amplification under control. The resulting first derivatives are used to construct the partial molar volume curves which are then checked against published results. Properties of the partial molar volumes are analysed by examining their derivatives. Finally the general shape of the second derivative curve of molar volume is explained qualitatively in terms of tripartite segmentation of the molar composition interval but quantitative comparisons are required to confirm this explanation

  5. Rate theory of solvent exchange and kinetics of Li(+) - BF4 (-)/PF6 (-) ion pairs in acetonitrile.

    Science.gov (United States)

    Dang, Liem X; Chang, Tsun-Mei

    2016-09-07

    In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li(+) and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li(+) in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li(+)-[BF4] and Li(+)-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li(+). We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li(+)-[BF4] and Li(+)-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

  6. (Butoxymethylidenedimethylazanium tetraphenylborate acetonitrile monosolvate

    Directory of Open Access Journals (Sweden)

    Ioannis Tiritiris

    2014-04-01

    Full Text Available In the title solvated salt, C7H16NO+·C24H20B−·C2H3N, the C—N bond lengths in the cation are 1.2831 (19, 1.467 (2 and 1.465 (2 Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.2950 (18 Å shows a double-bond character, pointing towards charge delocalization within the NCO plane of the iminium ion. The two C atoms of the n-butyl group are disordered over the two sites, with refined occupancy ratios of 0.890 (5:0.110 (5 and 0.888 (4:0.112 (4. In the crystal, C—H...π interactions occur between the methine H atom, H atoms of the –N(CH32 and –CH2 groups of the cation, and two of the phenyl rings of the tetraphenylborate anion. The latter interaction forms an aromatic pocket in which the cation is embedded. Thus, a two-dimensional pattern is created in the ac plane.

  7. Modulation of intra- and inter-sheet interactions in short peptide self-assembly by acetonitrile in aqueous solution

    International Nuclear Information System (INIS)

    Deng Li; Zhao Yurong; Zhou Peng; Xu Hai; Wang Yanting

    2016-01-01

    Besides our previous experimental discovery (Zhao Y R, et al . 2015 Langmuir , 31, 12975) that acetonitrile (ACN) can tune the morphological features of nanostructures self-assembled by short peptides KIIIIK (KI4K) in aqueous solution, further experiments reported in this work demonstrate that ACN can also tune the mass of the self-assembled nanostructures. To understand the microscopic mechanism how ACN molecules interfere peptide self-assembly process, we conducted a series of molecular dynamics simulations on a monomer, a cross- β sheet structure, and a proto-fibril of KI4K in pure water, pure ACN, and ACN-water mixtures, respectively. The simulation results indicate that ACN enhances the intra-sheet interaction dominated by the hydrogen bonding (H-bonding) interactions between peptide backbones, but weakens the inter-sheet interaction dominated by the interactions between hydrophobic side chains. Through analyzing the correlations between different groups of solvent and peptides and the solvent behaviors around the proto-fibril, we have found that both the polar and nonpolar groups of ACN play significant roles in causing the opposite effects on intermolecular interactions among peptides. The weaker correlation of the polar group of ACN than water molecule with the peptide backbone enhances H-bonding interactions between peptides in the proto-fibril. The stronger correlation of the nonpolar group of ACN than water molecule with the peptide side chain leads to the accumulation of ACN molecules around the proto-fibril with their hydrophilic groups exposed to water, which in turn allows more water molecules close to the proto-fibril surface and weakens the inter-sheet interactions. The two opposite effects caused by ACN form a microscopic mechanism clearly explaining our experimental observations. (paper)

  8. Europium, uranyl, and thorium-phenanthroline amide complexes in acetonitrile solution: an ESI-MS and DFT combined investigation.

    Science.gov (United States)

    Xiao, Cheng-Liang; Wang, Cong-Zhi; Mei, Lei; Zhang, Xin-Rui; Wall, Nathalie; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun

    2015-08-28

    The tetradentate N,N'-diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) ligand with hard-soft donor atoms has been demonstrated to be promising for the group separation of actinides from highly acidic nuclear wastes. To identify the formed complexes of this ligand with actinides and lanthanides, electrospray ionization mass spectrometry (ESI-MS) combined with density functional theory (DFT) calculations was used to probe the possible complexation processes. The 1 : 2 Eu-L species ([EuL2(NO3)](2+)) can be observed in ESI-MS at low metal-to-ligand ([M]/[L]) ratios, whereas the 1 : 1 Eu-L species ([EuL(NO3)2](+)) can be observed when the [M]/[L] ratio is higher than 1.0. However, ([UO2L(NO3)](+)) is the only detected species for the uranyl complexes. The [ThL2(NO3)2](2+) species can be observed at low [M]/[L] ratios; the 1 : 2 species ([ThL2(NO3)](3+)) and a new 1 : 1 species ([ThL(NO3)3](+)) can be detected at high [M]/[L] ratios. Collision-induced dissociation (CID) results showed that Et-Tol-DAPhen ligands can coordinate strongly with metal ions, and the coordination moieties remain intact under CID conditions. Natural bond orbital (NBO), molecular electrostatic potential (MEP), electron localization function (ELF), atoms in molecules (AIM) and molecular orbital (MO) analyses indicated that the metal-ligand bonds of the actinide complexes exhibited more covalent character than those of the lanthanide complexes. In addition, according to thermodynamic analysis, the stable cationic M-L complexes in acetonitrile are found to be in good agreement with the ESI-MS results.

  9. Catalytic oxidative desulfurization of diesel utilizing hydrogen peroxide and functionalized-activated carbon in a biphasic diesel-acetonitrile system

    Energy Technology Data Exchange (ETDEWEB)

    Haw, Kok-Giap; Bakar, Wan Azelee Wan Abu; Ali, Rusmidah; Chong, Jiunn-Fat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Kadir, Abdul Aziz Abdul [Department of Petroleum Engineering, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2010-09-15

    This paper presents the development of granular functionalized-activated carbon as catalysts in the catalytic oxidative desulfurization (Cat-ODS) of commercial Malaysian diesel using hydrogen peroxide as oxidant. Granular functionalized-activated carbon was prepared from oil palm shell using phosphoric acid activation method and carbonized at 500 C and 700 C for 1 h. The activated carbons were characterized using various analytical techniques to study the chemistry underlying the preparation and calcination treatment. Nitrogen adsorption/desorption isotherms exhibited the characteristic of microporous structure with some contribution of mesopore property. The Fourier Transform Infrared Spectroscopy results showed that higher activation temperature leads to fewer surface functional groups due to thermal decomposition. Micrograph from Field Emission Scanning Electron Microscope showed that activation at 700 C creates orderly and well developed pores. Furthermore, X-ray Diffraction patterns revealed that pyrolysis has converted crystalline cellulose structure of oil palm shell to amorphous carbon structure. The influence of the reaction temperature, the oxidation duration, the solvent, and the oxidant/sulfur molar ratio were examined. The rates of the catalytic oxidative desulfurization reaction were found to increase with the temperature, and H{sub 2}O{sub 2}/S molar ratio. Under the best operating condition for the catalytic oxidative desulfurization: temperature 50 C, atmospheric pressure, 0.5 g activated carbon, 3 mol ratio of hydrogen peroxide to sulfur, 2 mol ratio of acetic acid to sulfur, 3 oxidation cycles with 1 h for each cycle using acetonitrile as extraction solvent, the sulfur content in diesel was reduced from 2189 ppm to 190 ppm with 91.3% of total sulfur removed. (author)

  10. A ferrocene functionalized polymer: Poly [N-(ferrocenylmethyl)-o-phenylenediamine]. Electrochemical production and spectroelectroelectrochemical investigation in acetonitrile medium

    International Nuclear Information System (INIS)

    Gülce, Handan; Yetkin, Ahmet; Akgül, Eda; Gülce, Ahmet

    2013-01-01

    An electroactive and conductive polymer having pendant ferrocene units was prepared from the electrochemical polymerization of the synthesized monomer, N-(ferrocenylmethyl)-o-phenylenediamine in 0.1 M tetrabuthylammonium perchlorate/acetonitrile medium. The poly-N-(ferrocenylmethyl)-o-phenylenediamine (poly-FMOPD) was generated potentiodynamically or potentiostatically at both of indium tin oxide coated glass substrate and Pt electrodes. The poly-FMOPD film was characterized by cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, dry conductivity measurements, ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy. The electrical conductivity of polymer films was determined as 1.0 × 10 −1 and 4 × 10 −2 S cm −1 depending on the potential scanning range during electropolymerization. The electroactivity of the polymer film retained even after hundreds cycles between their reduced and oxidized states. The spectroelectrochemical analysis demonstrated that the polymer film reveals a reversible cycling with distinctive color changes between neutral and reduced/oxidized forms. For the polymer film, the maximum optical contrasts (ΔT%) were measured as 18% at and 37% at 480 nm by step the potential between (0.00 V)-(1.20 V) and (− 0.50 V)-(− 1.70 V), respectively. The optical energy band gaps as the onset energy for the π–π* transitions are calculated as 1.89 eV, 1.85 eV and 1.88 eV for the neutral, reduced and oxidized states of poly-FMOPD. - Highlights: • The ferrocene functionalized monomer and its polymer were synthesized electrochemically. • Spectroelectrochemical investigations were performed. • The polymer film showed reversible color changes between different redox forms. • It was found that the polymer film is conductive

  11. Effect of the pasteurization process on the contents of ascorbigen, indole-3-carbinol, indole-3-acetonitrile, and 3,3'-diindolylmethane in fermented cabbage.

    Science.gov (United States)

    Ciska, Ewa; Honke, Joanna

    2012-04-11

    The aim of the study was to investigate the effect of the pasteurization process on the content of ascorbigen, indole-3-carbinol, indole-3-acetonitrile, and 3,3'-diindolylmethane in fermented cabbage. Pasteurization was run at a temperature of 80 °C for 5-30 min. Significant changes were only observed in contents of ascorbigen and 3,3'-diindolylmethane. The total content of the compounds analyzed in cabbage pasteurized for 10-30 min was found to be decreased by ca. 20%, and the losses were due to thermal degradation of the predominating ascorbigen. Pasteurization was found not to exert any considerable effect on contents of indole-3-acetonitrile and indole-3-carbinol in cabbage nor did it affect contents of the compounds analyzed in juice.

  12. Cathodic electrochemical deposition of Magnéli phases TinO2n−1 thin films at different temperatures in acetonitrile solution

    International Nuclear Information System (INIS)

    Ertekin, Zeliha; Tamer, Uğur; Pekmez, Kadir

    2015-01-01

    Highlights: • TiO x films were prepared by cathodic electrodeposition in acetonitrile. • One-step electrodeposition of TiO x films without heat treatment process. • Different crystalline Ti n O 2n−1 films (γTi 3 O 5 , λTi 3 O 5 , Ti 4 O 7 , Ti 5 O 9 ) were obtained. - Abstract: The Magnéli phase titanium oxide films prepared by cathodic electrodeposition on indium–tin-oxide coated glass substrates from saturated peroxo-titanium solution in acetonitrile. Electrodeposited brownish semi-conductor thin films were identified via X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy (SEM). The effects of different potentials and temperatures on the crystallinity of the thin films have been discussed. Ti 3 O 5 , Ti 4 O 7 and Ti 5 O 9 as the most favorable forms of the Ti n O 2n−1 were electrodeposited on ITO electrode at electrochemical deposition potentials and different temperatures. The present investigation reveals that the electrochemical deposition of crystalline Ti n O 2n−1 films by a simple one-step electrodeposition method (without any heat treatment) in acetonitrile solution is possible and very promising as a preparation method for electrochemical applications

  13. Association of ionic liquids in solution: a combined dielectric and conductivity study of [bmim][Cl] in water and in acetonitrile.

    Science.gov (United States)

    Bešter-Rogač, Marija; Stoppa, Alexander; Hunger, Johannes; Hefter, Glenn; Buchner, Richard

    2011-10-21

    Ion association of the ionic liquid [bmim][Cl] in acetonitrile and in water was studied by dielectric spectroscopy for salt concentrations c ≤ 1.3 M at 298.15 K and by measurement of molar electrical conductivities, Λ, of dilute solutions (c ≤ 0.006 M) in the temperature range 273.15 ≲ T/K ≤ 313.15. Whilst acetonitrile solutions of [bmim][Cl] exhibit moderate ion pairing, with an association constant of K°(A) ≈ 60 M(-1) and increasing with temperature, [bmim][Cl] is only weakly associated in water (K°(A) ≈ 6 M(-1)) and ion pairing decreases with rising temperature. Only contact ion pairs were detected in both solvents. Standard-state enthalpy, entropy and heat capacity changes of ion association were derived, as well as the activation enthalpy of charge transport and the limiting conductivity of the cation, λ(∞) ([bmim](+)). These data, in conjunction with effective solvation numbers obtained from the dielectric spectra, suggest that the solvation of [bmim](+) is much weaker in water than in acetonitrile. This journal is © the Owner Societies 2011

  14. EIS study of the redox reaction of Fe(CN)63-/4- at glassy carbon electrode via diazonium reduction in aqueous and acetonitrile solutions

    Energy Technology Data Exchange (ETDEWEB)

    Khoshroo, M.; Rostami, A. [Mazandaran Univ., Babolsar (Iran, Islamic Republic of). Dept. of Physical Chemistry

    2008-07-01

    This paper reported on a study that characterized soluble electroactive species by cyclic voltammetry to investigate the presence of grafted films and their blocking properties. In particular, the authority of the glassy carbon electrode modification conditions on the cyclic voltammetric response of Fe(CN)63-/4- oxido-reduction was examined for 2 layers grafted by electrochemical reduction of diazonium salts in acetonitrile and aqueous solutions. PAA and Fast Black K modified glassy carbon electrodes exhibited a significant blocking behaviour for oxidation and reduction reactions of the Fe(CN)63-/4- redox system in aqueous and acetonitrile solutions. The study showed that the blocking effect increased which changes in time and concentration of diazonium salts in acetonitrile solution. Electrochemical impedance spectroscopy (EIS) measurements showed that the physical barrier of grafted layers prevent the access of Fe(CN)63-/4- to the underlying glassy carbon electrode. Therefore the RCT resistance increases during the modification treatment. The substituted phenyl layers are much more compact and less permeable in a nonaqueous solvent than with an aqueous solvent. Electrochemical impedance measurements indicate that the kinetics of electron transfer slow down when the time and the concentration used to modify the glassy carbon electrode increase. 4 refs., 1 fig.

  15. Influence of solvents on species crossover and capacity decay in non-aqueous vanadium redox flow batteries: Characterization of acetonitrile and 1, 3 dioxolane solvent mixture

    Science.gov (United States)

    Bamgbopa, Musbaudeen O.; Almheiri, Saif

    2017-02-01

    The importance of the choice of solvent in a non-aqueous redox flow battery (NARFB) cannot be overemphasized. Several studies demonstrated the influence of the solvent on electrolyte performance in terms of reaction rates, energy/power densities, and efficiencies. In this work, we investigate capacity decay as a direct consequence of varying reactant crossover rates through membranes in different solvent environments. Specifically, we demonstrate the superiority of an 84/16 vol% acetonitrile/1,3 dioxolane solvent mixture over pure acetonitrile in terms of energy efficiency (up to 89%) and capacity retention for vanadium NARFBs - while incorporating a Nafion 115 membrane. The permeability of Nafion to the vanadium acetylacetonate active species is an order of magnitude lower when pure acetonitrile is replaced by the solvent mixture. A method to estimate relative membrane permeability is formulated from numerical analysis of self-discharge experimental data. Furthermore, tests on a modified Nafion/SiO2 membrane, which generally offered low species permeability, also show that different solvents alter membrane permeability. Elemental and morphological analyses of cycled Nafion and NafionSi membranes in different solvent environments indicate that different crossover rates induced by the choice of solvent during cycling are due to changes in the membrane microstructure, intrinsic permeability, swelling rates, and chemical stability.

  16. A new acetonitrile-free mobile phase method for LC-ELSD quantification of fructooligosaccharides in onion (Allium cepa L.).

    Science.gov (United States)

    Downes, Katherine; Terry, Leon A

    2010-06-30

    Onion soluble non-structural carbohydrates consist of fructose, glucose and sucrose plus fructooligosaccharides (FOS) with degrees of polymerisation (DP) in the range of 3-19. In onion, sugars and FOS are typically separated using liquid chromatography (LC) with acetonitrile (ACN) as a mobile phase. In recent times, however, the production of ACN has diminished due, in part, to the current worldwide economic recession. A study was therefore undertaken, to find an alternative LC method to quantify sugars and FOS from onion without the need for ACN. Two mobile phases were compared; the first taken from a paper by Vågen and Slimestad (2008) using ACN mobile phase, the second, a newly reported method using ethanol (EtOH). The EtOH mobile phase eluted similar concentrations of all FOS compared to the ACN mobile phase. In addition, limit of detection, limit of quantification and relative standard deviation values were sufficiently and consistently lower for all FOS using the EtOH mobile phase. The drawback of the EtOH mobile phase was mainly the inability to separate all individual sugar peaks, yet FOS could be successfully separated. However, using the same onion extract, a previously established LC method based on an isocratic water mobile phase could be used in a second run to separate sugars. Although the ACN mobile phase method is more convenient, in the current economic climate a method based on inexpensive and plentiful ethanol is a valid alternative and could potentially be applied to other fresh produce types. In addition to the mobile phase solvent, the effect of extraction solvents on sugar and FOS concentration was also investigated. EtOH is still widely used to extract sugars from onion although previous literature has concluded that MeOH is a superior solvent. For this reason, an EtOH-based extraction method was compared with a MeOH-based method to extract both sugars and FOS. The MeOH-based extraction method was more efficacious at extracting sugars and

  17. Crystal structure of di-μ-chlorido-bis[chloridobis(1,2-dimethyl-5-nitro-1H-imidazole-κN3copper(II] acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Patrick J. Quinlivan

    2016-11-01

    Full Text Available 1,2-Dimethyl-5-nitroimidazole (dimetridazole, dimet is a compound that belongs to a class of nitroimidazole drugs that are effective at inhibiting the activity of certain parasites and bacteria. However, there are few reports that describe structures of compounds that feature metals complexed by dimet. Therefore, we report here that dimet reacts with CuCl2·H2O to yield a chloride-bridged copper(II dimer, [Cu2Cl4(C5H7N3O24] or [Cu(μ-ClCl(dimet2]2. In this molecule, the CuII ions are coordinated in an approximately trigonal–bipyramidal manner, and the molecule lies across an inversion center. The dihedral angle between the imidazole rings in the asymmetric unit is 4.28 (7°. Compared to metronidazole, dimetridazole lacks the hydroxyethyl group, and thus cannot form intermolecular O...H hydrogen-bonding interactions. Instead, [Cu(μ-ClCl(dimet2]2 exhibits weak intermolecular interactions between the hydrogen atoms of C—H groups and (i oxygen in the nitro groups, and (ii the terminal and bridging chloride ligands. The unit cell contains four disordered acetonitrile molecules. These were modeled as providing a diffuse contribution to the overall scattering by SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18], which identified two voids, each with a volume of 163 Å3 and a count of 46 electrons, indicative of a total of four acetonitrile molecules. These acetonitrile molecules are included in the chemical formula to give the expected calculated density and F(000.

  18. Study on complex formation of dicyclohexyl-18-crown-6 with Mg2+, Ca2+ and Sr2+ in acetonitrile-water binary mixtures by conductometry

    OpenAIRE

    Mallika Sanyal

    2017-01-01

    The complexation reactions between Mg2+, Ca2+ and Sr2+ cations and dicyclohexyl-18-crown-6 (DCH 18C6) have been studied in acetonitrile–water binary mixtures at different temperatures by conductometry. The formation constants of the resulting 1:1 (M:L) complexes for all the three cations were determined from computer fitting of the molar conductance versus mole ratio data. The results show that the selectivity order of DCH 18C6 for the metal cations in the acetonitrile-water binary solvent at...

  19. Thermal Thiocyanate Ligand Substitution Kinetics of the Solar Cell Dye N719 by Acetonitrile, 3-Methoxypropionitrile, and 4-tert-Butylpyridine

    DEFF Research Database (Denmark)

    Nguyen, Thai Hoang; Minh, Ha; Lund, Torben

    2007-01-01

    the same products as occur in the homogenous solutions; however, the reactions are approximately 10 times faster. For the reaction of a colloidal mixture of N719-dyed TiO2 particles in acetonitrile containing 0.5 M 4-TBP, a t1/2(het) of 120 h was calculated at 85°C. The N719-based DSSC cells...... by a factor of 2-10; it thus may be used as an additive to prevent the thermal degradation of thiocyanate-based ruthenium complexes in DSSC solar cells....

  20. DNA effects upon the reaction between acetonitrile pentacyanoferrate (II) and ruthenium pentammine pyrazine: Kinetic and thermodynamic evidence of the interaction of DNA with anionic species

    International Nuclear Information System (INIS)

    Grueso, E.; Prado-Gotor, R.; Lopez, M.; Gomez-Herrera, C.; Sanchez, F.

    2005-01-01

    The kinetics of the reaction between ruthenium pentaammine pyrazine and acetonitrile pentacyanoferrate (II) to obtain the binuclear anionic complex [Fe(CN) 5 pzRu(NH 3 ) 5 ] - , and the reverse (dissociation) process, have been studied in solutions containing DNA. The results corresponding to this reaction and those corresponding to the reverse (dissociation) process show a clear influence of DNA on their kinetics. The results can be interpreted using a modified Pseudophase Model. From the results obtained for the dissociation reaction one can conclude that the binuclear anionic complex [Fe(CN) 5 pzRu(NH 3 ) 5 ] - interacts with DNA

  1. Serendipitous preparation of fac-(acetonitrile-κNtrichlorido[(1,2,5,6-η-cycloocta-1,5-diene]iridium(III

    Directory of Open Access Journals (Sweden)

    David M. Morris

    2015-04-01

    Full Text Available A reaction between [(CODIrCl]2 (COD is cycloocta-1,5-diene, HCl and indene failed to provide the hoped for chloridoindenyliridium dimer, but instead produced the title compound, [IrCl3(CH3CN(C8H12], which is an octahedral complex of iridium(III with a chelating cycloocta-1,5-diene ligand, three chloride ligands in a fac arrangement, and one acetonitrile ligand. Attempts to devise a rational synthesis for the title compound were unsuccessful.

  2. Study of Belousov—Zhabotinsky oscillators in water—acetonitrile medium employing EMF and EPR techniques with o-vanillin, p-vanillin and adrenaline as substrates

    Science.gov (United States)

    Lalitha, P. V.; Ramaswamy, R.; Ramakrishnan, Geetha; Rao, P. Sambasiva

    1994-12-01

    The oscillatory behaviour of three substrates, ortho-vanillin, para-vanillin and adrenaline, in mixed media (water plus 20% acetonitrile) has been investigated using EPR and EMF techniques. All these substrates exhibit two types of oscillation involving Br 2/Br - and Mn(III)/Mn(II) redox couples. From the oscillatory characteristics (total time, number of oscillations and time per oscillation) obtained by employing these techniques, the reactivities of the vanillins have been correlated. The Field—Koros—Noyes mechanism, suggested for catalysed systems in pure aqueous medium, is established to be applicable even in mixed media.

  3. Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

    2015-09-01

    In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Structure and dynamics of propylammonium nitrate-acetonitrile mixtures: An intricate multi-scale system probed with experimental and theoretical techniques

    Science.gov (United States)

    Campetella, Marco; Mariani, Alessandro; Sadun, Claudia; Wu, Boning; Castner, Edward W.; Gontrani, Lorenzo

    2018-04-01

    In this article, we report the study of structural and dynamical properties for a series of acetonitrile/propylammonium nitrate mixtures as a function of their composition. These systems display an unusual increase in intensity in their X-ray diffraction patterns in the low-q regime, and their 1H-NMR diffusion-ordered NMR spectroscopy (DOSY) spectra display unusual diffusivities. However, the magnitude of both phenomena for mixtures of propylammonium nitrate is smaller than those observed for ethylammonium nitrate mixtures with the same cosolvent, suggesting that the cation alkyl tail plays an important role in these observations. The experimental X-ray scattering data are compared with the results of molecular dynamics simulations, including both ab initio studies used to interpret short-range interactions and classical simulations to describe longer range interactions. The higher level calculations highlight the presence of a strong hydrogen bond network within the ionic liquid, only slightly perturbed even at high acetonitrile concentration. These strong interactions lead to the symmetry breaking of the NO3 - vibrations, with a splitting of about 88 cm-1 in the ν3 antisymmetric stretch. The classical force field simulations use a greater number of ion pairs, but are not capable of fully describing the longest range interactions, although they do successfully account for the observed concentration trend, and the analysis of the models confirms the nano-inhomogeneity of these kinds of samples.

  5. Structure and dynamics of propylammonium nitrate-acetonitrile mixtures: An intricate multi-scale system probed with experimental and theoretical techniques.

    Science.gov (United States)

    Campetella, Marco; Mariani, Alessandro; Sadun, Claudia; Wu, Boning; Castner, Edward W; Gontrani, Lorenzo

    2018-04-07

    In this article, we report the study of structural and dynamical properties for a series of acetonitrile/propylammonium nitrate mixtures as a function of their composition. These systems display an unusual increase in intensity in their X-ray diffraction patterns in the low-q regime, and their 1 H-NMR diffusion-ordered NMR spectroscopy (DOSY) spectra display unusual diffusivities. However, the magnitude of both phenomena for mixtures of propylammonium nitrate is smaller than those observed for ethylammonium nitrate mixtures with the same cosolvent, suggesting that the cation alkyl tail plays an important role in these observations. The experimental X-ray scattering data are compared with the results of molecular dynamics simulations, including both ab initio studies used to interpret short-range interactions and classical simulations to describe longer range interactions. The higher level calculations highlight the presence of a strong hydrogen bond network within the ionic liquid, only slightly perturbed even at high acetonitrile concentration. These strong interactions lead to the symmetry breaking of the NO 3 - vibrations, with a splitting of about 88 cm -1 in the ν 3 antisymmetric stretch. The classical force field simulations use a greater number of ion pairs, but are not capable of fully describing the longest range interactions, although they do successfully account for the observed concentration trend, and the analysis of the models confirms the nano-inhomogeneity of these kinds of samples.

  6. μ-Hexa-thio-metadiphosphato-bis-[(1,4,7,10,13,16-hexa-oxa-cyclo-octa-decane-κ(6) O)rubidium] aceto-nitrile disolvate.

    Science.gov (United States)

    Gjikaj, Mimoza; Pook, Niels-Patrick; Qarri, Flora

    2013-12-01

    The asymmetric unit of the title compound, [Rb2(P2S6)(C12H24O6)2]·2CH3CN, contains one half of an [Rb(18-crown-6)2]2[P2S6] unit and one aceto-nitrile solvent mol-ecule. The [Rb(18-crown-6)]2[P2S6] unit is completed by inversion symmetry. Its Rb(+) ion is situated near the centre of the macrocyclic cavity, but is displaced by 0.8972 (1) Å from the O atoms of the crown in the direction of the [P2S6](2-) moiety. The overall coordination number of the cation is eight, defined by the six crown ether O atoms and by two terminal S atoms of the [P2S6](2-) anion. The hexa-thio-metadiphosphate anion is built up from two tetra-hedral PS4 units joined together by a common edge. The crystal structure is characterized by alternating layers of [Rb(18-crown-6)]2[P2S6] and aceto-nitrile solvent mol-ecules stacked along [010].

  7. Mechanism of [m+h]+ formation in atmospheric pressure photoionization mass spectrometry: identification of propionitrile in acetonitrile with high mass accuracy measurement and tandem mass spectrometry and evidence for its involvement in the protonation phenomenon.

    Science.gov (United States)

    Kamel, Amin; Jeanville, Patrick; Colizza, Kevin; J-Rivera, Lauren Elizabeth

    2008-11-01

    The role of propionitrile in the production of [M+H]+ under atmospheric pressure photoionization (APPI) was investigated. In dopant-assisted APPI using acetone and anisole, protonated acetone and anisole radical cations were the most prominent ions observed. In dopant-free or direct APPI in acetonitrile, however, a major ion in acetonitrile was detected and identified as propionitrile, using high accuracy mass measurement and collision induced dissociation studies. Vaporizing ca. 10(-5) M althiazide and bendroflumethazide under direct APPI in acetonitrile produced their corresponding protonated species [M+H]+. In addition to protonated acetonitrile, its dimers, and acetonitrile/water clusters, protonated propionitrile, propionitrile dimer, and propionitrile/water clusters were also observed. The role of propionitrile, an impurity in acetonitrile and/or a possible product of ion-molecule reaction, in the production of [M+H]+ of althiazide and bendroflumethazide was further investigated in the absence of dopant using propionitrile-d5. The formation of [M+D]+ species was observed, suggesting a possible role of propionitrile in the protonation process. Additionally, an increase in the [M+H]+ signal of althiazide and bendroflumethazide was observed as a function of propionitrile concentration in acetonitrile. Theoretical data from the literature supported the assumption that one possible mechanism, among others, for the formation of [M+H]+ could be attributed to photo-initiated isomerization of propionitrile. The most stable isomers of propionitrile, based on their calculated ionization energy (IE) and relative energy (DeltaE), were assumed to undergo proton transfer to the analytes, and mechanisms were proposed.

  8. The use of acetonitrile as the sole nitrogen and carbon source by Geotrichum sp. JR1 Uso de acetonitrila como única fonte de carbono e nitrogênio por Geotrichum sp. JR1

    Directory of Open Access Journals (Sweden)

    Rachel Passos Rezende

    2004-06-01

    Full Text Available A yeast strain identified as Geotrichum sp. JR1 was able to use acetonitrile as the sole carbon and nitrogen source. The strain grew in 0.5 to 2M acetonitrile. Ammonia generation as enzymatic product during the strain growth indicates the presence of an acetonitrile degrading enzyme. Acetic acid and acetamide were detected during assays with the resting cells cultivated in acetonitrile, indicating the presence of nitrile and amide degrading enzymes. This paper is the first to describe the use of acetonitrile as the sole carbon and nitrogen source by a yeast.Uma linhagem de levedura identificada como Geotrichum sp. JR1 foi capaz de utilizar acetonitrila, em concentrações de 0,5 a 2M, como única fonte de carbono e de nitrogênio. A geração de amônia durante o crescimento do microrganismo indica a presença de sistema enzimático capaz de degradar acetonitrila. Durante os ensaios enzimáticos, com células cultivadas em acetonitrila, foram detectados ácido acético e acetamida como produtos indicando a presença de sistema enzimático capaz de degradar acetonitrila e acetamida. Este trabalho é o primeiro a descrever a utilização de acetonitrila como única fonte de carbono e de nitrogênio por uma levedura.

  9. Artificial neural network modelling of retention of pesticides in various octadecylsiloxane-bonded reversed-phase columns and water-acetonitrile mobile phase

    International Nuclear Information System (INIS)

    D'Archivio, Angelo Antonio; Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio

    2009-01-01

    Previously, retention of 26 pesticides in the reversed-phase column Gemini (Phenomenex) and water-acetonitrile mobile phase was modelled using a feed-forward artificial neural network (ANN) learned by error back-propagation, accounting for both the effect of solute structure and mobile phase composition. To this end, log K ow of solutes and four quantum chemical molecular descriptors (the dipole moment, the mean polarizability, the anisotropy of the polarizability and an hydrogen-bonding descriptor based on the atomic charges located on the acid and basic functional groups) and acetonitrile % (v/v) in the eluent (%ACN) were used as ANN inputs. The above ANN-based approach is here tested on further five similar octadecylsiloxane-bonded columns in water-acetonitrile mobile phase within the %ACN range 30-70%. A quite good predictive performance evaluated on three external solutes in the whole %ACN range is observed, prediction errors being lower than ±0.1 log k units or slightly higher although still within ±0.15 log k units. On the other hand, multilinear regression used in place of ANN provides a more diffuse and non-uniform residual distribution for all the investigated columns. ANN multiple-column retention prediction is attempted by adding to the above variables a column descriptor defined as the average retention of calibration solutes extrapolated to 100% water. This more general model is built using 16 solutes and five 5-μm columns in calibration, while its predictive performance is tested on the remaining 10 compounds. Under these conditions, prediction errors are generally within ±0.2 log k units regardless of the kind of column. The possibility of cross-column prediction is evaluated by column leave-one-out cross-validation within the five 5-μm stationary phases and on a 4-μm external column. This analysis reveals that accuracy of retention prediction for unknown solutes in unknown columns is acceptable provided that the external column is not very

  10. Artificial neural network modelling of retention of pesticides in various octadecylsiloxane-bonded reversed-phase columns and water-acetonitrile mobile phase

    Energy Technology Data Exchange (ETDEWEB)

    D' Archivio, Angelo Antonio, E-mail: angeloantonio.darchivio@univaq.it [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)

    2009-07-30

    Previously, retention of 26 pesticides in the reversed-phase column Gemini (Phenomenex) and water-acetonitrile mobile phase was modelled using a feed-forward artificial neural network (ANN) learned by error back-propagation, accounting for both the effect of solute structure and mobile phase composition. To this end, log K{sub ow} of solutes and four quantum chemical molecular descriptors (the dipole moment, the mean polarizability, the anisotropy of the polarizability and an hydrogen-bonding descriptor based on the atomic charges located on the acid and basic functional groups) and acetonitrile % (v/v) in the eluent (%ACN) were used as ANN inputs. The above ANN-based approach is here tested on further five similar octadecylsiloxane-bonded columns in water-acetonitrile mobile phase within the %ACN range 30-70%. A quite good predictive performance evaluated on three external solutes in the whole %ACN range is observed, prediction errors being lower than {+-}0.1 log k units or slightly higher although still within {+-}0.15 log k units. On the other hand, multilinear regression used in place of ANN provides a more diffuse and non-uniform residual distribution for all the investigated columns. ANN multiple-column retention prediction is attempted by adding to the above variables a column descriptor defined as the average retention of calibration solutes extrapolated to 100% water. This more general model is built using 16 solutes and five 5-{mu}m columns in calibration, while its predictive performance is tested on the remaining 10 compounds. Under these conditions, prediction errors are generally within {+-}0.2 log k units regardless of the kind of column. The possibility of cross-column prediction is evaluated by column leave-one-out cross-validation within the five 5-{mu}m stationary phases and on a 4-{mu}m external column. This analysis reveals that accuracy of retention prediction for unknown solutes in unknown columns is acceptable provided that the external

  11. Facile electrochemical polymerization of 2-(thiophen-2-yl)furan and the enhanced capacitance properties of its polymer in acetonitrile electrolyte containing boron trifluoride diethyl etherate

    International Nuclear Information System (INIS)

    Mo, Daize; Zhou, Weiqiang; Ma, Xiumei; Xu, Jingkun

    2015-01-01

    Highlights: • The low-potential polymerization of 2-(thiophen-2-yl)furan into polymer (PTFu) was reported. • The electrochemical performance of PTFu was studied in three different electrolytes. • The specific capacitance of PTFu electrode reached 392.0 F g −1 at 5 A g −1 and had 67.0% retention after 500 cycles. • The addition of boron trifluoride diethyl etherate into acetonitrile electrolyte benefited to enhance the specific capacitance and stability of PTFu electrode. - ABSTRACT: In this study, a new simple hybrid poly(2-(thiophen-2-yl)furan) (PTFu) was easily electrodeposited by direct anodic oxidation of 2-(thiophen-2-yl)furan in acetonitrile solution containing 0.1 M lithium perchlorate (LiClO 4 ). The oxidation onset potential of 2-(thiophen-2-yl)furan monomer in this medium was measured to be 0.90 V, which was lower than those of thiophene (1.47 V) and furan (1.28 V). The structure and morphology of PTFu were characterized by Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal analysis. The electrochemical capacitance properties of PTFu electrode in three electrolytes were also investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscope techniques. The electrochemical results showed that the specific capacitance of PTFu electrode was enhanced to 392.0 F g −1 from 249.4 F g −1 at 5 A g −1 and the cycling stability was also enhanced to 67.0% retention from 25.5% retention after 500 cycles when the equivalent boron trifluoride diethyl etherate (BFEE) was added into the acetonitrile electrolyte. Furthermore, the PTFu electrode in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF 6 ) showed a lower specific capacitance value (209.4 F g −1 at 5 A g −1 ) and an improved stability (67.6% retention after 600 cycles). These results indicated that the conducting polymers based on furan should be a promising

  12. Ionic molar volumes in methanol mixtures with acetonitrile, N,N-dimethylformamide and propylene carbonate at T = 298.15 K

    International Nuclear Information System (INIS)

    Pietrzak, A.; Piekarski, H.

    2014-01-01

    Highlights: • Densities of electrolyte solutions in methanol mixtures were measured at T = 298.15 K. • Apparent molar volumes of sodium cation and iodide anion were determined. • TPTB as a calculation method was used. • Preferential solvation of ions by organic solvents was examined. - Abstract: The densities of dilute solutions of three electrolytes (NaI, NaBPh 4 and Ph 4 PI) in methanol mixtures with propylene carbonate (PC), N,N-dimethylformamide (DMF) and acetonitrile (AN) have been measured by Anton Paar 5000 densimeter at T = 298.15 K. Apparent molar volumes, V Φ have been determined at an electrolyte concentration of 0.06 mol · kg −1 over the entire mixed solvent composition range. Single ionic apparent molar volumes of transfer, Δ t V Φ (ion) were calculated using the tetraphenylphosphonium tetraphenylborate (TPTB) assumption. The results are discussed in terms of ionic preferential solvation

  13. Pyrazolone as a recognition site: Rhodamine 6G-based fluorescent probe for the selective recognition of Fe3+ in acetonitrile-aqueous solution.

    Science.gov (United States)

    Parihar, Sanjay; Boricha, Vinod P; Jadeja, R N

    2015-03-01

    Two novel Rhodamine-pyrazolone-based colorimetric off-on fluorescent chemosensors for Fe(3+) ions were designed and synthesized using pyrazolone as the recognition moiety and Rhodamine 6G as the signalling moiety. The photophysical properties and Fe(3+) -binding properties of sensors L(1) and L(2) in acetonitrile-aqueous solution were also investigated. Both sensors successfully exhibit a remarkably 'turn-on' response, toward Fe(3+) , which was attributed to 1: 2 complex formation between Fe(3+) and L(1) /L(2) . The fluorescent and colorimetric response to Fe(3+) can be detected by the naked eye, which provides a facile method for the visual detection of Fe(3+) . Copyright © 2014 John Wiley & Sons, Ltd.

  14. Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Maji, Siuli; Kumar, Satendra; Sankaran, Kannan [Indira Ghandi Centre for Atomic Research, Tamil Nadu (India). Materials Chemistry Div.

    2017-10-01

    Luminescence from UO{sub 2}{sup 2+} (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y{sup 3+}; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

  15. (Liquid + liquid) equilibrium in binary systems of isomeric C8 aliphatic monoethers with acetonitrile and its interpretation by the COSMO-SAC model

    International Nuclear Information System (INIS)

    Reda, Mateusz; Ruszczyński, Łukasz; Gliński, Marek; Hofman, Tadeusz

    2015-01-01

    The (liquid + liquid) solubility curves have been determined by a synthetic method for six binary mixtures of [acetonitrile + {heptyl methyl ether CH 3 O n C 7 H 15 , or ethyl hexyl ether C 2 H 5 O n C 6 H 13 , or pentyl propyl ether n C 3 H 7 O n C 5 H 11 , or isopentyl propyl ether n C 3 H 7 O i C 5 H 11 , or dibutyl ether n C 4 H 9 O n C 4 H 9 , or butyl isobutyl ether n C 4 H 9 O i C 4 H 9 }]. The possibility of the COSMO-SAC model to account for the thermodynamic differences between these systems has been tested and the discussion on the influence of screening charge of ethers on the system properties was undertaken

  16. Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

    International Nuclear Information System (INIS)

    Maji, Siuli; Kumar, Satendra; Sankaran, Kannan

    2017-01-01

    Luminescence from UO_2"2"+ (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y"3"+; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

  17. A potentiometric study of molecular heteroconjugation equilibria in (n-butylamine+acetic acid) systems in binary (acetonitrile +1,4-dioxane) solvent mixtures

    International Nuclear Information System (INIS)

    Czaja, Malgorzata; Makowski, Mariusz; Chmurzynski, Lech

    2006-01-01

    By using the potentiometric method the following quantities have been determined: acidity constants of molecular acid, K a (HA), of cationic acid, K a (BH + ), anionic and cationic homoconjugation constants, K AHA - and K BHB + , respectively, as well as molecular heteroconjugation constants, K AHB , in (n-butylamine+acetic acid) systems without proton transfer in binary (acetonitrile+1,4-dioxane), AN+D, solvent mixtures. The results of these measurements have shown that the magnitudes of the molecular heteroconjugation constants do not depend on the 1,4-dioxane content in the mixed solvent, i.e., on solvent polarity. It has also been found that in the (acid+base) systems without proton transfer, the manner of carrying out the titration (direct B+HA vs. reverse HA+B) does not affect the magnitudes of the molecular heteroconjugation constants

  18. A potentiometric study of molecular heteroconjugation equilibria in (n-butylamine+acetic acid) systems in binary (acetonitrile +1,4-dioxane) solvent mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Czaja, Malgorzata [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Makowski, Mariusz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chem.univ.gda.pl

    2006-05-15

    By using the potentiometric method the following quantities have been determined: acidity constants of molecular acid, K{sub a}(HA), of cationic acid, K{sub a}(BH{sup +}), anionic and cationic homoconjugation constants, K{sub AHA{sup -}} and K{sub BHB{sup +}}, respectively, as well as molecular heteroconjugation constants, K{sub AHB}, in (n-butylamine+acetic acid) systems without proton transfer in binary (acetonitrile+1,4-dioxane), AN+D, solvent mixtures. The results of these measurements have shown that the magnitudes of the molecular heteroconjugation constants do not depend on the 1,4-dioxane content in the mixed solvent, i.e., on solvent polarity. It has also been found that in the (acid+base) systems without proton transfer, the manner of carrying out the titration (direct B+HA vs. reverse HA+B) does not affect the magnitudes of the molecular heteroconjugation constants.

  19. Use of the sulfide mineral pyrite as electrochemical sensor in non-aqueous solutions: potentiometric titration of weak acids in acetonitrile, propionitrile and benzonitrile.

    Science.gov (United States)

    Mihajlović, Ljiljana; Nikolić-Mandić, Snezana; Vukanović, Branislav; Mihajlović, Randel

    2009-03-01

    Natural monocrystalline pyrite as a new indicator electrode for the potentiometric titration of weak acids in acetonitrile, propionitrile and benzonitrile was studied. The investigated electrode showed a linear dynamic response for p-toluenesulfonic acid concentrations in the range from 0.1 to 0.001 M, with a Nernstian slope of 74 mV per decade. Sodium methylate, potassium hydroxide and tetrabutylammonium hydroxide (TBAH) proved to be very suitable titrating agent for this titration. The response time was less than (11 s) and the lifetime of the electrode is long. The advantages of the electrode are log-term stability, fast response, and reproducibility, while the sensor is easy to prepare and of low cost.

  20. Polyethylene Glycols as Efficient Catalysts for the Oxidation of Xanthine Alkaloids by Ceric Ammonium Nitrate in Acetonitrile: A Kinetic and Mechanistic Approach

    Directory of Open Access Journals (Sweden)

    S. Shylaja

    2013-01-01

    Full Text Available Kinetics of oxidation of xanthine alkaloids, such as Xanthine (XAN, hypoxanthine (HXAN, caffeine (CAF, theophylline (TPL, and theobromine (TBR, have been studied with ceric ammonium nitrate (CAN using poly ethylene glycols (PEG as catalysts. Reaction obeyed first order kinetics in both [CAN] and [Xanthine alkaloid]. Highly sluggish CAN-xanthine alkaloid reactions (in acetonitrile media even at elevated temperatures are enhanced in presence PEGs (PEG-200, -300, -400, -600. An increase in [PEG] increased the rate of oxidation linearly. This observation coupled with a change in absorption of CAN in presence of PEG, [H–(OCH2–CH2n–O–NH4Ce(NO34(CH3CN] (PEG bound CAN species, is considered to be more reactive than CAN. The mechanism of oxidation in PEG media has been explained by Menger-Portnoy’s enzymatic model.

  1. N,N,N′,N′,N′′,N′′-Hexamethylguanidinium di-μ3-chlorido-tetra-μ2-chlorido-decachloridotetrabismuthate acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Ioannis Tiritiris

    2016-02-01

    Full Text Available The asymmetric unit of the solvated title compound, (C7H18N34[Bi4Cl16]·2CH3CN, comprises two cations, one half [Bi4Cl16]4− ion and one acetonitrile molecule. One N,N,N′,N′,N′′,N′′-hexamethylguanidinium ion shows orientational disorder and two sets of N- and C-atom positions were found, with an occupancy ratio of 0.941 (2:0.059 (2. The second cation is not disordered. The C—N bond lengths in the two guanidinium ions range from 1.334 (17 to 1.341 (17 Å, indicating double-bond character and pointing towards charge delocalization within the NCN planes. The four BiIII ions are coordinated by six chloride ions in distorted octahedral manner. Two [Bi2Cl8]2− dimers are fused together, forming a centrosymmetric tetranuclear [Bi4Cl16]4− cluster. The bond lengths of bismuth to the terminal chlorides [2.4982 (7–2.5509 (6 Å] are shorter than those of the double and triply bridging ones [2.7052 (6–3.0320 (6 Å]. The acetonitrile solvent molecule is disordered over two positions, with an occupancy ratio of 0.818 (4:0.182 (4 for the two orientations. The crystal structure is stabilized by a three-dimensional network of C—H...Cl hydrogen bonds.

  2. Complexing and analysis of cation selectivity of neutral phosphoryl-containing tripodaud of tris((0-diphenyl-phosphinoylmethyl)phenoxyethyl)amine to lithium sodium and potassium, in acetonitrile. Lithium selectivity and polymeclear compleses

    International Nuclear Information System (INIS)

    Baulin, V.E.; Solov'ev, V.P.; Strakhova, N.N.; Kazachenko, V.P.

    1996-01-01

    A new phosphoryl-containing tripodand-tris-[(0-diphenyl-phosphinoylmethyl)phenoxyethyl] amine-was synthesized. Constants of stability, enthalpy and entropy of reactions of tripodond complexing with lithium, sodium, potassium thiocyanates in acetonitrile at 298 k were determined. Investigation of complexing by the methods of calorimetry, 7 Li and 23 Na NMR, mass-spectrometry enabled to conclude that ligand formed polynuclear complexes with lithium thiocyanate of 2/1 and 3/1 composition along with 1/1 complex. High selectivity of podand to lithium cation in acetonitrile was conditioned by formation of polynuclear complexes. Refs. 29, figs. 3

  3. (Acetonitrile{2-[bis(pyridin-2-ylmethyl-κ2Namino-κN]-N-(2,6-dimethylphenylacetamide-κO}(perchlorato-κOzinc (acetonitrile{2-[bis(pyridin-2-ylmethyl-κ2Namino-κN]-N-(2,6-dimethylphenylacetamide-κO}zinc tris(perchlorate

    Directory of Open Access Journals (Sweden)

    Ove Alexander Høgmoen Åstrand

    2013-02-01

    Full Text Available In the title salt, [Zn(C22H24N4O(CH3CN][Zn(ClO4(C22H24N4O(CH3CN](ClO43, two differently coordinated zinc cations occur. In the first complex, the metal ion is coordinated by the N,N′,N′′,O-tetradentate acetamide ligand and an acetonitrile N atom, generating an approximate trigonal–bipyramidal coordination geometry, with the O atom in an equatorial site and the acetonitrile N atom in an axial site. In the second complex ion, a perchlorate ion is also bonded to the zinc ion, generating a distorted trans-ZnO2N4 octahedron. Of the uncoordinating perchlorate ions, one lies on a crystallographic twofold axis and one lies close to a twofold axis and has a site occupancy of 0.5. N—H...O and N—H...(O,O hydrogen bonds are observed in the crystal. Disordered solvent molecules occupy about 11% of the unit-cell volume; their contribution to the scattering was removed with the SQUEEZE routine of the PLATON program [Spek (2009. Acta Cryst. D65, 148–155.].

  4. Determination of polar pesticides with atmospheric pressure chemical ionisation mass spectrometry-mass spectrometry using methanol and/or acetonitrile for solid-phase desorption and gradient liquid chromatography.

    NARCIS (Netherlands)

    Geerdink, R.B.; Kooistra-Slijpersma, A.; Tiesnitsch, J.; Kienhuis, P.G.M.; Brinkman, U.A.T.

    1999-01-01

    Thirty-seven polar pesticides, mainly triazines, phenylurea herbicides and phenoxy acids, were determined by LC-atmospheric pressure chemical ionisation MS-MS with methanol and acetonitrile as the organic modifiers. For most pesticides, detection limits were the same irrespective of the modifier.

  5. Crystal structures of bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III complexes containing an acetonitrile or monodentate thyminate(1− ligand

    Directory of Open Access Journals (Sweden)

    Mika Sakate

    2016-04-01

    Full Text Available The crystal structures of bis[2-(pyridin-2-ylphenyl]rhodium(III complexes with the metal in an octahedral coordination containing chloride and acetonitrile ligands, namely (OC-6-42-acetonitrilechloridobis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [RhCl(C11H8N2(CH3CN] (1, thyminate(1− and methanol, namely (OC-6-42-methanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(CH3OH]·CH3OH·0.5H2O (2, and thyminate(1− and ethanol, namely (OC-6-42-ethanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(C2H5OH]·C2H5OH (3, are reported. The acetonitrile complex, 1, is isostructural with the IrIII analog. In complexes 2 and 3, the monodeprotonated thyminate (Hthym− ligand coordinates to the RhIII atom through the N atom, and the resulting Rh—N(Hthym bond lengths are relatively long [2.261 (2 and 2.252 (2 Å for 2 and 3, respectively] as compared to the Rh—N bonds in the related thyminate complexes. In each of the crystals of 2 and 3, the complexes are linked via a pair of intermolecular N—H...O hydrogen bonds between neighbouring Hthym− ligands, forming an inversion dimer. A strong intramolecular O—H...O hydrogen bond between the thyminate(1− and alcohol ligands in mutually cis positions to each other is also observed.

  6. Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

    Directory of Open Access Journals (Sweden)

    Gholam Hossein Rounaghi

    2011-09-01

    Full Text Available The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°c and DS°c for formation of (p-isopropyl-calix[6]arene·Cs+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.

  7. Conductance Studies on Complex Formation between c-Methylcalix[4]resorcinarene and Titanium (III in Acetonitrile-H2O Binary Solutions

    Directory of Open Access Journals (Sweden)

    Naghmeh Saadati

    2013-09-01

    Full Text Available Calixresorcinarenes have proved to be unique molecules for molecular recognition via hydrogen bonding, hydrophobic and ionic interactions with suitable substrates such as cations. The study of the interactions involved in the complexation of different cations with calixresorcinarenes in solvent mixtures is important for a better understanding of the mechanism of biological transport, molecular recognition, and other analytical applications. This article summarizes different aspects of the complexes of the Ti3+ metal cation with c-methylcalix[4]resorcinarene (CMCR as studied by conductometry in acetonitrile (AN–water (H2O binary mixtures at different temperatures. Conductance data show that the metal cation/ligand (ML stoichiometry of the complexes in solution is 1:1 in all cases. Non-linear behaviour was observed for the variation of logKf of the complexes vs. the composition of the binary solvent mixtures. Selectivity of CMCR for the Ti3+ cation is sensitive to solvent composition; in some cases and at certain compositions of the mixed solvent systems, the selectivity order is changed. Values of thermodynamic parameters (, for formation of the CMCR–Ti3+ complexes in AN–H2O binary systems were obtained from the temperature dependence of stability constants, and the results show that the thermodynamics of complexation reactions are affected by the nature and composition of the mixed solvents.

  8. Conjugated and fluorescent polymer based on dansyl-substituted pyrrole prepared by electrochemical polymerization in acetonitrile containing boron trifluoride diethyl etherate

    International Nuclear Information System (INIS)

    Almeida, Andresa K.A.; Dias, Jéssica M.M.; Silva, Ana Julia C.; Santos, Diego P.; Navarro, Marcelo; Tonholo, Josealdo; Goulart, Marília O.F.; Ribeiro, Adriana S.

    2014-01-01

    Graphical abstract: - Highlights: • A fluorescent pyrrole derivative bearing a dansyl substituent (PyPDG) was synthesized. • PyPDG was electropolymerized onto ITO in (C 4 H 9 ) 4 NBF 4 /CH 3 CN/BFEE mixed electrolyte. • The resulting polymer (PPyPDG) films displayed electrochromic behavior. • PPyPDG is a good green light emitter material. - Abstract: A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple synthetic route and electropolymerized onto Indium Tin Oxide (ITO) electrodes. The presence of the dansyl group in the monomer precursor prevents the electropolymerization in usual systems, such as (C 4 H 9 ) 4 NBF 4 in acetonitrile (CH 3 CN). For this reason, it was added 20% boron trifluoride diethyl etherate (BFEE) to this system, to achieve electropolymerization. The resulting poly[3-(N-pyrrolyl)propyl dansylglycinate] (PPyPDG) films displayed electrochromic behavior. Their color varied from greenish-yellow, in the neutral state, to greyish-green, in the oxidized state; moreover PPyPDG is a good green light emitter material. Therefore, PPyPDG films might be potentially applicable in displays and optoelectronic devices

  9. Densities and volumetric properties of (acetonitrile+an amide) binary mixtures at temperatures between 293.15K and 318.15K

    International Nuclear Information System (INIS)

    Nain, Anil Kumar

    2006-01-01

    The densities of binary mixtures of acetonitrile (ACN) with formamide (FA), N,N-dimethylformamide (DMF), N-methylacetamide (NMA), and N,N-dimethylacetamide (DMA), including those of pure liquids, over the entire composition range were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V m E , and partial molar volumes, V-bar m,1 and V-bar m,2 , were calculated over whole composition range. The variation of these parameters with composition and temperature of the mixtures has been discussed in terms of molecular interaction in these mixtures. The V m E values were found negative for all the mixtures and at each temperature studied, indicating the presence of specific interactions between ACN and amide molecules. The extent of negative deviations in V m E values follows the order: FA>NMA>DMA>DMF. It is observed that the V m E values depend upon the positions of methyl groups in these amide molecules

  10. Hydride, hydrogen, proton, and electron affinities of imines and their reaction intermediates in acetonitrile and construction of thermodynamic characteristic graphs (TCGs) of imines as a "molecule ID card".

    Science.gov (United States)

    Zhu, Xiao-Qing; Liu, Qiao-Yun; Chen, Qiang; Mei, Lian-Rui

    2010-02-05

    A series of 61 imines with various typical structures were synthesized, and the thermodynamic affinities (defined as enthalpy changes or redox potentials in this work) of the imines to abstract hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the imines to abstract hydrogen atoms and protons, and the thermodynamic affinities of the hydrogen adducts of the imines to abstract electrons in acetonitrile were determined by using titration calorimetry and electrochemical methods. The pure heterolytic and homolytic dissociation energies of the C=N pi-bond in the imines were estimated. The polarity of the C=N double bond in the imines was examined using a linear free-energy relationship. The idea of a thermodynamic characteristic graph (TCG) of imines as an efficient "Molecule ID Card" was introduced. The TCG can be used to quantitatively diagnose and predict the characteristic chemical properties of imines and their various reaction intermediates as well as the reduction mechanism of the imines. The information disclosed in this work could not only supply a gap of thermodynamics for the chemistry of imines but also strongly promote the fast development of the applications of imines.

  11. Rate theory of solvent exchange and kinetics of Li+ − BF4−/PF6− ion pairs in acetonitrile

    International Nuclear Information System (INIS)

    Dang, Liem X.; Chang, Tsun-Mei

    2016-01-01

    In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li + and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li + in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li + -[BF 4 ] and Li + -[PF 6 ] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li + . We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li + -[BF 4 ] and Li + -[PF 6 ] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

  12. Contributions to energy research. Beitraege zur Energieforschung; A: Energie und Gesellschaft, B: Mott-Schottky Plots von p-Silizium in Acetonitril

    Energy Technology Data Exchange (ETDEWEB)

    Zeyer, C J

    1993-01-01

    Part A of this thesis deals with the question whether solar energy research makes sense or not. Based on physical considerations, the state of solar energy technology and its future potential it is shown that it is impossible to realize the solar alternative with today's dynamic of energy consumption. Nevertheless in long terms, there is no alternative to solar energy, if we are taking into account the pollution problems by hydrocarbon and nuclear energy production. Therefore the factors that determine energy consumption have to be investigated. The analysis shows that energy consumption is not only determined by natural science but more than this by social aspects. In the author's opinion, the most important factors are: the structure of society (including aspects of organization and geographical structures of the economic system), the way how society deals with energy (including role of energy prize) and the ethic background of society and its connection to energy consumption. Focussed on environmental and energy problems, these aspects and its interconnections are discussed in 21 theses. Part B of this thesis describes an electrochemical method of characterization of semiconductors, the so-called Mott-Schottky plots and the results which have been obtained by this method with p-type silicon in acetonitrile. (author) figs., tabs., refs.

  13. Synthesis of Polypyrrole Inverse Opal in [bmim]PF6- Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2013-01-01

    Full Text Available Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered polypyrrole (PPy inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF6. PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF6- anions kept dedoping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF6- anions also kept dedoping from the PPy inverse opals, the PO43- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours.

  14. Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures

    International Nuclear Information System (INIS)

    Amiri, Ali Asghar; Hemmateenejad, Bahram; Safavi, Afsaneh; Sharghi, Hashem; Beni, Ali Reza Salimi; Shamsipur, Mojtaba

    2007-01-01

    The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter (π * ) and hydrogen-bond basicity (β), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents

  15. Effect of pendant group length upon metal ion complexation in acetonitrile by di-ionized calix[4]arenes bearing two dansyl fluorophores.

    Science.gov (United States)

    Ocak, Ummühan; Ocak, Miraç; Shen, Xin; Surowiec, Kazimierz; Bartsch, Richard A

    2009-11-01

    A series of three di-ionizable calix[4]arenes with two pendant dansyl (1-dimethylaminonaphthalene-5-sulfonyl) groups linked to the lower rims was synthesized. Structures of the three ligands were identical except for the length of the spacers which connected the two dansyl groups to the calix[4]arene scaffold. Following conversion of the ligands into their di-ionized di(tetramethylammonium) salts, absorption and emission spectrophotometry were utilized to probe the influence of metal cation (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Ag+, Cd2+, Co2+, Fe2+, Hg2+, Mn2+, Pb2+, Zn2+ and Fe3+) complexation in acetonitrile. Upon complexation with these metal cations, emission spectra underwent marked red shifts and quenching of the dansyl group fluorescence for the di-ionized ligand with the shortest spacer. A similar effect was noted for the di-ionized ligand with an intermediate spacer for all of the metal ions, except Ba2+. For the di-ionized ligand with the longest spacer, the metal cations showed different effects on the emission spectrum. Li+, Mg2+, Ca2+ and Ba2+ caused enhancement of emission intensity with a red shift. Other metal cations produce quenching with red shifts in the emission spectra. Transition metal cations interacted strongly with all three di-ionized ligands. In particular, Fe3+ and Hg2+ caused greater than 99% quenching of the dansyl fluorescence in the di-ionized ligands.

  16. Acetonitrile as a buffer additive for free zone capillary electrophoresis separation and characterization of maize (Zeamays L. ) and sorghum (Sorghum bicolor L. Moench) storage proteins.

    Science.gov (United States)

    Bean, S R; Lookhart, G L; Bietz, J A

    2000-02-01

    An improved method for separating and characterizing maize (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) storage proteins by free zone capillary electrophoresis (FZCE) was developed. Previous electrophoretic methods for analyzing these proteins required high concentrations of urea to maintain protein solubility during separation. To overcome disadvantages of urea, we developed a FZCE method that mimicked reversed-phase high-performance liquid chromatography (RP-HPLC) in that it used high levels of acetonitrile (ACN) at low pH. The optimized FZCE buffer system consisted of 80 mM phosphate-glycine buffer, nominal pH 2.5, containing 60% ACN and a cellulose derivative to dynamically coat capillary walls. Resolution was similar to or higher than that previously achieved by FZCE buffers utilizing 8 M urea as a buffer additive. ACN concentrations of at least 50% were necessary to achieve acceptable separations; this ACN concentration is approximately that necessary to extract these storage proteins. ACN was equally effective as traditional ethanol solvents and 8 M urea for solubilizing maize and sorghum proteins. The ACN-based FZCE buffer system gave high repeatability (buffers. This FZCE method may be applicable for the analysis of other hydrophobic proteins without the use of urea.

  17. Addition of 2-(ethylamino)acetonitrile group to nitroxoline results in significantly improved anti-tumor activity in vitro and in vivo.

    Science.gov (United States)

    Mitrović, Ana; Sosič, Izidor; Kos, Špela; Tratar, Urša Lampreht; Breznik, Barbara; Kranjc, Simona; Mirković, Bojana; Gobec, Stanislav; Lah, Tamara; Serša, Gregor; Kos, Janko

    2017-08-29

    Lysosomal cysteine peptidase cathepsin B, involved in multiple processes associated with tumor progression, is validated as a target for anti-cancer therapy. Nitroxoline, a known antimicrobial agent, is a potent and selective inhibitor of cathepsin B, hence reducing tumor progression in vitro and in vivo . In order to further improve its anti-cancer properties we developed a number of derivatives using structure-based chemical synthesis. Of these, the 7-aminomethylated derivative (compound 17 ) exhibited significantly improved kinetic properties over nitroxoline, inhibiting cathepsin B endopeptidase activity selectively. In the present study, we have evaluated its anti-cancer properties. It was more effective than nitroxoline in reducing tumor cell invasion and migration, as determined in vitro on two-dimensional cell models and tumor spheroids, under either endpoint or real time conditions. Moreover, it exhibited improved action over nitroxoline in impairing tumor growth in vivo in LPB mouse fibrosarcoma tumors in C57Bl/6 mice. Taken together, the addition of a 2-(ethylamino)acetonitrile group to nitroxoline at position 7 significantly improves its pharmacological characteristics and its potential for use as an anti-cancer drug.

  18. Thermodynamic Studies of (H2Rh(diphosphine)2)+ and (HRh(diphosphine)2(CH3CN))2+ Complexes in Acetonitrile

    International Nuclear Information System (INIS)

    Wilson, Aaron D.; Miller, Alexander J.M.; DuBois, Daniel L.; Labinger, Jay A.; Bercaw, John E.

    2011-01-01

    Thermodynamic studies of a series of (H2Rh(PP)2)+ and (HRh(PP)2(CH3CN))2+ complexes have been carried out in acetonitrile. Seven different diphosphine (PP) ligands were selected to allow variation of the electronic properties of the ligand substituents, the cone angles, and the natural bite angles (NBAs). Oxidative addition of H2 to (Rh(PP)2)+ complexes is favored by diphosphine ligands with large NBAs, small cone angles, and electron donating substituents, with the NBA being the dominant factor. Large pKa values for (HRh(PP)2(CH3CN))2+ complexes are favored by small ligand cone angles, small NBAs, and electron donating substituents with the cone angles playing a major role. The hydride donor abilities of (H2Rh(PP)2)+ complexes increase as the NBAs decrease, the cone angles decrease, and the electron donor abilities of the substituents increase. These results indicate that if solvent coordination is involved in hydride transfer or proton transfer reactions, the observed trends can be understood in terms of a combination of two different steric effects, NBAs and cone angles, and electron-donor effects of the ligand substituents.

  19. Efficacy of the amino-acetonitrile derivative, monepantel, against experimental and natural adult stage gastro-intestinal nematode infections in sheep.

    Science.gov (United States)

    Sager, Heinz; Hosking, Barry; Bapst, Béatrice; Stein, Philip; Vanhoff, Kathleen; Kaminsky, Ronald

    2009-01-22

    Multiple drug resistance by nematodes, against anthelmintics has become an important economic problem in sheep farming worldwide. Here we describe the efficacy of monepantel, a developmental molecule from the recently discovered anthelmintic class, the amino-acetonitrile derivatives (AADs). Efficacy was tested against adult stage gastro-intestinal nematodes (GINs) in experimentally and naturally infected sheep at a dose of 2.5mg/kg body weight when administered as an oral solution. Some of the isolates used in experimental infection studies were known to be resistant to the benzimidazoles or levamisole anthelmintics; strains resistant to the macrocyclic lactones were not available for these tests. Worm count-based efficacies of >98% were determined in these studies. As an exception, Oesophagostomum venulosum was only reduced by 88% in one study, albeit with a low worm burden in the untreated controls (geometric mean 15.4 worms). Similar efficacies for monepantel were also confirmed in naturally infected sheep. While the efficacy against most species was >99%, the least susceptible species was identified as Nematodirus spathiger, and although efficacy was 92.4% in one study it was generally >99%. Several animals were infected with Trichuris ovis, which was not eliminated after the treatment. Monepantel demonstrated high activity against a broad range of the important GINs of sheep, which makes this molecule an interesting candidate for use in this species, particularly in regions with problems of anthelmintic resistance. Monepantel was well tolerated by the treated sheep, with no treatment related adverse events documented.

  20. Critical evaluation of the stability of highly concentrated LiTFSI - Acetonitrile electrolytes vs. graphite, lithium metal and LiFePO4 electrodes

    Science.gov (United States)

    Nilsson, Viktor; Younesi, Reza; Brandell, Daniel; Edström, Kristina; Johansson, Patrik

    2018-04-01

    Highly concentrated LiTFSI - acetonitrile electrolytes have recently been shown to stabilize graphite electrodes in lithium-ion batteries (LIBs) much better than comparable more dilute systems. Here we revisit this system in order to optimise the salt concentration vs. both graphite and lithium metal electrodes with respect to electrochemical stability. However, we observe an instability regardless of concentration, making lithium metal unsuitable as a counter electrode, and this also affects evaluation of e.g. graphite electrodes. While the highly concentrated electrolytes have much improved electrochemical stabilities, their reductive decomposition below ca. 1.2 V vs. Li+/Li° still makes them less practical vs. graphite electrodes, and the oxidative reaction with Al at ca. 4.1 V vs. Li+/Li° makes them problematic for high voltage LIB cells. The former originates in an insufficiently stable solid electrolyte interphase (SEI) dissolving and continuously reforming - causing self-discharge, as observed by paused galvanostatic cycling, while the latter is likely caused by aluminium current collector corrosion. Yet, we show that medium voltage LiFePO4 positive electrodes can successfully be used as counter and reference electrodes.

  1. Quantification of volatile organic compounds in exhaled human breath. Acetonitrile as biomarker for passive smoking. Model for isoprene in human breath

    International Nuclear Information System (INIS)

    Prazeller, P.

    2000-03-01

    The topic of this thesis is the quantification of volatile organic compounds in human breath under various circumstances. The composition of exhaled breath reflects metabolic processes in the human body. Breath analysis is a non invasive technique which makes it most interesting especially for medical or toxicological applications. Measurements were done with Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS). This technique combines the advantage of small fragmentation of chemical ionization with highly time resolved mass spectrometry. A big part of this work is about investigations of exposition due to tobacco smoke. After smoking cigarettes the initial increase and time dependence of some compounds in the human breath are monitored . The calculated decrease resulting only from breathing out the compounds is presented and compared to the measured decline in the breath. This allows the distinction whether breathing is the dominant loss of a compound or a different metabolic process remover it more efficiently. Acetonitrile measured in human breath is presented as a biomarker for exposition to tobacco smoke. Especially its use for quantification of passive smoking, the exposition to environmental tobacco smoke (ETS) is shown. The reached accuracy and the fast way of measuring of acetonitrile in human breath using PTR-MS offer a good alternative to common used biomarkers. Numerous publications have described measurements of breath isoprene in humans, and there has been a hope that breath isoprene analyses could be a non-invasive diagnostic tool to assess serum cholesterol levels or cholesterol synthesis rate. However, significant analytical problems in breath isoprene analysis and variability in isoprene levels with age, exercise, diet, etc. have limited the usefulness of these measurements. Here, we have applied proton-transfer-reaction mass spectrometry (PTR-MS) to this problem, allowing on-line detection of breath isoprene. We show that breath isoprene

  2. The mixed-valent copper thiolate complex hexakis{μ3-2-[(1,3-dimethylimidazolideneamino]benzenethiolato}dicopper(IItetracopper(I bis(hexafluoridophosphate acetonitrile disolvate dichloromethane disolvate

    Directory of Open Access Journals (Sweden)

    Adam Neuba

    2013-01-01

    Full Text Available The molecular structure of the title compound, [Cu4ICu2II(C11H14N3S6](PF62·2CH3CN·2CH2Cl2, shows a mixed-valent copper(I/II thiolate complex with a distorted tetrahedral coordination of the CuI and CuII cations by one guanidine N atom and three S atoms each. Characteristic features of the Cu6S6 skeleton are a total of six chemically identical μ3-thiolate bridges and almost planar Cu2S2 units with a maximum deviation of 0.110 (1 Å from the best plane. Each Cu2S2 unit then shares common Cu–S edges with a neighbouring unit; the enclosed dihedral angle is 60.14 (2°. The geometric centre of the Cu6S6 cation lies on a crystallographic inversion centre. Cu—S bond lengths range from 2.294 (1 to 2.457 (1 Å, Cu—N bond lengths from 2.005 (3 to 2.018 (3 Å and the non-bonding Cu...Cu distances from 2.5743 (7 to 2.5892 (6 Å. C—H...F hydrogen-bond interactions occur between the PF6− anion and the complex molecule and between the PF6− anion and the acetonitrile solvent molecule.

  3. Terahertz Frequency-Domain Spectroscopy of Low-Pressure Acetonitrile Gas by a Photomixing Terahertz Synthesizer Referenced to Dual Optical Frequency Combs

    Science.gov (United States)

    Hsieh, Yi-Da; Kimura, Hiroto; Hayashi, Kenta; Minamikawa, Takeo; Mizutani, Yasuhiro; Yamamoto, Hirotsugu; Iwata, Tetsuo; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Yasui, Takeshi

    2016-09-01

    A terahertz (THz) frequency synthesizer based on photomixing of two near-infrared lasers with a sub-THz to THz frequency offset is a powerful tool for spectroscopy of polar gas molecules due to its broad spectral coverage; however, its frequency accuracy and resolution are relatively low. To tune the output frequency continuously and widely while maintaining its traceability to a frequency standard, we developed a photomixing THz synthesizer phase-locked to dual optical frequency combs (OFCs). While the phase-locking to dual OFCs ensured continuous tuning within a spectral range of 120 GHz, in addition to the traceability to the frequency standard, use of a broadband uni-traveling carrier photodiode for photomixing enabled the generation of CW-THz radiation within a frequency range from 0.2 to 1.5 THz. We demonstrated THz frequency-domain spectroscopy of gas-phase acetonitrile CH3CN and its isotope CH3 13CN in the frequency range of 0.600-0.720 THz using this THz synthesizer. Their rotational transitions were assigned with a frequency accuracy of 8.42 × 10-8 and a frequency resolution of 520 kHz. Furthermore, the concentration of the CH3CN gas at 20 Pa was determined to be (5.41 ± 0.05) × 1014 molecules/cm3 by curve fitting analysis of the measured absorbance spectrum, and the mixture ratio of the mixed CH3CN/CH3 13CN gas was determined to be 1:2.26 with a gas concentration of 1014-1015 molecules/cm3. The developed THz synthesizer is highly promising for high-precision THz-FDS of low-pressure molecular gases and will enable the qualitative and quantitative analyses of multiple gases.

  4. Tris(1,10-phenanthroline-κ2N,N′iron(II bis[(1,10-phenanthroline-κ2N,N′tetrakis(thiocyanato-κNchromate(III] acetonitrile trisolvate monohydrate

    Directory of Open Access Journals (Sweden)

    Volodymyr V. Bon

    2012-05-01

    Full Text Available Single crystals of the title heterometallic compound, [Fe(C12H8N23][Cr(NCS4(C12H8N2]2·3CH3CN·H2O or [Fe(Cphen3][Cr(NCS4(phen]2·3CH3CN·H2O, were prepared using the one-pot open-air reaction of iron powder, Reineckes salt and 1,10-phenanthroline (phen in acetonitrile. The asymetric unit consists of an [Fe(phen3]2+ cation, two [Cr(phen(NCS4]− anions, three acetonitrile solvent molecules and a water molecule. The Fe and Cr atoms both show a slightly distorted octahedral FeN6 and CrN6 coordination geometry with adjacent angles in the range 79.67 (12–95.21 (12°. No classical hydrogen bonding involving the water molecule is observed.

  5. Experimental study and ERAS modeling of the excess molar enthalpy of (acetonitrile + 1-heptanol or 1-octanol) mixtures at (298.15, 313.15, and 323.15) K and atmospheric pressure

    International Nuclear Information System (INIS)

    Figueiredo Checoni, Ricardo; D'Agostini, Luciane; Zaghini Francesconi, Artur

    2008-01-01

    As a continuation of our studies on excess functions of binary systems, experimental data of excess molar enthalpy (H m E ) of (acetonitrile + 1-heptanol or 1-octanol) mixtures have been determined as a function of composition at (298.15, 313.15, and 323.15) K at atmospheric pressure using a modified 1455 PARR mixture calorimeter. The H m E is positive for both systems over the whole composition range. The applicability of the ERAS-Model to correlate H m E of the mixtures studied was tested. The agreement between experimental and calculated values is satisfactory

  6. Crystal structure of trichlorido(4′-ferrocenyl-2,2′:6′,2′′-terpyridine-κ3N,N′,N′′iridium(III acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Bambar Davaasuren

    2015-03-01

    Full Text Available In the title compound, [FeIr(C5H5(C20H14N3Cl3]·2CH3CN, the central IrIII atom is sixfold coordinated by three chloride ligands and three terpyridine N atoms in a slightly distorted octahedral fashion. The terpyridine ligand is functionalized at the 4′-position with a ferrocenyl group, the latter being in an eclipsed conformation. In the crystal, molecules are stacked in rows parallel to [001], with the acetonitrile solvent molecules situated between the rows. An extensive network of intra- and intermolecular C—H...Cl interactions is present, stabilizing the three-dimensional structure.

  7. Quantification of volatile organic compounds in exhaled human breath. Acetonitrile as biomarker for passive smoking. Model for isoprene in human breath; Quantifizierung organischer Spurenkomponenten in der menschlichen Atemluft. Acetonitril als Biomarker fuer Passivrauchen. Modell fuer Isopren im Atem, Zusammenhang Isoprenkonzentration, Cholesterinsynthese, lebensmittelchemische Untersuchungen an Knoblauch und Zwiebel

    Energy Technology Data Exchange (ETDEWEB)

    Prazeller, P

    2000-03-01

    The topic of this thesis is the quantification of volatile organic compounds in human breath under various circumstances. The composition of exhaled breath reflects metabolic processes in the human body. Breath analysis is a non invasive technique which makes it most interesting especially for medical or toxicological applications. Measurements were done with Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS). This technique combines the advantage of small fragmentation of chemical ionization with highly time resolved mass spectrometry. A big part of this work is about investigations of exposition due to tobacco smoke. After smoking cigarettes the initial increase and time dependence of some compounds in the human breath are monitored . The calculated decrease resulting only from breathing out the compounds is presented and compared to the measured decline in the breath. This allows the distinction whether breathing is the dominant loss of a compound or a different metabolic process remover it more efficiently. Acetonitrile measured in human breath is presented as a biomarker for exposition to tobacco smoke. Especially its use for quantification of passive smoking, the exposition to environmental tobacco smoke (ETS) is shown. The reached accuracy and the fast way of measuring of acetonitrile in human breath using PTR-MS offer a good alternative to common used biomarkers. Numerous publications have described measurements of breath isoprene in humans, and there has been a hope that breath isoprene analyses could be a non-invasive diagnostic tool to assess serum cholesterol levels or cholesterol synthesis rate. However, significant analytical problems in breath isoprene analysis and variability in isoprene levels with age, exercise, diet, etc. have limited the usefulness of these measurements. Here, we have applied proton-transfer-reaction mass spectrometry (PTR-MS) to this problem, allowing on-line detection of breath isoprene. We show that breath isoprene

  8. Aqua(μ-cone-26,28-dibutoxy-25,27-bis{N-[5-(dimethylaminonaphthalene-1-sulfonyl]carbamoylmethoxy}-5,11,17,23-tetrakis(1,1-dimethylethylcalix[4]arene(2−disodium acetonitrile tetrasolvate

    Directory of Open Access Journals (Sweden)

    Pogisego Dinake

    2012-04-01

    Full Text Available The structure of the title complex, [Na2(C80H98N4O10S2(H2O]·4CH3CN, obtained after crystallization from acetonitrile, contains two formula units in the asymmetric unit (Z′ = 2 and an estimated four molecules of acetonitrile per calixarene moiety. It is unusual for two Na+ ions to occupy the lower rims of the cone calix[4]arene, as in this case, with one Na+ ion forming two O→ Na+ coordinate bonds with the two butoxy groups and four such bonds with the two N-dansyl carboxamide groups, forming six dative bonds between Na+ and O. On the other hand, the other Na+ ion forms only five O→Na+ coordinate bonds on the far end of the calix[4]arene lower rim, bringing the two dansyl groups in close proximity with each other. There also appears to be an O→Na+ coordination coming from a dangling water molecule. The structure contained both resolved and poorly resolved solvent molecules. The latter were treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  9. Water as a solute in aprotic dipolar solvents. 2. D2O-H2O solute isotope effects on the enthalpy of water dissolution in nitromethane, acetonitrile and propylene carbonate at 298.15 K

    International Nuclear Information System (INIS)

    Ivanov, Evgeniy V.; Smirnov, Valeriy I.

    2010-01-01

    The enthalpies of solution of ordinary (H 2 O) and heavy (D 2 O) water in nitromethane (NM), acetonitrile (ACN) and propylene carbonate (PC) were measured calorimetrically at 298.15 K. Standard (at the infinite dilution) enthalpies of solution and solvation, along with D 2 O-H 2 O solute isotope effects on the quantities in question, were calculated. The enthalpies of solution of water H/D isotopologues were found to be positive by sign and substantially increasing in magnitude on going from ACN and PC to NM, whereas the corresponding positive solute H/D isotope effect changes in a consequence: NM > ACN > PC. The qualitative interrelations between the enthalpy-isotopic effect of dissolution (solvation) of water and the electron-accepting/donating ability of aprotic dipolar solvent (within a series considered) were found.

  10. Structure, solvation, and dynamics of Mg{sup 2+}, Ca{sup 2+}, Sr{sup 2+}, and Ba{sup 2+} complexes with 3-hydroxyflavone and perchlorate anion in acetonitrile medium: A molecular dynamics simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Agieienko, Vira N.; Kolesnik, Yaroslav V.; Kalugin, Oleg N., E-mail: onkalugin@gmail.com [Department of Inorganic Chemistry, V. N. Karazin Kharkiv National University, Kharkiv 61022 (Ukraine)

    2014-05-21

    Molecular dynamics simulations of complexes of Mg{sup 2+}, Ca{sup 2+}, Sr{sup 2+}, and Ba{sup 2+} with 3-hydroxyflavone (flavonol, 3HF) and ClO {sub 4}{sup −} in acetonitrile were performed. The united atoms force field model was proposed for the 3HF molecule using the results of DFT quantum chemical calculations. 3HF was interpreted as a rigid molecule with two internal degrees of freedom, i.e., rotation of the phenyl ring and of the OH group with respect to the chromone moiety. The interatomic radial distribution functions showed that interaction of the cations with flavonol occurs via the carbonyl group of 3HF and it is accompanied with substitution of one of the acetonitrile molecules in the cations’ first solvation shells. Formation of the cation–3HF complexes does not have significant impact on the rotation of the phenyl ring with respect to the chromone moiety. However, the orientation of the flavonol's OH-group is more sensitive to the interaction with doubly charged cations. When complex with Mg{sup 2+} is formed, the OH-group turns out of the plane of the chromone moiety that leads to rupture of intramolecular H-bond in the ligand molecule. Complexation of Ca{sup 2+}, Sr{sup 2+}, and BaClO {sub 4}{sup +} with 3HF produces two structures with different OH-positions, as in the free flavonol with the intramolecular H-bond and as in the complex with Mg{sup 2+} with disrupted H-bonding. It was shown that additional stabilization of the [MgClO{sub 4}(3HF)]{sup +} and [BaClO{sub 4}(3HF)]{sup +} complexes is determined by strong affinity of perchlorate anion to interact with flavonol via intracomplex hydrogen bond between an oxygen atom of the anion and the hydrogen atom of the 3-hydroxyl group. Noticeable difference in the values of the self-diffusion coefficients for Kt{sup 2+} from one side and ClO {sub 4}{sup −}, 3HF, and AN in the cations’ coordination shell from another side implies quite weak interaction between cation, anion, and ligands in

  11. Preferential solvation of single ions in mixed solvents: Part 1. New experimental approach and solvation of monovalent ions in methanol-water and acetonitrile-water mixture. Part 2. Theoretical computation and comparison with experimental data

    International Nuclear Information System (INIS)

    Rege, Aarti C.; Venkataramani, B.; Gupta, A.R.

    1999-06-01

    Preferential solvation of single ion solutions has been studied with Li + , Na + , K + and Ag +- forms of Dowex 50W resins of different cross-linkings in methanol-water and acetonitrile (AN)- water mixtures. The solvent uptake by this alkali metal ionic forms of Dowex 50W resins was studied in an isopiestic set-up using 2,4,6 and 8 m LiCl solutions in 11.0, 20.8, 44.3 and 70.2 % (w/w) methanol-water mixtures and that of Na +- and Ag +- forms using 14.6 to 94.3 % (w/w) AN - water mixtures. The solvent sorbed in the resin phase was extracted by Rayleigh-type distillation and analysed gas chromatographically. The data were analysed by the N s (mole fraction of the organic solvent in the resin phase) vs n t au (total solvent content in the resin phase) plots and separation factor, alpha(ratio of mole fraction of the solvents in the resin and solution phases) or N s vs m (molality in the resin phase) plots. The limiting values of these plots gave the composition of the solvent in the primary solvation shell around the single ion. The compositions of the primary solvation shell around Li + , Na + , and K + in methanol-water mixtures and Na + and Ag + in acetonitrile (AN) - water mixtures have been computed using Franks equation and the approach of Marcus and compared with the experimental results obtained with the above mentioned ionic forms of Dowex 50W resins in different mixed solvents. The experimental results for Li + showed good agreement with the values computed using Franks equation for all methanol-water composition. However, in the case of Na + and K + in methanol-water mixtures and Na + in AN-water mixtures, there was agreement only at lower organic solvent content and the Franks equation predicted higher values for the organic solvent in the primary solvation shell around the cation at higher organic solvent content as compared to experimental results

  12. Retention of ionisable compounds on high-performance liquid chromatography. XV. Estimation of the pH variation of aqueous buffers with the change of the acetonitrile fraction of the mobile phase.

    Science.gov (United States)

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2004-12-03

    The most commonly used mobile phases in reversed-phase high-performance liquid chromatography (RP-HPLC) are hydro-organic mixtures of an aqueous buffer and an organic modifier. The addition of this organic solvent to buffered aqueous solutions involves a variation of the buffer properties (pH and buffer capacity). In this paper, the pH variation is studied for acetic acid-acetate, phosphoric acid-dihydrogenphosphate-hydrogenphosphate, citric acid-dihydrogencitrate-citrate, and ammonium-ammonia buffers. The proposed equations allow pH estimation of acetonitrile-water buffered mobile phases up to 60% (v/v) of organic modifier and initial aqueous buffer concentrations between 0.001 and 0.1 mol L(-1), from the initial aqueous pH. The estimated pH variation of the mobile phase and the pKa variation of the analytes allow us to predict the degree of ionisation of the analytes and from this and analyte hydrophobicities, to interpret the relative retention and separation of analyte mixtures.

  13. Crystal structure of tetrakis[μ2-2-(dimethylaminoethanolato-κ3N,O:O]di-μ3-hydroxido-dithiocyanato-κ2N-dichromium(IIIdilead(II dithiocyanate acetonitrile monosolvate

    Directory of Open Access Journals (Sweden)

    Julia A. Rusanova

    2016-04-01

    Full Text Available The tetranuclear complex cation of the title compound, [Cr2Pb2(NCS2(OH2(C4H10NO4](SCN2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The CrIII ion is coordinated in a distorted octahedron, which involves two N atoms of one bidentate ligand and one thiocyanate anion, two μ2-O atoms of 2-(dimethylaminoethanolate ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the PbII ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb...S interactions involving the coordinating and non-coordinating thiocyanate anions are observed. In the crystal, the complex cations are linked through the thiocyanate anions via the Pb...S interactions and O—H...N hydrogen bonds into chains along the c axis. The chains are further linked together via S...S contacts. The contribution of the disordered solvent acetonitrile molecule was removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] procedure in PLATON. The solvent is included in the reported molecular formula, weight and density.

  14. Design and synthesis of the first generation of novel potent, selective, and in vivo active (benzothiazol-2-yl)acetonitrile inhibitors of the c-Jun N-terminal kinase.

    Science.gov (United States)

    Gaillard, Pascale; Jeanclaude-Etter, Isabelle; Ardissone, Vittoria; Arkinstall, Steve; Cambet, Yves; Camps, Montserrat; Chabert, Christian; Church, Dennis; Cirillo, Rocco; Gretener, Denise; Halazy, Serge; Nichols, Anthony; Szyndralewiez, Cedric; Vitte, Pierre-Alain; Gotteland, Jean-Pierre

    2005-07-14

    Several lines of evidence support the hypothesis that c-Jun N-terminal kinase (JNKs) plays a critical role in a wide range of diseases including cell death (apoptosis)-related disorders (neurodegenerative diseases, brain, heart, and renal ischemia, epilepsy) and inflammatory disorders (multiple sclerosis, rheumatoid arthritis, inflammatory bowel diseases). Screening of our internal compound collection for inhibitors of JNK3 led to the identification of (benzothiazol-2-yl)acetonitrile derivatives as potent and selective JNK1, -2, -3 inhibitors. Starting from initial hit 1 (AS007149), the chemistry and initial structure-activity relationship (SAR) of this novel and unique kinase inhibitor template were explored. Investigation of the SAR rapidly revealed that the benzothiazol-2-ylacetonitrile pyrimidine core was crucial to retain a good level of potency on rat JNK3. Therefore, compound 6 was further optimized by exploring a number of distal combinations in place of the chlorine atom. This led to the observation that the presence of an aromatic group, two carbons away from the aminopyrimidine moiety and bearing substituents conferring hydrogen bond acceptor (HBA) properties, could improve the potency. Further improvements to the biological and biopharmaceutical profile of the most promising compounds were performed, resulting in the discovery of compound 59 (AS601245). The in vitro and in vivo anti-inflammatory potential of this new JNK inhibitor was investigated and found to demonstrate efficacy per oral route in an experimental model of rheumatoid arthritis (RA).

  15. Synthesis of nano-sized hydrogen phosphate-imprinted polymer in acetonitrile/water mixture and its use as a recognition element of hydrogen phosphate selective all-solid state potentiometric electrode.

    Science.gov (United States)

    Alizadeh, Taher; Atayi, Khalil

    2018-02-01

    Herein, a new recipe is introduced for the preparation of hydrogen phosphate ion-imprinted polymer nanoparticles (nano-IIP) in acetonitrile/water (63.5:36.5) using phosphoric acid as the template. The nano-IIP obtained was used as the recognition element of a carbon paste potentiometric sensor. The IIP electrode showed a Nernstian response to hydrogen phosphate anion; whereas, the non-imprinted polymer (NIP)-based electrode had no considerable sensitivity to the anion. The presence of both methacrylic acid and vinyl pyridine in the IIP structure, as well as optimization of the functional monomers-template proportion, was found to be important to observe the sensing capability of the IIP electrode. The nano-IIP electrode showed a dynamic linear range of 1 × 10 -5 -1 × 10 -1  mol L-1, Nernstian slope of 30.6 ± (0.5) mV decade -1 , response time of 25 seconds, and detection limit of 4.0 × 10 -6  mol L -1 . The utility of the electrodes was checked by potentiometric titration of hydrogen phosphate with La 3+ solution. Copyright © 2017 John Wiley & Sons, Ltd.

  16. Retention of ionisable compounds on high-performance liquid chromatography XVI. Estimation of retention with acetonitrile/water mobile phases from aqueous buffer pH and analyte pKa.

    Science.gov (United States)

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2006-07-21

    In agreement with our previous studies and those of other authors, it is shown that much better fits of retention time as a function of pH are obtained for acid-base analytes when pH is measured in the mobile phase, than when pH is measured in the aqueous buffer when buffers of different nature are used. However, in some instances it may be more practical to measure the pH in the aqueous buffer before addition of the organic modifier. Thus, an open methodology is presented that allows prediction of chromatographic retention of acid-base analytes from the pH measured in the aqueous buffer. The model presented estimates the pH of the buffer and the pKa of the analyte in a particular acetonitrile/water mobile phase from the pH and pKa values in water. The retention of the analyte can be easily estimated, at a buffer pH close to the solute pKa, from these values and from the retentions of the pure acidic and basic forms of the analyte. Since in many instances, the analyte pKa values in water are not known, the methodology has been also tested by using Internet software, at reach of many chemists, which calculates analyte pKa values from chemical structure. The approach is successfully tested for some pharmaceutical drugs.

  17. Tetrabromido[4-(triphenylphosphanyloxybutyl]tellurium acetonitrile monosolvate

    Directory of Open Access Journals (Sweden)

    Sari M. Närhi

    2013-02-01

    Full Text Available In the title compound, [TeBr4(C22H23OP]·CH3CN, the Te atom exhibits a square-pyramidal coordination with an apical Te—C bond and four basal Te—Br bonds. The conformation of the aliphatic C—C—C—C chain is gauche [torsion angle = −67.7 (8°]. A weak C—H...Br interaction helps to establish the conformation. In the crystal, there is a weak secondary bonding interaction [Te...N = 3.456 (11 Å] between the Te atom and the N atom of the solvent molecule, which completes a distorted TeNCBr4 octahedron. Inversion dimers linked by pairs of C—H...Br interactions are also observed.

  18. Ion-exchange voltammetry of tris(2,2'-bipyridine) nickel(II), cobalt(II), and Co(salen) at polyestersulfonated ionomer coated electrodes in acetonitrile: Reactivity of the electrogenerated low-valent complexes

    International Nuclear Information System (INIS)

    Buriez, Olivier; Moretto, Ligia M.; Ugo, Paolo

    2006-01-01

    The electrochemical behaviour of [Ni(bpy) 3 (BF 4 ) 2 ], [Co(bpy) 3 (BF 4 ) 2 ], and Co(salen) (where bpy = 2,2'-bipyridine, and salen N,N'-bis(salicylidene)ethylenediamine) is studied at a glassy carbon electrode modified with the poly(estersulfonate) ionomer Eastman AQ 55 in acetonitrile (MeCN). It is shown that the nickel complex is strongly incorporated into the polymer. The reduction of the divalent nickel compound features a two-electron process leading to a nickel(0) species which is released from the coating because of the lack of electrostatic attraction with the ionomer. Yet, the neutral zerovalent nickel-bipyridine complex is reactive towards ethyl 4-iodobenzoate and di-bromocyclohexane despite the presence of the polymer. The activation of the aryl halide occurs through an oxidative addition, whereas, an electron transfer is involved in the presence of the alkyl halide making the catalyst regeneration much faster in the latter case. The electrochemical study of [Co(bpy) 3 (BF 4 ) 2 ] shows that incorporation of the cobalt complex into the polymer is efficient, provided excess bpy is used. This excess bpy does not interfere with the electrocatalytic activity of the cobalt complex incorporated in the AQ coating and efficient electrocatalysis is observed towards di-bromocyclohexane and benzyl-bromide as substrates. Finally, replacement of the bpy ligand with the macrocycle N,N'-bis(salicylidene)ethylenediamine, salen, leads to the incorporation of the non-charged Co II (salen) complex into the AQ 55 polymer showing the relevancy of hydrophobic interactions. The reaction between the electrogenerated [Co I (salen)] - with 1,2-dibromocyclohexane exhibits a fast inner sphere electron transfer

  19. The reaction of Cs{sub 2}[Tc(NO)F{sub 5}] with BF{sub 3} in acetonitrile. Formation and structure of [{Tc(NO)(CH_3CN)_4}{sub 2}(μ-F)](BF{sub 4}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Balasekaran, Samundeeswari Mariappan [Institute of Chemistry and Biochemistry, Freie Universitaet Berlin (Germany); Department of Chemistry, University of Nevada, Las Vegas, NV (United States); Hagenbach, Adelheid; Spandl, Johann; Abram, Ulrich [Institute of Chemistry and Biochemistry, Freie Universitaet Berlin (Germany)

    2017-10-04

    The deep blue, paramagnetic Cs{sub 2}[Tc{sup II}(NO)F{sub 5}] is formed during reactions of pertechnetate, acetohydroxamic acid, and CsF in aqueous HF. A reaction of Cs{sub 2}[Tc(NO)F{sub 5}] with BF{sub 3}.MeOH in acetonitrile gives yellow blocks of the fluorido-bridged dimer [{Tc"I(NO)(CH_3CN)_4}{sub 2}F](BF{sub 4}){sub 3}. The compound is stable as solid and in acetonitrile solutions. The complex cation contains a bent μ-F{sup -} ligand and two linear nitrosyl groups. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Thermodynamics of the amalgam cells {l_brace}Cs-amalgam|CsX (m)|AgX|Ag{r_brace} (X=Cl, Br, I) and primary medium effects in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Falciola, Luigi [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: luigi.falciola@unimi.it; Longoni, Giorgio [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy); Mussini, Patrizia R. [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: patrizia.mussini@unimi.it; Mussini, Torquato [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, I-20133 Milan (Italy)]. E-mail: torquato.mussini@unimi.it

    2006-06-15

    The potential difference E of the amalgam cell {l_brace}Cs{sub x}Hg{sub 1-x}|CsX (m)|AgX|Ag{r_brace} (X=Cl, Br, I) has been measured as a function of the mole fraction x{sub Cs} of Cs metal in amalgams and of the molality m of CsX in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures containing up to 0.75 mass fraction of the organic component, at the temperature 298.15K. The respective standard molal potential differences E{sub m}{sup o} have been determined together with the relevant activity coefficients {gamma}{sub +}/- as functions of the CsX molality. The found E{sub m}{sup o} values show a parabolic decrease with increasing proportion of the organic component in the solvent mixture. Analysis of the relevant primary medium effects upon CsX shows that the CsX transfer from the standard state in water to the standard state in the (aqueous+organic) mixture is always unfavoured, and the acetonitrile is the least unfavoured co-solvent studied. Analysis of the primary medium effect upon CsI in terms of Feakins and French's theory leads to a primary hydration number close to zero, which is consistent with the results of supplementary EXAFS experiments on Cs{sup +} and I{sup -} in (acetonitrile+water) solvent mixtures.

  1. An Integrated approach (thermodynamic, structural, and computational) to the study of complexation of alkali-metal cations by a lower-rim calix[4]arene amide derivative in acetonitrile.

    Science.gov (United States)

    Horvat, Gordan; Stilinović, Vladimir; Hrenar, Tomica; Kaitner, Branko; Frkanec, Leo; Tomišić, Vladislav

    2012-06-04

    The calix[4]arene secondary-amide derivative L was synthesized, and its complexation with alkali-metal cations in acetonitrile (MeCN) was studied by means of spectrophotometric, NMR, conductometric, and microcalorimetric titrations at 25 °C. The stability constants of the 1:1 (metal/ligand) complexes determined by different methods were in excellent agreement. For the complexation of M(+) (M = Li, Na, K) with L, both enthalpic and entropic contributions were favorable, with their values and mutual relations being quite strongly dependent on the cation. The enthalpic and overall stability was the largest in the case of the sodium complex. Molecular and crystal structures of free L, its methanol and MeCN solvates, the sodium complex, and its MeCN solvate were determined by single-crystal X-ray diffraction. The inclusion of a MeCN molecule in the calixarene hydrophobic cavity was observed both in solution and in the solid state. This specific interaction was found to be stronger in the case of metal complexes compared to the free ligand because of the better preorganization of the hydrophobic cone to accept the solvent molecule. Density functional theory calculations showed that the flattened cone conformation (C(2) point group) of L was generally more favorable than the square cone conformation (C(4) point group). In the complex with Na(+), L was in square cone conformation, whereas in its adduct with MeCN, the conformation was slightly distorted from the full symmetry. These conformations were in agreement with those observed in the solid state. The classical molecular dynamics simulations indicated that the MeCN molecule enters the L hydrophobic cavity of both the free ligand and its alkali-metal complexes. The inclusion of MeCN in the cone of free L was accompanied by the conformational change from C(2) to C(4) symmetry. As in solution studies, in the case of ML(+) complexes, an allosteric effect was observed: the ligand was already in the appropriate square cone

  2. 5-(4-Cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydro-3-furyl-3-(1-methyl-1,4-dihydropyridin-4-ylidenepent-4-enyl 3,5-bis(benzyloxybenzoate acetonitrile 0.25-solvate: a synchrotron radiation study

    Directory of Open Access Journals (Sweden)

    Andrew J. Kay

    2009-12-01

    Full Text Available The title compound, C42H36N4O5·0.25CH3CN, crystallizes with a partial twofold disordered (1/4 acetonitrile solvent of crystallization. The linking atoms to the 3,5-bis(benzyloxybenzoic acid are disordered between two conformations in the ratio 0.780 (6:0.220 (6. In the crystal, the molecules pack using mainly C—H...N(cyano interactions coupled with weak C—H...O(ether interactions and C—H...π interactions. A brief comparison is made between a conventional and this synchrotron data collection.

  3. [μ2-trans-1,2-Bis(pyridin-4-ylethene-κ2N:N′]bis{[1,2-bis(pyridin-4-ylethene-κN]bis[N-(2-hydroxyethyl-N-isopropyldithiocarbamato-κ2S,S′]cadmium} acetonitrile tetrasolvate: crystal structure and Hirshfeld surface analysis

    Directory of Open Access Journals (Sweden)

    Mukesh M. Jotani

    2016-08-01

    Full Text Available The asymmetric unit of the title compound, [Cd2(C12H10N23(C6H12NOS24]·4C2H3N, comprises a CdII atom, two dithiocarbamate (dtc anions, one and a half trans-1,2-dipyridin-4-ylethylene (bpe molecules and two acetonitrile solvent molecules. The full binuclear complex is generated by the application of a centre of inversion. The dtc ligands are chelating, one bpe molecule coordinates in a monodentate mode while the other is bidentate bridging. The resulting cis-N2S4 coordination geometry is based on an octahedron. Supramolecular layers, sustained by hydroxy-O—H...O(hydroxy and hydroxy-O—H...N(bpe hydrogen bonding, interpenetrate to form a three-dimensional architecture; voids in this arrangement are occupied by the acetonitrile solvent molecules. Additional intermolecular interactions falling within the specified framework have been analysed by Hirshfeld surface analysis, including π–π interactions.

  4. (1,6,7,12-Tetraazaperylene-κ2N,N′bis(4,4′,5,5′-tetramethyl-2,2′-bipyridyl-κ2N,N′ruthenium(II bis(hexafluoridophosphate acetonitrile trisolvate

    Directory of Open Access Journals (Sweden)

    Thomas Brietzke

    2014-06-01

    Full Text Available In the title compound, rac-[Ru(C14H16N22(C16H8N4](PF62·3C2H3N, discrete dimers of complex cations, [Ru(tmbpy2tape]2+, of opposite chirality are formed (tmbpy = tetramethylbipyridine; tape = tetraazaperylene, held together by π–π stacking interactions between the tetraazaperylene moieties with centroid–centroid distances in the range 3.563 (3–3.837 (3 Å. These interactions exhibit a parallel displaced π–π stacking mode. Additional weak C—H...π-ring and C—H...N and C—H...F interactions are found, leading to a three-dimensional architecture. The RuII atom is coordinated in a distorted octahedral geometry. The counter-charge is provided by two hexafluoridophosphate anions and the asymmetric unit is completed by three acetonitrile solvent molecules of crystallization. Four F atoms of one PF6− anion are disordered over three sets of sites with occupancies of 0.517 (3:0.244 (3:0.239 (3. Two acetonitrile solvent molecules are highly disordered and their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  5. Pre-electrospray ionisation manifold methylation and post-electrospray ionisation manifold cleavage/ion cluster formation observed during electrospray ionisation of chloramphenicol in solutions of methanol and acetonitrile for liquid chromatography-mass spectrometry employing a commercial quadrupole ion trap mass analyser.

    Science.gov (United States)

    Sichilongo, Kwenga F; Famuyiwa, Samson O; Kibechu, Rose

    2011-01-01

    We have observed unusual mass spectra of chloramphenicol (CAP) in solutions of methanol or acetonitrile showing intense ions at m/z 297, m/z 311, m/z 325 and m/z 339. The observed ions were different from those which are traditionally observed in the full scan ESI mass spectra of CAP with ions of m/z 321, m/z 323 and m/z 325. We have evidence to show that this process starts with offline methylation of CAP in solutions of methanol or acetonitrile to give m/z 339. Investigations using nuclear magnetic resonance (NMR) spectroscopy showed that there is a methylene group somewhere within the CAP molecule but not attached to any of the carbon atoms when the CAP is dissolved in methanol or acetonitrile before infusion into the mass spectrometer. The possible locations of attachment were speculated to be the electronegative atoms apart from the chlorine atoms due to valence considerations. The methylene group is attached to the nitrogen atom and forms a bond as observed in the MS/MS spectra of m/z 297, m/z 311, m/z 325 and m/z 339 which give m/z 183 as the base peak in all cases. Further experiments showed that there is cleavage of the methylated CAP molecule followed by cluster ion formation involving addition of methylene groups to the CAP fragment with m/z 183 to produce ions of m/z including m/z 297, m/z 311, m/z 325 and m/z 339. This process occurs in the mass spectrometer in the region housing the tube lens and is triggered when the ions are accelerated through this region by application of a negative tube lens offset voltage. This region affords collision of the charged droplets with a collision gas in this case nitrogen to strip the droplets of their solvent molecules. Experiments to follow the intensities of m/z 183, m/z 311, m/z 321, m/z 323, m/z 325 and m/z 339 as the tube lens offset voltage was varied were done in which the intensities of m/z 311, m/z 325 and m/z 339 were observed to be at their peak when the tube lens offset voltage was set at -40 V. When

  6. PEMFC cathode catalyst contamination evaluation with a RRDE-Acetonitrile

    International Nuclear Information System (INIS)

    Ge, Junjie; St-Pierre, Jean; Zhai, Yunfeng

    2014-01-01

    The effect of CH 3 CN at different concentrations on the oxygen reduction reaction (ORR) was investigated using a rotating ring-disk electrode (RRDE). CH 3 CN is found to have a high affinity to Pt/C and therefore leads to the suppression of the electrochemical surface area (ECSA) and the mass activity for the ORR. More H 2 O 2 is collected on the ring during ORR, which indicates the shift from a 4-electron pathway to 2-electron pathway. Using the RRDE measurements and the Levich plots, the total charge transfer number is confirmed to decrease from 4 to approximately 3 at 0.2 V. The inhibition of the dual adsorption of the O 2 molecule due to the steric hindrance induced by the presence of CH 3 CN surface species is proposed as the cause of the shift in the reaction pathway. Oxidation/reduction of CH 3 CN is observed, in which both reversible oxidation/reduction (reactive adsorption products) and irreversible oxidation/reduction occur during the potential cycling process. For the reversible reaction, the products adsorb on the Pt surface and influence both the kinetics and reaction pathway. The hydrogenation of these products at lower potentials leads to higher coverage on the Pt, which leads to the generation of more H 2 O 2 due to the spatial limitation. For the irreversible reaction, at least one of the products possess higher affinity to Pt than the adsorbed reversible reaction products, which leads to a continuous decrease in the ECSA during potential cycling and therefore to even lower kinetic performance for the ORR. Using a Tafel plot, it is found that none of the above-mentioned products change the rate determining step (RDS) of the ORR, in which the first charge transfer remains the rate determining step

  7. Radiation chemistry of aqueous solutions of acetonitrile and propionitrile

    International Nuclear Information System (INIS)

    Shushtarian, M.J.

    1975-01-01

    The radiation chemistry of water and aqueous solutions is a branch of radiation chemistry dealing with chemical changes in water and aqueous solutions induced by high energy radiations. High energy radiations of interest in radiation chemistry are short-wave electromagnetic radiations (X- and γ-rays) and fast charged particles (α- and β-particles, electrons, deuterons and fission fragments). The energy of the particles and photons bringing about chemical reactions in the field of modern radiation chemistry is much higher than that of photons causing photochemical reactions

  8. Bis{(E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium} bis[μ-(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamido(2−]bis{[(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide]copper(II} bis((E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Andrii I. Buvailo

    2012-12-01

    Full Text Available The reaction between copper(II nitrate and (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide led to the formation of the dinuclear centrosymmetric copper(II title complex, (C8H18N3O22[Cu2(C8H15N3O22(C8H17N3O22](C9H16N3O42·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O22(C8H17N3O22] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu...Cu separation = 4.0608 (5 Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex molecule co-crystallizes with two molecules of acetonitrile, two molecules of the protonated ligand (E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium and two negatively charged (E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate anions, which were probably formed as a result of condensation between (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide and hydrogencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O22(C8H17N3O22] and the ion pair C8H18N3O2+.C9H16N3O4− are connected via an extended system of hydrogen bonds.

  9. Reductions in Aprotic Media. I. Cathodic Reduction Limits in Acetonitrile at a Platinum Electrode.

    Science.gov (United States)

    1981-08-15

    specifically; (1) The difference in the effect of water on lithium solutions and tetraalkylammonium solutions, (2) the passivation of a platinum electrode...solutions. 5 EXPERIMENTAL Procedure for Controlled Potential Electrolysis The electrolyses were performed in a glass H-cell. The anode and cathode...fine porous glass frit from the Luggin section. The electrolyses were run in constant potential mode. After electrolysis, the catholyte was removed and

  10. A conductivity study of preferential solvation of lithium ion in acetonitrile-dimethyl sulfoxide mixtures

    International Nuclear Information System (INIS)

    Mozhzhukhina, Nataliia; Longinotti, M. Paula; Corti, Horacio R.; Calvo, Ernesto J.

    2015-01-01

    The electrical mobility of LiPF 6 in acetonitrile–dimethyl sulfoxide (ACN–DMSO) mixtures, a potential electrolyte in oxygen cathodes of lithium-air batteries, has been studied using a very precise conductance technique, which allowed the determination of the infinite dilution molar conductivity and association constant of the salt in the whole composition range. In the search for preferential Li + ion solvation, we also measured the electrical conductivity of tetrabutylammonium hexafluorophosphate (TBAPF 6 ), a salt formed by a bulky cation, over the same composition range. The results show a qualitative change in the curvature of the LiPF 6 molar conductivity composition dependence for ACN molar fraction (x ACN ) ∼ 0.95, which was not observed for TBAPF 6 . The dependence of the measured Li/Li + couple potential with solvent composition also showed a pronounced change around the same composition. We suggest that these observations can be explained by Li + ion preferential solvation by DMSO in ACN–DMSO mixtures with very low molar fractions of DMSO

  11. An acetonitrile solvatomorph of dichlorido(1,10-phenanthroline-5,6-dioneplatinum(II

    Directory of Open Access Journals (Sweden)

    Amanda Hamala

    2014-01-01

    Full Text Available In the title complex, [PtCl2(C12H6N2O2]·CH3CN, the PtII atom lies in a slightly distorted square-planar arrangement defined by an N2Cl2 donor set. In the packed structure, columns of complex moieties are stacked such that the neighboring units are oriented at 180° and laterally displaced with respect to each other. This prevents any overlap of the phenanthroline rings and thus there is no possibility of any π–π interactions between aromatic rings.

  12. Application of the Kirkwood–Buff theory of solutions to acetonitrile + ...

    Indian Academy of Sciences (India)

    Administrator

    to binary mixtures can be found in which this theory has been to be used only for aqueous-alcohol. 14,18−22 binary mixtures and aqueous solutions containing electro- lytes. 23,24. To the best of our knowledge, very few studies have been made in the literature on non- aqueous binary mixtures. 25−28. The main objective ...

  13. Investigation of gadolinium (3)-, calcium (2)- and copper (2) complexes with riboflavin in acetonitrile

    International Nuclear Information System (INIS)

    Lugina, L.N.

    1984-01-01

    Electron and IR spectra of gadolinium-(3), calcium (2), and copper (2) complexes with riboflavin (RF) in acetopitrile against the background of LiClO 4 x3H 2 O are studied. The way of RF coordination by the atom of metal is shown to depend on the nature of metal. Gadolinium (3) coordinates RF through N and O atoms; copper - through O metal, calcium - through O atom and, evidently, through hydroxyl groups of ribitol. Directions of RF line shifts of π-π * electron transitions at RF complexing with metals are compared with the calculated results and directions of RF line shifts during the formation of hydrogen bonds with different donor atoms of the isoalloxazine ring

  14. The effect of deuterium substitution on the vapor pressure of acetonitrile

    International Nuclear Information System (INIS)

    Jancso, G.; Jakli, Gy.; Koritsanszky, T.

    1980-01-01

    The vapor pressure difference between CH 3 CN and CD 3 CN was measured by differential capacitance manometry between -40 and +80 deg C. The vapor pressure isotope effects (VPIE) derived from the results may be expressed by the equation: ln(psub(H)/Psub(D))=871.761/T 2 -13.577/T+0.006874. The experimental data were interpreted within the framework of the statistical theory of isotope effects in condensed systems. The largest contribution to the VPIE arises from the shifts in the CH stretching vibrations resulting from condensation which were found to be temperature dependent in good agreement with the available spectroscopic information. (author)

  15. Kinetics and Mechanism of the Pyridinolysis of Diisopropyl Chlorothiophosphate in Acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Hoque, Md. Ehtesham Ul; Lee, Hai Whang [Inha Univ., Incheon (Korea, Republic of)

    2012-10-15

    The nucleophilic substitution reactions of diisopropyl chlorothiophosphate with X-pyridines have been kinetically studied in MeCN at 35.0 .deg. C. The Hammett and Bronsted plots for the substituent X variations in the nucleophiles show biphasic concave upwards with a break point at X = 3-Ph. The pyridinolysis rate of 5 exhibits great negative deviation from the Taft plot. A concerted S{sub N}2 mechanism is proposed involving a change of the attacking direction of the X-pyridines from a frontside attack with the strongly basic pyridines to a backside attack with the weakly basic pyridines.

  16. Utilization of Cyanoacetohydrazide and Oxadiazolyl Acetonitrile in the Synthesis of Some New Cytotoxic Heterocyclic Compounds.

    Science.gov (United States)

    Shaker, Soheir A; Marzouk, Magda I

    2016-01-29

    A (pyridazinyl)acetate derivative was reacted with thiosemicarbazide and hydrazine hydrate to yield spiropyridazinone and acetohydrazide derivatives, respectively. The acetohydrazide derivative was used as a starting material for synthesizing some new heterocyclic compounds such as oxoindolinylidene, dimethylpyrazolyl, methylpyrazolyl, oxopyrazolyl, cyanoacetylacetohydrazide and oxadiazolylacetonitrile derivatives. The behavior of the cyanoacetylacetohydrazide and oxadiazolylacetonitrile derivatives towards nitrogen and carbon nucleophiles was investigated. The assigned structures of the prepared compounds were elucidated by spectral methods (IR, ¹H-NMR (13)C-NMR and mass spectroscopy). Some of the newly prepared compounds were tested in vitro against a panel of four human tumor cell lines, namely hepatocellular carcinoma (liver) HePG-2, colon cancer HCT-116, human prostate cancer PC3, and mammary gland breast MCF-7. Also they were tested as antioxidants. Almost all of the tested compounds showed satisfactory activity.

  17. Kinetics and Mechanism of the Reaction of Hydoxyl Radicals with Acetonitrile under Atmospheric Conditions

    Science.gov (United States)

    Hynes, A. J.; Wine, P. H.

    1997-01-01

    The pulsed laser photolysis-pulsed laser induced fluorescence technique has been employed to determine absolute rate coefficients for the reaction OH + CH3CN (1) and its isotopic variants, OH + CD3CN (2), OD + CH3CN (3), and OD + CD3CN (4). Reactions 1 and 2 were studied as a function of pressure and temperature in N2, N2/O2, and He buffer gases. In the absence of O2 all four reactions displayed well-behaved kinetics with exponential OH decays and pseudo-first rate constants which were proportional to substrate concentration. Data obtained in N2 over the range 50-700 Torr at 298 K are consistent with k(sub 1), showing a small pressure dependence. The Arrhenius expression obtained by averaging data at all pressures in k(sub 1)(T) = (1.1(sup +0.5)/(sub -0.3)) x 10(exp -12) exp[(-1130 +/- 90)/T] cu cm /(molecule s). The kinetics of reaction 2 are found to be pressure dependent with k(sub 2) (298 K) increasing from (1.21 +/- 0.12) x 10(exp -14) to (2.16 +/- 0.11) x 10(exp -14) cm(exp 3)/ (molecule s) over the pressure range 50-700 Torr of N2 at 298 K. Data at pressures greater than 600 Torr give k(sub 2)(T) = (9.4((sup +13.4)(sub -5.0))) x 10(exp -13) exp[(-1180 +/- 250)/T] cu cm/(molecule s). The rates of reactions 3 and 4 are found to be independent of pressure over the range 50-700 Torr of N2 with 298 K rate coefficient given by k(sub 3) =(3.18 +/- 0.40) x 10(exp -14) cu cm/(molecule s) and k(sub 4) = (2.25 +/-0.28) x 10(exp -14) cu cm/(molecule s). In the presence of O2 each reaction shows complex (non-pseudo-first-order) kinetic behavior and/or an apparent decrease in the observed rate constant with increasing [O2], indicating the presence of significant OH or OD regeneration. Observation of regeneration of OH in (2) and OD in (3) is indicative of a reaction channel which proceeds via addition followed by reaction of the adduct, or one of its decomposition products, with O2. The observed OH and OD decay profiles have been modeled by using a simple mechanistic scheme to extract kinetic information about the adduct reations with O2 and branching ratios for OH regeneration. A plausible mechanism for OH regeneration in (2) involves OH addition to the nitrogen atom followed by O2 addition to the cyano carbon atom, isomeriazation and decomposition to D2CO + DOCN + OH. Our results suggest that the OH + CH3CN reaction occurs via a complex mechanism involving both bimolecular and termolecular pathways, analogous to the mechanisms for the the important atmospheric reactions of OH with CO and HNO3.

  18. Acetonitrile Chemical Ionization Ion Trap Mass Spectrometry of Chemical Warfare Agents and Their Degradation Products

    National Research Council Canada - National Science Library

    Rohrbaugh, Dennis

    1998-01-01

    .... The protonated molecular ion was observed as the dominant ion and base peak for HD, VX, GA, 1,4-dithiane, 2-diisopropylaminoethanol, and the trimethylsilyl derivatives of methylphosphonic acid...

  19. Synthesis of Nitriles via Palladium-Catalyzed Water Shuffling from Amides to Acetonitrile

    OpenAIRE

    Zhang, Wandi; Haskins, Christopher W.; Yang, Yang; Dai, Mingji

    2014-01-01

    Palladium-catalyzed synthesis of nitriles from amides has been described. Two similar, but complementary reaction conditions have been identified to convert various amides including α,β,γ,δ-unsaturated amides, cinnamides, aromatic amides and alkyl amides to the corresponding nitriles in good to excellent yield.

  20. Synthesis of nitriles via palladium-catalyzed water shuffling from amides to acetonitrile.

    Science.gov (United States)

    Zhang, Wandi; Haskins, Christopher W; Yang, Yang; Dai, Mingji

    2014-12-07

    Palladium-catalyzed synthesis of nitriles from amides has been described. Two similar, but complementary reaction conditions have been identified to convert various amides including α,β,γ,δ-unsaturated amides, cinnamides, aromatic amides and alkyl amides to the corresponding nitriles in good to excellent yield.

  1. Competitive solvation of (bis)(trifluoromethanesulfonyl)imide anion by acetonitrile and water

    DEFF Research Database (Denmark)

    Chaban, Vitaly

    2014-01-01

    Competitive solvation of an ion by two or more solvents is one of the key phenomena determining the identity of our world. Solvation in polar solvents frequently originates from non-additive non-covalent interactions. Pre-parametrized potentials poorly capture these interactions, unless the force...

  2. CCDC 806717: Experimental Crystal Structure Determination : bis(acetonitrile)-chloro-(1-(2-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)ethyl)-3-methylimidazol-2-ylidene)-palladium hexafluorophosphate acetonitrile solvate

    KAUST Repository

    Goh, Serena L. M.; Hogerl, Manuel Peter; Jokić, Nadežda B.; Tanase, Alexandrina D.; Bechlars, Bettina; Baratta, Walter; Mink, Já nos; Kü hn, Fritz E.

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. CCDC 997388: Experimental Crystal Structure Determination : (1,1'-methylenebis(3-(2-thienyl)-2,3-dihydro-1H-imidazol-2-ylidene))-tetrakis(acetonitrile)-iron(ii) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  4. CCDC 997387: Experimental Crystal Structure Determination : (1,1'-methylenebis(3-(2-furyl)-2,3-dihydro-1H-imidazol-2-ylidene))-tetrakis(acetonitrile)-iron(ii) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 1420290: Experimental Crystal Structure Determination : (6,6'-bis((3-methyl-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,2'-bipyridine)-bis(acetonitrile)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.; Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. CCDC 1050374: Experimental Crystal Structure Determination : trichloro-(4'-ferrocenyl-2,2':6',2''-terpyridine)-iridium(iii) acetonitrile solvate

    KAUST Repository

    Davaasuren, Bambar; Padhy, Harihara; Rothenberger, Alexander

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. Effect of Growth Temperature on Bamboo-shaped Carbon–Nitrogen (C–N Nanotubes Synthesized Using Ferrocene Acetonitrile Precursor

    Directory of Open Access Journals (Sweden)

    Dobal PramodSingh

    2008-01-01

    Full Text Available Abstract This investigation deals with the effect of growth temperature on the microstructure, nitrogen content, and crystallinity of C–N nanotubes. The X-ray photoelectron spectroscopic (XPS study reveals that the atomic percentage of nitrogen content in nanotubes decreases with an increase in growth temperature. Transmission electron microscopic investigations indicate that the bamboo compartment distance increases with an increase in growth temperature. The diameter of the nanotubes also increases with increasing growth temperature. Raman modes sharpen while the normalized intensity of the defect mode decreases almost linearly with increasing growth temperature. These changes are attributed to the reduction of defect concentration due to an increase in crystal planar domain sizes in graphite sheets with increasing temperature. Both XPS and Raman spectral observations indicate that the C–N nanotubes grown at lower temperatures possess higher degree of disorder and higher N incorporation.

  8. CCDC 1444725: Experimental Crystal Structure Determination : catena-[bis(mu-4-(pyrimidin-5-yl)benzoato)-copper acetonitrile solvate

    KAUST Repository

    Abdul Halim, Racha Ghassan

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. 2-[(2-{Bis[2-(2-hydroxy-5-nitrobenzylideneaminoethyl]amino}ethyliminomethyl]-4-nitrophenol acetonitrile monosolvate

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2010-12-01

    Full Text Available In the title compound, C27H27N7O9·CH3CN, the three nitro groups of the polydentate tripodal Schiff base are located approximately parallel to their respective carrier benzene rings, making dihedral angles of 3.9 (4, 5.0 (4 and 6.3 (4°. Intramolecular O—H...N hydrogen bonds between the hydroxy O atoms and the imine N atoms, with O...N distances in the range 2.607 (3–2.665 (3 Å, form nearly planar six-membered rings. In the crystal, weak intermolecular C—H...O and C—H...N hydrogen bonds occur and several intra- and intermolecular π–π interactions are present between adjacent benzene rings, with a shortest centroid–centroid distance of 3.507 (2 Å.

  10. Fluorescence quenching of derivatives of anthracene by organic electron donors and acceptors in acetonitrile. Electron and proton transfer mechanism

    Science.gov (United States)

    Mac, Marek; Najbar, Jan; Wirz, Jakob

    1995-03-01

    Fluorescence quenching of anthracene derivatives by organic electron donors (amines) and acceptors was investigated using stationary fluorescence measurements. The dependence of log( kq) on Δ Get shows Rehm-Weller-type behavior. The formation of anion radicals of anthracene, bianthryl, and 9-cyanoanthracene was detected by flash photolysis in systems containing aromatic amines (aniline, 2-bromoaniline, 4-bromoaniline, N,N-dimethylaniline, 4-bromo-N,N-dimethylaniline, N,N-diethylaniline, and 1,4-diazabicyclo[2.2.2]octane). The radical yields decreased and triplet yields increased when bromo derivatives of amines were used as donor quenchers, indicating the heavy-atom effect on spin conversion within radical pairs. The importance of the heavy-atom effect decreased when the energy gap between the charge transfer and molecular triplet states was small. The formation of separated radicals decreased when primary amines were used as quenchers which indicated the existence of an additional path of deactivation of the radical pair. The behavior of amines as quenchers of bianthryl and anthracene is compared with that of inorganic anion quenchers.

  11. CCDC 997386: Experimental Crystal Structure Determination : 1,1'-methylenebis(3-(2-furyl)-1H-imidazol-3-ium) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  12. Gradient retention prediction of acid-base analytes in reversed phase liquid chromatography: a simplified approach for acetonitrile-water mobile phases.

    Science.gov (United States)

    Andrés, Axel; Rosés, Martí; Bosch, Elisabeth

    2014-11-28

    In previous work, a two-parameter model to predict chromatographic retention of ionizable analytes in gradient mode was proposed. However, the procedure required some previous experimental work to get a suitable description of the pKa change with the mobile phase composition. In the present study this previous experimental work has been simplified. The analyte pKa values have been calculated through equations whose coefficients vary depending on their functional group. Forced by this new approach, other simplifications regarding the retention of the totally neutral and totally ionized species also had to be performed. After the simplifications were applied, new prediction values were obtained and compared with the previously acquired experimental data. The simplified model gave pretty good predictions while saving a significant amount of time and resources. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Rate constants and temperature effects for reactions of Cl2sm-bullet- with unsaturated alcohols and hydrocarbons in aqueous and acetonitrile/water solutions

    International Nuclear Information System (INIS)

    Padmaja, S.; Neta, P.; Huie, R.E.

    1992-01-01

    Absolute rate constants for reactions of the dichlorine radical anion, Cl 2 sm-bullet- , with unsaturated alcohols and hydrocarbons have been measured at various temperatures. The alcohol reactions were measured in aqueous solutions and the hydrocarbon reactions in 1:1 aqueous acetonitirle (ACN) solutions. The rate constants for two alcohols and one hydrocarbon were also examined as a function of solvent composition. The room temperature rate constants varied between 10 6 and 10 9 M -1 s -1 . The pre-exponential factors, A, were about (1-5) x 10 9 M -1 s -1 for the alcohols in aqueous solutions and about (0.1-1) x 10 9 M -1 s -1 for the hydrocarbons in aqueous ACN solutions. The activation energies, E a , varied considerably, between 4 and 12 kJ mol -1 for the alcohols and between 2 and 8 kJ mol -1 for the hydrocarbons. The rate constants, k 298 , decrease with increasing ionization potential (IP) of the unsaturated compound, in agreement with an electrophilic addition mechanism. The activation energies for the unsaturated alcohols decrease when the IP decreases from 9.7 to 9.1 eV but appear to level off at lower IP. Most alkenes studied had IP a . Upon addition of ACN to the aqueous solution, the values of log k 298 decreased linearly by more than 1 order of magnitude with increasing ACN mole fraction. This decrease appears to result from a combination of changes in the activation energy and in the pre-exponential factor. The reason for these changes may lie in changes in the solvation shell of the Cl 2 sm-bullet- radical, which will affect the A factor, in combination with changes in solvation of Cl - , which will affect the energetics of the reactions as well. 20 refs., 7 figs., 6 tabs

  14. Comment on ;Red/blue shifting hydrogen bonds in acetonitrile - Dimethyl sulphoxide solutions: FTIR and theoretical studies; DOI: 10.1016/j.molstruc.2017.03.036

    Science.gov (United States)

    Kiefer, Johannes

    2017-09-01

    In the title paper, the DMSO sample obviously contains large amounts of water. This leads to a misinterpretation of the infrared spectra. Taking the presence of water into account, the observations can be explained in a straightforward manner.

  15. CCDC 810641: Experimental Crystal Structure Determination : Acetonitrile-(1,3-dimesitylimidazol-2-ylidene)-dicarbonyl-(eta^5^-cyclopentadienyl)-molybdenum tetrafluoroborate

    KAUST Repository

    Li, Shenyu

    2011-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. Transport-limited current and micro-sono-reactor characterization at 3 low frequencies in the presence of water, acetonitrile and imidazolium-based ionic liquids

    International Nuclear Information System (INIS)

    Costa, C.; Hihn, J. Y.; Rebetez, M.; Doche, M. L.; Bisel, I.; Moisy, P.

    2008-01-01

    A micro-sono-reactor, specially designed to carry out electrochemical tests in a room-temperature ionic liquid medium (RTIL), was studied. The cell, based on a particular design consisting of off-setting the ultrasonic probe out of the reaction volume, was characterized by several methods such as calorimetry, dosimetry and mass transfer measurements. The main result concerns the specific behaviour of the ionic liquid under ultrasonic irradiation. For example, the mass-transfer enhancement is particularly high, characterized by an average Sherwood number of 6500 while the value obtained with an electrode rotating at 4500 rpm is only 1200. (authors)

  17. Trichlorido[(meth­yl{2-[meth­yl(2-pyridyl­meth­yl)amino]eth­yl}amino)acetonitrile]iron(III) methanol hemisolvate

    Science.gov (United States)

    Nielsen, Anne; McKenzie, Christine J.; Bond, Andrew D.

    2009-01-01

    The title compound, [FeCl3(C12H18N4)]·0.5CH3OH, contains an FeIII ion in a distorted octa­hedral coordination environment. The neutral N,N′,N′′-tridentate ligand adopts a fac coordination mode, and chloride ligands lie trans to each of the three coordinated N atoms. In the crystal, the complexes form columns extending parallel to the approximate local threefold axes of the FeN3Cl3 octa­hedra, and the columns are arranged so that the uncoordinated nitrile groups align in an anti­parallel manner and the pyridyl rings form offset face-to-face arrangements [inter­planar separations = 2.95 (1) and 3.11 (1) Å; centroid–centroid distances = 5.31 (1) and 4.92 (1) Å]. The methanol solvent mol­ecule is disordered about a twofold rotation axis. PMID:21578169

  18. On the formation of radical dications of protonated amino acids in a "microsolution" of water or acetonitrile and their reactivity towards the solvent

    DEFF Research Database (Denmark)

    Sørensen, M; Forster, JS; Hvelplund, P

    2001-01-01

    +* in the "microsolution" depends on the energetics of the electron transfer reaction AH2+* +S --> AH++S+*, the hydrogen abstraction reaction AH2+*+S --> AH2(2+)+[S-H]*, and the proton transfer reaction AH2+* + S --> A+*+SH+. Using B3LYP/ 6-311+G(2d,p)//B3LYP/6-31+G(d) model chemistry, we describe these three reactions...

  19. Two-dimensional structure of poly[[[μ2-1,4-bis(pyridin-4-ylbutane]bis(μ4-pentanedioatodicopper(II] acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Do Nam Lee

    2017-10-01

    Full Text Available In the title compound, {[Cu2(μ4-C5H6O42(μ2-C14H16N2]·2CH3CN}n, the Cu2 dinuclear units are connected by glutartate ligands, forming one-dimensional double chains. These chains, are in turn bridged by 1,4-bis(pyridin-4-ylbutane ligands to form a two-dimensional layer structure parallel to (112. The carboxylate groups of the glutarate ligand bridge two copper(II ions, forming a paddle-wheel-type Cu2(CO24 dinuclear secondary building unit. A crystallographic inversion centre is located midway between two CuII ions, with a Cu...Cu distance of 2.639 (3 Å. The coordination geometry of the unique CuII ion is slightly disorted square pyramidal, formed by four equatorial carboxylate O atoms and an axial pyridyl N atom.

  20. 3,9-Dithia-6-azaundecane-appended Iridium (III) Complex for the Selective Detection of Hg2+ in Aqueous Acetonitrile

    International Nuclear Information System (INIS)

    Ann, Jee Hye; Li, Yinan; Hyun, Myung Ho

    2012-01-01

    Detection of mercuric ion (Hg 2+ ) originated from natural or industrial sources is very important because it is extremely toxic even at low levels and causes serious environmental and health problems. Consequently, many efforts have been devoted to the development of sensitive chemosensors for the detection of Hg 2+ . For example, various fluorescent chemosensors based on rhodamine, nitrobenzoxadiazole, fluorescein, boradiazaindacene (BODIPY), dansyl, pyrene, or other fluorophores have been developed for the selective detection of Hg 2+ . While various fluorescent chemosensors for the selective detection of Hg 2+ have been developed, phosphorescent chemosensors for the selective detection of Hg 2+ are relatively rare. Among various phosphors, iridium (III) complexes with sulfur containing cyclometalated ligands have been used as phosphorescent chemosensors for the selective detection of Hg 2+ . Azacrown ether-appended iridium (III) complex developed in our laboratory has also been utilized as a phosphorescent chemosensor for the selective detection of Hg 2+ . As an another iridium (III) complex-based phosphorescent chemosensors for the selective detection of Hg 2+ , in this study, we wish to prepare iridium (III) complex containing two 3,9-dithia-6-azaundecane units as chelating ligands for metal ions. Some fluorophores containing 3,9-dithia-6-azaundecane unit have been successfully applied for the selective detection of Hg 2+ . In this instance, iridium (III) complex containing two 3,9-dithia-6-azaundecane units is expected to be useful as a phosphorescent chemosensor for the selective detection of Hg 2+ . Iridium (III) complex containing two 3,9-dithia-6-azaundecane units was prepared starting from 2-phenylpyridine according to the procedure shown in Scheme 1. 2-Phenylpyridine was transformed into chloride bridged dimeric iridium complex, [(ppy) 2 IrCl] 2 , via the reported procedure. By treating [(ppy) 2 IrCl] 2 with 4,4'-bis(bromomethyl)-2,2'-bipyridine, which was prepared starting from 4,4'-dimethyl-2,2'-bipyridine according to the reported procedure, iridium (III) complex 1 was prepared. Finally iridium (III) complex 1 was treated with 3,9-dithia-6-azaundecane in the presence of NaH in tetrahydrofuran (THF) to afford iridium (III) complex 2 containing two 3,9-dithia-6-azaundecane units

  1. 3,9-Dithia-6-azaundecane-appended Iridium (III) Complex for the Selective Detection of Hg{sup 2+} in Aqueous Acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Ann, Jee Hye; Li, Yinan; Hyun, Myung Ho [Pusan National Univ., Busan (Korea, Republic of)

    2012-10-15

    Detection of mercuric ion (Hg{sup 2+}) originated from natural or industrial sources is very important because it is extremely toxic even at low levels and causes serious environmental and health problems. Consequently, many efforts have been devoted to the development of sensitive chemosensors for the detection of Hg{sup 2+}. For example, various fluorescent chemosensors based on rhodamine, nitrobenzoxadiazole, fluorescein, boradiazaindacene (BODIPY), dansyl, pyrene, or other fluorophores have been developed for the selective detection of Hg{sup 2+}. While various fluorescent chemosensors for the selective detection of Hg{sup 2+} have been developed, phosphorescent chemosensors for the selective detection of Hg{sup 2+} are relatively rare. Among various phosphors, iridium (III) complexes with sulfur containing cyclometalated ligands have been used as phosphorescent chemosensors for the selective detection of Hg{sup 2+}. Azacrown ether-appended iridium (III) complex developed in our laboratory has also been utilized as a phosphorescent chemosensor for the selective detection of Hg{sup 2+}. As an another iridium (III) complex-based phosphorescent chemosensors for the selective detection of Hg{sup 2+}, in this study, we wish to prepare iridium (III) complex containing two 3,9-dithia-6-azaundecane units as chelating ligands for metal ions. Some fluorophores containing 3,9-dithia-6-azaundecane unit have been successfully applied for the selective detection of Hg{sup 2+}. In this instance, iridium (III) complex containing two 3,9-dithia-6-azaundecane units is expected to be useful as a phosphorescent chemosensor for the selective detection of Hg{sup 2+}. Iridium (III) complex containing two 3,9-dithia-6-azaundecane units was prepared starting from 2-phenylpyridine according to the procedure shown in Scheme 1. 2-Phenylpyridine was transformed into chloride bridged dimeric iridium complex, [(ppy){sub 2}IrCl]{sub 2}, via the reported procedure. By treating [(ppy){sub 2}IrCl]{sub 2} with 4,4'-bis(bromomethyl)-2,2'-bipyridine, which was prepared starting from 4,4'-dimethyl-2,2'-bipyridine according to the reported procedure, iridium (III) complex 1 was prepared. Finally iridium (III) complex 1 was treated with 3,9-dithia-6-azaundecane in the presence of NaH in tetrahydrofuran (THF) to afford iridium (III) complex 2 containing two 3,9-dithia-6-azaundecane units.

  2. A new [(1R,2R)-1,2-diaminocyclohexane]platinum(II) complex: formation by nitrate-acetonitrile ligand exchange

    Czech Academy of Sciences Publication Activity Database

    Pažout, R.; Housková, J.; Dušek, Michal; Maixner, J.; Cibulková, J.; Kačer, P.

    2010-01-01

    Roč. 66, Part 10 (2010), m273-m275 ISSN 0108-2701 Institutional research plan: CEZ:AV0Z10100521 Keywords : platinum complexes * structure analysis * disorder * cyclohexane * diamine Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.745, year: 2010

  3. Stereoisomeric products of electrochemical reduction of heterocyclic Fischer aminocarbene Cr(0) complexes. Development of the electrochemistry-mass spectrometry tandem approach using biphasic (acetonitrile-hexane) preparative electrolysis

    Czech Academy of Sciences Publication Activity Database

    Metelková, R.; Hoskovcová, I.; Polášek, Miroslav; Urban, Jiří; David, T.; Ludvík, Jiří

    2015-01-01

    Roč. 162, APR 2015 (2015), s. 17-23 ISSN 0013-4686 R&D Projects: GA ČR GAP206/11/0727 Institutional support: RVO:61388955 Keywords : Fischer aminocarbene complexes biphasic electrolysis * EC-MS * HPLC-NMR Subject RIV: CG - Electrochemistry Impact factor: 4.803, year: 2015

  4. Vitamin D analysis in plasma by high performance liquid chromatography (HPLC) with C30 reversed phase column and UV detection - easy and acetonitrile-free

    DEFF Research Database (Denmark)

    Hymøller, Lone; Jensen, Søren Krogh

    2011-01-01

    Two physiologically important forms of vitamin D exist: vitamin D2 and vitamin D3, which by liver based hydroxylase enzymes are converted to 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3, respectively. These hydroxylated metabolites of vitamin D are measured in plasma to assess the vtamin D status...... detection at 265nm for quantifying vitamin D2, vitamin D3, 25-hydroxyvitamin D2, and 25-hydroxyvitamin D3. The method proved versatile with respect to plasma lipid content, sample amount, and plasma concentration of the vitamin D metabolites as it was tested using plasma from six different species: cattle...... material® 972 “Vitamin D in human serum” from the National Institute of Standards and Technology (NIST) (Gaithersburg, USA) the results for 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 concentrations were within the boundaries provided by NIST, reflected by Z-scores between 0.1 and 0.9....

  5. Characterization of p-Type CdTe Electrodes in Acetonitrile/Electrolyte Solutions. Nearly Ideal Behavior from Reductive Surface Pretreatments.

    Science.gov (United States)

    1983-06-30

    using Ag conductive palnt and the entire assembly was mounted in glass tubing with ordinary epoxy leaving only the front crystal face, ...energy set, several eV higher than either Te2- or Teo (as measured for sputtered CdTe and Te, respectively) is assigned to TeO2 , the lowest stable...binding energy reported for TeO2 (575.9 eV). 33 The lower binding energy set of bands, lying midway between Teo and Te2 - , results from both Teo and

  6. CCDC 1468927: Experimental Crystal Structure Determination : 5,13-dimesitylbenzo[4,5]cyclohepta[1,2-b]fluorene acetonitrile solvate

    KAUST Repository

    Yang, Xuejin; Shi, Xueliang; Aratani, Naoki; Goncalves, Theo; Huang, Kuo-Wei; Yamada, Hiroko; Chi, Chunyan; Miao, Qian

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from

  7. CCDC 810641: Experimental Crystal Structure Determination : Acetonitrile-(1,3-dimesitylimidazol-2-ylidene)-dicarbonyl-(eta^5^-cyclopentadienyl)-molybdenum tetrafluoroborate

    KAUST Repository

    Li, Shenyu; Kee, Choon Wee; Huang, Kuo-Wei; Hor, T.S.A.; Zhao, Jin

    2011-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from

  8. Capillary electrophoresis coupled with chloroform-acetonitrile extraction for rapid and highly selective determination of cysteine and homocysteine levels in human blood plasma and urine.

    Science.gov (United States)

    Ivanov, Alexander Vladimirovich; Bulgakova, Polina Olegovna; Virus, Edward Danielevich; Kruglova, Maria Petrovna; Alexandrin, Valery Vasil'evich; Gadieva, Viktoriya Aleksandrovna; Luzyanin, Boris Petrovich; Kushlinskii, Nikolai Evgen'evich; Fedoseev, Anatolij Nikolaevich; Kubatiev, Aslan Amirkhanovich

    2017-10-01

    A rapid and selective method has been developed for highly sensitive determination of total cysteine and homocysteine levels in human blood plasma and urine by capillary electrophoresis (CE) coupled with liquid-liquid extraction. Analytes were first derivatized with 1,1'-thiocarbonyldiimidazole and then samples were purified by chloroform-ACN extraction. Electrophoretic separation was performed using 0.1 M phosphate with 30 mM triethanolamine, pH 2, containing 25 μM CTAB, 2.5 μM SDS, and 2.5% polyethylene glycol 600. Samples were injected into the capillary (with total length 32 cm and 50 μm id) at 2250 mbar*s and subsequent injection was performed for 30 s with 0.5 M KОН. The total analysis time was less than 9 min, accuracy was 98%, and precision was <2.6%. The LOD was 0.2 μM for homocysteine and 0.5 μM for cysteine. The use of liquid-liquid extraction allowed the precision and sensitivity of the CE method to be significantly increased. The validated method was applied to determine total cysteine and homocysteine content in human blood plasma and urine samples obtained from healthy volunteers and patients with kidney disorders. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A QM/MM and QM/QM/MM study of Kerr, Cotton-Mouton and Jones linear birefringences in liquid acetonitrile

    DEFF Research Database (Denmark)

    Fahleson, Tobias; Olsen, Jógvan Magnus Haugaard; Norman, Patrick

    2018-01-01

    functions were computed using time-dependent Kohn-Sham density-functional theory with use of the standard CAM-B3LYP functional. In the liquid phase, a series of room temperature (293.15 K) molecular dynamics snapshots were selected, for which averaged values of the observables were obtained at an optical...

  10. CCDC 1468927: Experimental Crystal Structure Determination : 5,13-dimesitylbenzo[4,5]cyclohepta[1,2-b]fluorene acetonitrile solvate

    KAUST Repository

    Yang, Xuejin

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. CCDC 1420288: Experimental Crystal Structure Determination : bis(acetonitrile)-(1-((2,2'-bipyridin-6-yl)methyl)-3-((pyridin-2-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  12. CCDC 1420291: Experimental Crystal Structure Determination : (2-(3-((3-((3-methyl-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)pyridine)-bis(acetonitrile)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.; Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 963848: Experimental Crystal Structure Determination : bis(acetonitrile)-(1,3,6,8,11,13,16,18-octaazapentacyclo[16.2.1.13,6.18,11.113,16]tetracosa-4,9,14,19-tetraene-21,22,23,24-tetraylidene)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Anneser, Markus R.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. CCDC 1408064: Experimental Crystal Structure Determination : (mu2-1,1'-methylenebis(3-methyl-2,3-dihydro-1H-imidazol-2-ylidene))-bis(iodo)-di-gold bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Baron, Marco; Tubaro, Cristina; Basato, Marino; Isse, Abdirisak Ahmed; Gennaro, Armando; Cavallo, Luigi; Graiff, Claudia; Dolmella, Alessandro; Falivene, Laura; Caporaso, Lucia

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 1420289: Experimental Crystal Structure Determination : (2,2'-(methylenebis(1H-imidazol-2-ylidene-3,1(2H)-diylmethylene))dipyridine)-tris(acetonitrile)-iron bis(hexafluorophosphate) diethyl ether solvate

    KAUST Repository

    Weiss, Daniel T.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. CCDC 997389: Experimental Crystal Structure Determination : bis(1,1'-methylenebis(3-(2-furyl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(acetonitrile)-iron(ii) bis(hexafluorophosphate) acetone solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  17. CCDC 879411: Experimental Crystal Structure Determination : bis(bis(acetonitrile)-(2,6-bis(4,4-diphenyl-4,5-dihydro-1,3-oxazol-2-yl)pyridine)-chloro-iron) bis(mu-chloro)-tetrachloro-di-iron

    KAUST Repository

    Chen, Tao

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. CCDC 879410: Experimental Crystal Structure Determination : (acetonitrile)-(2,6-bis(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)pyridine)-bis(trifluoromethanesulfonato)-iron(ii)

    KAUST Repository

    Chen, Tao

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  19. CCDC 860715: Experimental Crystal Structure Determination : catena-[bis(mu-oxido)-tris(mu-5,5'-ethyne-1,2-diyldiisophthalato)-hexa-aqua-hexa-indium dinitrate acetonitrile N,N-dimethylformamide solvate sesquihydrate

    KAUST Repository

    Zheng, Bing; Sun, Xiaodong; Li, Guanghua; Cairns, Amy J.; Kravtsov, Victor Ch.; Huo, Qisheng; Liu, Yunling; Eddaoudi, Mohamed

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. CCDC 860716: Experimental Crystal Structure Determination : catena-[dimethylammonium hexakis(mu-5,5'-ethyne-1,2-diyldiisophthalato)-bis(mu-oxido)-hexa-aqua-nona-indium acetonitrile N,N-dimethylformamide solvate decahydrate

    KAUST Repository

    Zheng, Bing; Sun, Xiaodong; Li, Guanghua; Cairns, Amy J.; Kravtsov, Victor Ch.; Huo, Qisheng; Liu, Yunling; Eddaoudi, Mohamed

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  1. CCDC 992646: Experimental Crystal Structure Determination : (1,1'-methanediylbis(3-(pyridin-2-yl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(methyl isonicotinate)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Haslinger, Stefan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  2. CCDC 943025: Experimental Crystal Structure Determination : catena-(hexakis(mu~3~-3-Aminobenzoato-N,O,O')-(mu~3~-chloro)-(mu~3~-oxo)-triaqua-hexachloro-tri-chromium-tri-copper acetonitrile dimethylformamide solvate hydrate)

    KAUST Repository

    Elsaidi, Sameh K.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. Fluorescence imaging of sample zone narrowing and dispersion in a glass microchip: the effects of organic solvent (acetonitrile)-salt mixtures in the sample matrix and surfactant micelles in the running buffer.

    Science.gov (United States)

    Jia, Zhijian; Lee, Yi-kuen; Fang, Qun; Huie, Carmen W

    2006-03-01

    A mismatch in the EOF velocities between the sample zone and running buffer region is known to generate pressure-driven, parabolic flow profile of the sample plug in electrokinetic separation systems. In the present study, video fluorescence microscopy was employed to capture real-time dynamics of the sample plug (containing fluorescein as the probe molecule) in a discontinuous conductivity system within a glass microchip, in which the sample matrix consisted of a mixture of ACN and salt (NaCl), and the running buffer contained sodium cholate (SC) micelles as the pseudo-stationary phase (i.e., performing "ACN stacking" in the mode of MEKC). Upon application of the separation voltage, the video images revealed that zone narrowing and broadening of the probe molecules occurred as the sample plug headed toward the cathode during the initial time period, probably resulting in part from the stacking/sweeping, and destacking of the SC micelles at the boundaries between the sample zone and running buffer. Interestingly, a second sample zone narrowing event can be observed as the sample plug moved further toward the cathode, which could be attributed to the sweeping of the slower moving probe molecules by the faster moving SC micelles that originated from the anode. This phenomenon was studied as a function of pH, sample plug length, as well as the concentration of organic solvent and salt in the sample matrix. The data suggested that the presence of large amounts of an organic solvent (such as ACN or methanol) and salts in the sample matrix not only induces sample dispersion due to the formation of a pressure-driven (hydrodynamic) flow, but may also lead to the formation of a double sample zone narrowing phenomenon by altering the local EOF dynamics within the separation system.

  4. CCDC 948061: Experimental Crystal Structure Determination : catena-[bis(mu3-Oxo)-dodecakis(mu3-isonicotonato)-dodecaqua-tri-cadmium-hexa-chromium octanitrate acetonitrile N,N-dimethylformamide solvate

    KAUST Repository

    Schoedel, Alexander; Wojtas, Lukasz; Kelley, Stephen P.; Rogers, Robin D.; Eddaoudi, Mohamed; Zaworotko, Michael J.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 992644: Experimental Crystal Structure Determination : (1,1'-methanediylbis(3-(pyridin-2-yl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(N,N-dimethylpyridin-4-amine)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Haslinger, Stefan; Kü ck, Jens W.; Hahn, Eva M.; Cokoja, Mirza; Pö thig, Alexander; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. Low-temperature Fabrication of Highly-Efficient, Optically-Transparent (FTO-free) Graphene Cathode for Co-Mediated Dye-Sensitized Solar Cells with Acetonitrile-free Electrolyte Solution

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Liska, P.; Zakeeruddin, S. M.; Grätzel, M.

    2016-01-01

    Roč. 195, MAR 2016 (2016), s. 34-42 ISSN 0013-4686 R&D Projects: GA ČR GA13-07724S Institutional support: RVO:61388955 Keywords : dye sensitized solar cell * electrochemical impedance spectroscopy * stainless-steel Subject RIV: CG - Electrochemistry Impact factor: 4.798, year: 2016

  7. CCDC 782644: Experimental Crystal Structure Determination : tetrakis(mu~2~-4,5-imidazoledicarboxylato)-tetrakis(1,2-propanediamine)-tetra-indium tri-potassium trinitrate acetonitrile solvate hydrate

    KAUST Repository

    Wang, Shuang; Zhao, Tingting; Li, Guanghua; Wojtas, L.; Huo, Qisheng; Eddaoudi, Mohamed; Liu, Yunling

    2011-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  8. CCDC 1420292: Experimental Crystal Structure Determination : (3-methyl-1-((3-((3-((3-methyl-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-1H-imidazol-3-ium)-tris(acetonitrile)-iron tris(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. CCDC 1036603: Experimental Crystal Structure Determination : (nitrosyl)-(1,3,6,8,11,13,16,18-octaazapentacyclo[16.2.1.13,6.18,11.113,16]tetracosa-4,9,14,19-tetraene-21,22,23,24-tetraylidene)-iron(iii) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. Crystal structure of bis-[(acetato-κO)(imidazolidine-2-thione-κS)bis-(tri-phenyl-phosphane-κP)silver(I)] di-μ-imidazol-idine-2-thione-κ(4) S:S-bis-[(imidazol-id-ine-2-thione-κS)bis-(tri-phenyl-phosphane-κP)silver(I)] di-acetate aceto-nitrile disolvate tetra-hydrate.

    Science.gov (United States)

    Nimthong-Roldán, Arunpatcha; Ratthiwan, Janejira; Lakmas, Sawanya; Wattanakanjana, Yupa

    2016-04-01

    In the title compound, [Ag2(C3H6N2S)4(C18H15P)2](C2H3O2)2·[Ag(C2H3O2)(C3H6N2S)(C18H15P)2]2·2C2H3N·4H2O, the Ag(I) ion in the mononuclear neutral complex exhibits a distorted tetra-hedral environment with coordination by two P atoms from tri-phenyl-phosphane (PPh3) ligands, one S atom of an imidazolidine-2-thione (etu) ligand and one O atom of an acetate anion. The binuclear cationic complex comprises two inversion-related [Ag(C3H6N2S)2(C18H15P)] units with Ag(I) ions bridged by two S atoms from etu ligands forming a four-membered Ag-S-Ag-S ring. Each Ag(I) ion is coordinated by a P atom of a PPh3 ligand, two S atoms of bridging etu ligands and the terminal S atom of an etu ligand in a distorted tetra-hedral environment. In the crystal, the mononuclear complex is linked to lattice water mol-ecules through O-H⋯O and N-H⋯O hydrogen bonds, forming a chain along [100]. In addition, the binuclear complex mol-ecules are connected to acetate anions and lattice water mol-ecules via O-H⋯O, N-H⋯O and O-H⋯S hydrogen bonds, also along [100].

  11. 40 CFR Appendix Vii to Part 261 - Basis for Listing Hazardous Waste

    Science.gov (United States)

    2010-07-01

    ..., acetonitrile, hydrocyanic acid. K013 Hydrocyanic acid, acrylonitrile, acetonitrile. K014 Acetonitrile..., trichlorofluoromethane. F003 N.A. F004 Cresols and cresylic acid, nitrobenzene. F005 Toluene, methyl ethyl ketone, carbon... -tetrachlorophenols and their chlorophenoxy derivative acids, esters, ethers, amine and other salts. F021 Penta- and...

  12. μ-Acetato-κ2O:O′-[7,23-dibenzyl-15,31-dichloro-3,7,11,19,23,27-hexaazatricyclo[27.3.1.113,17]tetratriconta-1(32,2,11,13,15,17(34,18,27,29(33,30-decaene-33,34-diolato-κ10N4,N5,N6,O1,O2:N1,N2,N3,O1,O2]dinickel(II perchlorate acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Juan Kong

    2008-01-01

    Full Text Available The title complex, [Ni2(C42H46Cl2N6O2(C2H3O2]ClO4·2CH3CN, was synthesized by condensation of 2,6-diformyl-4-chlorophenol with N,N-bis(aminopropylbenzylamine in the presence of NiII ions. The ligand is a 28-membered macrocycle with two identical pendant arms. The coordination geometries of the Ni atoms are both octahedral. The two Ni atoms are bridged by two phenolate O atoms of the macrocyclic ligand and one acetate ligand, with an Ni...Ni distance of 3.147 (4 Å.

  13. [Selectivity tuning in multi-binary eluents for reversed-phase liquid chromatography (RPLC)].

    Science.gov (United States)

    Lü, M; Zou, H; Liang, X; Lu, P

    1999-01-01

    In this article, the retention equation and the relationship between retention parameters and the parameters of molecular structure deduced from statistical thermodynamics in RPLC have been used to explain the difference of selectivity towards a particular species of compounds polycyclic aromatic hydrocarbons (PAHs). Methanol/water, acetonitrile/water and isopropanol/acetonitrile have been provided in advance, then the retention behaviors of sixteen PAHs under three binary solvent systems have been investigated. It is found that each pair of binary solvents of methanol/water, acetonitrile/water and isopropanol/acetonitrile has its own unique selectivity. The best selectivity obtained for acenaphthene and fluorene is methanol/water system for fluoranthene and pyrene is acetonitrile/water, and for benzo[g,h,i]perylene and dibenzo[a,h]anthracene is isopropanol/acetonitrile. So a three-stepwise gradient elution of multi-binary mobile phase can be chosen for separation of 16 PAHs.

  14. The Determination of Rate-Limiting Steps during Soot Formation

    Science.gov (United States)

    1990-06-08

    and a CH3N precursor of acetonitrile such as 2H-aziridine although other intermediates of lower energy such as ketenimine have been identified on the...precursor of acetonitrile such as 2H-aziridine or ketenimine . Experimentally it was found that the overall rate of disappearance of pyrrole is first order

  15. Influence of organic solvents on interfacial water at surfaces of silica gel and partially silylated fumed silica

    International Nuclear Information System (INIS)

    Turov, V.V.; Gun'ko, V.M.; Tsapko, M.D.; Bogatyrev, V.M.; Skubiszewska-Zieba, J.; Leboda, R.; Ryczkowski, J.

    2004-01-01

    The effects of organic solvents (dimethylsulfoxide-d 6 (DMSO-d 6 ), chloroform-d, acetone-d 6 , and acetonitrile-d 3 ) on the properties of interfacial water at surfaces of silica gel Si-40 and partially silylated fumed silica A-380 were studied by means of the 1 H NMR spectroscopy with freezing-out of adsorbed water at 180 1 H NMR investigations were also analysed on the basis of the structural characteristics of silicas and quantum chemical calculations of the chemical shifts δ H and solvent effects. DMSO-d 6 and acetonitrile-d 3 are poorly miscible with water in silica gel pores in contrast to the bulk liquids. DMSO-d 6 and chloroform-d affect the structure of the interfacial water weaker than acetone-d 6 and acetonitrile-d 3 at amounts of liquids greater than the pore volume. Acetone-d 6 and acetonitrile-d 3 can displace water from pores under this condition. The chemical shift of protons in water adsorbed on silica gel is 3.5-6.5 ppm, which corresponds to the formation of two to four hydrogen bonds per molecule. Water adsorbed on partially silylated fumed silica has two 1 H NMR signals at 5 and 1.1-1.7 ppm related to different structures (droplets and small clusters) of the interfacial water

  16. (II) complexes containing isocyanide and labile nitrile ligands

    African Journals Online (AJOL)

    A new ruthenium(II) complex containing both acetonitrile and propionitrile moieties as coordinating ligands has been prepared. The treatment of the polymer [{RuCl2(COD)}x], (COD = cycloocta-1,5-diene) (1) with a mixture of acetonitrile and propionitrile under reflux produced a new precursor ...

  17. Towards a thermally regenerative all-copper redox flow battery

    OpenAIRE

    Peljo, Pekka; Lloyd, David; Nguyet, Doan; Majaneva, Marko; Kontturi, Kyosti

    2014-01-01

    An all-copper redox flow battery based on strong complexation of Cu+ with acetonitrile is demonstrated, exhibiting reasonable battery performance. More interestingly, the battery can be charged by heat sources of 100 degrees C, by distilling off the acetonitrile. This destabilizes the Cu+ complex, leading to recovery of the starting materials.

  18. Towards a thermally regenerative all-copper redox flow battery.

    Science.gov (United States)

    Peljo, Pekka; Lloyd, David; Doan, Nguyet; Majaneva, Marko; Kontturi, Kyösti

    2014-02-21

    An all-copper redox flow battery based on strong complexation of Cu(+) with acetonitrile is demonstrated, exhibiting reasonable battery performance. More interestingly, the battery can be charged by heat sources of 100 °C, by distilling off the acetonitrile. This destabilizes the Cu(+) complex, leading to recovery of the starting materials.

  19. CCDC 972510: Experimental Crystal Structure Determination : 8,21-bis(4-t-butylphenyl)-2,15-bis(2,6-diisopropylphenyl)-3a,5a,7,13a,16a,16b,20a,20b,22d,24a,26a,26b-dodecahydrobenzo[1,12]benzo[13',14']isoquinolino[6'',5'',4'':8',9',10']pentapheno[2',3':3,4]tetrapheno[9,8,7-def]isoquinoline-1,3,14,16(2H,15H)-tetrone toluene acetonitrile solvate

    KAUST Repository

    Das, Soumyajit

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. Tin(2) difluoride and antimony(3) trifluoride as fluorine donors in reactions with tantalum halides in various solvents

    International Nuclear Information System (INIS)

    Kokunov, Yu.V.; Ershova, M.M.; Razgonyaeva, G.A.; Buslaev, Yu.A.

    2001-01-01

    The reactions of SnF 2 , SbF 3 with TaF 5 and TaCl 5 in acetonitrile and dimethylsulfoxide were studied by means of 19 F and 119 Sn NMR. SnF 2 and SbF 3 were established to be donors of fluorine ions for the tantalum(5). It was found that the anion and cation tantalum fluorochloride complexes were formed in acetonitrile, and [TaF 6 ] - was dominated in dimethylsulfoxide. In the solution the tin(2) is present as fluorine-containing polymer cations. Dimethylsulfoxide, as distinct from acetonitrile, leads to disproportionation of tantalum fluorochlorides [ru

  1. Effect of various solvents on the viscosity-average molecular weight of poly (vinyl acetate)

    International Nuclear Information System (INIS)

    Rehman, W.U.; But, M.A.; Chughtai, A.; Jamil, T.; Sattar, A.

    2006-01-01

    Solution polymerization of Vinyl Acetate was carried out in various solvents (benzene, toluene, ethyl acetate, acetonitrile). Dilute solution viscometry was used to determine the viscosity-average molecular weight of the resulting Poly (Vinyl Acetate) (PV Ac) in each case. The viscosity-average molecular weight (M,J of PVAc was found to increase in the order benzene < toluene < ethyl acetate < acetonitrile, It was concluded that under the same reaction conditions (polymerization time, initiator quantity, solvent/monomer ratio, temperature), acetonitrile served as the best solvent for solution. polymerization of Vinyl Acetate monomer. (author)

  2. Establishment and optimization of NMR-based cell metabonomics study protocols for neonatal Sprague-Dawley rat cardiomyocytes.

    Science.gov (United States)

    Zhang, Ming; Sun, Bo; Zhang, Qi; Gao, Rong; Liu, Qiao; Dong, Fangting; Fang, Haiqin; Peng, Shuangqing; Li, Famei; Yan, Xianzhong

    2017-01-15

    A quenching, harvesting, and extraction protocol was optimized for cardiomyocytes NMR metabonomics analysis in this study. Trypsin treatment and direct scraping cells in acetonitrile were compared for sample harvesting. The results showed trypsin treatment cause normalized concentration increasing of phosphocholine and metabolites leakage, since the trypsin-induced membrane broken and long term harvesting procedures. Then the intracellular metabolite extraction efficiency of methanol and acetonitrile were compared. As a result, washing twice with phosphate buffer, direct scraping cells and extracting with acetonitrile were chosen to prepare cardiomyocytes extracts samples for metabonomics studies. This optimized protocol is rapid, effective, and exhibits greater metabolite retention. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. CYCLIC VOLTAMMETRY AND REDUCTION MECHANISTIC ...

    African Journals Online (AJOL)

    Preferred Customer

    potential at different scan rates and upon substrate concentrations confirm, ... All the experiments were performed in acetonitrile purchased from Sigma. ... on the pyrylium cation is followed by chemical reaction of the generated radical, as well.

  4. synthesis and characterisation of temperature responsive poly (2 ...

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... phase separation from solution while below LCST, the polymer is miscible in .... to remove impurities such as lutidinium salt that could interfere with the ... ppm was due to residual Acetonitrile that was used as polymerisation ...

  5. Structural systematics of some metal complexes with 4,5 ...

    Indian Academy of Sciences (India)

    study reveals that each metal(II) centre in the four complexes adopts distorted octahedral geometry with MN6 ... potassium permanganate (E Merck, India), potassium. 717 ... The final reaction solu- ..... ble in water, methanol, acetonitrile, etc.

  6. Preparation and stability study of ampouled polycyclic aromatic hydrocarbon solutions

    NARCIS (Netherlands)

    Vaessen; H.A.M.G.; Kamp; C.G. van de; Jekel; A.A.

    1986-01-01

    De stabiliteit van geampulleerde acetonitril- en tolueenoplossingen van zeven polycyclische aromatische koolwaterstoffen (PAK) werd bestudeerd gedurende een jaar. Beide oplossingen waren qua PAK- samenstelling en gehalte identiek en bereid uit een moederoplossing. Voor en vlak na het ampulleren

  7. Controlled laser biochemistry in room-temperature polar liquids by ultrashort laser pulses

    DEFF Research Database (Denmark)

    Gruzdev, Vitaly; Korkin, Dmitry; Mooney, Brian P.

    2018-01-01

    Traditional laser methods to control chemical modifications of biomolecules are not applicable under biologically relevant conditions. We report controlled modifications of peptides and insulin by femtosecond laser in water, methanol, and acetonitrile at room temperature...

  8. Optimization of process parameters for the production of alkali ...

    African Journals Online (AJOL)

    Yomi

    2012-01-16

    Jan 16, 2012 ... Research and Technology Applications, Alexandria, Egypt. 2Department of Chemistry .... size 3 µm) using a mobile phase of sodium dihydrogen phosphate buffer and acetonitrile ..... Doctorate Thesis,. Texas A&M University.

  9. Development and Validation of a Bioanalytical Method for Direct ...

    African Journals Online (AJOL)

    Erah

    2011-01-16

    Jan 16, 2011 ... acetonitrile in water (v/v) as mobile phase containing ammonium acetate and triethylamine (TEA), at a .... The pH of the mobile ..... and Application to a Human Pharmacokinetic ... (Thesis), Rhodes University, Grahamstown,.

  10. The DFT investigations of the electron injection in hydrazone-based sensitizers

    KAUST Repository

    Al-Sehemi, Abdullah G.; Irfan, Ahmad; Asiri, Abdullah M.

    2012-01-01

    solvent. The calculated absorption spectra in ethanol, acetonitrile, and methanol are in good agreement with experimental evidences. The absorption spectra are red shifted compared to System1. On the basis of electron injection and electronic coupling

  11. Solvation Effects on Electronic Transitions: Exploring the Performance of Advanced Solvent Potentials in Polarizable Embedding Calculations

    DEFF Research Database (Denmark)

    Schwabe, Tobias; Olsen, Magnus; Sneskov, Kristian

    2011-01-01

    The polarizable embedding (PE) approach, which combines quantum mechanics (QM) and molecular mechanics (MM), is applied to predict solvatochromic effects on excitation energies of several representative molecules in aqueous, methanol, acetonitrile, and carbon tetrachloride solutions. Good agreement...

  12. A REVERSED PHASE HPLC METHOD FOR THE ANALYSIS OF ...

    African Journals Online (AJOL)

    Preferred Customer

    2009-04-10

    2Department of Chemistry and Chemical Engineering, Hunan Institute of Science and. Technology, 414000 Yueyang, China. (Received April 10, 2009; revised .... acid, methanol, acetonitrile (gradient grade for chromatography), perchloric acid 70%, sodium dihydrogen phosphatemonohydrate, and sodium hydroxide were ...

  13. Development of a UPLC–MS/MS method for determining ɣ-hydroxybutyric acid (GHB) and GHB glucuronide concentrations in hair and application to forensic cases

    DEFF Research Database (Denmark)

    Wang, Xin; Johansen, Sys Stybe; Linnet, Kristian

    2016-01-01

    We present a series of forensic cases measuring concentrations in hair of γ-hydroxybutyric acid (GHB) and its glucuronide. The compounds were extracted from hair by incubation for 1.5 h in a 25:25:50 (v/v/v) mixture of methanol/acetonitrile/2 mM ammonium formate (8 % acetonitrile, pH 5.3). The co......We present a series of forensic cases measuring concentrations in hair of γ-hydroxybutyric acid (GHB) and its glucuronide. The compounds were extracted from hair by incubation for 1.5 h in a 25:25:50 (v/v/v) mixture of methanol/acetonitrile/2 mM ammonium formate (8 % acetonitrile, pH 5...... to detection of exogenous exposure. To our knowledge, this is the first report to present GHB glucuronide in human hair....

  14. Development and Validation of HPLC Analytical Method for Chlorantraniliprole in Bulk and in the Formulation

    Directory of Open Access Journals (Sweden)

    Kapupara Pankaj P.

    2018-03-01

    Full Text Available Background: Chlorantraniliprole is widely used as a pesticide. It is only soluble in dimethyl formamide. However, most of the reported methods used acetonitrile and other solvents.

  15. Determination and Distribution Study of Pogostone in Rat Tissues by ...

    African Journals Online (AJOL)

    BEH C18 column with acetonitrile-water containing 0.1 % formic acid (55:45, v/v) as the mobile phase, ... Keywords: Ultra-fast liquid chromatography, Tissue distribution, Pogostone, Honokiol, Rats .... sample extraction, storage, and intermittent.

  16. Elucidation of mechanism of Si-jun-zi decoction-induced reversal of ...

    African Journals Online (AJOL)

    Methods: Spleen deficiency syndrome was induced in a rat model with reserpine. Liquid ... high-throughput quantification ability for ... HPLC grade acetonitrile was purchased from ..... study on the antitumor effect of flavonoid derivative 3d in.

  17. Antioxidant and Antimicrobial Activity of Polyphenol Extracts from ...

    African Journals Online (AJOL)

    Methods: Polyphenol content was determined using spectrophotometric and High performance liquid ... Keywords: European cornel, Blackthorn, Wild blackberry, Polyphenols, Antioxidant, Antimicrobial. Tropical ... Acetonitrile, and acetic acid of HPLC-grade were ..... Anthocyanin Quantification and radical scavenging.

  18. Binding of molecular oxygen by an artificial heme analogue: investigation on the formation of an Fe–tetracarbene superoxo complex

    KAUST Repository

    Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; D'Elia, Valerio; Hö gerl, Manuel P.; Basset, Jean-Marie; Kü hn, Fritz E.

    2016-01-01

    The dioxygen reactivity of a cyclic iron(II) tetra–NHC-complex (NHC: N-heterocyclic carbene) is investigated. Divergent oxidation behavior is observed depending on the choice of the solvent (acetonitrile or acetone). In the first case, exposure

  19. Deprotection of oximes using urea nitrate under microwave irradiation

    Indian Academy of Sciences (India)

    Abstract. A new mild and efficient method for the cleavage of oximes to carbonyl compounds using readily available urea nitrate in acetonitrile-water (95 : 5), under microwave irradiation within 2 min, in good yields is reported.

  20. Effect of some organic solvents on oxidative phosphorylation in rat liver mitochondria

    DEFF Research Database (Denmark)

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2013-01-01

    The effect of acetone, acetonitrile, dimethyl sulfoxide (DMSO), ethanol and methanol on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria has been studied. All the organic solvents inhibited the oxidative phosphorylation in a concentration dependent manner, but with differences...... in potencies. Among the tested organic solvents, acetonitrile and acetone were more potent than ethanol, methanol, and DMSO. There was no significant difference in oxidative phosphorylation, compared to controls, when the concentrations of acetone was below 1% (v/v), of acetonitrile below 2% (v/v), of DMSO...... below 10% (v/v), of ethanol below 5% or of methanol below 2%, respectively. There was complete inhibition of oxidative phosphorylation at 50% (v/v) of acetone, acetonitrile and ethanol. But in the case of DMSO and methanol there were some residual activities observed at the 50% concentration level. DMSO...

  1. Synthesis and structure of a rhenium(V) complex containing a ...

    African Journals Online (AJOL)

    methylphenyl) salicylideneimine) was prepared by the reaction of [NH4][ReO4] with H3mps in the presence of triphenylphosphine and hydrochloric acid in glacial acetic acid. Crystallization from acetonitrile gave the product 1.CH3CN.

  2. ELECTROCHEMICAL STUDIES OF N'-FERROCENYLMETHYL-N ...

    African Journals Online (AJOL)

    2011-12-31

    Phenylbenzohydrazide. FcX was studied in acetonitrile with tetrabutylammonium hexafluorophosphate as the supporting electrolyte and aqueous ethanol using the electrochemical technique. This study using cyclic (CV) and rotating ...

  3. Anionic chromogenic chemosensors highly selective for fluoride or cyanide based on 4-(4-Nitrobenzylideneamine)phenol

    OpenAIRE

    Nicoleti,Celso R.; Marini,Vanderléia G.; Zimmermann,Lizandra M.; Machado,Vanderlei G.

    2012-01-01

    4-(4-Nitrobenzylideneamine)phenol was used in two strategies allowing the highly selective detection of F- and CN-. Firstly, the compound in acetonitrile acts as a chromogenic chemosensor based on the idea that more basic anions cause its deprotonation (colorless solution), generating a colored solution containing phenolate. The discrimination of CN- over F- was obtained by adding 1.4% water to acetonitrile: water preferentially solvates F-, leaving the CN- free to deprotonate the compound. A...

  4. Photodegradation of bifenthrin and deltamethrin-effect of copper amendment and solvent system.

    Science.gov (United States)

    Tariq, Saadia Rashid; Ahmed, Dildar; Farooq, Amna; Rasheed, Sonia; Mansoor, Mubarkah

    2017-02-01

    The photodegradation of bifenthrin and deltamethrin was studied in the presence of Cu salts and two different solvents, methanol and acetonitrile. Results of the study showed that in the absence of any metal salt, the two pesticides degraded more rapidly in acetonitrile than in methanol. After 24 h of UV irradiation, 70% of deltamethrin had degraded in acetonitrile, while only 41% bifenthrin degraded in this solvent. In methanol, bifenthrin degraded at a much enhanced rate than in acetonitrile while the rate of degradation of deltamethrin was comparable to that in acetonitrile. The photodegradation was further enhanced by the addition of copper to the solution of bifenthrin and deltamethrin in acetonitrile. The rate of photodegradation of deltamethrin increased from 2.4 × 10 -2 to 3.5 × 10 -2  h -1 in acetonitrile and 2.5 × 10 -2 to 3.4 × 10 -2  h -1 in methanol after the addition of copper. Similarly, the rate of photodegradation of bifenthrin was increased from 5.0 × 10 -3 to 9.0 × 10 -3  h -1 in acetonitrile and 7.0 × 10 -3 to 9.05 × 10 -3  h -1 in methanol with the addition of copper. Thus, copper has the potential to enhance the photodegradation of bifenthrin and deltamethrin in both the solvents.

  5. antiproliferative activity and dft studies

    Indian Academy of Sciences (India)

    f) Mobile phase A: 0.025 M ammonium bicarbonate. g) Mobile phase B: acetonitrile. 6. Method VI: Separation at pH 10.5 (mobile phase with basic buffer). a) Column used for analysis - C18 waters X-bridge. b) to e) same as method I. f) Mobile phase A: 10 mM ammonium formate + 0.1% NH3. g) Mobile phase B: acetonitrile + ...

  6. Effect of reagents and medium nature on direction of cation-radical transformations in the reaction of diarylamines with nitrosonium borofluoride

    International Nuclear Information System (INIS)

    Koshechko, V.G.; Inozemtsev, A.N.; Pokhodenko, V.O.

    1983-01-01

    Diphenylamine and 4, 4'-dimethoxydiphenylamine in acetonitrile are oxidized monoelectronically by NOBF 4 . On the 4, 4'-dimethoxydiphenylamine example a maximum current concentration of intermediate cation-radicals formed in this reaction is measured. Cation-radicals in acetonitrile get dimeric transforming into products of oxidizing condensation of amines, with no respective nitrozamines being observed. Nitrosamines production on through cation-radical-NO recombination is realized but in the presence of protonoacceptor solvents, in particular pyridine

  7. Molecular sieves as dehydrating agent of nonaqueous solutions of rare earths

    International Nuclear Information System (INIS)

    Kuya, M.K.; Mello Filho, A.E.C. de; Oliveira, D. de

    1982-01-01

    Systematic studies on drying solutions of hydrated lanthanide perchlorate salts in acetonitrile and ethanol, with 3A molecular sieves, are performed. Most of water is removed in the first hours period (about 70% in 2hs). Ion exchange process is negligible in ethanol but appreciable in acetonitrile solutions. This drying process may be important during the synthesis of lanthanide coordination compounds, since the success of preparation depends often, on the elimination or reduction of water present in the starting lanthanide solutions. (Author) [pt

  8. Photochemical Degradation of Composition B and Its Components

    Science.gov (United States)

    2007-09-01

    recorded on the toluene (5.7 mg yield ), ether I (35 mg), and aceto- nitrile (17.8 mg) fractions. Irradiation of solution explosives in soils A...the soil was Soxhlet extracted with acetonitrile for 93 hours. The acetonitrile was removed with a rotary evaporator and the residue redissolved in...ionization to yield an anion of m/z 226. The traces show differences observed in samples with different initial preparation protocols at 15 days. Distance

  9. JCSC_129_10_1627_1637_SI.doc

    Indian Academy of Sciences (India)

    Contents. Figure S1. UV-Vis spectrum of the [Cu(dpa)2(OAc)](ClO4) complex in ethanol. Figure S2. EPR plot of [Cu(dpa)2(OAc)](ClO4) in frozen acetonitrile (left) and in powder state (right) at low temperature (77K). Figure S3. Cyclic voltammogram of 10-3 M Cu(II) complex in acetonitrile solution containing 0.1 M TBAP at 25 ...

  10. A thermodynamic study of complexation process between N, N'-dipyridoxylidene(1,4-butanediamine) and Cd2+ in some binary mixed solvents using conductometry

    Science.gov (United States)

    Ebrahimpoor, Sonia; Khoshnood, Razieh Sanavi; Beyramabadi, S. Ali

    2016-12-01

    Complexation of the Cd2+ ion with N, N'-dipyridoxylidene(1,4-butanediamine) Schiff base was studied in pure solvents including acetonitrile (AN), ethanol (EtOH), methanol (MeOH), tetrahydrofuran (THF), dimethylformamide (DMF), water (H2O), and various binary solvent mixtures of acetonitrile-ethanol (AN-EtOH), acetonitrile-methanol (AN-MeOH), acetonitrile-tetrahydrofuran (AN-THF), acetonitrile-dimethylformamide (AN-DMF), and acetonitrile-water (AN-H2O) systems at different temperatures using the conductometric method. The conductance data show that the stoichiometry of complex is 1: 1 [ML] in all solvent systems. A non-linear behavior was observed for changes of log K f of [Cd( N, N'-dipyridoxylidene(1,4-butanediamine)] complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent interactions. The results show that the thermodynamics of complexation reaction is affected by the nature and composition of the mixed solvents.

  11. Thermodynamics of the sorption of 1,3,4-oxadiazole and 1,2,4,5-tetrazine derivatives from solutions on hypercrosslinked polystyrene

    Science.gov (United States)

    Saifutdinov, B. R.; Davankov, V. A.; Il'in, M. M.

    2014-03-01

    The sorption of a series of aromatic heterocycles on neutral hypercrosslinked polystyrene from maximally dilute acetonitrile and water.acetonitrile solutions of them is investigated by high-performance liquid chromatography in a range of column temperatures from 308 to 348 K at 5 K intervals. It is found that for all heterocycles, the logarithm of the retention factor versus the reciprocal of the temperature dependences can be approximated by linear functions with r 2 ≥ 0.999. It is established that the true compensation effect (which does not result from the correlation between enthalpy and entropy determination errors) occurs during the sorption of heterocycles on hypercrosslinked polystyrene from both acetonitrile and water-acetonitrile solutions. It is shown that in the compensation diagram, the points corresponding to sorbates are grouped together according to the type of sorbate-sorbent interactions. It is found that changes in the Gibbs energy, enthalpy, and entropy of sorption from acetonitrile solutions and for sorption from water-acetonitrile solutions are related to one another by linear dependences.

  12. In situ generation of diazonium cations in organic electrolyte for electrochemical modification of electrode surface

    International Nuclear Information System (INIS)

    Baranton, Steve; Belanger, Daniel

    2008-01-01

    The modification of glassy carbon electrode was achieved by electrochemical reduction of in situ generated diazonium cations in acetonitrile. The in situ generation of 4-nitrophenyl diazonium cations in acetonitrile was investigated by spectroscopic methods. UV-visible spectroscopy revealed slow kinetics for the reaction of 4-nitroaniline with tert-butylnitrite in acetonitrile to form the corresponding diazonium cation. As a result, a coupling reaction, which implies a consumption of the amine and loss of the already formed diazonium cations, was evidenced by 1 H NMR spectroscopy. This spectroscopic study allowed the optimization of the in situ diazonium cations generation prior to the modification step. The electrochemical modification of the carbon electrodes with 4-nitrophenyl, 4-bromophenyl and anthraquinone groups was characterized by cyclic voltammetry and the resulting grafted layer were characterized by electrochemical techniques. The cyclic voltammetric behaviour during the electrochemical grafting was very similar to the one observed for an isolated diazonium salt dissolved in acetonitrile. In the case of the anthraquinone-modified electrode, the use of acetonitrile, into which the corresponding amine is soluble but not in aqueous media, allowed for its grafting by the in situ approach. The barrier properties of these grafted layers are similar to those obtained from isolated diazonium salts. Finally, the chemical composition of the grafted layers was determined by X-ray photoelectron spectroscopy and surface coverage in the range 5-7 x 10 -10 mol cm -2 was estimated for films grown in our experimental conditions

  13. In situ generation of diazonium cations in organic electrolyte for electrochemical modification of electrode surface

    Energy Technology Data Exchange (ETDEWEB)

    Baranton, Steve [Departement de Chimie, Universite du Quebec a Montreal, Case Postale 8888, succursale Centre-Ville, Montreal (Quebec), H3C 3P8 (Canada); Belanger, Daniel [Departement de Chimie, Universite du Quebec a Montreal, Case Postale 8888, succursale Centre-Ville, Montreal (Quebec), H3C 3P8 (Canada)], E-mail: belanger.daniel@uqam.ca

    2008-10-01

    The modification of glassy carbon electrode was achieved by electrochemical reduction of in situ generated diazonium cations in acetonitrile. The in situ generation of 4-nitrophenyl diazonium cations in acetonitrile was investigated by spectroscopic methods. UV-visible spectroscopy revealed slow kinetics for the reaction of 4-nitroaniline with tert-butylnitrite in acetonitrile to form the corresponding diazonium cation. As a result, a coupling reaction, which implies a consumption of the amine and loss of the already formed diazonium cations, was evidenced by {sup 1}H NMR spectroscopy. This spectroscopic study allowed the optimization of the in situ diazonium cations generation prior to the modification step. The electrochemical modification of the carbon electrodes with 4-nitrophenyl, 4-bromophenyl and anthraquinone groups was characterized by cyclic voltammetry and the resulting grafted layer were characterized by electrochemical techniques. The cyclic voltammetric behaviour during the electrochemical grafting was very similar to the one observed for an isolated diazonium salt dissolved in acetonitrile. In the case of the anthraquinone-modified electrode, the use of acetonitrile, into which the corresponding amine is soluble but not in aqueous media, allowed for its grafting by the in situ approach. The barrier properties of these grafted layers are similar to those obtained from isolated diazonium salts. Finally, the chemical composition of the grafted layers was determined by X-ray photoelectron spectroscopy and surface coverage in the range 5-7 x 10{sup -10} mol cm{sup -2} was estimated for films grown in our experimental conditions.

  14. Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative.

    Science.gov (United States)

    Požar, Josip; Nikšić-Franjić, Ivana; Cvetnić, Marija; Leko, Katarina; Cindro, Nikola; Pičuljan, Katarina; Borilović, Ivana; Frkanec, Leo; Tomišić, Vladislav

    2017-09-14

    The medium effect on the complexation of alkali metal cations with a calix[4]arene ketone derivative (L) was systematically examined in methanol, ethanol, N-methylformamide, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. In all solvents the binding of Na + cation by L was rather efficient, whereas the complexation of other alkali metal cations was observed only in methanol and acetonitrile. Complexation reactions were enthalpically controlled, while ligand dissolution was endothermic in all cases. A notable influence of the solvent on NaL + complex stability could be mainly attributed to the differences in complexation entropies. The higher NaL + stability in comparison to complexes with other alkali metal cations in acetonitrile was predominantly due to a more favorable complexation enthalpy. The 1 H NMR investigations revealed a relatively low affinity of the calixarene sodium complex for inclusion of the solvent molecule in the calixarene hydrophobic cavity, with the exception of acetonitrile. Differences in complex stabilities in the explored solvents, apart from N,N-dimethylformamide and acetonitrile, could be mostly explained by taking into account solely the cation and complex solvation. A considerable solvent effect on the complexation equilibria was proven to be due to an interesting interplay between the transfer enthalpies and entropies of the reactants and the complexes formed.

  15. Modelling of the effect of solute structure and mobile phase pH and composition on the retention of phenoxy acid herbicides in reversed-phase high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Aschi, Massimiliano; D'Archivio, Angelo Antonio; Mazzeo, Pietro; Pierabella, Mirko; Ruggieri, Fabrizio

    2008-01-01

    A feed-forward artificial neural network (ANN) learned by error back-propagation is used to generate a retention predictive model for phenoxy acid herbicides in isocratic reversed-phase high-performance liquid chromatography. The investigated solutes (18 compounds), apart from the most common herbicides of this class, include some derivatives of benzoic acid and phenylacetic acid structurally related to phenoxy acids, as a whole covering a pK a range between 2.3 and 4.3. A mixed model in terms of both solute descriptors and eluent attributes is built with the aim of predicting retention in water-acetonitrile mobile phases within a large range of composition (acetonitrile from 30% to 70%, v/v) and acidity (pH of water before mixing with acetonitrile ranging between 2 and 5). The set of input variables consists of solute pK a and quantum chemical molecular descriptors of both the neutral and dissociated form, %v/v of acetonitrile in the mobile phase and pH of aqueous phase before mixing with acetonitrile. After elimination of redundant variables, a nine-dimensional model is identified and its prediction ability is evaluated by external validation based on three solutes not involved in model generation and by cross-validation. A multilinear counterpart in terms of the same descriptors is seen to provide a noticeably poorer retention prediction

  16. Modelling of the effect of solute structure and mobile phase pH and composition on the retention of phenoxy acid herbicides in reversed-phase high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Aschi, Massimiliano [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); D' Archivio, Angelo Antonio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)], E-mail: darchivi@univaq.it; Mazzeo, Pietro; Pierabella, Mirko; Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)

    2008-06-02

    A feed-forward artificial neural network (ANN) learned by error back-propagation is used to generate a retention predictive model for phenoxy acid herbicides in isocratic reversed-phase high-performance liquid chromatography. The investigated solutes (18 compounds), apart from the most common herbicides of this class, include some derivatives of benzoic acid and phenylacetic acid structurally related to phenoxy acids, as a whole covering a pK{sub a} range between 2.3 and 4.3. A mixed model in terms of both solute descriptors and eluent attributes is built with the aim of predicting retention in water-acetonitrile mobile phases within a large range of composition (acetonitrile from 30% to 70%, v/v) and acidity (pH of water before mixing with acetonitrile ranging between 2 and 5). The set of input variables consists of solute pK{sub a} and quantum chemical molecular descriptors of both the neutral and dissociated form, %v/v of acetonitrile in the mobile phase and pH of aqueous phase before mixing with acetonitrile. After elimination of redundant variables, a nine-dimensional model is identified and its prediction ability is evaluated by external validation based on three solutes not involved in model generation and by cross-validation. A multilinear counterpart in terms of the same descriptors is seen to provide a noticeably poorer retention prediction.

  17. Synthesis, characterization, and reactivity of furan- and thiophene-functionalized bis(n-heterocyclic carbene) complexes of iron(II)

    KAUST Repository

    Rieb, Julia

    2014-09-15

    The synthesis of iron(II) complexes bearing new heteroatom-functionalized methylene-bridged bis(N-heterocyclic carbene) ligands is reported. All complexes are characterized by single-crystal X-ray diffraction (SC-XRD), nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis. Tetrakis(acetonitrile)-cis-[bis(o-imidazol-2-ylidenefuran)methane]iron(II) hexafluorophosphate (2a) and tetrakis(acetonitrile)-cis-[bis(o-imidazol-2-ylidenethiophene)methane]iron(II) hexafluorophosphate (2b) were obtained by aminolysis of [Fe{N(SiMe3)2}2(THF)] with furan- and thiophene-functionalized bis(imidazolium) salts 1a and 1b in acetonitrile. The SC-XRD structures of 2a and 2b show coordination of the bis(carbene) ligand in a bidentate fashion instead of a possible tetradentate coordination. The four other coordination sites of these distorted octahedral complexes are occupied by acetonitrile ligands. Crystallization of 2a in an acetone solution by the slow diffusion of Et2O led to the formation of cisdiacetonitriledi[ bis(o-imidazol-2-ylidenefuran)methane]iron(II) hexafluorophosphate (3a) with two bis(carbene) ligands coordinated in a bidentate manner and two cis-positioned acetonitrile molecules. Compounds 2a and 2b are the first reported iron(II) carbene complexes with four coordination sites occupied by solvent molecules, and it was demonstrated that those solvent ligands can undergo ligand-exchange reactions.

  18. Validação de método analítico livre de acetonitrila para análise de microcistinas por cromatografia líquida de alta eficiência

    Directory of Open Access Journals (Sweden)

    Sérvio Túlio Alves Cassini

    2013-01-01

    Full Text Available Blooms of cyanobacteria represent a public health risk due to their cyanotoxins such as microcystins. Liquid chromatography techniques to separate and quantify microcystins invariably use acetonitrile as the organic component of the mobile phase. The price and availability of acetonitrile together with its elevated toxicity encourage the validation of acetonitrile-free methods of microcystin analysis. In this work, methanol was employed as the organic solvent of the mobile phase and the validation method was performed with different environmental water samples. The method showed limits of detection between 0.17 and 0.25 µg/L and of quantification between 0.55 and 0.82 µg/L for the microcystin variants: -RR, -YR, -LR, -LA.

  19. A Simple Thin Layer Chromatography Method for Separation of Selected Natural Steroid Hormones

    International Nuclear Information System (INIS)

    Nowakowska, J.; Rudnicka-Litka, K.; Ciura, K.; Pikul, P.; Piotrowicz, J.

    2015-01-01

    Chromatographic properties of seven steroids: estrogens (β-estradiol and estrone), androgens (testosterone, methyltestosterone, trans-androsterone), progesterone and cholesterol have been studied by planar chromatography with usage of High Performance Thin Layer Chromatography (HPTLC) and Thin Layer Chromatography (TLC) plates. Normal, reversed and cyano-bonded silica stationary phases were tested with five binary mobile phases (acetonitrile-water, acetonitrile-DMSO, acetonitrile-methanol, acetone-petroleum ether, acetone-water) in which the concentration of organic modifier varied from 0 to 100 % (v/v). This study reports the optimization of steroid hormones separation. Principal Component Analysis (PCA) based on calculated molecular descriptors quantitatively differentiating solutes was performed in order to investigate the similarity and dissimilarity between tested compounds. The separation abilities of mobile and stationary phases were compared based on separation factor α. Chromatographic retention data and possible retention mechanisms also were discussed. (author)

  20. Chromatographic determination of silicon and phosphorus as molybdic heteropoly acids with preconcentration

    International Nuclear Information System (INIS)

    Tikhomirova, T.I.; Krokhin, O.V.; Dubovik, D.B.; Ivanov, A.V.; Shpigun, O.A.

    2002-01-01

    Chromatographic behaviour of silicon and phosphorus as molybdic heteropoly acids with preconcentration as ion associations of heteropoly acid with tributylammonium bromide was studied. The technique of simultaneous analysis of silicon and phosphorus was developed. During investigation into the effect of acetonitril content in the probe on the form of chromatographic peak of molybdosilicic acid the negative influence of acetonitril on the form of peak was ascertained. This effect may be eliminated by the lowering of acetonitril content up to 50 %. It was found that under these conditions the chromatographic peak practically was absent, because of the heteropoly acid of the Mo(VI) abundance transformed in the MoO 2 2+ cation form without reaction with tributylammonium cation during concentration of heteropoly acid [ru

  1. Anionic chromogenic chemosensors highly selective for fluoride or cyanide based on 4-(4-Nitrobenzylideneamine)phenol

    International Nuclear Information System (INIS)

    Nicoleti, Celso R.; Marini, Vanderleia G.; Zimmermann, Lizandra M.; Machado, Vanderlei G.

    2012-01-01

    4-(4-Nitrobenzylideneamine)phenol was used in two strategies allowing the highly selective detection of F - and CN - . Firstly, the compound in acetonitrile acts as a chromogenic chemosensor based on the idea that more basic anions cause its deprotonation (colorless solution), generating a colored solution containing phenolate. The discrimination of CN - over F - was obtained by adding 1.4% water to acetonitrile: water preferentially solvates F - , leaving the CN - free to deprotonate the compound. Another strategy involved an assay comprised of the competition between phenolate dye and the analyte for calyx[4]pyrrole in acetonitrile, a receptor highly selective for F - . Phenolate and calyx[4]pyrrole form a hydrogen-bonded complex, which changes the color of the medium. On the addition of various anions, only F - was able to restore the original color corresponding to phenolate in solution due to the fact that the anion dislodges phenolate from the complexation site. (author)

  2. Direct-immersion solid-phase microextraction coupled to fast gas chromatography mass spectrometry as a purification step for polycyclic aromatic hydrocarbons determination in olive oil.

    Science.gov (United States)

    Purcaro, Giorgia; Picardo, Massimo; Barp, Laura; Moret, Sabrina; Conte, Lanfranco S

    2013-09-13

    The aim of the present work was to optimize a preparation step for polycyclic aromatic hydrocarbons in a fatty extract. Solid-phase microextraction is an easy preparation technique, which allows to minimize solvent consumption and reduce sample manipulation. A Carbopack Z/polydimethylsiloxane fiber, particularly suitable for extraction of planar compounds, was employed to extract polycyclic aromatic hydrocarbons from a hexane solution obtained after a previous extraction with acetonitrile from oil, followed by a liquid-liquid partition between acetonitrile and hexane. The proposed method was a rapid and sensitive solution to reduce the interference of triglycerides saving the column life and avoiding frequent cleaning of the mass spectrometer ion source. Despite the non-quantitative extraction of polycyclic aromatic hydrocarbons from oil using acetonitrile, the signal-to-noise ratio was significantly improved obtaining a limit of detection largely below the performance criteria required by the European Union legislation. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Volatile compounds from leaves of the African spider plant (Gynandropsis gynandra) with bioactivity against spider mite (Tetranychus urticae)

    DEFF Research Database (Denmark)

    Nyalala, Samuel Odeyo; Petersen, Mikael Agerlin; Grout, Brian William Wilson

    2013-01-01

    Previous studies have demonstrated that Gynandropsis gynandra emits acetonitrile as a foliar volatile from intact plants and isolated leaves, and that this compound is an effective spider mite repellent. This study has used gas chromatography–mass spectrometry to investigate volatile compounds...... emitted from homogenised G. gynandra leaves to evaluate their tissue acetonitrile content and to look for other compounds that might be exploited for the management of spider mites. Acetonitrile was absent from the homogenised tissues of five lines of G. gynandra, studied over two seasons. Thirteen...... volatile compounds were emitted by G. gynandra at significantly higher levels than mite-susceptible pot roses, including isothiocyanates, aldehydes, esters, alcohols and terpenes. Six representative compounds were selected to assess bioactivity. Spider mite populations were completely inactive after a 2¿h...

  4. What is measured by hyper-Rayleigh scattering from a liquid?

    Science.gov (United States)

    Rodriquez, Micheal B.; Shelton, David P.

    2018-04-01

    Polarization and angle dependence of hyper-Rayleigh scattering (HRS) measured for liquid acetonitrile and dimethyl sulfoxide (DMSO) is analyzed in terms of contributions from randomly oriented molecules and additional contributions produced during intermolecular collisions and induced by the electric field of dissolved ions. All three contributions show the effect of long-range correlation, and the correlation functions are determined using the HRS observations combined with the results of molecular dynamics simulations. HRS from acetonitrile is polarized transverse to the scattering vector. This is due to long-range molecular orientation correlation produced by the dipole-dipole interaction, and correlation at distances r > 100 nm must be included to account for the HRS observations. Analysis of the HRS measurements for acetonitrile determines the length scale a = 0.185 nm for the long-range longitudinal and transverse orientation correlation functions BL=-2 BT=a3/r3. Transverse polarized collision-induced HRS is also observed for acetonitrile, indicating long-range correlation of intermolecular modes. Strong longitudinal HRS is induced by the radial electric field of dissolved ions in acetonitrile. For DMSO, the angle between the molecular dipole and the vector part of the first hyperpolarizability tensor is about 100°. As a result, HRS from the randomly oriented molecules in DMSO is nearly unaffected by dipole correlation, and ion-induced HRS is weak. The strong longitudinal polarized HRS observed for DMSO is due to the collision-induced contribution, indicating long-range correlation of intermolecular modes. The HRS observations require correlation that has r-3 long-range asymptotic form, for molecular orientation and for intermolecular vibration and libration, for both acetonitrile and DMSO.

  5. Stable Isotope-Assisted Evaluation of Different Extraction Solvents for Untargeted Metabolomics of Plants

    Directory of Open Access Journals (Sweden)

    Maria Doppler

    2016-06-01

    Full Text Available The evaluation of extraction protocols for untargeted metabolomics approaches is still difficult. We have applied a novel stable isotope-assisted workflow for untargeted LC-HRMS-based plant metabolomics , which allows for the first time every detected feature to be considered for method evaluation. The efficiency and complementarity of commonly used extraction solvents, namely 1 + 3 (v/v mixtures of water and selected organic solvents (methanol, acetonitrile or methanol/acetonitrile 1 + 1 (v/v, with and without the addition of 0.1% (v/v formic acid were compared. Four different wheat organs were sampled, extracted and analysed by LC-HRMS. Data evaluation was performed with the in-house-developed MetExtract II software and R. With all tested solvents a total of 871 metabolites were extracted in ear, 785 in stem, 733 in leaf and 517 in root samples, respectively. Between 48% (stem and 57% (ear of the metabolites detected in a particular organ were found with all extraction mixtures, and 127 of 996 metabolites were consistently shared between all extraction agent/organ combinations. In aqueous methanol, acidification with formic acid led to pronounced pH dependency regarding the precision of metabolite abundance and the number of detectable metabolites, whereas extracts of acetonitrile-containing mixtures were less affected. Moreover, methanol and acetonitrile have been found to be complementary with respect to extraction efficiency. Interestingly, the beneficial properties of both solvents can be combined by the use of a water-methanol-acetonitrile mixture for global metabolite extraction instead of aqueous methanol or aqueous acetonitrile alone.

  6. Evaluation of a membrane desolvator for LC-ICPMS analysis of selenium and platinum species for application to peptides and proteins

    DEFF Research Database (Denmark)

    Møller, Laura Hyrup; Dam, Celina Støving; Nguyen, Tam T. T. N.

    2015-01-01

    no species dependent behavior. Linearity was obtained for flow injection analysis of SeMet, TMSe and a selenopeptide in 50% methanol and of inorganic Pt, cisplatin and oxaliplatin in 50% acetonitrile. The optimized system was applied for gradient elution LC-ICP-MS of a cisplatin-albumin adduct and lysate...... to sweep gas and nitrogen gas flow rates. Sensitivity was highly dependent on the combination of sweep gas flow and N2 addition, and the desolvator system should be optimized for each element. After optimization, 100% methanol and acetonitrile were tolerated by the ICP-MS with an eluent flow rate of 0.2 m...

  7. Estimation of thermodynamic acidity constants of some penicillinase-resistant penicillins.

    Science.gov (United States)

    Demiralay, Ebru Çubuk; Üstün, Zehra; Daldal, Y Doğan

    2014-03-01

    In this work, thermodynamic acidity constants (pssKa) of methicillin, oxacillin, nafcillin, cloxacilin, dicloxacillin were determined with reverse phase liquid chromatographic method (RPLC) by taking into account the effect of the activity coefficients in hydro-organic water-acetonitrile binary mixtures. From these values, thermodynamic aqueous acidity constants of these drugs were calculated by different approaches. The linear relationships established between retention factors of the species and the polarity parameter of the mobile phase (ET(N)) was proved to predict accurately retention in LC as a function of the acetonitrile content (38%, 40% and 42%, v/v). Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Online recovery of radiocesium from soil, tissue paper and plant samples by supercritical fluid extraction

    International Nuclear Information System (INIS)

    Kanekar, A.S.; Pathak, P.N.; Mohapatra, P.K.

    2014-01-01

    The feasibility of recovery of radio-cesium from soil, tissue papers, and plant samples has been evaluated by supercritical fluid extraction (SFE) route employing calix(4)arene-mono(crown-6) (CC) dissolved in acetonitrile. These studies showed that quantitative recovery of 137 Cs from soil samples was difficult under the conditions of these studies. However, experiments performed on tissue papers (cellulose matrix) showed quantitative recovery of 137 Cs. On the other hand, 137 Cs recovery from plant samples varied between ∼50 % (for stems) and ∼67.2 % (for leaves) employing 1x10 -3 M CC + 4 M HNO 3 dissolved in acetonitrile. (author)

  9. Magnetic Field Effect: An Efficient Tool To Investigate The Mechanism Of Reactions Using Laser Flash Photolysis Technique

    International Nuclear Information System (INIS)

    Basu, Samita; Bose, Adity; Dey, Debarati

    2008-01-01

    Magnetic field effect combined with laser flash photolysis technique have been used to study the mechanism of interactions between two drug-like quinone molecules, Menadione (1,4-naphthoquinone, MQ) and 9, 10 Anthraquinone (AQ) with one of the DNA bases, Adenine in homogeneous acetonitrile/water and heterogeneous micellar media. A switchover in reaction mode from electron transfer to hydrogen abstraction is observed with MQ on changing the solvent from acetonitrile/water to micelle; whereas, AQ retains its mode of interaction towards Adenine as electron transfer in both the media due to its bulky structure compared to MQ

  10. Reduction of single-walled carbon nanotube diameter to sub-nm via feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Thurakitseree, T.; Zhao, Pei; Chiashi, Shohei; Maruyama, Shigeo [Department of Mechanical Engineering, University of Tokyo (Japan); Kramberger, Christian [Faculty of Physics, University of Vienna (Austria); Einarsson, Erik [Department of Mechanical Engineering, University of Tokyo (Japan); Global Center of Excellence for Mechanical Systems Innovation, University of Tokyo (Japan)

    2012-12-15

    Vertically aligned single-walled carbon nanotube arrays were synthesized from dip-coated binary Co/Mo catalyst by no-flow chemical vapor deposition (CVD) from either pure ethanol or acetonitrile as carbon feedstock. By changing to acetonitrile the mean diameter was reduced from 2.1 nm to less than 1.0 nm despite using identically prepared catalyst. The demonstrated diameter control on flat substrates is a versatile approach towards the direct synthesis of tailored single-walled carbon nanotubes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Resorcarene-based receptor: versatile behavior in its interaction with heavy and soft metal cations.

    Science.gov (United States)

    Danil de Namor, Angela F; Chaaban, Jinane K; Piro, Oscar E; Castellano, Eduardo E

    2006-02-09

    Standard solution Gibbs energies, DeltasG degrees, of the resorcarene-based receptor 5,11,17,23-ethylthiomethylated calix[4]resorcarene, (characterized by 1H NMR and X-ray diffraction studies) in its monomeric state (established through partition experiments) in various solvents are for the first time reported in the area of resorcarene chemistry. Transfer Gibbs energies of from hexane (reference solvent) to other medium are calculated. Agreement between DeltatG degrees (referred to the pure solvents) and standard partition Gibbs energies, DeltapG degrees (solvent mutually saturated) is found. Cation-ligand interactions were investigated through 1H NMR (CD3CN and CD3OD) and conductometric titrations in acetonitrile and methanol. 1H NMR data revealed the sites of interaction of with the metal cation. The composition of the metal-ion complexes (Ag+ and Pb2+ in acetonitrile and Ag+ and Cu2+ in methanol) was established through conductometric titrations. Thus, complexes of 1:1 stoichiometry were formed between and Ag+ and Pb2+ in acetonitrile and Cu2+ in methanol. However, in moving from acetonitrile to methanol, the composition of the silver complex was altered. Thus, two metal cations are hosted by a unit of the ligand. As far as Cu2+ and in acetonitrile is concerned, conductance data suggest that metalates are formed in which up to four units of Cu2+ are taken up per unit of resorcarene. The contrasting behavior of with Cu2+ in acetonitrile relative to methanol is discussed. As far as mercury (II) is concerned, the unusual jump in conductance observed in the titration of Hg2+ with in acetonitrile and methanol after the formation of a multicharged complex (undefined composition) is attributed to the presence of highly charged smaller units (higher mobility) resulting from the departure of pendant arms from the resorcarene backbone. Isolation of these species followed by X-ray diffraction studies corroborated this statement. The thermodynamic characterization of metal

  12. Dissociation mechanisms and dynamics of doubly charged CD3CN observed by PEPIPICO spectroscopy

    International Nuclear Information System (INIS)

    Harada, C.; Tada, S.; Yamamoto, K.; Senba, Y.; Yoshida, H.; Hiraya, A.; Wada, S.; Tanaka, K.; Tabayashi, K.

    2006-01-01

    Dissociation of free acetonitrile-d 3 molecule, CD 3 CN induced by core level excitation was studied near the nitrogen K-edge by time-of-flight fragment mass spectroscopy. A variety of atomic and molecular fragment cations such as D + , CD n + , C 2 D n + , and CD n CN + were detected using the effusive CD 3 CN beam. Photoelectron-photoion-photoion coincidence technique was applied to analyse the dissociation mechanisms and dynamics of doubly charged CD 3 CN 2+ following the N(1s-π * ) excitation. The charge separation mechanisms of core-excited CD 3 CN were discussed in connection with Auger final state distributions

  13. Kinetics of formation of acrylamide and Schiff base intermediates from asparagine and glucose

    DEFF Research Database (Denmark)

    Hedegaard, Rikke Susanne Vingborg; Frandsen, Henrik; Skibsted, Leif H.

    2008-01-01

    From the concentration of glucose and asparagine as reactants and of acrylamide as product each determined by LC-MS during reaction in an acetonitrile/water (68:32) model system at pH 7.6 (0.04 M phosphate buffer) and from the relative concentration of the Schiff base intermediate, the decarboxyl......From the concentration of glucose and asparagine as reactants and of acrylamide as product each determined by LC-MS during reaction in an acetonitrile/water (68:32) model system at pH 7.6 (0.04 M phosphate buffer) and from the relative concentration of the Schiff base intermediate...

  14. Robotized synthesis of [3-11C]-L-alanine using reaction of asymmetric alkylation of 11CH3I nickel complex of glycine Schiff base with S-2-N-(N'-benzylpropyl)aminobenzophenone

    International Nuclear Information System (INIS)

    Mosevich, I.K.; Kuznetsova, O.F.; Vasil'ev, D.A.; Anichkov, A.A.; Korsakov, M.V.

    1999-01-01

    Synthesis of [3- 11 C]-L-alanine based on 11 CH 3 I nickel complex (1) alkylation using different solvents (tetrahydrofuran, dimethylformamide, acetonitrile, acetone) and catalysts (potassium butylate, sodium hydride) was investigated. It was shown that synthesis of amino acids labelled with 11 C based on complex (1) use permits to obtain preparations with high degree of enantiomeric enrichment. The best results (enantiomeric excess of L-alanine up to 99 %) were obtained in reaction with acetonitrile as a solvent and potassium tret-butylate as a catalyst

  15. Synthesis and characterization of an iron complex bearing a cyclic tetra-N-heterocyclic carbene ligand: An artifical heme analogue?

    KAUST Repository

    Anneser, Markus R.

    2015-04-20

    An iron(II) complex with a cyclic tetradentate ligand containing four N-heterocyclic carbenes was synthesized and characterized by means of NMR and IR spectroscopies, as well as by single-crystal X-ray structure analysis. The iron center exhibits an octahedral coordination geometry with two acetonitrile ligands in axial positions, showing structural analogies with porphyrine-ligated iron complexes. The acetonitrile ligands can readily be substituted by other ligands, for instance, dimethyl sulfoxide, carbon monoxide, and nitric oxide. Cyclic voltammetry was used to examine the electronic properties of the synthesized compounds. © 2015 American Chemical Society.

  16. Metal Oxide Materials and Collector Efficiency in Electrochemical Supercapacitors

    Science.gov (United States)

    2010-12-01

    However, even if thick tita - nium films and/or nanostructured layers were obtained using these methods, they were composed of non-conducting titanium...following electrochemical reduction in LiClO4/acetonitrile. Table 1 reports the electrochemical parameters and the atomic composition of the tita - nium

  17. Association constants of telluronium salts

    International Nuclear Information System (INIS)

    Kovach, N.A.; Rivkin, B.B.; Sadekov, T.D.; Shvajka, O.P.

    1996-01-01

    Association constants in acetonitrile of triphenyl telluronium salts, which are dilute electrolytes, are determined through the conductometry method. Satisfactory correlation dependence of constants of interion association and threshold molar electroconductivity on the Litvinenko-Popov constants for depositing groups is identified. 6 refs

  18. Association constants of telluronium salts; Konstanty assotsiatsii telluronievykh solej

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, N A; Rivkin, B B; Sadekov, T D; Shvajka, O P

    1997-12-31

    Association constants in acetonitrile of triphenyl telluronium salts, which are dilute electrolytes, are determined through the conductometry method. Satisfactory correlation dependence of constants of interion association and threshold molar electroconductivity on the Litvinenko-Popov constants for depositing groups is identified. 6 refs.

  19. Ligand-Free Nanocrystals of Highly Emissive Cs4PbBr6 Perovskite

    KAUST Repository

    Zhang, Yuhai; Sinatra, Lutfan; Alarousu, Erkki; Yin, Jun; El-Zohry, Ahmed M.; Bakr, Osman; Mohammed, Omar F.

    2018-01-01

    diode or solar cell. Here, we report a new approach to preparing ligand-free perovskite NCs of CsPbBr, which retained high photoluminescence quantum yield (44%). Such an approach involves a polar solvent (acetonitrile) and two small molecules (ammonium

  20. The Influence of Alcohol on the Pharmacokinetics of Antipyrine ...

    African Journals Online (AJOL)

    The filtrate was injected into a high pressure liquid chromatography using reversed phase Bondesil C18 (0.5um) column, with benzoic acid (as internal standard) and acetonitrile: acetic acid (in 1% water) (35:65) as mobile phase. The concentrations of the antipyrine were determined from the chromatographic calibration ...

  1. A fast and simple method for quantitative determination of fat-derived medium and low-volatile compounds in cheese

    NARCIS (Netherlands)

    Alewijn, M.; Sliwinski, E.L.; Wouters, J.T.M.

    2003-01-01

    Cheese flavour is a mixture of many (volatile) compounds, mostly formed during ripening. The current method was developed to qualify and quantify fat-derived compounds in cheese. Cheese samples were extracted with acetonitrile, which led to a concentrated solution of potential favour compounds,

  2. Production of parthenolide in organ and callus cultures of ...

    African Journals Online (AJOL)

    In addition, callusing capacity and weight of callus of different explants under different treatments were also determined. Parthenolide content was determined in the explants as well as in callus using RP-HPLC on Luna C18 column and SPD-10A UV detector. The mobile phase used was acetonitrile: water (55 : 45) and the ...

  3. SPECTROPHOTOMETRIC DETERMINATION OF PIZOTEFIN ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    respectively. Different experimental conditions for the two methods were optimized. Beer's law was obeyed in the concentration ranges of .... mixed in various proportions and the volume was diluted in a 10-mL volumetric flask with acetonitrile. The absorbance of the resulting solutions was measured at optimum wavelengths.

  4. Application of a Microfluidic Reactor for Screening Cancer Prodrug Activation Using Silica-Immobilized Nitrobenzene Nitroreductase

    Science.gov (United States)

    2006-01-01

    molecules18 can mediate an analogous reaction15 that combines the advantages of silica encapsulation with a signifi- cant reduction in cost... Alltech , Deerfield, IL) with a mobile phase of acetonitrile and water (containing 0.05% and 0.1% trifluoroacetic acid, respectively). The concentration

  5. The first actinyl cyanide

    International Nuclear Information System (INIS)

    Berthet, J.C.; Thuery, P.; Ephritikhine, M.

    2007-01-01

    Reaction of UO 2 (OTf) 2 with 5 molar equivalents of NEt 4 CN in acetonitrile led to the formation of the penta-cyano uranyl complex [NEt 4 ] 3 [UO 2 (CN) 5 ] which is monomeric in the solid state with the five C-coordinated cyanide ions lying in the equatorial plane perpendicular to the linear { UO 2 } axis. (authors)

  6. Determination of mycophenolic acid in mest products using mixed mode reversed phase-anion exchange clean-up and liquid chromatography-high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Nielsen, Kristian Fog; Jacobsen, Thomas

    2008-01-01

    A method for determination of mycophenolic acid (MPA) in dry-cured ham, fermented sausage and liver pate is described. MPA was extracted from meat with bicarbonate-acetonitrile, further cleaned-up by mixed mode reversed phase-anion exchange and detected using a LC-MS system with electrospray...

  7. Synthesis, characterization and study of catalytic activity of Silver ...

    Indian Academy of Sciences (India)

    The XRD results revealed that all the samples show wurtzite hexagonal phase of ZnO. .... (Zn(Ac)2.2H2O) was used as zinc oxide source. ... The catalytic experiments ... were filtered out from the catalyst and then oxidation ..... As shown in table 5, the best results were obtained when acetonitrile was used as the sol- vent.

  8. Selective oxidation of benzyl alcohol with tert-butylhydroperoxide ...

    Indian Academy of Sciences (India)

    the solvent and in this case, acetonitrile gives the best conversion results. The kinetic of ... Experimental. 2.1 Materials ... Subsequently, the products were filtered, washed thoroughly ..... mesh; benzyl alcohol 30 mmol; TBHP 30 mmol; 15 ml ace- tonitrile ... vent was changed for each run while the other condi- tions, (0.2 g of ...

  9. Bond Shortening (1.4 Å) in the Singlet and Triplet Excited States of [Ir2(dimen)4]2+ in Solution Determined by Time-Resolved X-ray Scattering

    DEFF Research Database (Denmark)

    Haldrup, Martin Kristoffer; Harlang, Tobias; Christensen, Morten

    2011-01-01

    Ground- and excited-state structures of the bimetallic, ligand-bridged compound Ir2(dimen)42+ are investigated in acetonitrile by means of time-resolved X-ray scattering. Following excitation by 2 ps laser pulses at 390 nm, analysis of difference scattering patterns obtained at eight different ti...

  10. 40 CFR Table 3 to Subpart Ggg of... - Soluble HAP

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Soluble HAP 3 Table 3 to Subpart GGG of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... HAP Compound 1,1-Dimethylhydrazine. 1,4-Dioxane. Acetonitrile. Acetophenone. Diethyl sulfate. Dimethyl...

  11. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. Hemant K Kashyap. Articles written in Journal of Chemical Sciences. Volume 119 Issue 5 September 2007 pp 391-399. Non-ideality in Born-free energy of solvation in alcohol-water and dimethylsulfoxide-acetonitrile mixtures: Solvent size ratio and ion size dependence.

  12. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Electrochemical oxidation of some catechol derivatives (1a-e) have been studied in water/acetonitrile solution containing 1-methylindole (3) as a nucleophile, using cyclic voltammetry and controlledpotential coulometry. An interesting diversity in the mechanisms has been observed in electrochemical oxidation of catechol ...

  13. Homogeneous Media Milling: Reactant-Assisted Mechanochemical Synthesis of Functionalized Nanoparticles from Malleable and Ductile Metals

    Science.gov (United States)

    2014-01-01

    equipped with valves ( McMaster -Carr part number 4912K96) that serve several purposes. The jars are loaded and sealed inside a N2-filled glove box...Temperature and Solvent Effects on Viscosity B Coefficients . Monovalent Ions in Acetonitrile at 15, 25, and 35 °C. Journal of Physical Chemistry 1990, 94

  14. Characterization and Fate of Gun and Rocket Propellant Residues on Testing and Training Ranges: Interim Report 2

    Science.gov (United States)

    2010-12-01

    Restoration Project 1481, Phase II. DISCLAIMER: The contents of this report are not to be used for advertising , publication, or promotional purposes...acetonitrile APFSDS armour -piercing fin-stabilized discarding sabot °C degrees Celsius CFB Canadian Forces Base CRREL Cold Regions Research Engineering

  15. Luminescence screening of enrofloxacin and ciprofloxacin residues in swine liver after dispersive liquid - liquid microextraction cleanup

    Science.gov (United States)

    A rapid luminescence method was developed to screen residues of enrofloxacin (ENRO) and its metabolite, ciprofloxacin (CIPRO), in swine liver. Target analytes were extracted in acetonitrile-2.5% trifluoroacetic acid-NaCl, cleaned up by dispersive liquid-liquid microextraction (DLLME), and finally de...

  16. Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers.

    Science.gov (United States)

    Otto, Nicola; Opatz, Till

    2012-01-01

    In the search for new ligands for the Ullmann diaryl ether synthesis, permitting the coupling of electron-rich aryl bromides at relatively low temperatures, 56 structurally diverse multidentate ligands were screened in a model system that uses copper iodide in acetonitrile with potassium phosphate as the base. The ligands differed largely in their performance, but no privileged structural class could be identified.

  17. Lipophilic Super-Absorbent Swelling Gels as Cleaners for Use on Weapons Systems and Platforms

    Science.gov (United States)

    2014-02-01

    Tetrahydrofuran (THF), isopropa- nol, acetonitrile, and dichloromethane were obtained from Acros Organics (Morris Plains, NJ). Dimethylsulfoxide ( DMSO ) and 1...1. In the following solvents , swelling degree did not change in both heating and cooling processes: water, DMSO , methanol, ethanol, isopropanol...available alkylstyrene copolymer (imbiber beads). The cleaning ability of the gels was compared with the standard solvent cleaner trichloroethylene

  18. Improvement of Arbutin Trans-Epidermal Delivery Using ...

    African Journals Online (AJOL)

    Furthermore, improved depigmentation effects in brown guinea pig in vivo after ... microporation technology was initially developed to remove .... using an isocratic mobile phase consisting of ... acetonitrile (92:8, v/v) at a flow rate of 1.0. μL/min.

  19. Quantitative determination of triterpene saponins and alkenated-phenolics from Labisia pumila using LC-UV/ELSD method and confirmation by LC-ESI-TOF

    Science.gov (United States)

    This study describes the first analytical method for the determination of saponins and alkenated-phenolics from the leaves, leaves/stems and roots of Labisia pumila using a HPLC-UV-ELSD method. The separation was achieved using a reversed phase column, PDA and ELS detection, and a water/acetonitrile...

  20. Quantitative determination of triperpene saponins and alkenated-phenolics from Labisia pumila using LC-UV/ELSD method and confirmation by LC-ESI-TOF

    Science.gov (United States)

    This study describes the first analytical method for the determination of saponins and alkenated-phenolics from the leaves, leaves/stems and roots of Labisia pumila using a HPLC-UV-ELSD method. The separation was achieved using a reversed phase column, PDA and ELS detection, and a water/acetonitrile...

  1. Reversed-phase liquid chromatography coupled on-line with capillary gas chromatography use of an anion-exchange membrane to remove an ion-pair reagent from the eluent.

    NARCIS (Netherlands)

    Brinkman, U.A.T.; Goosens, E.C.; de Jong, D.; de Jong, G.J.; Beerthuizen, I.M.

    1995-01-01

    In order to enable the coupling of reversed-phase liquid chromatography (RPLC) with capillary gas chromatography (GC), the performance of an anion-exchange micromembrane device has been studied to remove the ion-pair reagent methanesulphonic acid from an acetonitrile/water LC eluent. The regenerant

  2. Circumventing Therapeutic Resistance and the Emergence of Disseminated Breast Cancer Cells Through Non-Invasive Optical Imaging

    Science.gov (United States)

    2014-07-01

    Article Online View Journal | View Issue oxide) (PS-b-PEO),11–13 poly(styrene)-b-poly( acrylic acid) (PS-b-PAA),3,11,14 poly(ethylene oxide)-b-poly...cyanomethyl potassium as the protected initiator, which was prepared by metalation of acetonitrile with potas- sium naphthalenide in THF.49–52 While anionic

  3. Kinetics of hydrolysis of 4-methoxyphenyl-2,2-dichloroethanoate in binary water-cosolvent mixtures; the role of solvent activity and solute-solute interactions

    NARCIS (Netherlands)

    Rispens, T; Cabaleiro-Lago, C; Engberts, JBFN

    2005-01-01

    Rate constants are reported for the pH-independent hydrolysis of 4-methoxyphenyl-2,2-dichloroethanoate in aqueous solution as a function of the concentration of added cyanomethane ( acetonitrile), polyethylene glycol ( PEG 400) and tetrahydrofuran ( THF). The concentration of water was varied

  4. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    5-dihydroxybenzoic acid (Gentisic acid, GA) in oxygen environment. The iron(II) complex in the presence of two equivalent of triethylamine (Et3N) binds with GA stoichiometrically in acetonitrile medium at 25◦ C. Observation of GA-to-iron LMCT ...

  5. Tian et al., Afr J Tradit Complement Altern Med., (2017) 14 (5): 104 ...

    African Journals Online (AJOL)

    Materials and Methods: Protective effect of CSE was determined in silica-induced .... kept at 30 ◦C. The mobile phase was water and 0.1% FA and acetonitrile. .... exogenous agents can initiate the development of pulmonary fibrosis through ...

  6. Expanded metabolite coverage of Saccharomyces cerevisiae extract through improved chloroform/methanol extraction and tert-butyldimethylsilyl derivatization

    DEFF Research Database (Denmark)

    Khoomrung, Sakda; Martinez Ruiz, José Luis; Tippmann, Stefan

    2015-01-01

    and non-polar metabolites were derivatized using tert-butyldimethylsilyl (t-BDMS) dissolved in acetonitrile. Using microwave treatment of the samples, the derivatization process could be completed within 2 h (from >20 h of the conventional method), providing fully derivatized metabolites that contain...

  7. Phenylboronic acid catalysed synthesis of 1,5-benzodiazepines via ...

    Indian Academy of Sciences (India)

    Phenylboronic acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepine derivatives via cyclocondensation of -phenylenediamine and various ketones in good to excellent yields (82-91%) using acetonitrile as solvent at reflux condition. The remarkable advantages offered by this method are ...

  8. Mass and Charge Transport in Electronically Conductive Polymers

    Science.gov (United States)

    1990-08-02

    This method is based on coating an electrode surface with an insulating nitrile butadiene rubber ( NBR ). The electrolyte for polymerization (LiCIO4...in acetonitrile) etches channels through the NBR ; pyrrole is then polymerized in these channels. After polymerization the NBR is extracted away with

  9. Using a Combination of Experimental and Mathematical Method to Explore Critical Micelle Concentration of a Cationic Surfactant

    Science.gov (United States)

    Goronja, Jelena; Pejic´, Natas?a; Lez?aic´, Aleksandra Janos?evic´; Stanisavljev, Dragomir; Malenovic, Andelija

    2016-01-01

    An undergraduate electrical conductivity measurement experiment in a physical chemistry lab and basic fitting procedures are presented that allow a characterization of micellar system of hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide, CTAB) in binary mixture of water and acetonitrile (ACN) as a cosolvent (10%, v/v) at 30.0 °C.…

  10. Enhancement of Diosgenin Production in Plantlet and Cell Cultures ...

    African Journals Online (AJOL)

    HSCCC),. Sephadex LH-20 chromatography and preparative .... phase of acetonitrile-water (90:10, v/v) at a flow rate of 1 mL/min at 30 ºC, and an LC ..... Spirobisnaphthalenes from fungi and their biological activities. Mini-Rev Med Chem 2010; 10: ...

  11. Comparison of migration modeling in micellar electrokinetic chromatography by linear regression and by use of an artificial neural network

    NARCIS (Netherlands)

    Metting, HJ; van Zomeren, PV; van der Ley, CP; Coenegracht, PMJ; de Jong, GJ

    2000-01-01

    The concentrations of modifier (methanol or acetonitrile) and surfactant (sodium dodecyl sulfate SDS) in the running buffer are important factors influencing the mobility of analytes in micellar electrokinetic chromatography (MEKC). Response surfaces of the effective mobility can be used to predict

  12. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Abstract. SBA-15-Pr-SO3H catalyzes the multi-component condensation of aromatic aldehydes, ketones and acetonitrile in the presence of acetyl chloride at 80°C to afford -acetamido ketones in excellent yields. The catalyst can be recovered and recycled for subsequent reactions without any appreciable loss of efficiency.

  13. Comparison of concentration pulse and tracer pulse chromatography: experimental determination of eluent uptake by bridged-ethylene hybrid ultra high performance liquid chromatography packings

    Science.gov (United States)

    Excess volume isotherms of acetonitrile and methanol sorbed on a C18 BEH UHPLC packing were determined over a range of pressure, temperature, flow rate and eluent composition. The isotherm measurements were carried out by two independent experimental methods, viz., concentration pulse and tracer pul...

  14. The anomalous substituent effect of the ethyl group in the 13 C NMR and IR data of some aliphatic nitriles

    International Nuclear Information System (INIS)

    Garcia, Janaina C.; Barbarini, Jose E.; Rittner, Roberto; Rocco, Silvana A.; Tormena, Claudio F.

    1999-01-01

    This work reports a full assignment of 13 C and 1 H chemical shifts for some aliphatic nitriles from acetonitrile to octanonitrile and the observed shieldings for the carbon cyano group are correlated with the ν CN and with the electronic and steric parameters

  15. Triphenylphosphine dibromide: A useful reagent for conversion of aldoximes into nitriles

    Directory of Open Access Journals (Sweden)

    Fatemeh Darvish

    2015-11-01

    Full Text Available A simple and convenient method for the synthesis of nitriles by dehydration of aldoximes has been developed using triphenylphosphine dibromide in acetonitrile at room temperature. A variety of aromatic and heteroaromatic aldoximes are converted into the corresponding nitriles in high yields.

  16. Reactivity of nitriles

    International Nuclear Information System (INIS)

    Kukushkin, Yu.N.

    1987-01-01

    Reactivity of coordination nitriles in transition metal (Ru, Mo, W, Zr, Hf) complexes, namely: transformation of nitriles of the first coordination sphere into N-acyl-substituted amides, amidines, nitrile interaction; with water, alkalines, alcoholes, hydrogen, azide and cyanide ions is considered. Introduction of acetonitrile molecule to uranium (4)-carbon double bond is discussed

  17. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Synthesis and properties of Oxasmaragdyrins containing one ... Synthesis, crystal structure and photochemistry of Hexakis(butan-1-aminium) heptamolybdate(VI) tetrahydrate ... the active site of catechol oxidase enzyme in acetonitrile medium with a turnover number of 4.788 .... Derivatives through a Facile One-pot Process.

  18. Effects of Zinc and nitrogen application on agronomic traits and ...

    African Journals Online (AJOL)

    Aria

    2012-05-03

    May 3, 2012 ... Nitrogen fertilizer application improved seed number per silique and 1000-seed weight over .... mobile phase of acetonitrile and water at a flow rate of 1.0 ml/min ..... Ph.D. Thesis Faculty of Science, Botany Department, Cairo.

  19. Simultaneous determination of ochratoxin A, mycophenolic acid and fumonisin B-2 in meat products

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Mogensen, Jesper; Nielsen, Kristian Fog

    2010-01-01

    Here we present a method for simultaneous determination of the fungal metabolites mycophenolic acid, ochratoxin A (OTA) and fumonisin B-2 (FB2) in meat products. Extraction was performed with water-acetonitrile, followed by acetone-induced precipitation of salts and proteins. Purification...

  20. A cyclo olefin polymer microfluidic chip with integrated gold microelectrodes for aqueous ans non-aqueous electrochemistry

    DEFF Research Database (Denmark)

    Illa, Xavi; Sala, Olga Ordeig; Snakenborg, Detlef

    2010-01-01

    and 24 m deep channel was fabricated via hot embossing. Cyclic voltammetric measurements were carried out in aqueous and organic media, using a solution consisting of 5 mM ferrocyanide/ferricyanide in 0.5 M KNO3 and 5 mM ferrocene in 0.1 M TBAP/acetonitrile, respectively. Experimental currents obtained...

  1. 40 CFR Table 1 to Subpart F of... - Synthetic Organic Chemical Manufacturing Industry Chemicals

    Science.gov (United States)

    2010-07-01

    ... 123637 II Pentachlorophenol 87865 III Pentaerythritol 115775 I Peracetic acid 79210 II Perchloromethyl... 83329 V Acetal 105577 V Acetaldehyde 75070 II Acetamide 60355 II Acetanilide 103844 II Acetic acid 64197... Acetonitrile 75058 I Acetophenone 98862 I Acrolein 107028 IV Acrylamide 79061 I Acrylic acid 79107 IV...

  2. A triazole derivative as a new acid-base indicator | Numan Bulut ...

    African Journals Online (AJOL)

    1,2,4-triazole-5-on (BPNBAT), soluble in acetonitrile:water (1:4), was developed. The estimation of pH is possible either from the position of the absorption maxima or from the absorbance intensity at a constant wavelength. This feature allowed ...

  3. Insecticidal and fungicidal compounds from Isatis tinctoria.

    Science.gov (United States)

    Seifert, K; Unger, W

    1994-01-01

    Tryptanthrin (1), indole-3-acetonitrile (2) and p-coumaric acid methylester (3) were isolated from the aerial parts of Isatis tinctoria L. The compounds show insecticidal and anti-feedant activity against termites (Reticulitermis santonensis), insect preventive and control activity against larvae of the house longhorn beetle (Hylotrupes bajulus) and fungicidal activity against the brown-rot fungus (Coniophora puteana).

  4. Dynamics of Excited State Proton Transfer in Nitro Substituted 10-Hydroxybenzo[h]quinolines

    DEFF Research Database (Denmark)

    Marciak, H; Hristova, S.; Deneva, V

    2017-01-01

    The ground state tautomerism and excited state intramolecular proton transfer (ESIPT) of 10-hydroxybenzo[h]quinoline (HBQ) and its nitro derivatives, 7-nitrobenzo[h]quinolin-10-ol (2) and 7,9-dinitrobenzo[h]quinolin-10-ol (3), have been studied in acetonitrile using steady state as well as time d...

  5. A Stability Indicating HPLC Method for the Determination of ...

    African Journals Online (AJOL)

    Erah

    stability indicating reverse phase HPLC method for estimating meloxicam (MLX) in bulk ... acetonitrile-water-glacial acetic acid [55:40:5 (% v/v)] at a flow rate of 1ml/min and detection wavelength .... pore and degassed before use. ... determined to assess the effect of small but ... deviation, the standard error of slope, and the.

  6. New Highly-Sensitive Ultra-Performance Liquid Chromatography ...

    African Journals Online (AJOL)

    Waters, USA) using a mobile phase consisting of acetonitrile: 8 mM ammonium acetate containing 0.15. % formic acid (v/v) (70:30) ... suggest that the effects of telmisartan are ... (Millipore, Moscheim Cedex, France) having pore .... ratio, m is slope of the calibration curve, b is the ... Stability of TEL in plasma was assessed by.

  7. Development of Analytical Method for Detection of Some ...

    African Journals Online (AJOL)

    All compounds (hydrochlorothiazide, gliclazide, diclofenac-Na and mefenamic acid) were analysed in negative ion (NI) mode and eluted off the column with a mobile phase consisting of (A) 0.1% formic acid (FA) in deionised water (DIW) and (B) 40% acetonitrile (ACN) in methanol (MeOH) at 0.3 ml/min. Mass spectrometry ...

  8. Confirmatory analysis of malachite green, Leucomalachite green, crystal violet and leucocrystal violet in salmon by liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Dowling, A.P.G.; Mulder, P.P.J.; Duffy, C.; Regan, L.; Smyth, M.R.

    2007-01-01

    A method has been developed to analyse for malachite green (MG), leucornalachite green (LMG), crystal violet (CV) and leucocrystal violet (LCV) residues in salmon. Salmon samples were extracted with acetonitrile:Mclllvain pH 3 buffer (90: 10 v/v), sample extracts were purified on a Bakerbond strong

  9. Nigerian Journal of Chemical Research Vol. 22, No. 1, 2017 70 ...

    African Journals Online (AJOL)

    MR. S. O. OWALUDE

    Department of Chemistry, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria. E-mail for correspondence: owalude@unilorin.edu.ng; ... chemistry of transition metal complexes containing coordinated acetonitriles as ligands. This is due to ..... Inorganic Chemistry 51: 13334-13344. 11. Tanabiki, M., Tsuchiya, K.,. Kumanomido, Y.

  10. Synthesis, characterisation and modelling of a ferromagnetically coupled chromium(III) Dimer

    DEFF Research Database (Denmark)

    Morsing, Thorbjørn Juul; Weihe, Høgni; Bendix, Jesper

    2014-01-01

    A rare example of a ferromagnetically coupled dinuclear chromium(III) complex, the di-μ-hydroxobis[tetrakis(isothiocyanato)chromate(III)] anion, is reported. This complex has been synthesised from the oxo-bridged acetonitrile complex [(CH3CN)5CrOCr(NCCH3)5](BF4)4 and isolated as the solvated...

  11. Comparison of extraction and clean-up techniques for the ...

    African Journals Online (AJOL)

    user

    Six different extraction solvents: acetone, cyclohexane, 2- propanol, methanol, acetonitrile and dichloromethane, were tested to select the most suitable solvent for the extraction of the 16 PAHs from the certified soil reference material. The results were compared to determine the method with the highest extraction efficiency.

  12. Supporting Information for the article entitled, “Excited State Charge ...

    Indian Academy of Sciences (India)

    user

    Fig. S3: Mole fraction (of the relatively less polar component in the binary mixtures) dependence of Stokes shift of C153 in ethyl acetate and propanol binary mixtures (upper panel, 'PrOH-EA') and acetonitrile and propylene carbonate binary mixture (lower panel,. 'PC-ACN'). For (ethyl acetate + propanol) binary mixtures, ...

  13. JCSC_128_6_913_920_SI_a.doc

    Indian Academy of Sciences (India)

    bDepartment of Chemistry, Jalpaiguri Government Engineering College, Jalpaiguri, West Bengal, 735 102 India. cUniversità, degli Studi di Parma, ... Electronic absorption spectrum of the complex (conconcentration = 5.0 x 10-5 M, path length = 1.0 cm) in acetonitrile (inset shows d-d transition.) 3. Figure S5. PXRD pattern of ...

  14. Sub-ppb level detection of uranium using ligand sensitized luminescence

    International Nuclear Information System (INIS)

    Kumar, Satendra; Maji, S.; Joseph, M.; Sankaran, K.

    2015-01-01

    Uranyl ion (UO 2 2+ ) is known to exhibit weak luminescence in aqueous medium due to poor molar absorptivity and low quantum yield. In order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HClO 4 have been widely used. Like lanthanides, uranyl luminescence can also be sensitized by using some organic ligands. Pyridine 2,6-dicarboxylic acid (PDA) has shown enhancement of luminescence of uranyl in aqueous medium. Enhancement in intensity is due to sensitization of uranyl luminescence by PDA. In order to see the effect of non-aqueous medium, in this work, luminescence of uranyl-PDA complex has been studied in acetonitrile medium. More than one order luminescence enhancement has been observed compared to UO 2 2+ - PDA complex in aqueous medium. The lifetime of uranyl luminescence of the complex in acetonitrile medium is 90 μs which is very high compared to 10 μs in aqueous medium, suggesting that the luminescence enhancement is a result of reduction in non-radiative decay channels in acetonitrile medium. The large enhancement of uranyl luminescence of uranyl-PDA complex in acetonitrile medium can be used for ultra-trace level detection of uranium. Linearity in the luminescence intensity has been observed over the uranium concentration range of 5 to 80 ppb and the detection limit calculated using the criterion of 3 σ is ~ 0.2 ppb. (author)

  15. Molecular Innovations Toward Theranostics of Aggressive Prostate Cancer

    Science.gov (United States)

    2014-09-01

    18F]4-fluorobenzoic acid ([18F]FBA) as the corresponding TPA salt. After saponification , 1 ml of acetonitrile was added and evaporated (70°C, 5 min...with a stream of argon to remove any residual water left over from the saponification . O-(N-succinimidyl)-1,1,3,3-tetramethyluronium

  16. Characterization Of Cobalt-Exchanged Zeolite A By DRIFT Spectroscopy

    Science.gov (United States)

    Kappers, M. J.; van der Maas, John H.; Chalmers, J. M.; Howard, J.

    1989-12-01

    In-situ DRIFT spectroscopy has been succesfully used for the characterization of Co4Na4-A. Dehydration of the zeolite A appears to involve formation and breakdown of hydration complexes and hydrolysis. The position of cations and hydroxyl groups within the zeolite structure was derived from the adsorption of carbon monoxide and acetonitrile.

  17. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    pentafluorophenyl) porphynatoiron(III) chloride (F20TPPFe(III)Cl) has been studied in dichloromethane and acetonitrile medium at 25 ± 1° C. The reactive intermediates formed in this reaction have been quantitatively trapped by 2,4,6-tri -butylphenol ...

  18. Purification and characterization of laccase from Trametes hirsuta ...

    African Journals Online (AJOL)

    oem

    2012-02-21

    Feb 21, 2012 ... wine, and in beer stabilization (Minussi et al., 2002), paper pulp .... Laccase was incubated with ethanol and acetonitrile 20% at room temperature for 24 h. ... Apparent kinetic constants (Km, Vmax) were calculated using ..... from Trametes versicolor produced by solid-substrate fermentation. Adv. Biosci.

  19. Kinetics of hydrolysis of 4-methoxyphenyl-2,2-dichloroethanoate in binary water-cosolvent mixtures; the role of solvent activity and solute-solute interactions

    NARCIS (Netherlands)

    Rispens, Theo; Cabaleiro-Lago, Celia; Engberts, Jan B. F. N.

    2005-01-01

    Rate constants are reported for the pH-independent hydrolysis of 4-methoxyphenyl-2,2-dichloroethanoate in aqueous solution as a function of the concentration of added cyanomethane (acetonitrile), polyethylene glycol (PEG 400) and tetrahydrofuran (THF). The concentration of water was varied between

  20. Cycloadditions in mixed aqueous solvents : the role of the water concentration

    NARCIS (Netherlands)

    Rispens, Theo; Engberts, Jan B. F. N.

    We examined the kinetics of a series of cycloaddition reactions in mixtures of water with methanol, acetonitrile and poly(ethylene glycol) (MW 1000). The reactions include the Diels-Alder (DA) reaction between cyclopentadiene and N-n-butylmaleimide or acridizinium bromide, the retro-Diels-Alder

  1. Thermodynamic parameters for polyether adducts with neutral molecules

    International Nuclear Information System (INIS)

    Spencer, J.N.; Zafar, A.I.; Ganunis, T.F.

    1992-01-01

    Using calorimetry, thermodynamic parameters for the interaction of neutral molecules with polyether adducts are determined. When compared to its analogous acyclic ether, no macrocyclic effect is observed for 12-crown-4. The ether's collective oxygen atoms' action determines interaction with acetonitrile and malononitrile, with dimethyltin dichloride having a specific oxygen-binding site. 14 refs., 1 tab

  2. Rapid screening of oxytetracycline residue in catfish muscle by dispersive liquid-liquid microextraction and europium-sensitized luminescence

    Science.gov (United States)

    Oxytetracycline (OTC) residue in catfish muscle was screened by dispersive liquid-liquid microextraction (DLLME) and europium-sensitized luminescence (ESL). After extraction in EDTA, HCl, and acetonitrile, cleanup was carried out by DLLME, and ESL was measured at microgram = 385 nm and wavelength = ...

  3. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... behaves as an effective catalyst towards oxidation of 3,5-ditertiarybutyl catechol (3,5-DTBC) in acetonitrile to its corresponding quinone derivative in air. The reaction follows first-order reaction kinetics with rate constant 4.28 × 10−5 min-1. The reaction follows Michaelis-Menten enzymatic kinetics with a turnover number of ...

  4. Liquid chromatography-tandem mass spectrometric assay for the quantitative determination of the tyrosine kinase inhibitor quizartinib in mouse plasma using salting-out liquid-liquid extraction

    NARCIS (Netherlands)

    Retmana, Irene A; Wang, Jing; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2017-01-01

    A bioanalytical assay for quizartinib -a potent, and selective FLT3 tyrosine kinase inhibitor- in mouse plasma was developed and validated. Salting-out assisted liquid-liquid extraction (SALLE), using acetonitrile and magnesium sulfate, was selected as sample pretreatment with deuterated quizartinib

  5. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The reaction also produced an unexpected dipyridyl-NH-ketimine organometallic compound. [(η⁵-C₅Me₅)M {(C₅H₄N) ₂C=NH}Cl]PF6 as minor product when the reaction was performed under refluxing acetonitrile. The NH-ketimine compounds were formed via N-C single bond cleavage of imine ligand resulting in ...

  6. Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue.

    Science.gov (United States)

    Idowu, Olutosin R; Kijak, Philip J; Meinertz, Jeffery R; Schmidt, Larry J

    2004-01-01

    Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.

  7. Validation of a method for the targeted analysis of 96 drugs in hair by UPLC-MS/MS

    DEFF Research Database (Denmark)

    Montesano, Camilla; Johansen, Sys Stybe; Nielsen, Marie Katrine Klose

    2014-01-01

    are extracted from 10mg of washed hair in 18h by a mixture of methanol:acetonitrile:ammonium formate (pH 5.3). Absolute recovery ranged from 70% to 106% for 75% of the analytes. The limits of detection in the low pg/mg range, may allow the detection of single dose drug exposure, with possible application...

  8. Synthesis, crystal structure determination of two-dimensional ...

    Indian Academy of Sciences (India)

    Abstract. The 2-D polymeric complex (I) has the formula [Ag(phSE)(NO3)]n, which has been crystallized from methanol-acetonitrile mixture and characterized by elemental analysis and single-crystal X-ray diffraction analysis. In this polymer, each Ag(I) ion occupies distorted trigonal pyramidal geometry coordinating with two.

  9. [Simultaneous analysis of four diuretic drugs by HPLC and its application to health food supplements advertising weight reduction].

    Science.gov (United States)

    Goto, Tomomi; Mikami, Eiichi; Ohno, Tsutomu; Matsumoto, Hiroshi

    2002-04-01

    A high-performance liquid chromatographic (HPLC) method for the simultaneous analysis of triamterene, trichlormethiazide, furosemide and spironolactone is presented for application in the examination of health food supplements advertising weight reduction and in the analysis of pharmaceuticals. The HPLC assay was performed under gradient conditions using a Wakosil ODS 5C18 column (5 microns, 150 x 4.6 mm i.d.). The mobile phase consisted of a gradient program with a mixture of water and acetonitrile containing 0.1% triethylamine adjusted with phosphoric acid to pH 3.0: from 0 to 6 min, 15% acetonitrile; from 6 to 20 min, linear gradient from 15 to 50% acetonitrile; and from 20 to 40 min, 50% acetonitrile. The column effluent was monitored from 0 to 20 min at 260 nm and from 20 to 40 min at 235 nm. The calibration curves of the four drugs showed good linearity and the correlation coefficients were better than 0.999 in all cases. The lower limits of detection were approximately 40 ng for each drug. Commercially available health food supplements and pharmaceuticals were analyzed after extraction with a mixture of methanol and acetic acid (99:1). The procedure described here is suitable for the screening of four diuretic drugs in adulterated supplements and for the quality control of pharmaceuticals with minimal sample preparation.

  10. Determination of cordycepin content of Cordyceps militaris ...

    African Journals Online (AJOL)

    was determined by reversed-phase HPLC with water:acetonitrile (95:5, v/v) as mobile phase, detection wavelength of 260 nm, and flow rate of 1.0 mL/min. ... Keywords: Recombinant rice, Cordycepin, Chinese caterpillar fungus, Aweto, ...

  11. Detection of quorum sensing molecules from Vibrio harveyi and use ...

    African Journals Online (AJOL)

    This paper explores the extraction and detection processes of quorum sensing molecules such as N-aceyl homoserine lactone compounds (AHL) from marine Vibrio harveyi. The spent culture of V. harveyi was solvent partitioned for AHL, rotary evaporated and re-suspended in 50% acetonitrile then detected with reporter ...

  12. bipyridine host: Synthesis, X-ray structure, DNA cleavage

    Indian Academy of Sciences (India)

    (III) complex is soluble in all the common solvents like methanol, acetonitrile, water, etc. The IR spectrum ... tion at room temperature.28 ESI-Mass spectral analysis of the cobalt ... hydrogen bond and forms a polymeric cationic chain through a ...

  13. Influence of ampicllin/cloxacilin combination on pharmacokinetics of ...

    African Journals Online (AJOL)

    Samples were chromatographed on Agilent Technologies 1120 Compact LG model of HPLC, on column Eclipse x BD C-8,4.6 x 150 nm for metformin with mobile phase acetonitrile: potassium dihydrogen orthophosphate (79:21), using UV detector. The results obtained from the study indicated a statistically significant (P ...

  14. The synthesis of N–Zn, N–Cu complexes involving 2-amino pyridine ...

    Indian Academy of Sciences (India)

    Administrator

    alcohol, and the reaction mixture was refluxed for. 14 h. The mixture was filtered to furnish white cry- .... benzaldehyde to 2-nitro-1-phenylethanol was esta- blished according to the content ratio of the remin- ... Zn(OAc)2 ·2 H2O in ethanol, THF or acetonitrile, the corresponding complexes were obtained after reflux- ing for 14 ...

  15. Zhou et al., Afr J Tradit Complement Altern Med. (2011) 8(4):405 ‐411

    African Journals Online (AJOL)

    AJTCAM

    from six different habitats in China: Zhejiang Province, Anhui Province, Jiangxi Province, Chongqing City, Hunan Province and Hebei Province. Chemicals and reagents. Analytical grade-methanol was purchased from Sigma Aldrich, UK. HPLC-grade water, acetonitrile and tetrahydrofuran (THF) were purchased from Fisher ...

  16. Solvent-dependent regioselective oxidation of trans-chalcones using aqueous hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wang; Jiabin, Yang; Lushen, Li, E-mail: jimin@seu.edu.cn [Southeast University, Nanjing (China). School of Biological Science and Medical Engineering; Jin, Cai; Chunlong, Sun; Min, Ji [Southeast University, Nanjing (China). School of Chemistry and Chemical Engineering

    2013-03-15

    A novel method for regioselective oxidation of trans-chalcones with hydrogen peroxide in acetonitrile to afford cinnamic acids is reported. Only trans-b-arylacrylic acids were observed. A wide range of functionalized products can be effectively produced from various chalcones in good to excellent yields. (author)

  17. SHORT COMMUNICATION SYNTHESIS AND CRYSTAL ...

    African Journals Online (AJOL)

    Preferred Customer

    The title compound 1-[2-(3-ethyl-2,2-dimethylcyclobutyl)acetyl]-3-phenylthiourea has been synthesized and ... residue was added dropwise to the mixture of KSCN (3.0 g, 0.030 mol) and acetonitrile (30. mL). .... 111. Note. Elements of symmetry transformation: a 1-x, -y, 1-z;b intermolecular hydrogen bond; c intramolecular.

  18. The Synthesis of Nitrogen-Doped Multiwalled Carbon Nanotubes ...

    African Journals Online (AJOL)

    ACVDmethod was used to prepare high-quality nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) using acetonitrile as the nitrogen and carbon source and acetylene as a carbon source over an Fe-Co/CaCO3 catalyst in the temperature range 700–850 °C. This represents a continuation of earlier work in which ...

  19. Prediction of Molar Extinction Coefficients of Proteins and Peptides Using UV Absorption of the Constituent Amino Acids at 214 nm To Enable Quantitative Reverse Phase High-Performance Liquid Chromatography-Mass Spectrometry Analysis

    NARCIS (Netherlands)

    Kuipers, B.J.H.; Gruppen, H.

    2007-01-01

    The molar extinction coefficients of 20 amino acids and the peptide bond were measured at 214 nm in the presence of acetonitrile and formic acid to enable quantitative comparison of peptides eluting from reversed-phase high-performance liquid chromatography, once identified with mass spectrometry

  20. Development of a New RP-UPLC Method for the Determination of ...

    African Journals Online (AJOL)

    Development of a New RP-UPLC Method for the Determination of Rabeprazole Sodium in Pharmaceutical Formulation and Application in Dissolution Studies. ... particle size 1.7 μm) column using an isocratic method with mobile phase composed of acetonitrile and phosphate buffer (pH 7.4) in the ratio of 35:65 (v/v).

  1. Transport of biomass burning smoke to the upper troposphere by deep convection in the equatorial region

    NARCIS (Netherlands)

    Andreae, M. O.; Artaxo, P.; Fischer, H.; Freitas, S. R.; Grégoire, J.-M.; Hansel, A.; Hoor, P.; Kormann, R.; Krejci, R.; Lange, L.; Lelieveld, J.; Lindinger, W.; Longo, K.; Peters, W.; de Reus, M.; Scheeren, B.; Silva Dias, M. A. F.; Ström, J.; van Velthoven, P. F. J.; Williams, J.

    2001-01-01

    During LBA-CLAIRE-98, we found atmospheric layers with aged biomass smoke at altitudes >10 km over Suriname. CO, CO2, acetonitrile, methyl chloride, hydrocarbons, NO, O3, and aerosols were strongly enhanced in these layers. We estimate that 80-95% of accumulation mode aerosols had been removed

  2. Characterization and screening of pyrrolizidine alkaloids and N-oxides from various parts of many botanicals and dietary supplements using liquid chromatography high resolution mass spectrometry

    Science.gov (United States)

    The UHPLC-QToF-MS analysis of pyrrolizidine alkaloids from various parts of 37 botanicals and 7 dietary supplements was performed. A separation by LC was achieved using a reversed-phase column and a gradient of water/acetonitrile each containing formic acid as the mobile phase. MS-MS detection was u...

  3. A non-aqueous all-copper redox flow battery with highly soluble active species

    International Nuclear Information System (INIS)

    Li, Yun; Sniekers, Jeroen; Malaquias, João; Li, Xianfeng; Schaltin, Stijn; Stappers, Linda; Binnemans, Koen; Fransaer, Jan; Vankelecom, Ivo F.J.

    2017-01-01

    A metal-based redox pair with acetonitrile as ligand [Cu(MeCN)_4][Tf_2N] is described for use in non-aqueous redox flow battery (RFB). The electrode kinetics of the anode and cathode are studied using cyclic voltammetry. The Cu"2"+/Cu"+ and Cu"+/Cu couples in this system yield a cell potential of 1.24 V. The diffusion coefficient for [Cu(MeCN)_4][Tf_2N] in acetonitrile is estimated to be 6.8 × 10"−"6 cm"2 s"−"1 at room temperature. The copper-acetonitrile complex has a very high solubility of 1.68 M in acetonitrile, the most widely used organic solvent for non-aqueous electrochemical applications. Hence, a maximum theoretical energy density around 28 Wh L"−"1 can be reached with the reported system. The RFB with this electrolyte shows a promising performance, with coulombic efficiencies of 87% and energy efficiencies of 44% (5 mA cm"−"2).

  4. The Synthesis of Novel 3-Substituted Poly(pyrroles) Bearing Crown-ether Moieties and a Study of their Electrochemical Properties

    DEFF Research Database (Denmark)

    Guernion, Nicolas J.L.; Blencowe, A.; Hayes, Wayne

    2006-01-01

    A series of fourteen novel pyrrole monomers substituted at the 3-position with aliphatic and aromatic crown-ether moieties have been synthesised in good yield and characterised extensively. Several of those compounds were electropolymerised successfully in acetonitrile, using both potentiostatic ...

  5. Experimental interstellar organic chemistry - Preliminary findings

    Science.gov (United States)

    Khare, B. N.; Sagan, C.

    1973-01-01

    Review of the results of some explicit experimental simulation of interstellar organic chemistry consisting in low-temperature high-vacuum UV irradiation of condensed simple gases known or suspected to be present in the interstellar medium. The results include the finding that acetonitrile may be present in the interstellar medium. The implication of this and other findings are discussed.

  6. Picolinic acid promoted oxidative decarboxylation of ...

    African Journals Online (AJOL)

    The kinetics and mechanism of picolinic acid promoted reaction of phenylsulfinylacetic acid (PSAA) with Cr(VI) was carried out in aqueous acetonitrile medium under pseudo first order conditions. The reaction follows Michaelis-Menten type of kinetics with respect to PSAA. The catalytic activity by picolinic acid can be ...

  7. Relaxation dynamics in the excited states of a ketocyanine dye ...

    Indian Academy of Sciences (India)

    WINTEC

    non-linear optics, harmonic generation, optical limi- tation as well as optical imaging, .... and produces laser pulses of 6 nJ energy at 800 nm. These pulses are ... electric polarity of acetonitrile as compared to those of ethanol and TFE ..... age solvation time (〈τs〉) and the rotational correlation time (τOR) of the OH group of.

  8. {Fe6O2}-Based Assembly of a Tetradecanuclear Iron Nanocluster

    Directory of Open Access Journals (Sweden)

    Svetlana G. Baca

    2011-01-01

    Full Text Available The tetradecanuclear FeIII pivalate nanocluster [Fe14O10(OH4(Piv18], comprising a new type of metal oxide framework, has been solvothermally synthesized from a hexanuclear iron pivalate precursor in dichlormethane/acetonitrile solution. Magnetic measurements indicate the presence of very strong antiferromagnetic interactions in the cluster core.

  9. Diversity in electrochemical oxidation of dihydroxybenzenes in the ...

    Indian Academy of Sciences (India)

    Abstract. Electrochemical oxidation of some catechol derivatives (1a–e) have been studied in water/ acetonitrile solution containing 1-methylindole (3) as a nucleophile, using cyclic voltammetry and controlled- potential coulometry. An interesting diversity in the mechanisms has been observed in electrochemical oxidation ...

  10. Development and validation of a novel RP-HPLC method for simultaneous determination of paracetamol, phenylephrine hydrochloride, caffeine, cetirizine and nimesulide in tablet formulation

    Directory of Open Access Journals (Sweden)

    A.P. Dewani

    2015-07-01

    Full Text Available The present work describes development and validation of a high-performance liquid chromatography–diode array detection (HPLC–DAD procedure for the analysis of phenylephrine hydrochloride (PHE, paracetamol (PAR, caffeine anhydrous (CAF, cetirizine Dihydrochloride (CET, nimesulide (NIM in pharmaceutical mixture. Effective chromatographic separation of PHE, PAR, CAF, CET and NIM was achieved using a Kinetex-C18 (4.6 mm, 150 mm, 5 mm column with gradient elution of the mobile phase composed of 10 mM phosphate buffer (pH 3.3 and acetonitrile. The elution was a three step gradient elution program step-1 started initially with 2% (by volume acetonitrile and 98% phosphate buffer (pH 3.3 for first 2 min. In step-2 acetonitrile concentration changed linearly to 20% up to 12 min the analysis was concluded by step-3 changing acetonitrile to 2% up to 20 min. The proposed HPLC method was statistically validated with respect to linearity, ranges, precision, accuracy, selectivity and robustness. Calibration curves were linear in the ranges of 5–100, 100–1000 and 10–200 mg/mL for PHE, PAR, CAF, CET and NIM respectively, with correlation coefficients >0.9996. The HPLC method was applied to tablet dosage form in which the analytes were successfully quantified with good recovery values with no interfering peaks from the excipients.

  11. Li et al., Afr J Tradit Complement Altern Med. (2016) 13(1):105-113 ...

    African Journals Online (AJOL)

    PROF ADEWUNMI

    sampler, a degasser, an automatic thermostatic column compartment ... 35°C. A linear gradient elution of A (0.1% formate acid water) and B (acetonitrile) was used with the gradient procedure as follows: 0 min, B .... Identification of Compounds.

  12. NMR evidence for protonated tetraethyl p-tert-butylcalix[4]arene tetracacetate

    Czech Academy of Sciences Publication Activity Database

    Kříž, Jaroslav; Dybal, Jiří; Makrlík, E.; Vaňura, P.

    2007-01-01

    Roč. 81, č. 7 (2007), s. 1321-1326 ISSN 0137- 5083 Institutional research plan: CEZ:AV0Z40500505 Keywords : calix[4]arene * protonation * NMR * acetonitrile Subject RIV: CC - Organic Chemistry Impact factor: 0.483, year: 2007

  13. Conformational intermediate of the amyloidogenic protein beta 2-microglobulin at neutral pH

    DEFF Research Database (Denmark)

    Heegaard, N H; Sen, J W; Kaarsholm, N C

    2001-01-01

    electrophoresis that two conformers spontaneously exist in aqueous buffers at neutral pH. Upon treatment of wild-type beta(2)-microglobulin with acetonitrile or trifluoroethanol, two conformations were also observed. These conformations were in equilibrium dependent on the sample temperature and the percentage...

  14. Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

    Science.gov (United States)

    A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

  15. Two related lithium calixarene complexes, [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN and {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, determined using synchrotron radiation.

    Science.gov (United States)

    Lee, Darren S; Elsegood, Mark R J; Redshaw, Carl; Zhan, Shuzhong

    2009-08-01

    The crystal structures of acetonitrile solvates of two related lithium calixarene complexes have been determined by low-temperature single-crystal X-ray diffraction using synchrotron radiation. Bis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25-methoxy-27-oxidocalix[4]arene)dilithium(I) acetonitrile tetrasolvate, [Li2(C45H57O4)2].4C2H3N or [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN, (I), crystallizes with the complex across a centre of symmetry and with four molecules of unbound acetonitrile of crystallization per complex. Tetraacetonitrilebis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25,27-dioxidocalix[4]arene)tetralithium(I) acetonitrile octasolvate, [Li4(C44H54O4)2(C2H3N)4].8C2H3N or {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, (II), also crystallizes with the complex lying across a centre of symmetry and contains eight molecules of unbound acetonitrile per complex plus four more directly bound to two of the lithium ions, two on each ion. The cores of both complexes are partially supported by O-H...O hydrogen bonds. The methoxy methyl groups in (I) prevent the binding of any more than two Li+ ions, while the corresponding two O-atom sites in (II) bind an extra Li(+) ion each, making four in total. The calixarene cone adopts an undistorted cone conformation in (I), but an elliptical one in (II).

  16. Enhancement of catalytic activity of enzymes by heating in anhydrous organic solvents: 3D structure of a modified serine proteinase at high resolution.

    Science.gov (United States)

    Sharma, S; Tyagi, R; Gupta, M N; Singh, T P

    2001-01-01

    For the first time, it is demonstrated that exposure of an enzyme to anhydrous organic solvents at optimized high temperature enhances its catalytic power through local changes at the binding region. Six enzymes, namely, proteinase K, wheat germ acid phosphatase, alpha-amylase, beta-glucosidase, chymotrypsin and trypsin were exposed to acetonitrile at 70 degrees C for three hr. The activities of these enzymes were found to be considerably enhanced. In order to understand the basis of this change in the activity of these enzymes, proteinase K was analyzed in detail using X-ray diffraction method. The overall structure of the enzyme was found to be similar to the native structure in aqueous environment. The hydrogen bonding system of the catalytic triad remained intact after the treatment. However, the water structure in the substrate binding site underwent some rearrangement as some of the water molecules were either displaced or completely absent. The most striking observation concerning the water structure was the complete deletion of the water molecule which occupied the position at the so-called oxyanion hole in the active site of the native enzyme. Three acetonitrile molecules were found in the present structure. All the acetonitrile molecules were located in the recognition site. Interlinked through water molecules, the sites occupied by acetonitrile molecules were independent of water molecules. The acetonitrile molecules are involved in extensive interactions with the protein atoms. The methyl group of one of the acetonitrile molecules (CCN1) interacts simultaneously with the hydrophobic side chains of Leu 96, Ile 107 and Leu 133. The development of such a hydrophobic environment at the recognition site introduced a striking conformation change in Ile 107 by rotating its side chain about C alpha-C beta bond by 180 degrees to bring about the delta-methyl group within the range of attractive van der Waals interactions with the methyl group of CCN1. A similar

  17. Enhancement of catalytic efficiency of enzymes through exposure to anhydrous organic solvent at 70 degrees C. Three-dimensional structure of a treated serine proteinase at 2.2 A resolution.

    Science.gov (United States)

    Gupta, M N; Tyagi, R; Sharma, S; Karthikeyan, S; Singh, T P

    2000-05-15

    The enzyme behavior in anhydrous media has important applications in biotechnology. So far chemical modifications and protein engineering have been used to alter the catalytic power of the enzymes. For the first time, it is demonstrated that an exposure of enzyme to anhydrous organic solvents at optimized high temperature enhances its catalytic power through local changes at the binding region. Six enzymes: proteinase K, wheat germ acid phosphatase, alpha-amylase, beta-glucosidase, chymotrypsin and trypsin have been exposed to acetonitrile at 70 degrees C for three hours. The activities of these enzymes were found to be considerably enhanced. In order to understand the basis of this change in the activity of these enzymes, the structure of one of these treated enzymes, proteinase K has been analyzed in detail using X-ray diffraction method. The overall structure of the enzyme is similar to the native structure in aqueous environment. The hydrogen bonding system of the catalytic triad is intact after the treatment. However, the water structure in the substrate binding site undergoes some rearrangement as some of the water molecules are either displaced or completely absent. The most striking observation concerning the water structure pertains to the complete deletion of the water molecule which occupied the position at the so-called oxyanion hole in the active site of the native enzyme. Three acetonitrile molecules were found in the present structure. All the acetonitrile molecules are located in the recognition site. The sites occupied by acetonitrile molecules are independent of water molecules. The acetonitrile molecules are involved in extensive interactions with the protein atoms. All of them are interlinked through water molecules. The methyl group of one of the acetonitrile molecules (CCN1) interacts simultaneously with the hydrophobic side chains of Leu-96, Ile-107, and Leu-133. The development of such a hydrophobic environment at the recognition site

  18. Quantification of the Triazole Antifungal Compounds Voriconazole and Posaconazole in Human Serum or Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

    Science.gov (United States)

    Molinelli, Alejandro R; Rose, Charles H

    2016-01-01

    Voriconazole and posaconazole are triazole antifungal compounds used in the treatment of fungal infections. Therapeutic drug monitoring of both compounds is recommended in order to guide drug dosing to achieve optimal blood concentrations. In this chapter we describe an HPLC-ESI-MS/MS method for the quantification of both compounds in human plasma or serum following a simple specimen preparation procedure. Specimen preparation consists of protein precipitation using methanol and acetonitrile followed by a cleanup step that involves filtration through a cellulose acetate membrane. The specimen is then injected into an HPLC-ESI-MS/MS equipped with a C18 column and separated over an acetonitrile gradient. Quantification of the drugs in the specimen is achieved by comparing the response of the unknown specimen to that of the calibrators in the standard curve using multiple reaction monitoring.

  19. Dynamics of anion exchange of lanthanides in aqueous-organic complexing media

    International Nuclear Information System (INIS)

    Sheveleva, I.V.; Bogatyrev, I.O.

    1987-01-01

    Effect of organic solvents (ethanol, acetone, acetonitrile) on change in kinetic parameters of the anion exchange process (anion-exchange column chromatography) of r.e.e. (europium and gadolinium) in complexing nitric acid media has been studied. It is established that complex LnA 4 anion is the only sorbing form of europium and gadolinium on anionite. When the organic component content of the solution being the same, the dynamic parameters of lanthanide exchange have higher values in aqueous-acetonitrile and aqueous-acetone media in comparison with aqueous-enthanol solutions of nitric acid. Lesser mobility of complex lanthanide anions in aqueous-alcoholic solutions can be explained by stronger solvation in the presence of solvents with higher acceptor properties

  20. Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

    KAUST Repository

    Haslinger, Stefan

    2014-11-03

    This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

  1. Highly selective enrichment of phosphorylated peptides using titanium dioxide

    DEFF Research Database (Denmark)

    Thingholm, Tine; Jørgensen, Thomas J D; Jensen, Ole N

    2006-01-01

    -column. Although phosphopeptide enrichment can be achieved by using TFA and acetonitrile alone, the selectivity is dramatically enhanced by adding DHB or phthalic acid since these compounds, in conjunction with the low pH caused by TFA, prevent binding of nonphosphorylated peptides to TiO2. Using an alkaline...... a protocol for selective phosphopeptide enrichment using titanium dioxide (TiO2) chromatography. The selectivity toward phosphopeptides is obtained by loading the sample in a 2,5-dihydroxybenzoic acid (DHB) or phthalic acid solution containing acetonitrile and trifluoroacetic acid (TFA) onto a TiO2 micro...... solution (pH > or = 10.5) both monophosphorylated and multiphosphorylated peptides are eluted from the TiO2 beads. This highly efficient method for purification of phosphopeptides is well suited for the characterization of phosphoproteins from both in vitro and in vivo studies in combination with mass...

  2. Application of point-to-point matching algorithms for background correction in on-line liquid chromatography-Fourier transform infrared spectrometry (LC-FTIR).

    Science.gov (United States)

    Kuligowski, J; Quintás, G; Garrigues, S; de la Guardia, M

    2010-03-15

    A new background correction method for the on-line coupling of gradient liquid chromatography and Fourier transform infrared spectrometry has been developed. It is based on the use of a point-to-point matching algorithm that compares the absorption spectra of the sample data set with those of a previously recorded reference data set in order to select an appropriate reference spectrum. The spectral range used for the point-to-point comparison is selected with minimal user-interaction, thus facilitating considerably the application of the whole method. The background correction method has been successfully tested on a chromatographic separation of four nitrophenols running acetonitrile (0.08%, v/v TFA):water (0.08%, v/v TFA) gradients with compositions ranging from 35 to 85% (v/v) acetonitrile, giving accurate results for both, baseline resolved and overlapped peaks. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  3. Determination of Ivermectin in Medicated Feeds by Liquid Chromatography with Fluorescence Detection

    Science.gov (United States)

    2013-01-01

    A labour- and time-effective analytical procedure for determination of ivermectin in medicated feed at recommended level of 2.0 mg kg−1 has been developed and validated. The analyte was extracted from grinded feed samples with acetonitrile and derivatisated with N-methylimidazole and trifluoracetic anhydride. The fluorescent derivatives were analysed by liquid chromatography method using C8 column. The isocratic conditions using acetonitrile, methanol, water, and tetrahydrofuran were applied. Fluorescence detection was performed at 365 nm (excitation) and 475 nm (emission) wavelengths. The total analysis time was 10 min. The validation results of the method (within-laboratory reproducibility 4.0% CV, mean recovery 100.1%) confirm the appropriate precision and accuracy of the developed method. PMID:24453835

  4. Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

    KAUST Repository

    Haslinger, Stefan; Kü ck, Jens W.; Hahn, Eva M.; Cokoja, Mirza; Pö thig, Alexander; Basset, Jean-Marie; Kü hn, Fritz

    2014-01-01

    This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

  5. Cooling crystallization of Indomethacin from different organic solvents

    DEFF Research Database (Denmark)

    Malwade, Chandrakant Ramkrishna; Qu, Haiyan

    , 25, 35, and 45 °C. The solvents with varying polarities (ethanol, methanol, ethyl acetate, acetone, acetonitrile, and dichloromethane) were used for solubility measurement. Maximum solubility of IMC was observed in acetone, while acetonitrile showed the lowest solubility. Solid phase analysis...... of excess solute with XRPD and Raman spectroscopy confirmed formation of IMC solvate in acetone, methanol and dichloromethane at 15 °C. Based on solubility of IMC, the solvents ethanol, ethyl acetate, acetone, and dichloromethane were selected for crystallization experiments. Nucleation kinetics of IMC...... in selected solvents was investigated through the measurement of induction time at 5 °C and 15 °C. Longer induction times were observed for IMC in ethanol at both temperatures compared to the one in acetone. Metastable α form of IMC was obtained from ethanol, while solvate of IMC was produced from acetone....

  6. 4-Hydroxy-1-naphthaldehydes: proton transfer or deprotonation

    DEFF Research Database (Denmark)

    Manolova, Y; Kurteva, V; Antonov, L

    2015-01-01

    A series of naphthaldehydes, including a Mannich base, have been investigated by UV-Vis spectroscopy, NMR and theoretical methods to explore their potential tautomerism. In the case of 4-hydroxy-1-naphthaldehyde concentration dependent deprotonation has been detected in methanol and acetonitrile....... For 4-hydroxy-3-(piperidin-1-ylmethyl)-1-naphthaldehyde (a Mannich base) an intramolecular proton transfer involving the OH group and the piperidine nitrogen occurs. In acetonitrile the equilibrium is predominantly at the OH-form, whereas in methanol the proton transferred tautomer is the preferred form....... In chloroform and toluene, the OH form is completely dominant. Both 4-hydroxy-1-naphthaldehyde and 4-methoxy-1-naphthaldehyde (fixed enol form) show dimerization in the investigated solvents and the crystallographic data, obtained for the latter, confirm the existence of a cyclic dimer...

  7. The quantum-chemical investigation of N-cyclization reaction mechanism for epichlorohydrin aminolysis products

    Directory of Open Access Journals (Sweden)

    Andrey V. Tokar

    2014-12-01

    Full Text Available The mechanism of intramolecular cyclization for products of epichlorohydrin aminolysis by secondary amines has been investigated at ab initio level of theory. By comparative analysis of energetic characteristics, which obtained in vacuo as well as in acetonitrile solution with the trace quantities of water as an «active» solvation partner of reaction, it has been shown a decisive role of solvent, which occurs mainly at the expense of the polarizable effects for nonspecific solvation. Indeed, the addition to the substrate of one water molecule have decreased corresponding EACT values only 24.1 kJ/mol, while the appearance of acetonitrile surroundings have the same influence ~42.0 kJ/mol. The results of calculations are in good agreement with that data, which have been obtained for such type modeling previously.

  8. Effect of electrode mass ratio on aging of activated carbon based supercapacitors utilizing organic electrolytes

    Science.gov (United States)

    Cericola, D.; Kötz, R.; Wokaun, A.

    2011-03-01

    The accelerated degradation of carbon based supercapacitors utilizing 1 M Et4NBF4 in acetonitrile and in propylene carbonate as electrolyte is investigated for a constant cell voltage of 3.5 V as a function of the positive over total electrode mass ratio. The degradation rate of the supercapacitor using acetonitrile as a solvent can be decreased by increasing the mass of the positive electrode. With a mass ratio (positive electrode mass/total electrode mass) of 0.65 the degradation rate is minimum. For the capacitor utilizing propylene carbonate as a solvent a similar effect was observed. The degradation rate was smallest for a mass ratio above 0.5.

  9. Studies of the reactions of uranium pentabromide and hexabromouranate(V) in non-aqueous solvents

    International Nuclear Information System (INIS)

    Dehos, R.F.

    1984-01-01

    With the help of IR and electron spectra, the behaviour of uranium pentabromide and hexabromo uranate in non-aqueous nitromethane, nitroethane, bromine, dichlormethane, dibromomethane and acetonitrile was studied. By comparison of the spectra of the solutions in nitromethane with the solutions using other solvents on one side, and on the other side with the solids spectra of the end products, the redox reactions of the uranium V in nitromethane solutions could be more than clarified. Studies were also carried out on the time-dependency of the uranium IV and uranium V contents of the solutions at room temperature and at -20 0 C. The existence of the HUBr 6 which probably appears as an intermediate product was tested in another experiment. First evidence for the existence of UBr 6 as a disproportionation product of UBr 5 were achieved by tests in solutions of acetonitrile at -47 0 C. (RB) [de

  10. Avaliação de solventes de extração por ultrassom usando-se cromatografia líquida de alta eficiência para a determinação de hidrocarbonetos policíclicos aromáticos em solos contaminados Evaluation of solvent extraction by ultrasound by using high performance liquid chromatography for the determination of polycyclic aromatic hydrocarbons in contaminated soils

    Directory of Open Access Journals (Sweden)

    Jussara Aparecida Oliveira Cotta

    2009-01-01

    Full Text Available A method using ultrasonication extraction for the determination of 17 polycyclic aromatic hydrocarbons (PAHs, selected by the USEPA and NIOSH as "consent decree" priority pollutants, in soil by High Performance Liquid Chromatography (HPLC was studied. Separation and detection were completed in 20 min with a C18 columm, acetonitrile-water gradient elution and ultraviolet absorption and fluorescence detections. The detection limits, for a 10 µL of solution injection, were less than 9,917 ng/g in UV detection and less than 1,866 ng/g in fluorescence detection. Several organic solvents were tested for extraction of the 17 PAHs from soils. Acetone was the best solvent among the three solvents tested, and the order of the extraction efficiencies was: acetone>methanol>acetonitrile. Ultrasonication using acetone as solvent extraction was used to evaluate the biodegradation of those compounds in contaminated soil during a vermicomposting process.

  11. Flexibility transition and guest-driven reconstruction in a ferroelastic metal-organic framework†Electronic supplementary information (ESI) available: Atomic coordinates and lattice parameter data. CCDC 1016797. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ce01572jClick here for additional data file.

    Science.gov (United States)

    Hunt, Sarah J; Cliffe, Matthew J; Hill, Joshua A; Cairns, Andrew B; Funnell, Nicholas P; Goodwin, Andrew L

    2015-01-14

    The metal-organic framework copper(i) tricyanomethanide, Cu(tcm), undergoes a ferroelastic transition on cooling below T f = 240 K. Thermal expansion measurements reveal an order-of-magnitude variation in framework flexibility across T f . The low-temperature phase α-Cu(tcm) exhibits colossal positive and negative thermal expansion that is the strongest ever reported for a framework material. On exposure to acetonitrile, Cu(tcm) undergoes a reconstructive solid-phase transition to acetonitrilocopper(i) tricyanomethanide. This transition can be reversed by heating under vacuum. Infrared spectroscopy measurements are sensitive to the phase change, suggesting that Cu(tcm) may find application in solid-phase acetonitrile sensing.

  12. Employing a hydrazine linked asymmetric double naphthalene hybrid for efficient naked eye detection of F-: Crystal structure with real application for F-

    Science.gov (United States)

    Bhattacharyya, Arghyadeep; Makhal, Subhash Chandra; Ghosh, Soumen; Guchhait, Nikhil

    2018-06-01

    An asymmetric hydrazide, (12E, 13E)-2-((naphthalen-1-yl) methylene)-1-(1-(2-hydroxynaphthalen-6-yl) ethylidene) hydrazine (abbreviated as AH) is synthesized and characterized by standard techniques and crystal structure of AH has been obtained. The naked eye detection of F- in aqueous acetonitrile (acetonitrile: water = 7:3/v:v) by AH has been investigated by UV-Visible titration and in presence of other anions, the limit of detection being 1.31 × 10-6(M). The mechanism of F- sensing has been explored by 1H NMR titration. AH undergoes hydrogen bonding with F- followed by deprotonation. The practical utility of AH has been explored by successful test kit response and color change in toothpaste solution.

  13. Simultaneous Quantification of Antidiabetic Agents in Human Plasma by a UPLC-QToF-MS Method.

    Directory of Open Access Journals (Sweden)

    Mariana Millan Fachi

    Full Text Available An ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry method for the simultaneous quantification of chlorpropamide, glibenclamide, gliclazide, glimepiride, metformin, nateglinide, pioglitazone, rosiglitazone, and vildagliptin in human plasma was developed and validated, using isoniazid and sulfaquinoxaline as internal standards. Following plasma protein precipitation using acetonitrile with 1% formic acid, chromatographic separation was performed on a cyano column using gradient elution with water and acetonitrile, both containing 0.1% formic acid. Detection was performed in a quadrupole time-of-flight analyzer, using electrospray ionization operated in the positive mode. Data from validation studies demonstrated that the new method is highly sensitive, selective, precise (RSD 0.99, free of matrix and has no residual effects. The developed method was successfully applied to volunteers' plasma samples. Hence, this method was demonstrated to be appropriate for clinical monitoring of antidiabetic agents.

  14. The solvation of L-serine in mixtures of water with some aprotic solvents at 298.15 K

    Science.gov (United States)

    Mezhevoi, I. N.; Badelin, V. G.

    2009-03-01

    The integral enthalpies of solution Δsol H m of L-serine in mixtures of water with acetonitrile, 1,4-dioxane, dimethylsulfoxide (DMSO), and acetone were measured by solution calorimetry at organic component concentrations up to 0.31 mole fractions. The standard enthalpies of solution (Δsol H°), transfer (Δtr H°), and solvation (Δsolv H°) of L-serine from water into mixed solvents were calculated. The dependences of Δsol H°, Δsolv H°, and Δtr H° on the composition of aqueous-organic solvents contained extrema. The calculated enthalpy coefficients of pair interactions of the amino acid with cosolvent molecules were positive and increased in the series acetonitrile, 1,4-dioxane, DMSO, acetone. The results obtained were interpreted from the point of view of various types of interactions in solutions and the influence of the nature of organic solvents on the thermochemical characteristics of solutions.

  15. Quality control of residual solvents in [18F]FDG preparations by gas chromatography

    International Nuclear Information System (INIS)

    Lee, Hak Jeong; Jeong, Jae Min; Lee, Yun Sang; Kim, Hyung Woo; Chang, Young Soo; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul

    2007-01-01

    Analysis of volatile organic solvents in 2-deoxy-2[ 18 F] fluoro-D-glucose ([ 18 F]FDG) preparations was performed by gas chromatography (GC), in accordance with USP. Analyses were carried out on a Hewlett-Packard 6890 gas chromatography equipped with an FID. We determined the amounts of ethanol and acetonitrile on every batch of our routine [ 18 F]FDG preparations, ranging between 5000 ppm and 100 ppm. In our routine preparation of [ 18 F]FDG, the amount of acetonitrile and ethanol in the final product were well below the maximum allowable limit described in the USP. Our [ 18 F]FDG preparations were in accordance with the suggested USP maximum allowable levels of the quality control analysis of volatile organic compounds

  16. Influence of temperature and electrolyte on the performance of activated-carbon supercapacitors

    Science.gov (United States)

    Liu, Ping; Verbrugge, Mark; Soukiazian, Souren

    For hybrid electric vehicle traction applications, energy storage devices with high power density and energy efficiency are required. A primary attribute of supercapacitors is that they retain their high power density and energy efficiency even at -30 °C, the lowest temperature at which unassisted starting must be provided to customers. More abuse-tolerant electrolytes are preferred to the high-conductivity acetonitrile-based systems commonly employed. Propylene carbonate based electrolytes are a promising alternative. In this work, we compare the electrochemical performance of two high-power density electrical double layer supercapacitors employing acetonitrile and propylene carbonate as solvents. From this study, we are able to elucidate phenomena that control the resistance of supercapacitor at lower temperatures, and quantify the difference in performance associated with the two electrolytes.

  17. Novel Reaction of N,N'-Bisarylmethanediamines with Formaldehyde. Synthesis of Some New 1,3,5-Triaryl-1,3,5-hexahydrotriazines

    Directory of Open Access Journals (Sweden)

    Abolfazl Olyaei

    2006-07-01

    Full Text Available The acid-catalyzed cyclocondensation of N,N'-bisaryl (aryl = 2-pyrimidinyl, 2- pyrazinyl and 4-nitrophenyl methanediamines 5a-c with aqueous formaldehyde in refluxing acetonitrile leads to the formation of the corresponding 1,3,5-triaryl-1,3,5-hexa- hydrotriazines 6a-c. The stoichiometric reactions of 2-aminopyrimidine and 2-amino- pyrazine with aqueous formaldehyde in acetonitrile under reflux conditions also afforded 6a and 6b, respectively. Treatment of 2-aminopyrimidine with aqueous formaldehyde in a 3:2 ratio yielded N,N',N"-tris(2-pyrimidinyldimethylenetriamine (7a as a sole product, which upon subsequent reaction with formaldehyde also afforded 6a. The reaction of N,N'-biphenylmethanediamine with formaldehyde was also investigated.

  18. Validation Study on a Rapid Method for Simultaneous Determination of Pesticide Residues in Vegetables and Fruits by LC-MS/MS.

    Science.gov (United States)

    Sato, Tamaki; Miyamoto, Iori; Uemura, Masako; Nakatani, Tadashi; Kakutani, Naoya; Yamano, Tetsuo

    2016-01-01

    A validation study was carried out on a rapid method for the simultaneous determination of pesticide residues in vegetables and fruits by LC-MS/MS. Preparation of the test solution was performed by a solid-phase extraction technique with QuEChERS (STQ method). Pesticide residues were extracted with acetonitrile using a homogenizer, followed by salting-out and dehydration at the same time. The acetonitrile layer was purified with C18 and PSA mini-columns. The method was assessed for 130 pesticide residues in 14 kinds of vegetables and fruits at the concentration level of 0.01 μg/g according to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan. As a result 75 to 120 pesticide residues were determined satisfactorily in the tested samples. Thus, this method could be useful for a rapid and simultaneous determination of multi-class pesticide residues in various vegetables and fruits.

  19. Enantioseparation of dansyl amino acids by ultra-high pressure liquid chromatography using cationic β-cyclodextrins as chiral additives.

    Science.gov (United States)

    Xiao, Yin; Tan, Timothy Thatt Yang; Ng, Siu-Choon

    2011-04-07

    This work reports the application of ultra-high pressure liquid chromatography (UHPLC) for reasonably fast enantiorecognition of some dansyl amino acids by employing three cationic β-cyclodextrins (β-CDs) as chiral additives. Good resolutions were obtained on an Agilent C18 column (2.1 mm i.d.; 1.8 μm; 50 mm length) with 1% (v/v) triethylammonium acetate buffered at pH 4.7 and acetonitrile as the mobile phase. Most of the analytes could be baseline resolved within 10 min. Increased cationic CD concentration or acetonitrile proportion in the mobile phase results in a decreased retention factor but accentuated selectivity. Furthermore, molecular mechanics calculation was performed and found to be consistent with the experimental results. © The Royal Society of Chemistry 2011

  20. Chemical models of chains electron transfer in hydroxylating ferment systems

    International Nuclear Information System (INIS)

    Akhrem, A.A.; Kiselev, P.A.; Metelitsa, D.I.

    1977-01-01

    The rate constants are measured of consumption of nicotineamidedinucleotide (NAD-N) during its oxidation by molecular oxygen with the participation of Ti 4+ , Sn 4+ , Cu 2+ , Fe 3+ , VO 2+ , and Ce 4+ ions in mixtures of acetonitrile with water and of dioxane with water taken in a volume ratio of 1:1 (46 deg C). The kinetics of oxidation of NAD-N with the participation of Ti 4+ at 37 deg C in a water-acetonitrile medium is studied in detail. The hydroxylating capacity of the system NAD-N - Ti 4+ - O 2 with respect to naphthalene is proved. The reaction mechanism and its relationship with the microsomal chains of electron transport are discussed

  1. Reaction kinetics of resveratrol with tert-butoxyl radicals

    International Nuclear Information System (INIS)

    Džeba, Iva; Pedzinski, Tomasz; Mihaljević, Branka

    2012-01-01

    The rate constant for the reaction of t-butoxyl radicals with resveratrol was studied under pseudo-first order conditions. The rate constant was determined by measuring the phenoxyl radical formation rate at 390 nm as function of resveratrol concentration in acetonitrile. The rate constant was determined to be 6.5×10 8 M −1 s −1 . This high value indicates the high reactivity consistent with the strong antioxidant activity of resveratrol. - Highlights: ► tert-butoxyl radicals were generated directly using laser flash photolysis. ► Rate constant was determined by the phenoxyl radical formation rate in acetonitrile. ► Rate constant was determined to be 6.5×10 8 M −1 s −1 .

  2. Synthesis and characterization of oxytetracycline imprinted magnetic polymer for application in food

    Science.gov (United States)

    Aggarwal, Sneha; Rajput, Yudhishthir Singh; Singh, Gulab; Sharma, Rajan

    2016-02-01

    Magnetic imprinted polymer was prepared by polymerization of methacrylate and ethyleneglycoldimethacrylate in the presence of oxytetracycline on the surface of iron magnetite. Selectivity of prepared polymer was calculated from ratio of partition coefficient of oxytetracycline for imprinted and non- imprinted polymer in water, acetonitrile, methanol and at different pH in aqueous buffer. pH of solvent exhibited pronounced effect on selectivity. Selectivity at pH 7.0, 6.0 and 5.0 was 36.0, 2.25 and 1.61 fold higher than at pH 4.0. Imprinted polymer was not selective for oxytetracycline in methanol. However, selectivity in water and acetonitrile was 19.42 and 2.86, respectively. Oxytetracycline did bind to imprinted polymer in water or aqueous buffer (pH 7.0) and could be eluted with methanol. Prepared polymer extracted 75-80 % oxytetracycline from water, honey and egg white.

  3. ELECTROCHEMICAL PROPERTIES OF NANOPOROUS CARBON ELECTRODES

    Directory of Open Access Journals (Sweden)

    P.Nigu

    2002-01-01

    Full Text Available Electrical double layer and electrochemical characteristics at the nanoporous carbon | (C2H54NBF4 + acetonitrile interface have been studied by the cyclic voltammetry and impedance spectroscopy methods. The value of zero charge potential (0.23 V vs. SCE in H2O, the region of ideal polarizability and other characteristics have been established. Analysis of complex plane plots shows that the nanoporous carbon | x M (C2H54NBF4 + acetonitrile interface can be simulated by the equivalent circuit, in which the two parallel conduction parts in the solid and liquid phases are interconnected by the double layer capacitance in parallel with the complex admittance of hindered reaction of the charge transfer process. The values of the characteristic frequency depend on the electrolyte concentration and on the electrode potential, i.e. on the nature of ions adsorbed at the surface of nanoporous carbon electrode.

  4. Targeted analysis of 116 drugs in hair by UHPLC-MS/MS and its application to forensic cases

    DEFF Research Database (Denmark)

    Wang, Xin; Johansen, Sys Stybe; Nielsen, Marie Katrine Klose

    2017-01-01

    A multi-target method that can detect a broad range of drugs of abuse in human hair, such as hypnotics, anxiolytics, analgesics, benzodiazepines, antihistamines, antidepressants, antipsychotics, and anticonvulsants, was developed based on ultra-high-performance liquid chromatography-tandem mass...... spectrometry (UHPLC-MS/MS). The drugs were extracted from 10 mg of washed hair by incubation for 18 h in a 25:25:50 (v/v/v) mixture of methanol/acetonitrile/2 mM ammonium formate (8% acetonitrile, pH 5.3). For 51% of the basic drugs, the lower limits of quantification (LLOQs) were in the range of 0.05-0.5 pg...... studies, the present method is sensitive enough to detect single dose drug exposure for many of the drugs. The accuracy was within 75-125% for the majority of drugs. Good precision was observed (relative standard deviations [RSD%] 

  5. Ionic Liquid-Bonded Fused Silica as a New Solid-Phase Microextraction Fiber for the Liquid Chromatographic Determination of Bisphenol A as an Endocrine Disruptor.

    Science.gov (United States)

    Mohammadnezhad, Nasim; Matin, Amir Abbas; Samadi, Naser; Shomali, Ashkan; Valizadeh, Hassan

    2017-01-01

    Linear ionic liquid bonded to fused silica and its application as a solid-phase microextraction fiber for the extraction of bisphenol A (BPA) from water samples were studied. After optimization of microextraction conditions (15 mL sample volume, extraction time of 40 min, extraction temperature of 30 ± 1°C, 300 μL acetonitrile as the desorption solvent, and desorption time of 7 min), the fiber was used to extract BPA from packed mineral water, followed by HPLC-UV on an XDB-C18 column (150 × 4.6 mm id, 3.5 μm particle) with a mobile phase of acetonitrile-water (45 + 55%, v/v) and flow rate of 1 mL . min-1). A low LOD (0.20 μg . L-1) and good linearity (0.9977) in the calibration graph indicated that the proposed method was suitable for the determination of BPA.

  6. Liquid-chromatographic determination of sarafloxacin residues in channel catfish muscle-tissue

    Science.gov (United States)

    Meinertz, J.R.; Dawson, V.K.; Gingerich, W.H.; Cheng, B.; Tubergen, M.M.

    1994-01-01

    A liquid chromatographic method is described for the determination of sarafloxacin hydrochloride residues i n channel catfish (ictalurus punctatus) fillets. Sarafloxacin was extracted from fillet tissue with acetonitrile=water (1 + 1). The extract was centrifuged and the supernatant was partitioned with hexane. The aqueous fraction was filtered through a 0.45 Mum filter and evaporated to dryness. The sample was redissolved with 20% acetonitrile-methanol (3 + 2) and 80% trifluoroacetic acid (0.1%), Centrifuged, and filtered to remove proteins. Samples were analyzed by chromatography with gradient elution on a c18 column and with fluorescence detection (excitation at 280 nm and emission above 389 nm). Mean recoveries ranged from 85.4 To 104%, and relative standard deviations ranged from 1.06 To 5.58% In samples spiked at concentrations of 10.0-863.8 Ng/g. The method detection limit for sarafloxacin was 1.4 Ng/g.

  7. Cryochemistry: freezing effect on peptide coupling in different organic solutions.

    Science.gov (United States)

    Vajda, T; Szókán, G; Hollósi, M

    1998-06-01

    The freezing effect on peptide coupling in organic solutions of different polarity has been investigated and compared with the results obtained in liquid phase. The model reaction of DCC-activated coupling of Boc-Ala-Phe-OH with H-Ala-OBu(t) has been carried out in dioxane, dimethylsulfoxide and formamide, as well as in mixtures (90%/10%, v/v) of dioxane with acetonitrile, dimethylformamide, dimethylsulfoxide and formamide. The reactions have been traced and evaluated by RP-HPLC analysis. Freezing the reaction mixture resulted in all cases in a significant suppression of the N-dipeptidylurea side-product formation together with a slight decrease of tripeptide epimerization. The coupling yields and the side effects depended on the solvent, with the dioxane and dioxane/acetonitrile mixture produced the best results. The role of freezing and solvent in the improved results is discussed.

  8. Enhancing the stability and performance of a battery cathode using a non-aqueous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Yeol [Division of Engineering, Brown University, Providence, RI 02912 (United States); Sen, Sujat [Department of Chemistry, Brown University, Providence, RI 02912 (United States); Song, Hyun-Kon [Interdisciplinary School of Green Energy and School of Nano-Biotechnology and Chemical Engineering, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulju-gun, Ulsan 689-798 (Korea); Palmore, G. Tayhas R. [Division of Biology and Medicine, Brown University, Providence, RI 02912 (United States)

    2010-06-15

    For conductive polymers to be considered materials for energy storage, both their electroactivity and stability must be optimized. In this study, a non-aqueous electrolyte (0.2 M LiClO{sub 4} in acetonitrile) was studied for its effect on the charge storage capacity and stability of two materials used in batteries developed in our laboratory, polypyrrole (pPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) doped with 2,2'-azino-bis(3-ethylbenzothiaxoline-6-sulfonic acid (ABTS)). The results are compared to the performance of these materials in an aqueous electrolyte (0.2 M HCl/aq). Loss of ABTS dopant was eliminated principally due to the low solubility of ABTS in acetonitrile, resulting in cathode materials with improved stability in terms of load cycling and performance. (author)

  9. Determination of mercury by liquid chromatography in fresh water fishes using 2-thiophenealdehyde-4-phenyl-3-thiosemicarbazone

    International Nuclear Information System (INIS)

    Khuhawar, M.Y.; Languani, S.N.

    2001-01-01

    Co (II), Ag (I) and Hg (II) or Co (II), Ni (II), Fe (II), Cu (II) and Hg (II) are simultaneously extracted as metal chelates compounds of 2-thiophenealdehyde-4-phenyl-3-thiosemicarbazone (TAPT) in chloroform. The complexes were separated from microsorb C-18, 5 mue m column when eluted with methanol/acetonitrile/water/aqueous sodium acetate 1 m mol or methanol/acetonitrile/water/sodium acetate (1 mmol) tetrabutyl ammonium bromide (1mmol) with a flow rate of 1 ml-1 and detection UV at 254 nm. Linear calibrations were made with 10-50 ml-1 and detection limit was 0.4 ml-1, corresponding to 2 ng/injection in Co and Hg. The method was used for the determination of mercury in surface water fishes. It was found within 0.125 to 1.18 g-1 of fish muscles with coefficient of variation (C.V) 3.4-5.8%. (author)

  10. Optimization of soy isoflavone extraction with different solvents using the simplex-centroid mixture design.

    Science.gov (United States)

    Yoshiara, Luciane Yuri; Madeira, Tiago Bervelieri; Delaroza, Fernanda; da Silva, Josemeyre Bonifácio; Ida, Elza Iouko

    2012-12-01

    The objective of this study was to optimize the extraction of different isoflavone forms (glycosidic, malonyl-glycosidic, aglycone and total) from defatted cotyledon soy flour using the simplex-centroid experimental design with four solvents of varying polarity (water, acetone, ethanol and acetonitrile). The obtained extracts were then analysed by high-performance liquid chromatography. The profile of the different soy isoflavones forms varied with different extractions solvents. Varying the solvent or mixture used, the extraction of different isoflavones was optimized using the centroid-simplex mixture design. The special cubic model best fitted to the four solvents and its combination for soy isoflavones extraction. For glycosidic isoflavones extraction, the polar ternary mixture (water, acetone and acetonitrile) achieved the best extraction; malonyl-glycosidic forms were better extracted with mixtures of water, acetone and ethanol. Aglycone isoflavones, water and acetone mixture were best extracted and total isoflavones, the best solvents were ternary mixture of water, acetone and ethanol.

  11. Robust optimization of psychotropic drug mixture separation in hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Rakić, Tijana; Jovanović, Marko; Dumić, Aleksandra; Pekić, Marina; Ribić, Sanja; Stojanović, Biljana Jancić

    2013-01-01

    This paper presents multiobjective optimization of complex mixtures separation in hydrophilic interaction liquid chromatography (HILIC). The selected model mixture consisted of five psychotropic drugs: clozapine, thioridazine, sulpiride, pheniramine and lamotrigine. Three factors related to the mobile phase composition (acetonitrile content, pH of the water phase and concentration of ammonium acetate) were optimized in order to achieve the following goals: maximal separation quality, minimal total analysis duration and robustness of an optimum. The consideration of robustness in early phases of the method development provides reliable methods with low risk for failure in validation phase. The simultaneous optimization of all goals was achieved by multiple threshold approach combined with grid point search. The identified optimal separation conditions (acetonitrile content 83%, pH of the water phase 3.5 and ammonium acetate content in water phase 14 mM) were experimentally verified.

  12. Wobbled electronic properties of lithium clusters: Deterministic approach through first principles

    Science.gov (United States)

    Kushwaha, Anoop Kumar; Nayak, Saroj Kumar

    2018-03-01

    The innate tendency to form dendritic growth promoted through cluster formation leading to the failure of a Li-ion battery system have drawn significant attention of the researchers towards the effective destabilization of the cluster growth through selective implementation of electrolytic media such as acetonitrile (MeCN). In the present work, using first principles density functional theory and continuum dielectric model, we have investigated the origin of oscillatory nature of binding energy per atom of Lin (n ≤ 8) under the influence of MeCN. In the gas phase, we found that static mean polarizability is strongly correlated with binding energy and shows oscillatory nature with cluster size due to the open shell of Lin cluster. However, in acetonitrile medium, the binding energy has been correlated with electrostatic Lin -MeCN interaction and it has been found that both of them possess wobbled behavior characterized by the cluster size.

  13. Gene Expression Patterns Associated With Histopathology in Toxic Liver Fibrosis

    Science.gov (United States)

    2016-05-09

    will have greater applicability across a wide range of chemical-dose-exposure scenarios (Alfirevic and Pirmohamed, 2012; Meldrum et al., 2011...microliters of mobile phase was added to the sample (3% formic acid : 2 mM ammonium formate: 25% acetonitrile in water). Samples were fractionated using...described. The column compartment temperature was set at 35C and sample injection volume was 1 ml. Separation sol- vents were solvent A (3% formic acid

  14. Synthesis of 14C labelled lidocaine (α-diethylamino acet-2,6-dimethylanilide)

    International Nuclear Information System (INIS)

    Zhou Zhentang; Qian Guojun; Lin Fenzhi; Zhuang Daoling; Zhang Yulong; He Zhanjun

    2002-01-01

    14 C-lidocaine was composed by 14 C-diethylamine reaction with ω-chloroacetic-2,6-dimethylaniline. 14 C-diethylamine was prepared from Ba 14 CO 3 via K 14 CN and 14 C-acetonitrile which was hydrogenated. Radiochemical purity of 14 C-diethylamine and 14 C-lidocaine is >99% by HPLC and TLC respectively. 14 C-lidocaine is needed for breath assay of mouse for measuring liver function

  15. One pot obtention of a tetrabutylammonium hydroxide solution for ironporphyrin-OH- interaction studies in organic solvents

    Directory of Open Access Journals (Sweden)

    Lídia S. Iwamoto

    1999-04-01

    Full Text Available In this work we report the obtention of a tetrabutylammonium hydroxide (TBAOH solution in acetonitrile in a one pot process in order to study the interaction ironporphyrinOH- in non-aqueous systems. All the reactions were carried out under dry argon atmosphere to prevent the contamination of the solution with CO2, which leads to the formation of (TBA2CO3.

  16. Simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation by ultra-high performance liquid chromatography coupled with nano quantity analyte detector

    OpenAIRE

    Honggen Zhang; Zhenyu Wang; Oscar Liu

    2016-01-01

    A novel method for simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation was developed using ultra-high performance liquid chromatography coupled with a nano quantitation analytical detector (UHPLC–NQAD). All components in kolliphor HS15 and miglyol 812 were well separated on an Acquity BEH C18 column. Mobile phase A was 0.1% trifluoroacetic acid (TFA) in water and mobile phase B was acetonitrile. A gradient elution sequence was programed initially with 60%...

  17. Liquid chromatographic-tandem mass spectrometric assay for ...

    African Journals Online (AJOL)

    Methods: Blood and urine samples were obtained from healthy volunteers who admitted to not being on any medications. The investigated analytes were chromatographically separated on a C18 column (Luna®-PFP 100Å column, 50 mm × 2.0 mm i.d., 3.0 μm) with the aid of a mobile phase containing A; acetonitrile (ACN) ...

  18. Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

    DEFF Research Database (Denmark)

    Brandt van Driel, Tim; Kjær, Kasper Skov; Hartsock, Robert W.

    2016-01-01

    The interactions between the reactive excited state of molecular photocatalysts and surrounding solvent dictate reaction mechanisms and pathways, but are not readily accessible to conventional optical spectroscopic techniques. Here we report an investigation of the structural and solvation dynami...... of the iridium atoms by the acetonitrile solvent and demonstrate the viability of using diffuse X-ray scattering at free-electron laser sources for studying the dynamics of photocatalysis....

  19. Double-layer effects and distance dependence of electron transfer in reduction of nitro aromatic radical anions

    Czech Academy of Sciences Publication Activity Database

    Mořkovská, Petra; Hromadová, Magdaléna; Pospíšil, Lubomír; Giannarelli, S.

    2006-01-01

    Roč. 22, č. 4 (2006), s. 1896-1902 ISSN 0743-7463 R&D Projects: GA ČR GA203/03/0821; GA AV ČR IAA400400505; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : mercury-acetonitrile interface * aprotic-solvents * transfer kinetics Subject RIV: CG - Electrochemistry Impact factor: 3.902, year: 2006

  20. Chemical constituents of Bauhinia aurea.

    Science.gov (United States)

    Shang, Xiao-Ya; Li, Shuai; Wang, Su-Juan; Yang, Yong-Chun; Shi, Jian-Gong

    2012-01-01

    A new dihydroflavonol glycoside dimer 6,6-bisastilbin (1) and a new nitrile-containing metabolite (Z)-5α,6β-dihydroxy-4β-methoxy-2-cyclohexene-Δ(1,α)-acetonitrile (2), together with three known analogs, bauhinin, bauhinilide, and dehydrodicatechin A, have been isolated from an ethanol extract of Bauhinia aurea. Their structures were determined by spectroscopic and chemical methods.

  1. Boric acid as cost-effective and recyclable catalyst for trimethylsilyl protection and deprotection of alcohols and phenols

    Energy Technology Data Exchange (ETDEWEB)

    Rostami, Amin; Akradi, Jamal; Ahmad-Jangi, Firoz, E-mail: a_rostami372@yahoo.co [University of Kurdistan, Sanandaj (Iran, Islamic Republic of). Faculty of Science. Dept. of Chemistry

    2010-07-01

    Boric acid has been used as a green, selective and recyclable catalyst for trimethysilylation of alcohols and phenols using hexamethyldisilazane in acetonitrile. Deprotection of trimethylsilyl ethers to their parent alcohols and phenols was also achieved using this catalyst in water at room temperature. The salient features of this methodology are cheap processing, mild acidity conditions, excellent yields of products and easy availability of the catalyst. (author)

  2. An 131I iodotamoxifen: no carrier added iodination via a diazonium salt

    International Nuclear Information System (INIS)

    Hunter, D.H.; Strickland, L.A.

    1986-01-01

    An 131 I-labeled iodotamoxifen has been prepared by a ''no carrier added'' procedure in a 40% radiochemical yield via an aryl diazonium ion salt intermediate. Two approaches were used to produce high specific activity iodotamoxifen: nonaqueous solvents and copper catalysis. The use of the nonaqueous solvent acetonitrile has proved successful while neither copper powder, copper-bronze, copper(I)oxide nor Cu(II) sulphate showed any catalytic effects. (author)

  3. Validated HPLC method for determination of sennosides A and B in senna tablets.

    Science.gov (United States)

    Sun, Shao Wen; Su, Hsiu Ting

    2002-07-31

    This study developed an efficient and reliable ion-pair liquid chromatographic method for quantitation of sennosides A and B in commercial senna tablets. Separation was conducted on a Hypersil C 18 column (250 x 4.6 mm, 5 microm) at a temperature of 40 degrees C, using a mixture of 0.1 M acetate buffer (pH 6.0) and acetonitrile (70:30, v/v) containing 5 mM tetrahexylammonium bromide as mobile phase. Sennosides A and B were completely separated from other constituents within 14 min. The developed method was validated. Both run-to-run repeatability (n=10) and day-to-day reproducibility (n=3) of peak area were below 0.4% RSD. Linearity of peak area was tested in the range 30-70 microg/ml (r>0.9997). Accuracy was assessed with recovery and the recoveries for sennosides A and B were 101.73+/-1.30% and 101.81+/-2.18% (n=3 x 6), respectively. Robustness of the analytical method was tested using a three-leveled Plackett-Burman design in which 11 factors were assessed with 23 experiments. Eight factors (column, concentration of ion pair reagent, % of organic modifier (acetonitrile), buffer pH, column temperature, flow rate, time constant and detection wavelength) were investigated in a specified range above and below the nominal method conditions. It was found that: (1) column and % acetonitrile affected significantly resolution and retention time, (2) column, % acetonitrile, column temperature, flow rate and time constant affected significantly the plate number of sennoside A, and (3) column and time constant affected significantly the tailing factor.

  4. Simultaneous determination of anthraquinones, their 8-beta-D-glucosides, and sennosides of Rhei Rhizoma by capillary electrophoresis.

    Science.gov (United States)

    Koyama, Junko; Morita, Izumi; Fujiyoshi, Hirotaka; Kobayashi, Norihiro

    2005-05-01

    The simultaneous separation and determination of major anthraquinones (emodin, chrysophanol, rhein and their glucosides, aloe-emodin, sennoside A, and sennoside B) of Rhei Rhizoma were achieved by cyclodextrin modified capillary zone electrophoresis. The running electrolyte used in this method was 0.005 M alpha-cyclodextrin in 0.03 M borate buffer (pH 10.0) containing 20% acetonitrile, with an applied voltage of 20 kV.

  5. Reactions of phosphorus- and tantalum pentafluorides with picolinic acid

    International Nuclear Information System (INIS)

    Il'in, E.G.; Shcherbakova, M.N.; Ignatov, M.E.

    1985-01-01

    Using the NMR 19 F method complexing of PF 5 and TaF 5 with picolinic acid (LH) with different quantity ratio of reagents in acetonitrile solution is studied. It is shown that PF 5 either may coordinate LH in a monodentate maner through a nitrogen atom or may form a stable 5-member chelate cycle. in complexes with TaF 5 coordination proceeds only through a nitrogen atom

  6. Solubility and crystallization of piroxicam from different solvents in evaporative and cooling crystallizations

    DEFF Research Database (Denmark)

    Qu, Haiyan; Ostergaard, Iben

    2018-01-01

    polarities; It has been found that the solubility of piroxicam in the solvents is in the following order: chloroform > dichloromethane > acetone > ethyl acetate > acetonitrile > acetic acid > methanol > hexane. Crystallization of piroxicam from different solvents has been performed with evaporative.......Results obtained in the present work showed the stochastic nature of nucleation of different polymorphs as well as the complexity of the crystallization of a polymorphic system....

  7. Redox cycles of vitamin E: Hydrolysis and ascorbic acid dependent reduction of 8a-(alkyldioxy)tocopherones

    International Nuclear Information System (INIS)

    Liebler, D.C.; Kaysen, K.L.; Kennedy, T.A.

    1989-01-01

    Oxidation of the biological antioxidant α-tocopherol (vitamin E; TH) by peroxyl radicals yields 8a-(alkyldioxy)tocopherones, which either may hydrolyze to α-tocopheryl quinone (TQ) or may be reduced by ascorbic acid to regenerate TH. To define the chemistry of this putative two-electron TH redox cycle, we studied the hydrolysis and reduction of 8a-[(2,4-dimethyl-1-nitrilopent-2-yl)dioxyl]tocopherone (1) in acetonitrile/buffer mixtures and in phospholipid liposomes. TQ formation in acetonitrile/buffer mixtures, which was monitored spectrophotometrically, declined with increasing pH and could not be detected above pH 4. The rate of TQ formation from 1 first increased with time and then decreased in a first-order terminal phase. Rearrangement of 8a-hydroxy-α-tocopherone (2) to TQ displayed first-order kinetics identical with the terminal phase for TQ formation from 1. Both rate constants increased with decreasing pH. Hydrolysis of 1 in acetonitrile/H 2 18 O yielded [ 18 O]TQ. These observations suggest that 1 loses the 8a-(alkyldioxy) moiety to produce the tocopherone cation (T + ), which hydrolyzes to 2, the TQ-forming intermediate. Incubation of either 1 or 2 with ascorbic acid in acetonitrile/buffer yielded TH. Reduction of both 1 and 2 decreased with increasing pH. In phosphatidylcholine liposomes at pH 7, approximately 10% of the T + generated from 1 was reduced to TH by 5 mM ascorbic acid. The results collectively demonstrate that T + is the ascorbic acid reducible intermediate in a two-electron TH redox cycle, a process that probably would require biocatalysis to proceed in biological membranes

  8. Graphene-based supercapacitors in the parallel-plate electrode configuration: ionic liquids versus organic electrolytes.

    Science.gov (United States)

    Shim, Youngseon; Kim, Hyung J; Jung, Younjoon

    2012-01-01

    Supercapacitors with two single-sheet graphene electrodes in the parallel plate geometry are studied via molecular dynamics (MD) computer simulations. Pure 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI+BF4-) and a 1.1 M solution of EMI+BF4- in acetonitrile are considered as prototypes of room-temperature ionic liquids (RTILs) and organic electrolytes. Electrolyte structure, charge density and associated electric potential are investigated by varying the charges and separation of the two electrodes. Multiple charge layers formed in the electrolytes in the vicinity of the electrodes are found to screen the electrode surface charge almost completely. As a result, the supercapacitors show nearly an ideal electric double layer behavior, i.e., the electric potential exhibits essentially a plateau behavior in the entire electrolyte region except for sharp changes in screening zones very close to the electrodes. Due to its small size and large charge separation, BF4- is considerably more efficient in shielding electrode charges than EMI+. In the case of the acetonitrile solution, acetonitrile also plays an important role by aligning its dipoles near the electrodes; however, the overall screening mainly arises from ions. Because of the disparity of shielding efficiency between cations and anions, the capacitance of the positively-charged anode is significantly larger than that of the negatively-charged cathode. Therefore, the total cell capacitance in the parallel plate configuration is primarily governed by the cathode. Ion conductivity obtained via the Green-Kubo (GK) method is found to be largely independent of the electrode surface charge. Interestingly, EMI+BF4- shows higher GK ion conductivity than the 1.1 M acetonitrile solution between two parallel plate electrodes.

  9. Determination of the light-induced degradation rate of the solar cell sensitizer N719 on TiO2 nanocrystalline particles

    DEFF Research Database (Denmark)

    Nour-Mohammadi, Farahnaz; Doan Nguyen, Sau; Boschloo, Gerrit

    2005-01-01

    The oxidative degradation rate, kdeg of the solar cell dye (Bu4N+)2 [Ru(dcbpyH)2(NCS)2]2–, referred to as N719 or [RuL2(NCS)2], was obtained by applying a simple model system. Colloidal solutions of N719-dyed TiO2 particles in acetonitrile were irradiated with 532-nm monochromatic light, and the ...

  10. Studies with β-Oxoalkanonitriles: Simple Novel Synthesis of 3-[2,6-Diaryl-4- pyridyl]-3-oxopropanenitriles

    Directory of Open Access Journals (Sweden)

    Sayed M. Riyadh

    2008-12-01

    Full Text Available Heteroaromatization of ethyl 2-cyano-4-oxo-2-(2-oxo-2-arylethyl-4-arylbutanoates 3a,b with ammonium acetate gave ethyl 2,6-diarylisonicotinates 4a,b. Treatment of the latter with acetonitrile afforded novel β-oxoalkanonitriles 6a,b. Reactions of 6a,b with phenyl hydrazine and hydroxylamine gave the corresponding pyridyl aminopyrazoles 8a,b and pyridyl aminoisoxazoles 10a,b, respectively.

  11. Standardized Sample Preparation Using a Drop-on-Demand Printing Platform

    Science.gov (United States)

    2013-05-07

    and Materials Ammonium nitrate (AN), methanol (MeOH), distilled water (H2O), acetonitrile, sugar, urea, and potassium chlorate (KClO3) were...various pre-determined energetic and interferent compounds. The evaluated analytes were: AN, potassium chlorate , HMX, TNT, RDX, PETN, urea, and...KClO3 molecules dissolving and then breaking into potassium and chlorate ions in H2O. An additional concern was the interaction of adjacent

  12. Trinitromethyl Ethers and Other Derivatives as Superior Oxidizers

    Science.gov (United States)

    2011-08-26

    metathetical reaction between anhy- drous silver perchlorate and potassium nitroformate in acetonitrile (separating the potassium per- chlorate precipitate...It was desired that the well known trimethylsilanolate anion, (CH3)3SiO– (commercially available as the sodium and potassium salts), could similarly...not reported. We tested the feasibility of similar reactions under very mild conditions, attempting a metathesis between potassium trimethylsilanolate

  13. Electrospray Ionization Mass Spectrometric Analysis of Highly Reactive Glycosyl Halides

    Directory of Open Access Journals (Sweden)

    Lajos Kovács

    2012-07-01

    Full Text Available Highly reactive glycosyl chlorides and bromides have been analysed by a routine mass spectrometric method using electrospray ionization and lithium salt adduct-forming agents in anhydrous acetonitrile solution, providing salient lithiated molecular ions [M+Li]+, [2M+Li]+ etc. The role of other adduct-forming salts has also been evaluated. The lithium salt method is useful for accurate mass determination of these highly sensitive compounds.

  14. Ultrafast Infrared and UV-vis Studies of the Photochemistry of Methoxycarbonylphenyl Azides in Solution

    OpenAIRE

    Xue, Jiadan; Luk, Hoi Ling; Eswaran, S. V.; Hadad, Christopher M.; Platz, Matthew S.

    2012-01-01

    The photochemistry of 4-methoxycarbonylphenyl azide (2a), 2-methoxycarbonylphenyl azide (3a) and 2-methoxy-6-methoxycarbonylphenyl azide (4a) were studied by ultrafast time-resolved infrared (IR) and UV-vis spectroscopies in solution. Singlet nitrenes and ketenimines were observed and characterized for all three azides. Isoxazole species 3g and 4g are generated after photolysis of 3a and 4a, respectively, in acetonitrile. Triplet nitrene 4e formation correlated with the decay of singlet nitre...

  15. Ruthenium(III Chloride Catalyzed Acylation of Alcohols, Phenols, and Thiols in Room Temperature Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Mingzhong Cai

    2009-09-01

    Full Text Available Ruthenium(III chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]. The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.

  16. Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers

    Directory of Open Access Journals (Sweden)

    Nicola Otto

    2012-07-01

    Full Text Available In the search for new ligands for the Ullmann diaryl ether synthesis, permitting the coupling of electron-rich aryl bromides at relatively low temperatures, 56 structurally diverse multidentate ligands were screened in a model system that uses copper iodide in acetonitrile with potassium phosphate as the base. The ligands differed largely in their performance, but no privileged structural class could be identified.

  17. Influence of organic solvents on interfacial water at surfaces of silica gel and partially silylated fumed silica

    Energy Technology Data Exchange (ETDEWEB)

    Turov, V.V.; Gun' ko, V.M.; Tsapko, M.D.; Bogatyrev, V.M.; Skubiszewska-Zieba, J.; Leboda, R.; Ryczkowski, J

    2004-05-15

    The effects of organic solvents (dimethylsulfoxide-d{sub 6} (DMSO-d{sub 6}), chloroform-d, acetone-d{sub 6}, and acetonitrile-d{sub 3}) on the properties of interfacial water at surfaces of silica gel Si-40 and partially silylated fumed silica A-380 were studied by means of the {sup 1}H NMR spectroscopy with freezing-out of adsorbed water at 180acetonitrile-d{sub 3} are poorly miscible with water in silica gel pores in contrast to the bulk liquids. DMSO-d{sub 6} and chloroform-d affect the structure of the interfacial water weaker than acetone-d{sub 6} and acetonitrile-d{sub 3} at amounts of liquids greater than the pore volume. Acetone-d{sub 6} and acetonitrile-d{sub 3} can displace water from pores under this condition. The chemical shift of protons in water adsorbed on silica gel is 3.5-6.5 ppm, which corresponds to the formation of two to four hydrogen bonds per molecule. Water adsorbed on partially silylated fumed silica has two {sup 1}H NMR signals at 5 and 1.1-1.7 ppm related to different structures (droplets and small clusters) of the interfacial water.

  18. Analysis of residual solvents in PET radiopharmaceuticals by GC

    International Nuclear Information System (INIS)

    Li Yungang; Zhang Xiaojun; Liu Jian; Tian Jiahe; Zhang Jinming

    2013-01-01

    The residual solvents in PET radiopharmaceuticals were analyzed by GC, which were acetonitrile, ethanol, N, N-dimethylethanolamine (DMEA), dimethylsulfoxide (DMSO). The standard curves were established with the AT-624 capillary column at GC, and the sensitivity of acetonitrile and ethanol were 0.004-0.320 g/L and 0.010-0.120 g/L respectively. The residual solvents of acetonitrile, ethanol, DMEA and DMSO in PET radio- pharmaceuticals were analyzed by GC. The linearity were 0.9994, 0.9999, 0.9997, 0.999 6 respectively. The residual of acetonitrile were (0.0313±0.0433), (0.0829±0.0668), (0.0156±0.0059), (0.0254±0.0266) g/L in 18 F-FDG, 18 F-FLT, 11 C-CFT, 11 C-PIB respectively. The residual of ethanol was (0.0505±0.00528) g/L in 18 F-FDG. The residual of DMSO were (0.0331±0.0180) g/L, (0.0238±0.0100) g/L in 18 F-W372 and 11 C-DTBZ respectively. The residual of DMEA was (0.0348±0.0022) g/L in 11 C-Choline. The survived of organic solvent in PET radiopharmaceuticals can be analyzed with GC directly. The results showed that the QC should be done in PET radiopharmaceuticals purity with semi-HPLC to avoid the high residual. (authors)

  19. Rational Design of Therapeutic and Diagnostic Against Botulinum Neurotoxin

    Science.gov (United States)

    2006-12-01

    induced fluorescence Da, kDa Dalton, Kilodalton DMPS 2, 3-dimercaptopropanesulfonate DMSO Dimethylsulfoxide Dnp 2, 4-dinitrophenol DRDC Defence...high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS) experiment. H1R3 was dissolved in 10% DMSO / 0.1...separation of peptides. A linear solvent gradient was used in the HPLC separation at an initial condition of 5% acetonitrile in 0.1% TFA/water, up to

  20. Addition compounds of lanthanide-and yttrium trifluoromethanesulfonates and N,N-dimethylacetamide (DMA)

    International Nuclear Information System (INIS)

    Vicentini, G.; Tamura, T.

    1982-01-01

    Preparation of addition compounds of hydrated lanthanide trifluoromethanesulfonates and DMA, with general formula Ln (CF 3 SO 3 ) 3 .6H 2 O.x DMA is described. The compounds obtained are characterized by elemental analysis, X-ray diagrams, infrared absorption spectra, electrolytical conductance in nitromethane and acetonitrile, absorption spectra of the neodymium compound and emission spectra of the europium compound. (A.R.H.) [pt

  1. Effect of hydrostatic pressure, temperature, and solvent on the rate of the Diels-Alder reaction between 9,10-anthracenedimethanol and maleic anhydride

    Science.gov (United States)

    Kiselev, V. D.; Kornilov, D. A.; Anikin, O. V.; Latypova, L. I.; Konovalov, A. I.

    2017-03-01

    The rate of the reaction between 9,10-anthracenedimethanol and maleic anhydride in 1,4-dioxane, acetonitrile, trichloromethane, and toluene is studied at 25, 35, 45°C in the pressure range of 1-1772 bar. The rate constants, enthalpies, entropies and activation volumes are determined. It is shown that the rate of reaction with 9,10-anthracenedimethanol is approximately one order of magnitude higher than with 9-anthracenemethanol.

  2. Photoinduced intramolecular substitution reaction of aryl halide with carbonyl oxygen of amide group

    CERN Document Server

    Park, Y T; Kim, M S; Kwon, J H

    2002-01-01

    Photoreaction of N-(o-halophenyl)acetamide in basic acetonitrile produces an intramolecular substituted product, 2-methylbenzoxazole in addition to reduced product, acetanilide, whereas photoreaction of N-(o-halobenzyl)acetamide affords a reduced product, N-benzylacetamide only. On the basis of preparative reaction, kinetics, and UV/vis absorption behavior, an electrophilic aromatic substitution of aryl halide with oxygen of its amide bond are proposed.

  3. Development and Validation of a Stability-Indicating LC-UV Method ...

    African Journals Online (AJOL)

    Development and Validation of a Stability-Indicating LC-UV Method for Simultaneous Determination of Ketotifen and Cetirizine in Pharmaceutical Dosage Forms. ... 5 μm) using an isocratic mobile phase that consisted of acetonitrile and 10 mM disodium hydrogen phosphate buffer (pH 6.5) in a ratio of 45:55 % v/v at a flow ...

  4. Hydrophilic interaction liquid chromatography in analysis of granisetron HCl and its related substances. Retention mechanisms and method development.

    Science.gov (United States)

    Maksić, Jelena; Tumpa, Anja; Stajić, Ana; Jovanović, Marko; Rakić, Tijana; Jančić-Stojanović, Biljana

    2016-05-10

    In this paper separation of granisetron and its two related substances in HILIC mode is presented. Separation was done on silica column derivatized with sulfoalkylbetaine groups (ZIC-HILIC). Firstly, retention mechanisms were assessed whereby retention factors of substances were followed in wide range of acetonitrile content (80-97%), at constant concentration of aqueous buffer (10mM) as well as at constant pH value of 3.0. Further, in order to developed optimal HILIC method, Design of Experiments (DoE) methodology was applied. For optimization full factorial design 3(2) was employed. Influence of acetonitrile content and ammonium acetate concentration were investigated while pH of the water phase was kept at 3.3. Adequacy of obtained mathematical models was confirmed by ANOVA. Optimization goals (α>1.15 and minimal run time) were accomplished with 94.7% of acetonitrile in mobile phase and 70 mM of ammonium acetate in water phase. Optimal point was in the middle of defined Design Space. In the next phase, robustness was experimetally tested by Rechtschaffen design. The investigated factors and their levels were: acetonitrile content (±1%), ammonium acetate molarity in water phase (±2 mM), pH value of water phase (±0.2) and column temperature (±4 °C). The validation scope included selectivity, linearity, accuracy and precision as well as determination of limit of detection (LOD) and limit of quantification (LOQ) for the related substances. Additionally, the validation acceptance criteria were met in all cases. Finally, the proposed method could be successfully utilized for estimation of granisetron HCl and its related substances in tablets and parenteral dosage forms, as well as for monitoring degradation under various stress conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Desulfurization of Diesel Fuel by Oxidation and Solvent Extraction

    OpenAIRE

    Wadood Taher Mohammed; Raghad Fareed Kassim Almilly; Sheam Bahjat Abdulkareem Al-Ali

    2015-01-01

    This research presents a study in ultra-desulfurization of diesel fuel produced from conventional hydro desulfurization process, using oxidation and solvent extraction techniques. Dibenzothiophene (DBT) was the organosulfur compound that had been detected in sulfur removal. The oxidation process used hydrogen peroxide as an oxidant and acetic acid as homogeneous catalyst . The solvent extraction process used acetonitrile (ACN) and N-methyl – 2 - pyrrolidone (NMP) as extractants . Also the ef...

  6. Fluorescence lifetime measurement of radical ions

    International Nuclear Information System (INIS)

    Ichinose, Nobuyuki; Kinugasa, Jun-ichiro; Hagiri, Masahide; Nakayama, Toshihiro; Murakami, Hiroshi; Kishimoto, Maki; Daido, Hiroyuki

    2004-01-01

    One-photonic excitation of a charge transfer complex of hexamethoxybenzene (HMB) and nitrosonium tetrafluoroborate (NO + BF 4 - ) in acetonitrile afforded fluorescences emission from excited radical cation of HMB (HMB + *). Lifetime of the excited radical ion species was measured to be 7 ps by the pump-probe transient absorption technique. The lifetime was much shorter than that of free radical ion (63 ps), indicating the presence of an interaction between HMB + * and NO in the excited complex. (author)

  7. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The chemical reaction of PtII(L1)Cl2 [L1 = 2-(phenylazo)pyridine] with a bidentate N,S-donor atom ligand, 2-phenylthioaniline, (HL2) in alkaline acetonitrile yielded a mixed ligand donor acceptor complex, [PtII(L1)(L2)−]Cl, [1]Cl. The complex has been characterized by using a host of physical methods: X-ray crystallography, ...

  8. Engineered Joint Lubrication for OA Prevention and Treatment

    Science.gov (United States)

    2015-09-01

    that work together with liquid lubricants to achieve low-friction systems. Lubrication between tissues is also important to maintain low-friction...movement within a number of biological systems, including the pleural cavity, the surface of the eye, visceral organs, and diarthroidal joints3. In...purified using reverse-phase high-performance liquid chromatography (C18 Grace-Vydac column) on a water/acetonitrile gradient. Purified peptides were

  9. SOLUTION THERMODYNAMICS OF TRICLOSAN AND TRICLOCARBAN IN SOME VOLATILE ORGANIC SOLVENTS

    OpenAIRE

    DELGADO, Daniel R.; R. HOLGUIN, Andres; MARTÍNEZ, Fleming

    2012-01-01

    Thermodynamic functions of Gibbs energy, enthalpy, and entropy for the solution processes of the antimicrobial drugs Triclosan and Triclocarban in five volatile organic solvents were calculated from solubility values at temperatures from 293.15 to 313.15 K. Triclosan and Triclocarban solubility was determined in acetone, acetonitrile (AcCN), ethyl acetate (AcOEt), methanol (MetOH), and cyclohexane (CH). The excess of Gibbs energy and the activity coefficients of the solutes were also calculat...

  10. High-performance liquid chromatographic method for the determination of dansyl-polyamines

    Science.gov (United States)

    Subhash C. Minocha; Rakesh Minocha; Cheryl A. Robie

    1990-01-01

    This paper describes a fast reliable, and a sensitive technique for the separation and quantification of dansylated polyamines by high-performance liquid chromatography. Using a small 33 x 4.6 mm I.D., 3 ?m particle size, C18 reversed-phase cartridge column and a linear gradient of acetonitrile-heptanesulfonate (10 mM, pH 3.4...

  11. Short and Efficient Synthesis of Optically Active N-Tosyl Aziridines from 2-Amino Alcohols

    Directory of Open Access Journals (Sweden)

    Maria C. F. de Araújo

    2002-12-01

    Full Text Available Two alternative and complementary one-pot procedures for the direct transformation of 2-amino alcohols to N-tosyl aziridines are presented. The unsubstituted parent compound and its less hindered homologues can be obtained in high yields by tosylation and in situ cyclisation effected by potassium hydroxide in water/dichloromethane. Higher substituted amino alcohols give better yields using potassium carbonate in acetonitrile. Both procedures use simple inorganic bases and produce only inorganic salts as byproducts.

  12. Effect of solvent on cocrystallization of Es2+ with SrCl2

    International Nuclear Information System (INIS)

    Mikheev, N.B.; Veleshko, I.E.; Kulyukhin, S.A.

    1994-01-01

    Complexation of Es 2+ with tetraphenylborate (BPh 4 - ) in acetonitrile (CH 3 CN) and tetrahydrofuran (THF) is studied by cocrystallization. The dependence of the cocrystallization coefficients of Es 2+ on [LiBPh 4 ] demonstrated that in THF, in contrast with CH 3 CN, Es 2+ is not complexed by BPh 4 . The stability constants β 1 and β 2 of the Es 2+ -BPh 4 complexes are 6.6 and 16.0, respectively, in CH 3 CN

  13. Kinetics of acyl transfer reactions in organic media catalysed by Candida antarctica lipase B.

    Science.gov (United States)

    Martinelle, M; Hult, K

    1995-09-06

    The acyl transfer reactions catalysed by Candida antartica lipase B in organic media followed a bi-bi ping-pong mechanism, with competitive substrate inhibition by the alcohols used as acyl acceptors. The effect of organic solvents on Vm and Km was investigated. The Vm values in acetonitrile was 40-50% of those in heptane. High Km values in acetonitrile compared to those in heptane could partly be explained by an increased solvation of the substrates in acetonitrile. Substrate solvation caused a 10-fold change in substrate specificity, defined as (Vm/Km)ethyl octanoate/(Vm/Km)octanoic acid, going from heptane to acetonitrile. Deacylation was the rate determining step for the acyl transfer in heptane with vinyl- and ethyl octanoate as acyl donors and (R)-2-octanol as acyl acceptor. With 1-octanol, a rate determining deacylation step in heptane was indicated using the same acyl donors. Using 1-octanol as acceptor in heptane, S-ethyl thiooctanoate had a 25- to 30-fold lower Vm/Km value and vinyl octanoate a 4-fold higher Vm/Km value than that for ethyl octanoate. The difference showed to be a Km effect for vinyl octanoate and mainly a Km effect for S-ethyl thiooctanoate. The Vm values of the esterification of octanoic acid with different alcohols was 10-30-times lower than those for the corresponding transesterification of ethyl octanoate. The low activity could be explained by a low pH around the enzyme caused by the acid or a withdrawing of active enzyme by nonproductive binding by the acid.

  14. Therapeutic Efficacy of the Small Molecule GS-5734 against Ebola virus in Rhesus Monkeys

    Science.gov (United States)

    2016-03-02

    culture. The diastereomeric mixture at phosphorous 858 containing GS-5734 was incubated continuously for 72 h at 1 µM and levels of intracellular NTP...constants (J) in Hertz. Analytical thin–layer chromatography was performed using Merck KGaA Silica gel 60 F254 glassplates with UV visualization. Preparative...trifluoroacetic acid in water and 0.1% trifluoroacetic acid in acetonitrile; flow rate, 2 mL/min; acquisition time, 6 min; wavelength, UV 214 and 254 nm

  15. Advances in propane ammoxidation catalyst technology

    Energy Technology Data Exchange (ETDEWEB)

    Prada Silvy, R.; Grange, P. [Unite de Catalyse et Chimie des Materiaux Divises, Univ. Cathologique de Louvain, Louvain-la-Neuve (Belgium)

    2003-09-01

    Comparison of the catalytic performance of different propane ammoxidation catalyst systems from the patent literature is established in order to identify the most promising formulation towards process commercialization scale. Vanadium aluminum oxynitride material shows the highest acrylonitrile production level per hour and per amount of catalyst with respect to conventional vanadium-molybdate and vanadium- antimonate mixed oxide propane ammoxidation systems. Acrylonitrile, hydrogen cyanide and acetonitrile production from propane ammoxidation is the key factor for obtaining competitive advantages over current propylene technology. (orig.)

  16. Desulfurization of AL-Ahdab Crude Oil using Oxidative Processes

    OpenAIRE

    Neran Khalel Ibrahim; Saja Mohsen Jabbar

    2015-01-01

    Two different oxidative desulfurization strategies based on oxidation/adsorption or oxidation/extraction were evaluated for the desulfurization of AL-Ahdab (AHD) sour crude oil (3.9wt% sulfur content). In the oxidation process, a homogenous oxidizing agent comprising of hydrogen peroxide and formic acid was used. Activated carbons were used as sorbent/catalyst in the oxidation/adsorption process while acetonitrile was used as an extraction solvent in the oxidation/extraction process. For the ...

  17. Novel Oxidative Desulfurization of a Model Fuel with H2O2 Catalyzed by AlPMo12O40 under Phase Transfer Catalyst-Free Conditions

    OpenAIRE

    José da Silva, Márcio; Faria dos Santos, Lidiane

    2013-01-01

    A novel process was developed for oxidative desulfurization (ODS) in the absence of a phase transfer catalyst (PTC) using only Keggin heteropolyacids and their aluminum salts as catalysts. Reactions were performed in biphasic mixtures of isooctane/acetonitrile, with dibenzothiophene (DBT) as a model sulfur compound and hydrogen peroxide as the oxidant. Remarkably, only the AlPMo12O40-catalyzed reactions resulted in complete oxidation of DBT into DBT sulfone, which was totally extracted by ace...

  18. Thermal Decomposition Reaction of Acetophenone Cyclic Diperoxide in Solvents of Different Physicochemical Properties

    Directory of Open Access Journals (Sweden)

    C. M. Mateo

    2000-03-01

    Full Text Available The thermal decomposition reaction of acetophenone cyclic diperoxide (trans-3,6-dimethyl-3,6-diphenyl-1,2,4,5-tetroxane; APDP at the initial concentration of c.a. 0.01 mol kg-1 and temperature ranges of 135.5 to 185.0° C has been investigated in dioxane and acetonitrile solutions, and in an 2-propanol/benzene mixture.

  19. Functionalized zinc porphyrin as light harvester in dye sensitized ...

    Indian Academy of Sciences (India)

    Wintec

    2008-09-10

    Sep 10, 2008 ... with dyad. Both dyad and triad were also tested in DSSC using a polymer gel redox electrolyte and ob- ... extended π-conjugated acrylic acid derivative, which has shown the .... 0⋅6 M tert-butyl pyridine (TBP) in acetonitrile and. AH3 is 0⋅5 M ... 5 ml of propylene carbonate (PC), 5 ml of acetoni- trile, 1⋅5 g ...

  20. 15-00273_SI_NP.doc

    Indian Academy of Sciences (India)

    ... 2−4 in Toluene. 18. Figure S8. Cyclic voltammogram (complete Scan) of compounds 2−4 and Xanthone. measured in acetonitrile solution at 100mV/sec. 19 ̶ 20. Figure S9. DTA plots of compound 2‒4. 21. Figure S10. CIE coordinates of compounds 2‒4. 22. Figure S11. Photograph of compound 2‒4 in solution form. 23 ...