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Sample records for barbituric acid complex

  1. A convenient method for the preparation of barbituric and thiobarbituric acid transition metal complexes

    Science.gov (United States)

    Refat, Moamen S.; El-Korashy, Sabry A.; Ahmed, Ahmed S.

    2008-12-01

    A convenient method for the preparation of barbiturate transition metal complexes: (i) Cr 3+, Mn 2+, Fe 3+, Zn 2+ and Cd 2+ ions with barbituric acid (H 2L) and (ii) Cr 3+ and Mo 5+ with 2-thiobarbituric acid (H 2L') was reported and this has enabled seven complexes to be formulated as: [Cr(HL) 2(OH)(H 2O)]·H 2O, [Mn(HL) 2(H 2O) 2], [Fe 2(L)(OH) 3(H 2O) 4]·2H 2O, [Zn(HL) 2], [Cd(HL) 2], [Cr(HL')(OH) 2(H 2O)]·H 2O and [Mo(HL') 2]Cl. These new barbiturate complexes were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid infrared, 1H NMR, mass, X-ray powder diffraction and UV/vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. The molar conductance measurements proved that, all complexes of barbituric and 2-thiobarbituric acids are non-electrolytes except for [Mo(HL') 2]Cl. The electronic spectra and magnetic susceptibility measurements were used to infer the structures. The IR spectra of the ligands and their complexes are used to identify the mode of coordination. Kinetic and thermodynamic parameters such as: E*, Δ H*, Δ S* and Δ G* are estimated according to the DTG curves. The two ligands and their complexes have been studied for their possible biological antifungal activity.

  2. Estimation of very low concentrations of Ruthenium by spectrophotometric method using barbituric acid as complexing agent

    International Nuclear Information System (INIS)

    Spectrophotometric method employing numerous chromogenic reagents like thiourea, 1,10-phenanthroline, thiocyanate and tropolone is reported in the literature for the estimation of very low concentrations of Ru. A sensitive spectrophotometric method has been developed for the determination of ruthenium in the concentration range 1.5 to 6.5 ppm in the present work. This method is based on the reaction of ruthenium with barbituric acid to produce ruthenium(ll)tris-violurate, (Ru(H2Va)3)-1 complex which gives a stable deep-red coloured solution. The maximum absorption of the complex is at 491 nm due to the inverted t2g → Π(L-L ligand) electron - transfer transition. The molar absorptivity of the coloured species is 9,851 dm3 mol-1 cm-1

  3. Synthesis of New Azo Dyes and Copper(II) Complexes Derived from Barbituric Acid and 4-Aminobenzoylhydrazone

    OpenAIRE

    GUP, Bülent KIRKAN and Ramazan

    2008-01-01

    Four new azo dyes, L1, L2, L3, and L4, were prepared by linking benzaldehyde p-aminobenzoylhydrazone (3) and p-hydroxybenzaldehyede p--aminobenzoylhydrazone (4) to barbituric acid and 1,3-dimethylbarbituric acid through diazo-coupling reactions. Reactions of the azo-dyes with copper chloride and bidentate ligand, 1,10-phenanthroline, produced mixed-ligand dinuclear complexes with general stoichiometry [Cu2L(phen)2]Cl2 (7, 8, 9, and 10). The structures of both azo dyes and their compl...

  4. Interaction between metals and nucleic acids. Part 3. Synthesis and structural studies of copper(II) complexes with Schiff base ligands derived from barbituric acid

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, I.; Gaudemer, A.; Chiaroni, A.; Riche, C.

    1986-02-17

    Schiff bases have been prepared from 5-formylbarbituric acid and 5-formyl-1,3-dimethyl-barbituric acid and various di- or tri-amines. The structure of the corresponding copper(II) complexes have been established by elemental analysis and spectroscopic methods. The molecular structure of one of the complexes, Cu(DiMeBardpt), was determined by X-ray diffraction. Electrochemical study shows that these complexes are reduced at slightly more negative potentials than the corresponding complexes obtained from uracil, which suggests that these new ligands are better electron-donors.

  5. Hydrogen-bonded complexes resulting from the interaction of alkylated barbituric acid and 2,6-diamidopyridine derivatives

    Science.gov (United States)

    Sideratou, Z.; Tsiourvas, D.; Paleos, C. M.; Peppas, E.; Anastassopoulou, J.; Theophanides, T.

    1999-06-01

    In the present study a hydrophilic or a lipophilic alkylated barbituric acid derivative was allowed to interact in the melt and in solution with a complementary series of alkylated diamidopyridine derivatives, both hydrophilic or lipophilic. The interaction between the molecules was mainly studied by FT-IR spectroscopy. Phase transitions of reaction mixtures were studied with polarized optical microscopy and differential scanning calorimetry. It was found that the molecular recognition of the interacting components is only effective between the molecularly compatible ones. Specifically, employing Methods I and II, (see text) the short chain derivatives form 1 : 1 complexes whereas the long-chain derivatives are only partially complexed. Derivatives of dissimilar lipophilicity do not form complexes employing the same methods. However, comparing the two methods, complexation is more effective employing Method II. The induction of molecular recognition in the presence of an apolar solvent is enhanced in solution, Method III. The equilibrium which was established in solution is shifted to different directions during the evaporation step (Method II), leading either to the formation of complexes or to self-association.

  6. Optical characterization and blu-ray recording properties of metal(II) azo barbituric acid complex films

    International Nuclear Information System (INIS)

    Smooth thin films of nickel(II), cobalt(II) and zinc(II) complexes with azo barbituric acid were prepared by the spin-coating method. Absorption spectra of the thin films on K9 glass substrates in 300-700 nm wavelength region were measured. Optical constants (complex refractive index N = n + ik) of the thin films prepared on single-crystal silicon substrates in 275-695 nm wavelength region were investigated on rotating analyzer-polarizer type of scanning ellipsometer, and dielectric constant ε (ε = ε1 + iε2) as well as absorption coefficient α of thin films were calculated at 405 nm. In addition, static optical recording properties of the cobalt(II) complex thin film with an Ag reflective layer was carried out using a 406.7 nm blue-violet laser and a high numerical aperture (NA) of 0.90. Clear recording marks with high reflectivity contrast (>60%) at proper laser power and pulse width were obtained, and the size of recording mark was as small as 250 nm. The results indicate that these metal(II) complexes are promising organic recording medium for the blu-ray optical storage system

  7. Optical characterization and blu-ray recording properties of metal(II) azo barbituric acid complex films

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.Y. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)], E-mail: xyli@siom.ac.cn; Wu, Y.Q. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Lab of Functional Inorganic Material Chemistry (Heilongjiang University), Ministry of Education, Haerbin 150080 (China)], E-mail: yqwu@siom.ac.cn; Gu, D.D.; Gan, F.X. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2009-02-25

    Smooth thin films of nickel(II), cobalt(II) and zinc(II) complexes with azo barbituric acid were prepared by the spin-coating method. Absorption spectra of the thin films on K9 glass substrates in 300-700 nm wavelength region were measured. Optical constants (complex refractive index N = n + ik) of the thin films prepared on single-crystal silicon substrates in 275-695 nm wavelength region were investigated on rotating analyzer-polarizer type of scanning ellipsometer, and dielectric constant {epsilon} ({epsilon} = {epsilon}{sub 1} + i{epsilon}{sub 2}) as well as absorption coefficient {alpha} of thin films were calculated at 405 nm. In addition, static optical recording properties of the cobalt(II) complex thin film with an Ag reflective layer was carried out using a 406.7 nm blue-violet laser and a high numerical aperture (NA) of 0.90. Clear recording marks with high reflectivity contrast (>60%) at proper laser power and pulse width were obtained, and the size of recording mark was as small as 250 nm. The results indicate that these metal(II) complexes are promising organic recording medium for the blu-ray optical storage system.

  8. Synthesis of cyclic bis- and trismelamine derivatives and their complexation properties with barbiturates.

    Science.gov (United States)

    Kondo, Shin-Ichi; Hayashi, Tomohiro; Sakuno, Yuichi; Takezawa, Yoko; Yokoyama, Takashi; Unno, Masafumi; Yano, Yumihiko

    2007-03-21

    Cyclic bis- and trismelamine derivatives were prepared from cyanuric chloride by stepwise substitutions with appropriate amines. The complexation abilities of these melamine derivatives with barbituric acid derivatives were evaluated by UV-vis spectroscopy and (1)H NMR. The structure was also confirmed by X-ray crystallography. Both the acyclic and the cyclic bismelamine derivatives formed a 1 : 1 complex via six hydrogen bonds with barbituric acid derivatives. van't Hoff analyses on the complexation of the bismelamines with the barbituric acid derivative revealed that the complexation of the cyclic bismelamine was entropically favored and enthalpically less favored process than those of the acyclic bismelamine. X-Ray crystallographic analysis and (1)H NMR studies revealed that the cyclic trismelamine bound one barbituric acid derivative into the cavity via six hydrogen bonds by two melamine moieties and another barbituric acid via three hydrogen bonds by the residual melamine moiety. PMID:17340006

  9. Electrochemical study of iodide in the presence of barbituric acid. Application to the catalytic determination of barbituric acid

    International Nuclear Information System (INIS)

    Electrochemical oxidation of iodide has been studied in the presence of barbituric acid using cyclic voltammetry and controlled-potential coulometry. The results indicate that barbituric acid participating in halogenation reaction convert to iodo derivative of parent compound. Moreover the results are indication of the suitability of iodide as mediator for determination of barbituric acid in aqueous solutions. The quasicatalytic peak current is linearly dependent on the barbituric acid concentration. The calibration graph is parabolic, with two linear sections of 6.0 x 10-5 - 1.0 x 10-3 M and 1.0 x 10-3 - 1.0 x 10-2 M. The relative standard deviation for 10 determinations of 2.0 x 10-4 M barbituric acid is 2.1 % and the detection limit of the method is 3.97 x 10-5 M

  10. Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

    OpenAIRE

    Best, Daniel; Burns, David J.; Lam, Hon Wai

    2015-01-01

    A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor.

  11. Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

    Science.gov (United States)

    Best, Daniel; Burns, David J; Lam, Hon Wai

    2015-01-01

    A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

  12. Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds.

    Science.gov (United States)

    Best, Daniel; Burns, David J; Lam, Hon Wai

    2015-06-15

    A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N-H groups are tolerated on the barbituric acid, with no complications arising from N-H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

  13. 1,3-Dimethyl-5-(3,4,5-tris(alkoxy)benzoyl) barbituric acid derivatives and their liquid crystalline difluoroboron complexes: Synthesis, characterization and comparative investigations of mesomorphic, thermotropic and thermo-morphologic properties

    Science.gov (United States)

    Giziroglu, Emrah; Nesrullajev, Arif; Orhan, Nil

    2014-01-01

    A series of 1,3-dimethyl-5-(3,4,5-tris(alkoxy)benzoyl) barbituric acid derivatives 1a-4a with various chain length were synthesized by our group for the first time through the addition of 1,3-dimethyl barbituric acid to 3,4,5-tris(alkoxy)benzoyl chloride at room temperature in presence of pyridine. For preparation of their difluoroboron complexes, the derivatives 1a-4a reacts with borontrifluoride in the presence of triethylamine affording 1b-4b in moderate yields. All derivatives and complexes have been fully characterized by MS, FT-IR and multinuclear NMR spectroscopy. We also explored their liquid crystal properties by using POM, OM, CTW and DSC techniques. The results show that 3b and 4b with longer alkyl chain are monomorphic mesogens and exhibited enantiotropic thermotropic liquid crystalline mesophases. Investigation of their mesomorphic, thermo-morphologic and thermotropic properties is presented in this work.

  14. Gamma irradiation study on barbituric acid and its phosphorus trimer

    International Nuclear Information System (INIS)

    Phosphorus tri barbiturate was synthesized from barbituric acid and structure was substantiated on the basis of microanalytical and spectroscopic techniques. The reactant and product were irradiated by gamma-rays and the ultraviolet measurements taken before and after irradiation were discussed. The effect of dose rate on UV absorption was found to be insignificant. The PH values were also measured before and after irradiation and the variation was correlated with the UV shifts at various concentrations of the aqueous solution of the compound. The results suggested, that the possible radiolysis decomposition site in the product is the carbon-phosphorus bond. The thermal analysis results were also studied

  15. Barbituric and thiobarbituric acids: a conformational and spectroscopic study

    Science.gov (United States)

    Zuccarello, Felice; Buemi, Giuseppe; Gandolfo, Concetta; Contino, Annalinda

    2003-01-01

    A conformational study on Barbituric (BA) and Thiobarbituric (TBA) acids was performed at ab initio MP2/6-31G** level on the neutral, protonated, mono- and di-anionic forms. Acid-base equilibria were studied by comparing the electronic transitions evaluated for the most stable conformations and the experimental spectra at different pH values. The electronic transitions were obtained through the ZINDO approach.

  16. Effect of Cd, Zn and Hg complexes of barbituric acid and thiouracil on rat brain monoamine oxidase-B (in vitro).

    Science.gov (United States)

    Shaban, Nadia Z; Masoud, Mamdouh S; Awad, Doaa; Mawlawi, Mai A; Sadek, Omayma M

    2014-02-01

    Metal pyrimidine complexes (MPCs) including cadmium-barbiturate (Cd-BA), zinc-barbiturate (Zn-BA), cadmium-thiouracil (Cd-TU) and mercury-thiouracil (Hg-TU) were prepared and their analysis was carried out. These MPCs were evaluated as monoamine oxidase-B (MAO-B) inhibitors. Rat brain MAO-B was inhibited (in vitro) by Cd-BA, Zn-BA, Cd-TU and Hg-TU complexes. The inhibition of MAO-B by these complexes was time and concentration dependent. The values of IC50 of Zn-BA, Cd-BA, Hg-TU and Cd-TU were 10.2, 15.8, 16.2 and 20.4 nM, respectively. The effect of different substrate concentrations in the absence and in the presence of MPCs was determined. Lineweaver-Burk plots were plotted and the values of apparent Michaelis constant (Km), maximum velocity (Vmax), the dissociation constant of enzyme inhibitor complex (Ki) and the percent of inhibition (i%) were calculated. The data showed that the inhibition of MAO-B by all studied MPCs was the non-competitive type. The sequence of inhibition zone was: Zn-BA>Cd-BA and Hg-TU>Cd-TU affected by the chemistry of both the metal and the ligand. Otherwise, the results of the present study showed that the inhibition of MAO-B by all MPCs was fully reversible. The data showed that the presence of Cd-BA, Zn-BA, Cd-TU and Hg-TU complexes changed the optimum temperature and pH of MAO-B. PMID:24300193

  17. Benzothiazole incorporated barbituric acid derivatives: synthesis and anticonvulsant screening.

    Science.gov (United States)

    Siddiqui, Nadeem; Ahsan, Waquar

    2009-08-01

    A series of 1-(6-substituted-1,3-benzothiazol-2-yl)-3-(substituted phenyl)hexahydro-2,4,6-pyrimidinetriones 4a-t were synthesized starting from substituted anilines. These compounds contained two active anticonvulsant pharmacophores, benzothiazole and barbituric acid. Structures of the compounds were confirmed on the basis of different spectroscopic techniques. All the compounds were evaluated for their anticonvulsant activity. Three compounds 4c, 4d, and 4s showed promising anticonvulsant activities in Maximal Electroshock Seizure test (MES) and subcutaneous pentylenetetrazole test (scPTZ). They also displayed a wide safety profile when tested for the minimal motor impairment test. PMID:19565603

  18. The synthesis of barbituric acid and some of its derivatives isotopically labelled with 15N

    International Nuclear Information System (INIS)

    Full text: Barbituric acid is the parent compound of a large class of barbiturates that have central nervous system depressant properties, although barbituric acid itself is not pharmacologically active. In recent years, barbituric acid derivatives have been studied as antitumor, anticancer and anti-osteoporosis agents. The aim of this paper is to present the synthesis of barbituric acid-15N, 5,5-diethylbarbituric acid-15N (Veronal-15N) and 5-ethyl-5-phenylbarbituric acid- 15N (Phenobarbitone-15N) . As isotopically labelled material we used urea-15N2, 99 at.% 15N produced at National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania. All compounds were fully characterized by Mass Spectrometry analyses, by FT-IR Spectroscopy and RX Diffraction, and the isotopic label was determined by MS on the molecular compounds. (author)

  19. 13C hyperpolarization of a barbituric acid derivative via parahydrogen induced polarization

    Science.gov (United States)

    Roth, Meike; Koch, Achim; Kindervater, Petra; Bargon, Joachim; Spiess, Hans Wolfgang; Münnemann, Kerstin

    2010-05-01

    Significant 13C NMR signal enhancement by a factor of 5000 of a barbituric acid derivative (5-methyl-5-propenyl-barbituric acid) via parahydrogen induced polarization is presented. This hyperpolarization is achieved by hydrogenating 5-methyl-5-propargyl-barbituric acid with 98% enriched para-H 2 under elevated temperature and pressure and transferring the initially created 1H hyperpolarization with an INEPT-derived pulse sequence to 13C. The polarization can be selectively transferred to different carbons in the barbituric acid derivative by applying different pulse delays in the INEPT pulse sequence. These results demonstrate the potential of using hyperpolarized barbituric acid derivatives as " active" contrast agents in MRI and visualizing their pharmacokinetics in vivo.

  20. (13)C hyperpolarization of a barbituric acid derivative via parahydrogen induced polarization.

    Science.gov (United States)

    Roth, Meike; Koch, Achim; Kindervater, Petra; Bargon, Joachim; Spiess, Hans Wolfgang; Münnemann, Kerstin

    2010-05-01

    Significant (13)C NMR signal enhancement by a factor of 5000 of a barbituric acid derivative (5-methyl-5-propenyl-barbituric acid) via parahydrogen induced polarization is presented. This hyperpolarization is achieved by hydrogenating 5-methyl-5-propargyl-barbituric acid with 98% enriched para-H(2) under elevated temperature and pressure and transferring the initially created (1)H hyperpolarization with an INEPT-derived pulse sequence to (13)C. The polarization can be selectively transferred to different carbons in the barbituric acid derivative by applying different pulse delays in the INEPT pulse sequence. These results demonstrate the potential of using hyperpolarized barbituric acid derivatives as "active" contrast agents in MRI and visualizing their pharmacokinetics in vivo. PMID:20207180

  1. Interactions of Enolizable Barbiturate Dyes.

    Science.gov (United States)

    Schade, Alexander; Schreiter, Katja; Rüffer, Tobias; Lang, Heinrich; Spange, Stefan

    2016-04-11

    The specific barbituric acid dyes 1-n-butyl-5-(2,4-dinitro-phenyl) barbituric acid and 1-n-butyl-5-{4-[(1,3-dioxo-1H-inden-(3 H)-ylidene)methyl]phenyl}barbituric acid were used to study complex formation with nucleobase derivatives and related model compounds. The enol form of both compounds shows a strong bathochromic shift of the UV/Vis absorption band compared to the rarely coloured keto form. The keto-enol equilibria of the five studied dyes are strongly dependent on the properties of the environment as shown by solvatochromic studies in ionic liquids and a set of organic solvents. Enol form development of the barbituric acid dyes is also associated with alteration of the hydrogen bonding pattern from the ADA to the DDA type (A=hydrogen bond acceptor site, D=donor site). Receptor-induced altering of ADA towards DDA hydrogen bonding patterns of the chromophores are utilised to study supramolecular complex formation. As complementary receptors 9-ethyladenine, 1-n-butylcytosine, 1-n-butylthymine, 9-ethylguanidine and 2,6-diacetamidopiridine were used. The UV/Vis spectroscopic response of acid-base reaction compared to supramolecular complex formation is evaluated by (1) H NMR titration experiments and X-ray crystal structure analyses. An increased acidity of the barbituric acid derivative promotes genuine salt formation. In contrast, supramolecular complex formation is preferred for the weaker acidic barbituric acid. PMID:26945529

  2. Green Synthesis and Urease Inhibitory Activity of Spiro-Pyrimidinethiones/Spiro-Pyrimidinones-Barbituric Acid Derivatives

    OpenAIRE

    Mohammadi Ziarani, Ghodsi; Asadi, Shima; Faramarzi, Sakineh; Amanlou, Massoud

    2015-01-01

    Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) with pore size 6 nm as an efficient heterogeneous nanoporous solid acid catalyst exhibited good catalytic activity in the Biginelli-like reaction in the synthesis of spiroheterobicyclic rings with good yield and good recyclability. Spiro-pyrimidinethiones/spiro-pyrimidinones-barbituric acid derivatives were synthesized in a simple and efficient method using the one-pot three-component reaction of a cyclic 1,3- dicarbonyl compounds (barbituric ...

  3. Thermodynamic Proton – Ligand Satability Constants in Dioxane – Water Media, Pka , Δg0, Δ H0 And Δ S0 , Values for 1, 3 – Disubstituted Barbituric Acid

    OpenAIRE

    Manoj Kumar; Singh, B. R.

    2014-01-01

    Thermodynamic protonation constants of dimethyl barbituric acid [DMBA], Diphenyl barbituric acid [DPBA], di-o-tolyl barbitiuric acid[D-O-TBA], di-m-tolyl barbituric acid [D-m-TBA], di-p-tolyl, barbituric acid [D-p-TBA], di-o-xylyl barbituric acid [D-o-XBA], di-m-xylyl barbituric acid [ D-m-XBA], di-p-xylyl barbituric acid [D-p-XBA], di-α napthyl barbituric acid [D-α-NBA] and di-p-anisyl barbituric acid [D-p-ABA] have been determined in different mole fraction of deoxane [ 0.175 – 0.350 ] at 2...

  4. New method for spectrophotometric determination of quinones and barbituric acid through their reaction. A kinetic study

    Science.gov (United States)

    Medien, H. A. A.

    1996-11-01

    A new and sensitive spectrophotometric method is described for the determination of p-benzoquinone, p-chloranil and 1.4-naphthoquinone. The method is based on the reaction between quinones and barbituric acid, by which a color is developed with maximum absorption between 485 and 555 nm in 50% methyl alcohol-water mixture. The absorption of the product obeys Beer's law within the concentration range 0.025-05 mM of orginal quinone. The kinetics of the reaction between p-benzoquinone and barbituric acid was studied in a range of methyl alcohol-water mixtures. The reaction follows overall second order kinetics, first order in each of the reactants. The rate increases with increasing dielectric constant. The method was applied for determination of barbituric acid with p-benzoquinone in the concentration range of 0.025-0.345 mM. Other barbiturates do not interfere.

  5. Determination of the rate constants of the reactions CO2+OH- -> HCO3- and barbituric acid -> barbiturate anion -> H- using the pulse radiolyse technique

    International Nuclear Information System (INIS)

    The kinetics of the reactions of CO2 + OH --> HCO3- (i) and barbituric acid -> barbiturate anion + H+ (ii) have been remeasured using as a new approach the pulse radiolysis technique with optical and conductivity detection. The rate constants obtained in the present study, ksub(j) (210C) = 6900 +- 700 M-1 s-1 and ksub(II) (190C) = 22 +- 2 s-1 agree within experimental errors with values obtained earlier by other methods. (orig.)

  6. Synthesis of 5-,6-, and 7-membered heterocycles from barbituric acid derivatives

    OpenAIRE

    Guyader, David

    2011-01-01

    SUMMARY A new procedure has been developed for the synthesis of barbituric acid derivatives. The reactions were performed under solvent free conditions without any catalyst. Employing this synthetic route, a large number of chalconoids and 5-,6-, and 7-membered heterocycles have been successfully synthesized in a very short time. The chalconoids have been synthesized from a barbituric derivative and substituted benzaldehydes. The effect of different substituents on the yield of the re...

  7. [The use of enzymatic hydrolysis for isolation of barbituric acid derivatives from blood (as exemplified by phenobarbital and barbamyl)].

    Science.gov (United States)

    Chuvina, N A; Kolupaeva, A S; Strelova, O Iu; Zabolotskaia, I V; Gorbacheva, T V

    2010-01-01

    Modern isolation techniques by direct extraction with organic solvents or after protein precipitation by various sedimenting or salting-out agents are characterized by low efficiency and do not permit to liberate derivatives of barbituric acid from their complexes with blood proteins. The use of enzymatic hydrolysis makes it possible to break bonds between barbiturates and protein and thereby improve the efficiency of isolation. We performed enzymatic hydrolysis of the model phenobarbital-blood and barbamyl-blood complexes with the use of trypsin, pepsin, chymotrypsin, and papain. The degree of phenobarbital extraction with trypsin and barbamyl was estimated at 62.1 +/- 1.2% and 75.1 +/- 1.6% respectively; in other words, it was 32.7 +/- 1.0% and 51.1 +/- 1.0% higher than that achieved by traditional methods. Certain validation characteristics of the new method are presented. PMID:21265178

  8. Synthesis and steriostructure of 5-(5-R-2- furfur lidene)- barbituric acid

    International Nuclear Information System (INIS)

    Heterocyclic compounds 5-(5-R-2-furfur lidene)- barbituric acid were obtained and their physical and chemical properties were studied. Their structures were identified by spectroscopic methods. This study proved by 1H-NMR Spectroscopy data that these compounds exist in S-cis form. (author)

  9. 1 H and 13 C NMR studies on the enoling of 5-benzyl barbituric acids

    International Nuclear Information System (INIS)

    This work shows that the derivatives of the 5-benzyl barbituric acids hydroxylated at the ortho position of the aromatic ring only exist in the enol form. and that the alkylation of this hydroxyl gives products which exist mainly in the ketone form of the DMSO

  10. An NMR study of merocyanine-type dyes derived from barbituric acid

    Science.gov (United States)

    Rezende, Marcos Caroli; Flores, Patricio; Guerrero, Juan; Villarroel, Luis

    2004-06-01

    The 13C NMR of two solvatochromic dyes derived from a barbituric acid acceptor and dimethylaminophenyl donor fragments, compound 1 and the related merocyanine 2, were recorded in various solvents. The observed chemical-shift variations were used to interpret their structural differences and solvatochromic behavior in solution.

  11. Spiro-annulation of barbituric acid derivatives and its analogs by ring-closing metathesis reaction.

    Science.gov (United States)

    Kotha, Sambasivarao; Deb, Ashoke Chandra; Kumar, Ramanatham Vinod

    2005-02-15

    Barbituric acid 1 and related beta-dicarbonyl compounds were dialkenylated under the phase-transfer catalyst [e.g., benzyltriethylammonium chloride (BTEAC)] conditions to generate the diallylated products. These diallylated products were subjected to the ring-closing metathesis (RCM) reaction to deliver the corresponding spiro-annulated derivatives. PMID:15686908

  12. Selective cell adhesion inhibitors: Barbituric acid based alpha4beta7--MAdCAM inhibitors.

    Science.gov (United States)

    Harriman, Geraldine C; Brewer, Matthias; Bennett, Robert; Kuhn, Cyrille; Bazin, Marc; Larosa, Greg; Skerker, Paul; Cochran, Nancy; Gallant, Debra; Baxter, Deborah; Picarella, Dominic; Jaffee, Bruce; Luly, Jay R; Briskin, Michael J

    2008-04-01

    A novel series of barbituric acid derivatives were identified as selective inhibitors of alpha4beta7 MAdCAM (mucosal addressin cell adhesion molecule-1) interactions via a high throughput screening exercise. These inhibitors were optimized to submicromolar potencies in whole cell adhesion assays, retaining their selectivity over alpha4beta1 VCAM. PMID:18331794

  13. Weak interactions in barbituric acid derivatives. Unusually steady intermolecular organic “sandwich” complexes. π π Stacking versus hydrogen bonding interactions

    Science.gov (United States)

    Khrustalev, Victor N.; Krasnov, Konstantin A.; Timofeeva, Tatiana V.

    2008-04-01

    The 4-methoxy-6,6-dimethyl-5,6,7,8-tetrahydro[1,3]dioxolo[4,5- g]isoquinolin-6-ium ( 1) and 2-(1 H-indol-3-yl)-1-ethanaminium (tryptaminium) ( 2) salts of 1,3-dimethyl-2,4,6-trioxoperhydro-pyrimidine-5-spiro-6'-{4'-methoxy-7'-(1,3-dimethyl-2,4,6-trioxoper-hydropyrimidin-5-yl)-5',6',7',8'-tetrahydro[1,3]dioxolo[4,5- g]naphthalene} ( 3) have been prepared and their structures have been investigated by single-crystal X-ray diffraction analysis. It has been found on the basis of the crystal packing arrangement as well as physical and chemical properties that derivatives 1 and 2 form unusually steady intermolecular sandwich-like complexes both in the crystal and in solution, which are stabilized by weak C sbnd H… n(O dbnd C) hydrogen bonds and π-π stacking. The interplay between the intermolecular π-π stacking and strong N sbnd H…O hydrogen bond interactions and its influence on the "sandwich" structures of 1 and 2 are discussed.

  14. Spectrophotometric reaction rate method for determination of barbituric acid by inhibition of the hydrochloric acid-bromate reaction

    Science.gov (United States)

    Ensafi, Ali A.; Movahedinia, H.

    2003-11-01

    A new kinetic-spectrophotometric method was developed for the determination of barbituric acid. The method is based on its inhibition effect on the reaction between hydrochloric acid and bromate. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 510 nm. The variable affecting the rate of the reaction was investigated. The method is simple, rapid, relatively sensitive and precise. The limit of detection is 7.9×10 -7 M and calibration rang is 1×10 -6-6.0×10 -4 M barbituric acid. The linearity range of the calibration graph is depends on bromate concentration. The relative standard deviation of seven replication determination of 5.6×10 -6 M barbituric acid was 1.8%. The influence of potential interfering substance was studied.

  15. Synthesis of barbituric acid-2 14C and alloxan-2 14C from urea 14C

    International Nuclear Information System (INIS)

    Urea 14C and ethyl malonate have given rise to barbituric acid with a 93 per cent yield. The latter has been converted into its benzylidene derivative with a 81 per cent yield. Oxidation of the latter, by chromic oxide in anhydrous acetic acid provided alloxan-2 14C with 60 per cent yield. Purity of the compounds has been checked by paper chromatography. (author)

  16. Barbituric acid as a substituent at aryl methylium ions.

    Science.gov (United States)

    Spange, Stefan; Bauer, Mirko; Walfort, Bernhard; Lang, Heinrich

    2006-09-29

    Activation of different benzophenone derivatives with triflic anhydride for electrophilic aromatic substitution of 5-phenylbarbituric acids leads to regioselective formation of the ortho-substituted product. The resulting triphenylmethylium salt can be isolated when the Michlers ketone is used. More electrophilic cations form cyclic enol ethers such as 1-n-butyl-9,9-diaryl-1,9-dihydro-10-oxa-1,3-diazaphenanthrene-2,4-diones. Alternatively, supramolecular complex formation with 2,6-diacetamido pyridine as well as carbenium ion generation have been studied. Although in dilute acid only protonation of one of the carbonyl oxygens occurs, ring opening of the cyclic enol ether toward the carbenium ion is observed in 96% sulfuric acid. PMID:16995696

  17. Behaviour of Some Activated Nitriles Toward Barbituric Acid, Thiobarbituric Acid and 3-Methyl-1-Phenylpyrazol-5-one

    OpenAIRE

    M. M. Habashy; M. H. Nassar; Mahmoud, M. R.; H. M. F. Madkour

    2000-01-01

    The effect of some active methylene containing heterocyclic compounds, namely barbituric acid, thiobarbituric acid and 3-methyl-1-phenylpyrazol-5-one on a-cyano-3,4,5-trimethoxycinnamonitrile and ethyl a-cyano-3,4,5-trimethoxycinnamate (1a,b) was investigated. The structure of the new products was substantiated by their IR,1H-NMR and mass spectra.

  18. Green Synthesis and Urease Inhibitory Activity of Spiro-Pyrimidinethiones/Spiro-Pyrimidinones-Barbituric Acid Derivatives.

    Science.gov (United States)

    Mohammadi Ziarani, Ghodsi; Asadi, Shima; Faramarzi, Sakineh; Amanlou, Massoud

    2015-01-01

    Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) with pore size 6 nm as an efficient heterogeneous nanoporous solid acid catalyst exhibited good catalytic activity in the Biginelli-like reaction in the synthesis of spiroheterobicyclic rings with good yield and good recyclability. Spiro-pyrimidinethiones/spiro-pyrimidinones-barbituric acid derivatives were synthesized in a simple and efficient method using the one-pot three-component reaction of a cyclic 1,3- dicarbonyl compounds (barbituric acid), an aromatic aldehyde and urea or thiourea in the presence of nanoporous silica SBA-Pr-SO3H under solvent free conditions. Urease inhibitory activity of spiro compounds were tested against Jack bean urease using Berthelot alkaline phenol-hypochlorite method. Five of 13 compounds were inhibitor and two of them were enzyme activators. Analysis of the docking results showed that, in most of the spiro molecules, one of the carbonyl groups is coordinated with both nickel atoms, while the other one is involved in the formation of hydrogen bonds with important active-site residues. The effect of inserting two methyl groups on N atoms of barbiturate ring, S substituted, ortho, meta and para substituted compounds were investigated too. PMID:26664377

  19. Colorimetric barbiturate sensing with hybrid spin crossover assemblies.

    Science.gov (United States)

    Young, Michael C; Liew, Erica; Hooley, Richard J

    2014-05-21

    Spin crossover complexes based on either iron(II) or iron(III) give a colorimetric response upon self-assembly with barbituric acids. They can be used as visible sensors for these narcotics, selectively detecting barbiturates in the presence of other biologically-relevant hydrogen bonding species. PMID:24715100

  20. Hydrogen bonding in barbituric and 2-thiobarbituric acids: a theoretical and FT-IR study

    Science.gov (United States)

    Ramondo, Fabio; Pieretti, Andrea; Gontrani, Lorenzo; Bencivenni, Luigi

    2001-09-01

    The effects of intermolecular hydrogen bonding on the molecular properties of barbituric acid (BA) and thiobarbituric acid are discussed on the basis of density functional theory calculations. B3LYP methods were applied to monomers and cyclic dimers. Trimer and hexamer of BA were studied as examples where several CO and NH groups are involved in hydrogen bonding. The theoretical IR spectra of monomers and all oligomers here considered are compared with the FT-IR spectra measured in Ar and nitrogen matrices at different concentrations.

  1. Behaviour of Some Activated Nitriles Toward Barbituric Acid, Thiobarbituric Acid and 3-Methyl-1-Phenylpyrazol-5-one

    Directory of Open Access Journals (Sweden)

    M. M. Habashy

    2000-05-01

    Full Text Available The effect of some active methylene containing heterocyclic compounds, namely barbituric acid, thiobarbituric acid and 3-methyl-1-phenylpyrazol-5-one on a-cyano-3,4,5-trimethoxycinnamonitrile and ethyl a-cyano-3,4,5-trimethoxycinnamate (1a,b was investigated. The structure of the new products was substantiated by their IR,1H-NMR and mass spectra.

  2. Photochemical synthesis and anticancer activity of barbituric acid, thiobarbituric acid, thiosemicarbazide, and isoniazid linked to 2-phenyl indole derivatives.

    Science.gov (United States)

    Laxmi, S Vijaya; Rajitha, G; Rajitha, B; Rao, Asha Jyothi

    2016-04-01

    2-Phenyl-1H-indole-3-carbaldehyde-based barbituric acid, thiobarbituric acid, thiosemicarbazide, isoniazid, and malononitrile derivatives were synthesized under photochemical conditions. The antitumor activities of the synthesized compounds were evaluated on three different human cancer cell lines representing prostate cancer cell line DU145, Dwivedi (DWD) cancer cell lines, and breast cancer cell line MCF7. All the screened compounds possessed moderate anticancer activity, and out of all the screened compounds, 5-{1[2-(4-chloro-phenyl)2-oxo-ethyl]-2-phenyl-1H-indole-3-ylmethylene}-2-thioxo-dihydro-pyrimidine-4,6-dione (2b) and 5-{1[2-(4-methoxy-phenyl)2-oxo-ethyl]-2-phenyl-1H-indole-3-ylmethylene}-2-thioxo-dihydro-pyrimidine-4,6-dione (2d) exhibited marked antitumor activity against used cell lines. Additionally, barbituric acid derivatives were selective to inhibit cell line DWD and breast cancer cell lines. PMID:27118996

  3. Laser properties of nonlinear optical benzal barbituric acid crystals

    Science.gov (United States)

    Kondo, Koichi; Fukutome, Masato; Ohnishi, Noriaki; Aso, Hideyuki; Kitaoka, Yasuo; Sasaki, Takatomo

    1991-12-01

    A nonlinear optical crystal, p-methylbenzal-1,3-dimethylbarbituric acid is grown in benzene by means of a temperature-depression method into a large single crystal (10 x 16 x 17 cu mm). The cut-off wavelength is 460 nm, and the effective nonlinear optical coefficient of type I for second-harmonic generation is 8.0 pm/v.

  4. A Greener, Efficient Approach to Michael Addition of Barbituric Acid to Nitroalkene in Aqueous Diethylamine Medium

    Directory of Open Access Journals (Sweden)

    Hany J. Al-Najjar

    2014-01-01

    Full Text Available An efficient method for the synthesis of a variety of pyrimidine derivatives 3a–t by reaction of barbituric acids 1a,b as Michael donor with nitroalkenes 2a–k as Michael acceptor using an aqueous medium and diethylamine is described. This 1,4-addition strategy offers several advantages, such as using an economic and environmentally benign reaction media, high yields, versatility, and shorter reaction times. The synthesized compounds were identified by 1H-NMR, 13C-NMR, CHN, IR, and MS. The structure of compound 3a was further confirmed by single crystal X-ray structure determination.

  5. A greener, efficient approach to Michael addition of barbituric acid to nitroalkene in aqueous diethylamine medium.

    Science.gov (United States)

    Al-Najjar, Hany J; Barakat, Assem; Al-Majid, Abdullah M; Mabkhot, Yahia N; Weber, Manuel; Ghabbour, Hazem A; Fun, Hoong-Kun

    2014-01-01

    An efficient method for the synthesis of a variety of pyrimidine derivatives 3a-t by reaction of barbituric acids 1a,b as Michael donor with nitroalkenes 2a-k as Michael acceptor using an aqueous medium and diethylamine is described. This 1,4-addition strategy offers several advantages, such as using an economic and environmentally benign reaction media, high yields, versatility, and shorter reaction times. The synthesized compounds were identified by 1H-NMR, 13C-NMR, CHN, IR, and MS. The structure of compound 3a was further confirmed by single crystal X-ray structure determination. PMID:24445342

  6. A Greener, Efficient Approach to Michael Addition of Barbituric Acid to Nitroalkene in Aqueous Diethylamine Medium

    OpenAIRE

    Hany J. AL-Najjar; Assem Barakat; Al-Majid, Abdullah M.; Mabkhot, Yahia N.; Manuel Weber; Ghabbour, Hazem A.; Hoong-Kun Fun

    2014-01-01

    An efficient method for the synthesis of a variety of pyrimidine derivatives 3a–t by reaction of barbituric acids 1a,b as Michael donor with nitroalkenes 2a–k as Michael acceptor using an aqueous medium and diethylamine is described. This 1,4-addition strategy offers several advantages, such as using an economic and environmentally benign reaction media, high yields, versatility, and shorter reaction times. The synthesized compounds were identified by 1H-NMR, 13C-NMR, CHN, IR, and MS. The str...

  7. Merocyanine-type dyes from barbituric acid derivatives

    Science.gov (United States)

    Rezende, Marcos Caroli; Campodonico, Paola; Abuin, Elsa; Kossanyi, Jean

    2001-05-01

    The preparation and the solvatochromic behavior of two dyes, obtained by condensation of N, N'-dimethylbarbituric acid with dimethylaminobenzaldehyde and with 4,4'-bis( N, N-dimethylamino)benzophenone (Michler's ketone) are described. The latter dye is rather sensitive to the polarity of the medium, and in particular, to the hydrogen-bond-donor ability of protic solvents. The solvatochromism of both compounds is discussed in terms of the π* and ET(30) solvent polarity scales and their differences in behavior interpreted with the aid of semiempirical calculations.

  8. Bactericidal evaluation of N-halamine-functionalized silica nanoparticles based on barbituric acid.

    Science.gov (United States)

    Dong, Alideertu; Xue, Min; Lan, Shi; Wang, Qin; Zhao, Yue; Wang, Ying; Zhang, Yanling; Gao, Ge; Liu, Fengqi; Harnoode, Chokto

    2014-01-01

    Novel N-halamine-functionalized silica nanoparticles (NHFS NPs) were facilely fabricated from the 5-allylbarbituric acid (ABBA) by a seeded copolymerization using colloidal silica nanoparticles as support and ABBA-based N-halamine copolymers as shell. The NHFS NPs with spherical morphology and legible core-shell structure have the average diameter of 538.5 nm and the average shell thickness of 19.8 nm. The NHFS NPs possessed improved antimicrobial activity against both Gram-positive and Gram-negative bacteria compared with their bulk powder counterparts. The structural effect of N-halamine on bactericidal activity was clarified through the comparison between barbituric acid-based NHFS NPs and hydantoin-structural NHFS NPs. Effects of colloidal silica support and comonomer methyl methacrylate on particles morphology and the corresponding antimicrobial activity were comparatively investigated as well. Antibacterial tests revealed that N-halamine nanomaterials originated from barbituric acid derivative displayed powerful antibacterial performance and long-term stability. PMID:24144511

  9. Physicochemical studies of the reaction of (99m)Tc with 5,5'-diethyl barbituric acid, adenine, d-glucose and thiobarbituric acid at different temperatures.

    Science.gov (United States)

    Masoud, M S; El-Shahat, M F; Elkholany, A S

    2014-06-01

    The reaction of (99m)Tc pertechnetate with 5,5'-diethyl barbituric acid, adenine, d-glucose and thiobarbituric acid at different temperatures was studied. The solvent effect on the electronic absorption spectra of the reactions was recorded. The reaction mixtures have been analyzed at different times using TLC and a radiodetctor to show the peaks at the plates. (99m)Tc pertechnetate is obtained from the Mo generators. It is difficult to separate the complexes in the solid state. The percentage of (99m)Tc involved in the complexes can be determined. Characterization of the (99m)Tc complexes as well as the determination of the extent of radiolabeling was done by thin layer chromatography using 0.9% NaCl solution as a solvent. The Rf value of (99m)TcO4(-) is (≈1). The solvatochromism for the reaction of (99m)Tc with d-glucose was mainly affected by solute permanent dipole-solvent permanent dipole interaction, the dipolar interaction for the reaction of (99m)Tc with of 5,5'-diethyl barbituric acid and for the reaction of (99m)Tc with adenine and thiobarbituric was solute-solvent hydrogen bonding. PMID:24632174

  10. Structure-energy relationship in barbituric acid: a calorimetric, computational, and crystallographic study.

    Science.gov (United States)

    Roux, María Victoria; Temprado, Manuel; Notario, Rafael; Foces-Foces, Concepción; Emel'yanenko, Vladimir N; Verevkin, Sergey P

    2008-08-14

    This paper reports the value of the standard (p(o) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K for barbituric acid. The enthalpies of combustion and sublimation were measured by static bomb combustion calorimetry and transference (transpiration) method in a saturated N2 stream and a gas-phase enthalpy of formation value of -(534.3 +/- 1.7) kJ x mol(-1) was determined at T = 298.15 K. G3-calculated enthalpies of formation are in very good agreement with the experimental value. The behavior of the sample as a function of the temperature was studied by differential scanning calorimetry, and a new polymorph of barbituric acid at high temperature was found. In the solid state, two anhydrous forms are known displaying two out of the six hydrogen-bonding patterns observed in the alkyl/alkenyl derivatives retrieved from the Cambridge Crystallographic Database. The stability of these motifs has been analyzed by theoretical calculations. X-ray powder diffraction technique was used to establish to which polymorphic form corresponds to the commercial sample used in this study and to characterize the new form at high temperature. PMID:18646743

  11. Temperature- and moisture-dependent phase changes in crystal forms of barbituric acid

    International Nuclear Information System (INIS)

    The dihydrate of barbituric acid (BAc) and its dehydration product, form II were investigated by means of moisture sorption analysis, hot-stage microscopy, differential scanning calorimetry, thermogravimetry, solution calorimetry, IR- and Raman-spectroscopy as well as powder X-ray diffraction. The dihydrate desolvates already at and below 50% relative humidity (RH) at 25 deg. C whereas form II is stable up to 80% RH, where it transforms back to the dihydrate. The thermal dehydration of barbituric acid dihydrate (BAc-H2) is a single step, nucleation controlled process. The peritectic reaction of the hydrate was measured at 77 deg. C and a transformation enthalpy of ΔtrsHH2-II = 17.3 kJ mol-1 was calculated for the interconversion between the hydrate and form II. An almost identical value of 17.0 kJ mol-1 was obtained from solution calorimetry in water as solvent (ΔsolHH2 = 41.5, ΔsolHII = 24.5 kJ mol-1). Additionally a high-temperature form (HT-form) of BAc, which is enantiotropically related to form II and unstable at ambient conditions has been characterized. Furthermore, we observed that grinding of BAc with potassium bromide (KBr) induces a tautomeric change. Therefore, IR-spectra recorded with KBr-discs usually display a mixture of tautomers, whereas the IR-spectra of the pure trioxo-form of BAc are obtained if alternative preparation techniques are used

  12. Anharmonic IR and Raman spectra and electronic and vibrational (hyper)polarizabilities of barbituric, 2-thiobarbituric and 2-selenobarbituric acids

    Science.gov (United States)

    Alparone, Andrea

    2014-01-01

    Infrared, Raman and electronic absorption spectra, electronic and vibrational (hyper)polarizabilities, of barbituric, 2-thiobarbituric and 2-selenobarbituric acids were studied in gas using ab initio and density functional theory levels. The vibrational spectra were computed using harmonic and anharmonic methods. Anharmonic contributions improve the agreement between calculated and available experimental wavenumbers, especially in the highest-energy spectral region (wavenumbers >1700 cm-1). Vibrational and electronic transitions potentially useful to identify the investigated compounds were explored. The electronic and vibrational hyperpolarizabilities for the IDRI nonlinear optical (NLO) process at the λ value of 790 nm were computed. Supported by spectroscopic results, electronic and vibrational polarizabilities and second-order hyperpolarizabilities increase progressively in the order barbituric acid acid acid. The seleno-derivative is predicted to be ca. three/four times more hyperpolarizable than the barbituric acid. The Se → O or Se → S substitutions can be practical strategies to enhances the NLO properties of barbituric and thiobarbituric acid-based materials.

  13. The synthesis and evaluation of near-infrared probes with barbituric acid acceptors for in vivo detection of amyloid plaques.

    Science.gov (United States)

    Zhou, Kaixiang; Fu, Hualong; Feng, Liang; Cui, Mengchao; Dai, Jiapei; Liu, Boli

    2015-07-25

    A new array of near-infrared probes containing barbituric acid acceptors has been developed as Aβ imaging agents. These probes displayed long-emission wavelengths and large Stokes shifts, as well as high affinities for Aβ aggregates. In vivo and ex vivo studies demonstrated that BBTOM-3 could intensely label Aβ plaques in the brains of transgenic mice. PMID:26103205

  14. Two polymorphs of 5-cyclohexyl-5-ethylbarbituric acid and their packing relationships with other barbiturates.

    Science.gov (United States)

    Gelbrich, Thomas; Meischberger, Isabella; Griesser, Ulrich J

    2015-03-01

    Polymorph (Ia) (m.p. 474 K) of the title compound, C(12)H(18)N(2)O(3), displays an N-H...O=C hydrogen-bonded layer structure which contains R(6)(6)(28) rings connecting six molecules, as well as R2(2)(8) rings linking two molecules. The 3-connected hydrogen-bonded net resulting from these interactions has the hcb topology. Form (Ib) (m.p. 471 K) displays N-H...O=C hydrogen-bonded looped chains in which neighbouring molecules are linked to one another by two different R(2)(2)(8) rings. Polymorph (Ia) is isostructural with the previously reported form II of 5-(2-bromoallyl)-5-isopropylbarbituric acid (noctal) and polymorph (Ib) is isostructural with the known crystal structures of four other barbiturates. PMID:25734851

  15. Design and synthesis of novel Y-shaped barbituric acid derivatives as PPARγ activators.

    Science.gov (United States)

    Dixit, Vaibhav A; Rathi, Prakash Chandra; Bhagat, Shweta; Gohlke, Holger; Petersen, Rasmus K; Kristiansen, Karsten; Chakraborti, Asit K; Bharatam, Prasad V

    2016-01-27

    Novel Y-shaped barbituric acid (BA) derivatives have been designed using rational methods including molecular docking. Fourteen novel compounds were synthesized using hydroxyl group protection-deprotection strategies for PPARγ activation. Competitive binding analysis of the synthesized molecules using time-resolved fluorescence resonance energy transfer (FRET) method was carried out, and the IC50 values were determined. The symmetrically substituted derivatives have shown greater binding affinity than unsymmetrically substituted derivatives. Nitrobenzyl and cyanophenyl substituted derivatives have shown reasonable binding affinities (10.1 and 6.5 μM, respectively), while mono and diacetate derivatives were found inactive. Molecular dynamics simulations show that the designed compounds have interaction profiles similar to partial agonists. The most significant finding of our study is that BA derivatives with symmetrically substituted weakly polar side chains result in the desired moderate level of PPARγ binding affinities. PMID:26708109

  16. Synthesis and dynamics studies of barbituric acid derivatives as urease inhibitors

    OpenAIRE

    Barakat, Assem; Al-Majid, Abdullah Mohammed; Lotfy, Gehad; Arshad, Fiza; Yousuf, Sammer; Choudhary, M Iqbal; Ashraf, Sajda; Ul-Haq, Zaheer

    2015-01-01

    Background Discovery of potent inhibitors of urease (jack bean) enzyme is the first step in the development of drugs against diseases caused by ureolytic enzyme. Results Thirty-two derivatives of barbituric acid as zwitterionic adducts of diethyl ammonium salts were synthesized. All synthesized compounds (4a–z and 5a–s) were screened for their in vitro inhibition potential against urease enzyme (jack bean urease). The compounds 4i (IC50 = 17.6 ± 0.23 µM) and 5l (IC50 = 17.2 ± 0.44 µM) were fo...

  17. Parahydrogen induced polarization of barbituric acid derivatives: 1H hyperpolarization studies.

    Science.gov (United States)

    Roth, Meike; Bargon, Joachim; Spiess, Hans Wolfgang; Koch, Achim

    2008-08-01

    Homogeneous hydrogenation of barbituric acid derivatives with parahydrogen yields a substantial increase of the (1)H NMR signals of the reaction products. These physiologically relevant compounds were hydrogenated at both ambient and elevated temperatures and pressures using a standard cationic rhodium catalyst. The resulting nonthermal nuclear spin polarization (hyperpolarization) is limited by the spin-lattice relaxation time T(1) of the corresponding nuclei in the products, being shorter than the time constant of the hydrogenation. The signal-to-noise ratio of the NMR spectra could be further increased upon signal averaging the antiphase PHIP signals of 25 successive scans following 30 degrees pulse experiments and a delay of 10 s. PMID:18470863

  18. Synthesis, activity evaluation, and docking analysis of barbituric acid aryl hydrazone derivatives as RSK2 inhibitors.

    Science.gov (United States)

    Xue, Mengzhu; Xu, Minghao; Lu, Weiqiang; Huang, Jin; Li, Honglin; Xu, Yufang; Liu, Xiaofeng; Zhao, Zhenjiang

    2013-08-01

    The 90 kDa ribosomal S6 kinases (RSKs), especially RSK2, have attracted attention for the development of new anticancer agents. Through structural optimization of the hit compound 1 from our previous study, a series of barbituric acid aryl hydrazone analogues were designed and synthesized as potential RSK2 inhibitors. The most potent one, compound 9, showed a higher activity against RSK2 with an IC50 value of 1.95 μM. To analyze and elucidate their structure-activity relationship, the homology model of RSK2 N-terminal kinase domain was built and molecular docking simulations were performed, which provide helpful clues to design new inhibitors with desired activities. PMID:22545939

  19. Temperature- and moisture-dependent phase changes in crystal forms of barbituric acid

    Energy Technology Data Exchange (ETDEWEB)

    Zencirci, Neslihan; Gstrein, Elisabeth; Langes, Christoph [Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52, 6020 Innsbruck (Austria); Griesser, Ulrich J. [Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52, 6020 Innsbruck (Austria)], E-mail: ulrich.griesser@uibk.ac.at

    2009-03-10

    The dihydrate of barbituric acid (BAc) and its dehydration product, form II were investigated by means of moisture sorption analysis, hot-stage microscopy, differential scanning calorimetry, thermogravimetry, solution calorimetry, IR- and Raman-spectroscopy as well as powder X-ray diffraction. The dihydrate desolvates already at and below 50% relative humidity (RH) at 25 deg. C whereas form II is stable up to 80% RH, where it transforms back to the dihydrate. The thermal dehydration of barbituric acid dihydrate (BAc-H2) is a single step, nucleation controlled process. The peritectic reaction of the hydrate was measured at 77 deg. C and a transformation enthalpy of {delta}{sub trs}H{sub H2-II} = 17.3 kJ mol{sup -1} was calculated for the interconversion between the hydrate and form II. An almost identical value of 17.0 kJ mol{sup -1} was obtained from solution calorimetry in water as solvent ({delta}{sub sol}H{sub H2} = 41.5, {delta}{sub sol}H{sub II} = 24.5 kJ mol{sup -1}). Additionally a high-temperature form (HT-form) of BAc, which is enantiotropically related to form II and unstable at ambient conditions has been characterized. Furthermore, we observed that grinding of BAc with potassium bromide (KBr) induces a tautomeric change. Therefore, IR-spectra recorded with KBr-discs usually display a mixture of tautomers, whereas the IR-spectra of the pure trioxo-form of BAc are obtained if alternative preparation techniques are used.

  20. Influence of physico-chemical parameters of some barbituric acid derivatives on their retention on an amide embedded RP silica column.

    Science.gov (United States)

    Jakab, Annamaria; Prodan, Miklos; Forgács, Esther

    2002-03-01

    Retention parameters of 45 different barbituric acid derivatives were determined on an amide embedded RP silica column (Discovery RP-AmideC16) using non-buffered water-acetonitrile eluent systems. Linear correlation were calculated between the logarithm of the capacity factor and the acetonitrile concentration in the eluent. To determine the retention behavior of barbituric acid derivatives, stepwise regression analysis (SRA) and principal component analysis (PCA) followed by two-dimensional nonlinear and modified nonlinear mapping was used. It can be concluded, the retention of barbituric acid derivatives are governed mainly by the steric parameters of the substituents. Principal component analysis indicated that the barbituric acid derivatives have mixed retention on this amide embedded RP silica column in water-acetonitrile eluent. PMID:11836055

  1. Determination of the rate constants of the reactions CO/sub 2/+OH/sup -/ -> HCO/sub 3//sup -/ and barbituric acid -> barbiturate anion -> H/sup -/ using the pulse radiolyse technique

    Energy Technology Data Exchange (ETDEWEB)

    Schuchmann, M.N.; von Sonntag, C.

    1982-09-01

    The kinetics of the reactions of CO/sub 2/ + OH /sup -/-> HCO/sub 3//sup -/ (i) and barbituric acid -> barbiturate anion + H/sup +/ (ii) have been remeasured using as a new approach the pulse radiolysis technique with optical and conductivity detection. The rate constants obtained in the present study, ksub(j) (21/sup 0/C) = 6900 +- 700 M/sup -1/ s/sup -1/ and ksub(II) (19/sup 0/C) = 22 +- 2 s/sup -1/ agree within experimental errors with values obtained earlier by other methods.

  2. Thermodynamic Proton – Ligand Satability Constants in Dioxane – Water Media, Pka , Δg0, Δ H0 And Δ S0 , Values for 1, 3 – Disubstituted Barbituric Acid

    Directory of Open Access Journals (Sweden)

    Manoj Kumar

    2014-06-01

    Full Text Available Thermodynamic protonation constants of dimethyl barbituric acid [DMBA], Diphenyl barbituric acid [DPBA], di-o-tolyl barbitiuric acid[D-O-TBA], di-m-tolyl barbituric acid [D-m-TBA], di-p-tolyl, barbituric acid [D-p-TBA], di-o-xylyl barbituric acid [D-o-XBA], di-m-xylyl barbituric acid [ D-m-XBA], di-p-xylyl barbituric acid [D-p-XBA], di-α napthyl barbituric acid [D-α-NBA] and di-p-anisyl barbituric acid [D-p-ABA] have been determined in different mole fraction of deoxane [ 0.175 – 0.350 ] at 20, 30, and 40 0.100C. The thermodynamic protonation constant [ ] values do not vary linearly with reciprocal of dielectric constant of medium, but a plot of pkTa versus the mole fraction of dioxane is linear at all given temperatures. The mean ionic radii are for barbiturates ions, being in the region of 2.12 – 2.72 A0, slightly increases with dioxane percentages. The values of ΔG0, Δ H0 and Δ S0 have been evaluated. The effect of temperature as well as medium effect are briefly discussed.

  3. Anti-inflammatory effects of novel barbituric acid derivatives in T lymphocytes.

    Science.gov (United States)

    Xu, Chenjia; Wyman, Arlene R; Alaamery, Manal A; Argueta, Shannon A; Ivey, F Douglas; Meyers, John A; Lerner, Adam; Burdo, Tricia H; Connolly, Timothy; Hoffman, Charles S; Chiles, Thomas C

    2016-09-01

    We have used a high throughput small molecule screen, using a fission yeast-based assay, to identify novel phosphodiesterase 7 (PDE7) inhibitors. One of the most effective hit compounds was BC12, a barbituric acid-based molecule that exhibits unusually potent immunosuppressive and immunomodulatory actions on T lymphocyte function, including inhibition of T cell proliferation and IL-2 cytokine production. BC12 treatment confers a >95% inhibition of IL-2 secretion in phytohaemagglutinin (PHA) plus phorbol-12-myristate-13-acetate (PMA) stimulated Jurkat T cells. The effect of BC12 on IL-2 secretion is not due to decreased cell viability; rather, BC12 blocks up-regulation of IL-2 transcription in activated T cells. BC12 also inhibits IL-2 secretion in human peripheral T lymphocytes stimulated in response to CD3/CD28 co-ligation or the combination of PMA and ionomycin, as well as the proliferation of primary murine T cells stimulated with PMA and ionomycin. A BC12 analog that lacks PDE7 inhibitory activity (BC12-4) displays similar biological activity, suggesting that BC12 does not act via PDE7 inhibition. To investigate the mechanism of inhibition of IL-2 production by BC12, we performed microarray analyses using unstimulated and stimulated Jurkat T cells in the presence or absence of BC12 or BC12-4. Our studies show these compounds affect the transcriptional response to stimulation and act via one or more shared targets to produce both anti-inflammatory and pro-stress effects. These results demonstrate potent immunomodulatory activity for BC12 and BC12-4 in T lymphocytes and suggest a potential clinical use as an immunotherapeutic to treat T lymphocyte-mediated diseases. PMID:27302770

  4. [On the history of barbiturates].

    Science.gov (United States)

    Norn, Svend; Permin, Henrik; Kruse, Edith; Kruse, Poul R

    2015-01-01

    Throughout the history of humanity, numerous therapeutic agents have been employed for their sedative and hypnotic properties such as opium, henbane (Hyoscyamus niger) and deadly nightshade (Atropa belladonna), but also alcohol and wine. In the 19th century potassium bromide was introduced as a sedative - and antiepileptic drug and chloral hydrate as sedative-hypnotics. A new era was reached by the introduction of barbiturates. The story started with the chemist Adolf von Baeyer. His breakthrough in the synthesis of new agents as barbituric acid and indigo and his education of young chemists was of great importance for the science of organic chemistry and the development of the dye and medicine industry in the late 19th century. The next important step was the development of barbiturates. The pioneers were Josef von Mering and Emil Fischer. Using the Grimaux-method they synthesized various barbiturates. It was von Mering who got the idea of introducing ethyl groups in the inactive barbituric acid to obtain sedatives, but the synthesis was succeeded by the chemist Emil Fischer. Experiments with dogs clearly showed sedative and hypnotic effect of the barbiturates and the oral administration of barbital (Veronal) confirmed the effect in humans. Barbital was commercialized in 1903 and in 1911 phenobarbital (Luminal) was introduced in the clinic, and this drug showed hypnotic and antiepileptic effects. Thereafter a lot of new barbiturates appeared. Dangerous properties of the drugs were recognized as abuse, addiction, and poisoning. An optimum treatment of acute barbiturate intoxication was obtained by the "Scandinavian method", which was developed in the Poison Centre of the Bispebjerg Hospital in Copenhagen. The centre was established by Carl Clemmesen in 1949 and the intensive care treatment reduced the mortality of the admitted persons from 20% to less than 2%. To-day only a few barbiturates are used in connection with anaesthesia and for the treatment of epilepsy

  5. Stereoselective capture of N-acyliminium ions generated from α-hydroxy-N-acylcarbamides: direct synthesis of uracils from barbituric acids enabled by SmI2 reduction.

    Science.gov (United States)

    Szostak, Michal; Sautier, Brice; Procter, David J

    2014-01-17

    Lewis acid promoted cleavage of α-amino alcohols derived from barbituric acids via chemoselective Sm(II)-mediated electron transfer affords a wide range of C6-substituted 5,6-dihydrouracils. The reaction involves the first generation of N-acyliminium ions directly from the versatile barbituric acids and proceeds with excellent stereoselectivity. The products are shown to be active in generic transition metal catalyzed reactions, thus providing a modular and highly practical sequence to the biologically significant uracil derivatives. PMID:24359321

  6. Synthesis of barbituric acid containing nucleotides and their implications for the origin of primitive informational polymers.

    Science.gov (United States)

    Mungi, Chaitanya V; Singh, Sachin Kumar; Chugh, Jeetender; Rajamani, Sudha

    2016-07-27

    Given that all processes in modern biology are encoded and orchestrated by polymers, the origin of informational molecules had to be a crucial and significant step in the origin of life on Earth. An important molecule in this context is RNA that is thought to have allowed the transition from chemistry to biology. However, the RNA molecule is comprised of intramolecular bonds which are prone to hydrolysis, especially so under the harsh conditions of the early Earth. Furthermore, the formation of nucleotides with extant bases and their subsequent polymerization have both been problematic, to say the least. Alternate heterocycles, in contrast, have resulted in nucleosides in higher yields, suggesting a viable and prebiotically relevant solution to the longstanding "nucleoside problem". In the present study, we have synthesized a nucleotide using ribose 5'-monophosphate (rMP) and barbituric acid (BA), as the base analog, using dry-heating conditions that are thought to be prevalent in several regimes of the early Earth. Polymerization of the resultant monomers, i.e. BA-nucleotides, was also observed when dehydration-rehydration cycles were carried out at low pH and high temperature. The resulting RNA-like oligomers have intact bases unlike in reactions that were carried out with canonical nucleotides, which resulted in abasic sites under acidic conditions due to cleavage of the N-glycosidic linkages. Furthermore, the incorporation of BA directly into preformed sugar-phosphate backbones was also observed when rMP oligomers were subjected to heating with BA. The results from our aforementioned experiments provide preliminary evidence that BA could have been a putative precursor of modern nucleobases, which could have been incorporated into primitive informational polymers that predated the molecules of an RNA world. Moreover, they also highlight that the prebiotic soup, which would have been replete with alternate heterocycles, could have allowed the sampling of other

  7. Physicochemical studies of the reaction of 99mTc with 5,5‧-diethyl barbituric acid, adenine, D-glucose and thiobarbituric acid at different temperatures

    Science.gov (United States)

    Masoud, M. S.; El-Shahat, M. F.; Elkholany, A. S.

    2014-06-01

    The reaction of 99mTc pertechnetate with 5,5‧-diethyl barbituric acid, adenine, D-glucose and thiobarbituric acid at different temperatures was studied. The solvent effect on the electronic absorption spectra of the reactions was recorded. The reaction mixtures have been analyzed at different times using TLC and a radiodetctor to show the peaks at the plates. 99mTc pertechnetate is obtained from the Mo generators. It is difficult to separate the complexes in the solid state. The percentage of 99mTc involved in the complexes can be determined. Characterization of the 99mTc complexes as well as the determination of the extent of radiolabeling was done by thin layer chromatography using 0.9% NaCl solution as a solvent. The Rf value of 99TcO4- is (≈1). The solvatochromism for the reaction of 99mTc with D-glucose was mainly affected by solute permanent dipole-solvent permanent dipole interaction, the dipolar interaction for the reaction of 99mTc with of 5,5‧-diethyl barbituric acid and for the reaction of 99mTc with adenine and thiobarbituric was solute-solvent hydrogen bonding.

  8. Synthesis and biological activity of novel barbituric and thiobarbituric acid derivatives against non-alcoholic fatty liver disease.

    Science.gov (United States)

    Ma, Liang; Li, Shilin; Zheng, Hao; Chen, Jinying; Lin, Lin; Ye, Xia; Chen, Zhizhi; Xu, Qinyuan; Chen, Tao; Yang, Jincheng; Qiu, Neng; Wang, Guangcheng; Peng, Aihua; Ding, Yi; Wei, Yuquan; Chen, Lijuan

    2011-06-01

    Forty-four barbituric acid or thiobarbituric acid derivatives were synthesized and evaluated for their effects on adipogenesis of 3T3-L1 adipocytes by measuring the expression of adiponectin in vitro. Four compounds (3a, 3o, 3s, 4t) were found to increase the expression of adiponectin and lower the leptin level in 3T3-L1 adipocytes at respective concentration of 10 μM. Among them, 3s showed the most efficacious. Oral administration of 3s effectively reduced body weight, liver weight, and visceral fat and regulated serum levels of biochemical markers in the high-fat/diet-induced Wistar rats. Histopathological evaluation of liver sections by Oil Red O and H&E staining confirmed 3s as a potent, orally active molecule for reducing fat deposition against non-alcoholic fatty liver disease. PMID:21429633

  9. An N-ethylated barbituric acid end-capped bithiophene as an electron-acceptor material in fullerene-free organic photovoltaics.

    Science.gov (United States)

    Sullivan, Paul; Collis, Gavin E; Rochford, Luke A; Arantes, Junior Ferreira; Kemppinen, Peter; Jones, Tim S; Winzenberg, Kevin N

    2015-04-11

    A new evaporable electron acceptor material for organic photovoltaics based on N-ethyl barbituric acid bithiophene (EBB) has been demonstrated. Bilayer devices fabricated with this non-fullerene acceptor and boron subphthalocyanine chloride (SubPc) donor produce power conversion efficiencies as high as 2.6% with an extremely large open-circuit voltage approaching 1.4 V. PMID:25761144

  10. Determination of the retention behavior of barbituric acid derivatives in reversed-phase high-performance liquid chromatography by using quantitative structure-retention relationships.

    Science.gov (United States)

    Jakab, Annamaria; Schubert, Gábor; Prodan, Miklos; Forgács, Esther

    2002-04-25

    Retention parameters of 45 barbituric acid derivatives were determined on an amide embedded RP silica column using non-buffered water-dioxan eluent systems. Linear correlations were calculated between the logarithm of the capacity factor and the dioxan concentration in the eluent. Six different retention parameters of each barbituric acid derivative were correlated with different conventional and quantum chemical structural descriptors using quantitative structure-retention relationship (QSRR). The different parameters were: intercept (log k0) and slope (b) values of the linear, the combined retention parameter (log k0/b), asymmetry factor (AF5) and theoretical plate values (N(USP) and N(JP), according to the United States and Japanese Pharmacopoeia calculations). Stepwise regression analysis (SRA) and principal component analysis (PCA) followed by two-dimensional nonlinear mapping were used to determine the retention behavior of barbituric acid derivatives. SRA and PCA led to similar results. The results indicated that the retention of barbituric acid derivatives are mainly governed by the polaric and steric parameters of the substituents. PMID:12013230

  11. On relation between acidic-base properties of O,O'-dioxyazocompounds and analytical characteristics of their complexes with vanadium

    International Nuclear Information System (INIS)

    Vanadium (4) interaction with azo compounds, obtained on the basis of o-aminophenols and barbituric acid are studied by spectrophotometric method. The complex composition and certain analytical characteristics and correlation dependences are determined

  12. [Studies on the structure-activity relationship of allyl substituted oxopyrimidines searching for the novel antagonist or agonist of barbiturates to the sleep mechanism based on the uridine receptor theory--barbituric acid to uridine (part I)].

    Science.gov (United States)

    Yamamoto, Ikuo

    2005-01-01

    Thirty-six allyl substituted oxopyrimidine analogues such as barbituric acid (BA), barbiturates, uracil, thymine, and related derivatives including 13 new compounds were synthesized and their pharmacologic effects ([hypnotic activity, anticonvulsant activity against pentylentetrazol (PTZ)-induced seizures, and LD(50)]) and interactions with the barbiturates were evaluated in mice and rats. The results are briefly and parially summarized as follows. BA prolonged pentobarbital (PB)-induced sleep and had some central depressant effects. N,5,5-triallyl-BA exhibited some hypnotic and anticonvulsant activities, although the other 5,N-allyl-compounds did not show any activity except for allobarbital (AlloB). N-allyl-BA, 5-allyl-BA, N(1),N(3),5-triallyl-BA, N,5,5-triallyl-BA, and N(1),N(3),5,5-tetraallyl-BA also prolonged PB-induced sleep. Interestingly, N,5,5-triallyl-BA was the most potent in the interaction with AlloB, phenobarbital (PheB), amobarbital (AB), PB, and thiopental (TP) but not barbital (B). N(1),N(3),5,5-tetraallyl-BA prolonged AlloB-, PB-, and AB-induced sleep but not B-, PheB-, and TP-induced sleep. N(1),N(3),5-triallyl-B prolonged only PB- and TP-induced sleep. 5,5-diallyl-BA prolonged PheB- and TP-induced sleep. N,5-diallyl-BA prolonged only TP-induced sleep. In contrast, BA and N(1),N(3),5-triallyl-AB tended to antagonize AlloB, AB, and B. N(1),N(3),5,5-tetraallyl-BA also slightly antagonized B, PheB, and TP. 5,5-diallyl-BA antagonized only AB. The prolonging effects of BA, N,5,5-triallyl-BA, and N(1),N(3),5,5-tetraallyl-BA on PB-induced sleep were dose dependent. These results indicate that the position and number of allyl groups substituted on the structure of BA play an important role in their depressant activities. This review deals with the structure-activity relationship of allyl-substituted oxopyrimidines as part of our search for antagonists and agonists of barbiturates as well as their mechanisms of action. PMID:15635282

  13. Knoevenagel condensation of α,β-unsaturated aromatic aldehydes with barbituric acid under non-catalytic and solvent-free conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An efficient route for the synthesis of 5-(arylpropenylidine)-2,4,6-pyrimidinetrione 3 from an appropriate α,β-unsaturated aromatic aldehydes 1 and barbituric acid 2 under both non-catalytic and solvent-free microwave irradiation conditions was described. In this way, a range of biologically important compounds 3 was obtained in good to excellent yields (86-98 %) in a very short reaction time (30-80 s).

  14. Hydrogen-bond motifs in N-monosubstituted derivatives of barbituric acid: 5-allyl-5-isopropyl-1-methylbarbituric acid (enallylpropymal) and 1,5-di(but-2-enyl)-5-ethylbarbituric acid.

    Science.gov (United States)

    Gelbrich, Thomas; Zencirci, Neslihan; Griesser, Ulrich J

    2010-01-01

    Both title structures exhibit essentially planar barbiturate rings. The crystal structure of enallylpropymal (5-allyl-5-isopropyl-1-methylbarbituric acid), C(11)H(16)N(2)O(3), is composed of centrosymmetric N-H...O hydrogen-bonded dimers, while 1,5-di(but-2-enyl)-5-ethylbarbituric acid, C(14)H(20)N(2)O(3), forms N-H...O hydrogen-bonded helical chains. Each of the ten known crystal structures of closely related N-monosubstituted derivatives of barbituric acid displays one of the fundamental N-H...O hydrogen-bonded motifs of the two title structures, i.e. either a dimer or a chain. PMID:20048427

  15. Imidazol and barbituric acid derivatives - heterocyclic carbene fragments with pi-donor and acceptor properties

    OpenAIRE

    Sweidan, Kamal

    2006-01-01

    New derivatives of 1,3-dimethylbarbituric acid and imidazol-2-ylidene were prepared and characterized by different spectroscopic techniques. The resulting derivatives are classified into zwitterionic, salts and neutral derivatives of 1,3-dimethylbarbituric acid and salts derivatives of 2,3-dihydroimidazole-2-ylidenes. The crystal structures of most of these compounds reveal the presence of N-H-O and C-H-O hydrogen bonds.

  16. Design and synthesis of new barbituric- and thiobarbituric acid derivatives as potent urease inhibitors: Structure activity relationship and molecular modeling studies.

    Science.gov (United States)

    Rauf, Abdul; Shahzad, Sohail; Bajda, Marek; Yar, Muhammad; Ahmed, Faiz; Hussain, Nazar; Akhtar, Muhammad Nadeem; Khan, Ajmal; Jończyk, Jakub

    2015-09-01

    In this study 36 new compounds were synthesized by condensing barbituric acid or thiobarbituric acid and respective anilines (bearing different substituents) in the presence of triethyl orthoformate in good yields. In vitro urease inhibition studies against jack bean urease revealed that barbituric acid derived compounds (1-9 and 19-27) were found to exhibit low to moderate activity however thiobarbituric acid derived compounds (10-18 and 28-36) showed significant inhibition activity at low micro-molar concentrations. Among the synthesized compounds, compounds (15), (12), (10), (36), (16) and (35) showed excellent urease inhibition with IC50 values 8.53 ± 0.027, 8.93 ± 0.027, 12.96 ± 0.13, 15 ± 0.098, 18.9 ± 0.027 and 19.7 ± 0.63 μM, respectively, even better than the reference compound thiourea (IC50 = 21 ± 0.011). The compound (11) exhibited comparable activity to the standard with IC50 value 21.83 ± 0.19 μM. In silico molecular docking studies for most active compounds (10), (12), (15), (16), (35) and (36) and two inactive compounds (3) and (6) were performed to predict the binding patterns. PMID:26081763

  17. 1-Benzyl-2-methyl-3-indolylmethylene barbituric acid derivatives: Anti-cancer agents that target nucleophosmin 1 (NPM1).

    Science.gov (United States)

    Penthala, Narsimha Reddy; Ketkar, Amit; Sekhar, Konjeti R; Freeman, Michael L; Eoff, Robert L; Balusu, Ramesh; Crooks, Peter A

    2015-11-15

    In the present study, we have designed and synthesized a series of 1-benzyl-2-methyl-3-indolylmethylene barbituric acid analogs (7a-7h) and 1-benzyl-2-methyl-3-indolylmethylene thiobarbituric acid analogs (7 i-7 l) as nucleophosmin 1 (NPM1) inhibitors and have evaluated them for their anti-cancer activity against a panel of 60 different human cancer cell lines. Among these analogs 7 i, 7 j, and 7 k demonstrated potent growth inhibitory effects in various cancer cell types with GI50 values <2 μM. Compound 7 k exhibited growth inhibitory effects on a sub-panel of six leukemia cell lines with GI50 values in the range 0.22-0.35 μM. Analog 7 i also exhibited GI50 values <0.35 μM against three of the leukemia cell lines in the sub-panel. Analogs 7 i, 7 j, 7 k and 7 l were also evaluated against the mutant NPM1 expressing OCI-AML3 cell line and compounds 7 k and 7 l were found to cause dose-dependent apoptosis (AP50 = 1.75 μM and 3.3 μM, respectively). Compound 7k also exhibited potent growth inhibition against a wide variety of solid tumor cell lines: that is, A498 renal cancer (GI50 = 0.19 μM), HOP-92 and NCI-H522 lung cancer (GI50 = 0.25 μM), COLO 205 and HCT-116 colon cancer (GI50 = 0.20 and 0.26 μM, respectively), CNS cancer SF-539 (GI50 = 0.22 μM), melanoma MDA-MB-435 (GI50 = 0.22 μM), and breast cancer HS 578T (GI50 = 0.22 μM) cell lines. Molecular docking studies suggest that compounds 7 k and 7 l exert their anti-leukemic activity by binding to a pocket in the central channel of the NPM1 pentameric structure. These results indicate that the small molecule inhibitors 7 i, 7 j, 7 k, and 7 l could be potentially developed into anti-NPM1 drugs for the treatment of a variety of hematologic malignancies and solid tumors. PMID:26602084

  18. 3D-QSAR Studies on Barbituric Acid Derivatives as Urease Inhibitors and the Effect of Charges on the Quality of a Model.

    Science.gov (United States)

    Ul-Haq, Zaheer; Ashraf, Sajda; Al-Majid, Abdullah Mohammed; Barakat, Assem

    2016-01-01

    Urease enzyme (EC 3.5.1.5) has been determined as a virulence factor in pathogenic microorganisms that are accountable for the development of different diseases in humans and animals. In continuance of our earlier study on the helicobacter pylori urease inhibition by barbituric acid derivatives, 3D-QSAR (three dimensional quantitative structural activity relationship) advance studies were performed by Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) methods. Different partial charges were calculated to examine their consequences on the predictive ability of the developed models. The finest developed model for CoMFA and CoMSIA were achieved by using MMFF94 charges. The developed CoMFA model gives significant results with cross-validation (q²) value of 0.597 and correlation coefficients (r²) of 0.897. Moreover, five different fields i.e., steric, electrostatic, and hydrophobic, H-bond acceptor and H-bond donors were used to produce a CoMSIA model, with q² and r² of 0.602 and 0.98, respectively. The generated models were further validated by using an external test set. Both models display good predictive power with r²pred ≥ 0.8. The analysis of obtained CoMFA and CoMSIA contour maps provided detailed insight for the promising modification of the barbituric acid derivatives with an enhanced biological activity. PMID:27144563

  19. 3D-QSAR Studies on Barbituric Acid Derivatives as Urease Inhibitors and the Effect of Charges on the Quality of a Model

    Directory of Open Access Journals (Sweden)

    Zaheer Ul-Haq

    2016-04-01

    Full Text Available Urease enzyme (EC 3.5.1.5 has been determined as a virulence factor in pathogenic microorganisms that are accountable for the development of different diseases in humans and animals. In continuance of our earlier study on the helicobacter pylori urease inhibition by barbituric acid derivatives, 3D-QSAR (three dimensional quantitative structural activity relationship advance studies were performed by Comparative Molecular Field Analysis (CoMFA and Comparative Molecular Similarity Indices Analysis (CoMSIA methods. Different partial charges were calculated to examine their consequences on the predictive ability of the developed models. The finest developed model for CoMFA and CoMSIA were achieved by using MMFF94 charges. The developed CoMFA model gives significant results with cross-validation (q2 value of 0.597 and correlation coefficients (r2 of 0.897. Moreover, five different fields i.e., steric, electrostatic, and hydrophobic, H-bond acceptor and H-bond donors were used to produce a CoMSIA model, with q2 and r2 of 0.602 and 0.98, respectively. The generated models were further validated by using an external test set. Both models display good predictive power with r2pred ≥ 0.8. The analysis of obtained CoMFA and CoMSIA contour maps provided detailed insight for the promising modification of the barbituric acid derivatives with an enhanced biological activity.

  20. Electronic structure and biological activity: Barbiturates vs. thiobarbiturates

    Science.gov (United States)

    Novak, Igor; Kovač, Branka

    2010-06-01

    The electronic structure of the derivatives of thiobarbituric acid: 1,3-diethyl-2-thiobarbituric acid ( I) and 1,3-dibutyl-2-thiobarbituric acid ( II) has been investigated by HeI and HeII UV photoelectron spectroscopy (UPS) and quantum chemical calculations. We discuss their electronic structures and compare them with barbituric acid. We also relate the difference in electronic structure between barbituric and thiobarbituric acids to difference in biological activity of their derivatives.

  1. Formation of C═C bond via knoevenagel reaction between aromatic aldehyde and barbituric acid at liquid/HOPG and vapor/HOPG interfaces.

    Science.gov (United States)

    Geng, Yanfang; Dai, Hongliang; Chang, Shaoqing; Hu, Fangyun; Zeng, Qingdao; Wang, Chen

    2015-03-01

    Controlling chemical reactions on surface is of great importance to constructing self-assembled covalent nanostructures. Herein, Knoevenagel reaction between aromatic aldehyde compound 2,5-di(5-aldehyde-2-thienyl)-1,4-dioctyloxybenzene (PT2) and barbituric acid (BA) has been successfully performed for the first time at liquid/HOPG interface and vapor/HOPG interface. The resulting surface nanostructures and the formation of C═C bond are recorded through scanning tunneling microscopy (STM), and confirmed by attenuated total reflectance Fourier-transform infrared (ATR/FT-IR) spectrometer and UV-vis absorption. The obtained results reveal that Knoevenagel condensation reaction can efficiently occur at both interfaces. This surface reaction would be an important step toward further reaction to produce innovative conjugated nanomaterial on the surface. PMID:25664650

  2. 5-(2-Cyclohexylideneethyl)-5-ethyl barbituric acid (CHEB): correlation of hypnotic and convulsant properties with alterations of synaptosomal 45Ca2+ influx

    International Nuclear Information System (INIS)

    Male ICR mice were given either 5-(2-cyclohexylideneethyl)-5-ethyl barbituric acid (CHEB) alone or CHEB after a 1 h pretreatment with phenobarbital CHEB alone produced excitatory behavior but not convulsive seizures. Higher doses produced convulsive seizures resulting in death. Pretreatment with phenobarbital prevented seizure activity. In vitro, CHEB significantly inhibited 'fast-phase' K+-stimulated 45Ca2+ uptake into cerebrocortical synaptosomes. CHEB also significantly increased basal 45Ca2+ uptake. The addition of CHEB or pentobarbital to striatal synaptosomes inhibited 'fast-phase' K+-stimulated 45Ca2+ uptake and endogenous dopamine release. CHEB, but not pentobarbital, produced a time- and dose-dependent increase in the resulting release of endogenous dopamine from striatal synaptosomes. The results of this study show that CHEB possesses hypnotic activity if its lethal convulsant actions are blocked. The hypnotic actions of CHEB appear to correlate with inhibition of voltage-dependent calcium channels in brain synaptosomes. (Auth.)

  3. Identifying Barbiturate Binding Sites in a Nicotinic Acetylcholine Receptor with [3H]Allyl m-Trifluoromethyldiazirine Mephobarbital, a Photoreactive Barbiturate

    OpenAIRE

    Hamouda, Ayman K.; Stewart, Deirdre S.; Chiara, David C.; Savechenkov, Pavel Y.; Bruzik, Karol S.; Cohen, Jonathan B.

    2014-01-01

    At concentrations that produce anesthesia, many barbituric acid derivatives act as positive allosteric modulators of inhibitory GABAA receptors (GABAARs) and inhibitors of excitatory nicotinic acetylcholine receptors (nAChRs). Recent research on [3H]R-mTFD-MPAB ([3H]R-5-allyl-1-methyl-5-(m-trifluoromethyldiazirinylphenyl)barbituric acid), a photoreactive barbiturate that is a potent and stereoselective anesthetic and GABAAR potentiator, has identified a second class of intersubunit binding si...

  4. Structural analysis and reactivity of unusual tetrahedral intermediates enabled by SmI2-mediated reduction of barbituric acids: vinylogous N-acyliminium additions to α-hydroxy-N-acyl-carbamides.

    Science.gov (United States)

    Szostak, Michal; Sautier, Brice; Procter, David J

    2014-03-01

    Structural characterisation and reactivity of new tetrahedral intermediates based on a highly modular barbituric acid scaffold, formed via chemoselective electron transfer using the SmI2-H2O reagent, are reported. Lewis acid promoted cleavage of bicyclic α-amino alcohols affords vinylogous N-acyliminium ions, which undergo selective (>95 : 5, 1,4 over 1,2) capture with a suite of diverse nucleophiles in a practical sequence to biologically active uracil derivatives. PMID:24463565

  5. Solvent influence on the excited states of the oxo form of barbituric acid and the mechanisms of the out-of-plane non-radiative elongation of the N-H bond: a comparative theoretical and experimental study.

    Science.gov (United States)

    Shterev, Ivan G; Delchev, Vassil B

    2014-05-01

    The solvent influence on the excited states, emission and absorption energies of the oxo for of barbituric acid was studied with experimental (UV and fluorescence spectra) and theoretical methods. The excited-state reaction paths of the out-pf-plane elongation of the N-H bond of the oxo form of barbituric acid were also investigated (TD DFT level) to the conical intersections mediating internal conversions to the ground state. The (1)nσ* excited state was found to be the driven electronic state. We found that the increase of the polarity of the solvent reduces the (1)nσ* excited state decay rate through a non-planar conical intersection and increases its energy. Thus, solvents with higher polarity disfavor the non-radiative decay through conical intersections. PMID:24566117

  6. Solvent influence on the excited states of the oxo form of barbituric acid and the mechanisms of the out-of-plane non-radiative elongation of the Nsbnd H bond: A comparative theoretical and experimental study

    Science.gov (United States)

    Shterev, Ivan G.; Delchev, Vassil B.

    The solvent influence on the excited states, emission and absorption energies of the oxo for of barbituric acid was studied with experimental (UV and fluorescence spectra) and theoretical methods. The excited-state reaction paths of the out-pf-plane elongation of the Nsbnd H bond of the oxo form of barbituric acid were also investigated (TD DFT level) to the conical intersections mediating internal conversions to the ground state. The 1nσ* excited state was found to be the driven electronic state. We found that the increase of the polarity of the solvent reduces the 1nσ* excited state decay rate through a non-planar conical intersection and increases its energy. Thus, solvents with higher polarity disfavor the non-radiative decay through conical intersections.

  7. Antibacterial Barbituric Acid Analogues Inspired from Natural 3-Acyltetramic Acids; Synthesis, Tautomerism and Structure and Physicochemical Property-Antibacterial Activity Relationships

    Directory of Open Access Journals (Sweden)

    Yong-Chul Jeong

    2015-02-01

    Full Text Available The synthesis, tautomerism and antibacterial activity of novel barbiturates is reported. In particular, 3-acyl and 3-carboxamidobarbiturates exhibited antibacterial activity, against susceptible and some resistant Gram-positive strains of particular interest is that these systems possess amenable molecular weight, rotatable bonds and number of proton-donors/acceptors for drug design as well as less lipophilic character, with physicochemical properties and ionic states that are similar to current antibiotic agents for oral and injectable use. Unfortunately, the reduction of plasma protein affinity by the barbituric core is not sufficient to achieve activity in vivo. Further optimization to reduce plasma protein affinity and/or elevate antibiotic potency is therefore required, but we believe that these systems offer unusual opportunities for antibiotic drug discovery.

  8. Antibacterial barbituric acid analogues inspired from natural 3-acyltetramic acids; synthesis, tautomerism and structure and physicochemical property-antibacterial activity relationships.

    Science.gov (United States)

    Jeong, Yong-Chul; Moloney, Mark G

    2015-01-01

    The synthesis, tautomerism and antibacterial activity of novel barbiturates is reported. In particular, 3-acyl and 3-carboxamidobarbiturates exhibited antibacterial activity, against susceptible and some resistant Gram-positive strains of particular interest is that these systems possess amenable molecular weight, rotatable bonds and number of proton-donors/acceptors for drug design as well as less lipophilic character, with physicochemical properties and ionic states that are similar to current antibiotic agents for oral and injectable use. Unfortunately, the reduction of plasma protein affinity by the barbituric core is not sufficient to achieve activity in vivo. Further optimization to reduce plasma protein affinity and/or elevate antibiotic potency is therefore required, but we believe that these systems offer unusual opportunities for antibiotic drug discovery. PMID:25710842

  9. NMR studies of the complexes of uramildiacetic acid

    International Nuclear Information System (INIS)

    Proton spectra of 1,3 dimethyluramildiacetic acid and its complexes with several lanthanide ions as well as titration curves of uramildiacetic and barbituric acids where 13C chemical shifts were followed as a function of pH, have enabled the establishment of the conformation in solution of the complexes of the uramildiacetate-type ligands and of the most probable mechanism of ionization of these compounds. It is definitely shown that uramildiacetic acid is tetradentate and that it coordinates to metal ions through the iminodiacetate group and one of the carboxyl groups in position 4,6 of the molecule. The pyrimidinic ring and one of the chelator rings are coplanar and the complexes have axial symmetry. (author)

  10. A new synthetic methodology for the preparation of biocompatible and organo-soluble barbituric- and thiobarbituric acid based chitosan derivatives for biomedical applications.

    Science.gov (United States)

    Shahzad, Sohail; Shahzadi, Lubna; Mahmood, Nasir; Siddiqi, Saadat Anwar; Rauf, Abdul; Manzoor, Faisal; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur; Yar, Muhammad

    2016-09-01

    Chitosan's poor solubility especially in organic solvents limits its use with other organo-soluble polymers; however such combinations are highly required to tailor their properties for specific biomedical applications. This paper describes the development of a new synthetic methodology for the synthesis of organo-soluble chitosan derivatives. These derivatives were synthesized from chitosan (CS), triethyl orthoformate and barbituric or thiobarbituric acid in the presence of 2-butannol. The chemical interactions and new functional motifs in the synthesized CS derivatives were evaluated by FTIR, DSC/TGA, UV/VIS, XRD and (1)H NMR spectroscopy. A cytotoxicity investigation for these materials was performed by cell culture method using VERO cell line and all the synthesized derivatives were found to be non-toxic. The solubility analysis showed that these derivatives were readily soluble in organic solvents including DMSO and DMF. Their potential to use with organo-soluble commercially available polymers was exploited by electrospinning; the synthesized derivatives in combination with polycaprolactone delivered nanofibrous membranes. PMID:27207049

  11. Single-Crystal X-ray Diffraction Structure of the Stable Enol Tautomer Polymorph of Barbituric Acid at 224 and 95 K.

    Science.gov (United States)

    Marshall, Madalynn G; Lopez-Diaz, Valerie; Hudson, Bruce S

    2016-01-01

    The thermodynamically stable enol crystal form of barbituric acid, previously prepared as powder by grinding or slurry methods, has been obtained as single crystals by slow cooling from methanol solution. The selection of the enol crystal was facilitated by a density-gradient method. The structure at 224 and 95 K confirms the enol inferred on the basis of powder data. The enol has bond lengths that are consistent with the expected bond order and with DFT calculations that include treatment of hydrogen bonding. In isolation, the enol is higher in energy than the tri-keto form by 50 kJ mol(-1) which must be more than compensated by enhanced hydrogen bonding. Both crystal forms have four normal H-bonds; the enol has two additional H-bonds with O-O distances of 2.49 Å. Conversion into the enol form occurs spontaneously in the solid state upon prolonged storage of the commercial tri-keto material. Slurry conversion of tri-one to enol in ethanol is reversed in direction in ethanol-D1 . PMID:26662287

  12. Experimental and computational thermochemical study of 1,3,5-trimethyl-, 1,5,5-trimethyl-, and 1,3,5,5-tetramethyl-barbituric acids

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The enthalpies of formation in condensed phase have been obtained. • The enthalpies of sublimation have been measured by transpiration method. • The gas-phase enthalpies of formation have been obtained. • The gas-phase enthalpies of formation have been calculated at G3 and G4 levels. - Abstract: This paper reports an experimental and computational thermochemical study on three barbituric acid derivatives: 1,3,5-trimethylbarbituric acid or (1,3,5-trimethyl-2,4,6(1H,3H,5H)pyrimidinetrione, CAS 7358-61-4), 1,5,5-trimethylbarbituric acid or (1,5,5-trimethyl-2,4,6(1H,3H,5H)pyrimidinetrione, CAS 702-47-6), and 1,3,5,5-tetramethylbarbituric acid or (1,3,5,5-tetramethyl-2,4,6(1H,3H,5H)pyrimidinetrione, CAS 13566-66-0). Values of standard (p0 = 0.1 MPa) molar enthalpies of formation in the gas phase at T = 298.15 K have been derived from experiment. Energies of combustion were measured by static bomb combustion calorimetry and standard molar enthalpies of formation in the crystalline state at T = 298.15 K were calculated. Enthalpies of sublimation were derived from temperature dependence of vapour pressures measured by transpiration method. From these results, values of −(570.6 ± 2.3), −(599.4 ± 1.4), and −(605.1 ± 2.9) kJ · mol−1 for the gas-phase enthalpies of formation at T = 298.15 K of 1,3,5-trimethylbarbituric acid, 1,5,5-trimethylbarbituric acid, and 1,3,5,5-tetramethylbarbituric acid, respectively, were determined. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular and electronic structure of the compounds has been carried out. Calculated enthalpies of formation were in good agreement with the experimental values

  13. PPL catalyzed four-component PASE synthesis of 5-monosubstituted barbiturates: Structure and pharmacological properties.

    Science.gov (United States)

    Bihani, Manisha; Bora, Pranjal P; Verma, Alakesh K; Baruah, Reshita; Boruah, Hari Prasanna Deka; Bez, Ghanashyam

    2015-12-15

    Enzymatic four-component reactions are very rare although three-component enzymatic promiscuous reactions are widely reported. Herein, we report an efficient PASE protocol for the synthesis of potentially lipophilic zwitterionic 5-monosubstituted barbiturates by four component reaction of mixture of ethyl acetoacetate, hydrazine hydrate, aldehyde and barbituric acid in ethanol at room temperature. Seven different lipases were screened for their promiscuous activity towards the synthesis of 5-monosubstituted barbiturates and the lipase from porcine pancreas (PPL) found to give optimum efficiency. The zwitterionic 5-monosubstituted barbiturates with pyrazolyl ring showed promising pharmacological activity upon screening for antibacterial and apoptotic properties. PMID:26546212

  14. Free radicals in pyrimidines: ESR of. gamma. -irradiated 5-cyclohexenyl-1,5-dimethyl barbituric acid. [/sup 60/Co

    Energy Technology Data Exchange (ETDEWEB)

    Benson, B. (Lehigh Univ., Bethlehem, PA); Erich, L.

    1981-06-01

    ESR studies have determined that ionizing radiation damage of hexobarbital (5-cyclohexenyl-1,5-dimethylbarbituric acid) causes the formation of a free radical (A) by hydrogen abstraction from the cyclohexenyl group. Hyperfine coupling tensors were determined for coupling of the unpaired electron to four protons. Visible light of wavelengths near 450 nm reversibly converts this radical to a second free radical (B) which also has the unpaired electron localized in the cyclohexenyl group. The activation energy for a thermally induced reverse conversion (B ..-->.. A) was determined to be 1.4 eV.

  15. Free radicals in pyrimidines: ESR of γ-irradiated 5-cyclohexenyl-1,5-dimethyl barbituric acid

    International Nuclear Information System (INIS)

    ESR studies have determined that ionizing radiation damage of hexobarbital (5-cyclohexenyl-1,5-dimethylbarbituric acid) causes the formation of a free radical (A) by hydrogen abstraction from the cyclohexenyl group. Hyperfine coupling tensors were determined for coupling of the unpaired electron to four protons. Visible light of wavelengths near 450 nm reversibly converts this radical to a second free radical (B) which also has the unpaired electron localized in the cyclohexenyl group. The activation energy for a thermally induced reverse conversion (B → A) was determined to be 1.4 eV

  16. The Hydrogen Bonded Structures of Two 5-Bromobarbituric Acids and Analysis of Unequal C5–X and C5–X′ Bond Lengths (X = X′ = F, Cl, Br or Me in 5,5-Disubstituted Barbituric Acids

    Directory of Open Access Journals (Sweden)

    Thomas Gelbrich

    2016-04-01

    Full Text Available The crystal structure of the methanol hemisolvate of 5,5-dibromobarbituric acid (1MH displays an H-bonded layer structure which is based on N–H∙∙∙O=C, N–H∙∙∙O(MeOH and (MeOHO–H∙∙∙O interactions. The barbiturate molecules form an H-bonded substructure which has the fes topology. 5,5′-Methanediylbis(5-bromobarbituric acid 2, obtained from a solution of 5,5-dibromobarbituric acid in nitromethane, displays a N–H···O=C bonded framework of the sxd type. The conformation of the pyridmidine ring and the lengths of the ring substituent bonds C5–X and C5–X′ in crystal forms of 5,5-dibromobarbituric acid and three closely related analogues (X = X′ = Br, Cl, F, Me have been investigated. In each case, a conformation close to a C5-endo envelope is correlated with a significant lengthening of the axial C5–X′ in comparison to the equatorial C5–X bond. Isolated molecule geometry optimizations at different levels of theory confirm that the C5-endo envelope is the global conformational energy minimum of 5,5-dihalogenbarbituric acids. The relative lengthening of the axial bond is therefore interpreted as an inherent feature of the preferred envelope conformation of the pyrimidine ring, which minimizes repulsive interactions between the axial substituent and pyrimidine ring atoms.

  17. UJI AKTIVITAS ANTIOKSIDAN HASIL DEGRADASI LIGNIN DARI SERBUK GERGAJI KAYU KALBA (Albizia falcataria DENGAN METODE TBA (Thio Barbituric Acid

    Directory of Open Access Journals (Sweden)

    Undri Rastuti

    2010-11-01

    Full Text Available Antioxidants are compounds that can delay, retard or inhibit the oxidation reaction. Lignin is a natural polymer consisting of monomeric substituted phenols. Wood lignin degradation Kalba (Albizia falcataria yields substituted phenol. The purpose of this study was to test the antioxidant activity of compounds of lignin degradation products Kalba using TBA (Thiobarbituric Acid. Wood lignin degradation products Kalba tested antioxidant activity using the TBA method. Phase test phase of this antioxidant activity is sample preparation, determination of the maximum wavelength, determination of equilibrium time, absorbance measurements and determination of the percentage of inhibition. The wavelength maximum for BHT test solution was obtained at 530 nm. The stability of absorbance achieved after 80 minutes equilibrium time. BHT test solution and sample solution containing the degradation of lignin 0.10% (w/v increased but not as sharp as the absorbance of control, this suggests that the degradation of wood lignin Kalba have activity as an antioxidant, which relative minimize 13,70 % compare with BHT.

  18. The Physicochemical and Pharmacokinetic Relationships of Barbiturates - From the Past to the Future.

    Science.gov (United States)

    Ernst, Britton J; Clark, Gerald F; Grundmann, Oliver

    2015-01-01

    The pharmacokinetics of different barbiturates have been studied extensively and the relationship of their duration of action to their clinical use has been known for decades. While these particular compounds have largely been displaced by agents with better therapeutic indices, barbiturate use remains relatively common and important in both inpatient and outpatient settings. Their mechanism of action is to bind to inhibitory GABAA receptors in the CNS causing and potentiating the opening of neuronal chloride ion channels thus having a sedative and CNS depressant effect. All psychotropic barbiturates feature di-substitution at the C5 position of the barbituric acid prototype. This is also the primary factor by which physiologically active barbiturates differ from one another and a major mediator of lipophilicity and duration of action. However, in this review, inconsistencies in certain commonly held notions about the structure-activity relationship of barbiturates were found. Commonly accepted chemistry for the structure-activity relationship of barbiturates holds that substitution of larger alkyl groups, alicyclic, and aromatic groups, as well as branching and unsaturation, lead in general to more lipophilic compounds with a shorter biological half-life. This rationale may have limitations in the case of barbiturates as proposed in this review. There is poor correlation between nine clinically used barbiturates' octanol:water partition coefficients (log(P) values) and their respective half-lives. However, a strong correlation between pKa values and half-life was found. The current clinical relevance of these findings is discussed as well as their pertinence to future design and use of barbiturates. PMID:25824249

  19. Two polymorphs and the diethylammonium salt of the barbiturate eldoral.

    Science.gov (United States)

    Gelbrich, Thomas; Rossi, Denise; Griesser, Ulrich J

    2012-02-01

    Polymorph (Ia) of eldoral [5-ethyl-5-(piperidin-1-yl)barbituric acid or 5-ethyl-5-(piperidin-1-yl)-1,3-diazinane-2,4,6-trione], C(11)H(17)N(3)O(3), displays a hydrogen-bonded layer structure parallel to (100). The piperidine N atom and the barbiturate carbonyl group in the 2-position are utilized in N-H···N and N-H···O=C hydrogen bonds, respectively. The structure of polymorph (Ib) contains pseudosymmetry elements. The two independent molecules of (Ib) are connected via N-H···O=C(4/6-position) and N-H···N(piperidine) hydrogen bonds to give a chain structure in the [100] direction. The hydrogen-bonded layers, parallel to (010), formed in the salt diethylammonium 5-ethyl-5-(piperidin-1-yl)barbiturate [or diethylammonium 5-ethyl-2,4,6-trioxo-5-(piperidin-1-yl)-1,3-diazinan-1-ide], C(4)H(12)N(+)·C(11)H(16)N(3)O(3)(-), (II), closely resemble the corresponding hydrogen-bonded structure in polymorph (Ia). Like many other 5,5-disubstituted derivatives of barbituric acid, polymorphs (Ia) and (Ib) contain the R(2)(2)(8) N-H···O=C hydrogen-bond motif. However, the overall hydrogen-bonded chain and layer structures of (Ia) and (Ib) are unique because of the involvement of the hydrogen-bond acceptor function in the piperidine group. PMID:22307256

  20. Nucleobase-Based Barbiturates: Their Protective Effect against DNA Damage Induced by Bleomycin-Iron, Antioxidant, and Lymphocyte Transformation Assay

    OpenAIRE

    Dhorajiya, Bhaveshkumar D.; Dholakiya, Bharatkumar Z.; Ibrahim, Ahmed S; Badria, Farid A.

    2014-01-01

    A number of nucleobase-based barbiturates have been synthesized by combination of nucleic acid bases and heterocyclic amines and barbituric acid derivatives through green and efficient multicomponent route and one pot reaction. This approach was accomplished efficiently using aqueous medium to give the corresponding products in high yield. The newly synthesized compounds were characterized by spectral analysis (FT-IR, 1H NMR, 13C NMR, HMBC, and UV spectroscopy) and elemental analysis. Represe...

  1. Barbiturate bearing aroylhydrazine derivatives: Synthesis, NMR investigations, single crystal X-ray studies and biological activity

    Science.gov (United States)

    Giziroglu, Emrah; Sarikurkcu, Cengiz; Aygün, Muhittin; Basbulbul, Gamze; Soyleyici, H. Can; Firinci, Erkan; Kirkan, Bulent; Alkis, Ayse; Saylica, Tayfur; Biyik, Halil

    2016-03-01

    A series of barbituric acid aroylhydrazine derivatives have been prepared from their corresponding 1,3-dimethyl-5-acetyl barbituric acid and aroylhydrazines. All compounds have been fully characterized by using FT-IR, multinuclear NMR (1H, 13C) and Mass (MS) spectrometry. We also describe the X-ray crystal structure of 3a, which crystallizes in the monoclinic P21/n space group. The crystal structure is stabilized with infinite linear chains of dimeric units. Furthermore, all compounds were investigated for their tyrosinase inhibition, antioxidative and antimicrobial activies. The results from biological activity assays have shown that all of compounds have excellent antioxidant, significant tyrosinase inhibition and moderate antimicrobial activity.

  2. Synthesis, characterization, thermal behaviour and single crystal X-ray analysis of two new insensitive high energy density materials [8-hydroxyquinolinium 5-(2,4,6-trinitrophenyl)barbiturate (I) and 8-hydroxyquinolinium 5-(5-chloro-2,4-dinitrophenyl)-1,3-dimethyl barbiturate (II)

    Science.gov (United States)

    Manickkam, V.; Devi, P. Poornima; Kalaivani, D.

    2014-12-01

    Barbiturates I and II have been synthesized as maroon red and red orange coloured solids by mixing the ethanolic solutions of 2-chloro-1,3,5-trinitrobenzene ( TNCB), pyrimidine-2,4,6(1 H,3 H,5 H)-trione [barbituric acid ( BA)] and 8-hydroxyquinoline and 1,3-dichloro-4,6-dinitrobenzene ( DCDNB), 1,3-dimethylpyrimidine-2,4,6(1 H,3 H,5 H)-trione(1,3-dimethylbarbituric acid) and 8-hydroxyquinoline respectively. The structures of these two barbiturates have been predicted from the spectral studies (UV-VIS, IR, 1H NMR, 13C NMR, mass) and elemental analysis. Qualitative tests have been carried out to infer the presence of nitrogen and nitro groups and also chlorine atom in barbiturate II. Slow evaporation of ethanol-dimethylsulphoxide/ethanol solutions of barbiturate I/barbiturate II at 293 K yielded good for X-Ray diffraction crystals. Single crystal X-ray diffraction studies of the crystals further confirm the putative structures of the barbiturates. The asymmetric unit of the barbiturate I comprises of 8-hydroxyquinolinium cation, 5-(2,4,6-trinitrophenyl) barbiturate anion and a molecule of dimethylsulphoxide (DMSO), which is used as a recrystallizing solvent. It crystallizes in the triclinic system with space group (centrosymmetric). Barbiturate II crystallizes in the orthorhombic system with space group P212121 (non-centrosymmetric). Barbiturates I and II are stable towards an impact sensitivity test, when a weight of 2 kg mass hammer is dropped from a height of 160 cm of the instrument. TGA/ DTA analyses at four different heating rates (5, 10, 20, and 40 K/min) imply that they undergo exothermic decomposition (˜85%) in three different stages between 273 and 873 K. Activation energies for these decomposition processes have been calculated by employing Kissinger and Ozawa plots. Impact sensitivity test and activation energies have revealed that the titled barbiturates are insensitive high energy density materials ( IHEDMS).

  3. A green four-component synthesis of zwitterionic alkyl/benzyl pyrazolyl barbiturates and their photophysical studies.

    Science.gov (United States)

    Bihani, Manisha; Bora, Pranjal P; Bez, Ghanashyam; Askari, Hassan

    2014-11-01

    A novel series of unsymmetrically substituted alkyl/benzyl pyrazolyl barbiturates incorporating highly biologically active pyrazolone and barbiturate moieties was synthesized by four-component reactions of a mixture of ethyl acetoacetate, hydrazine hydrate, aldehydes and barbituric acid/thiobarbituric acid in ethanol without using a catalyst. The photophysical properties of the newly designed alkyl/benzyl pyrazolyl barbiturates were studied, and good quantum yield of some products indicated a definitive scope in the field of biochemical applications. Single-crystal X-ray crystallographic studies revealed that the newly synthesized compounds exist in zwitterionic form. The zwitterionic nature of the new chimera makes them interesting candidates for drug delivery as zwitterionic drugs are known to have highly water soluble properties, specific protein absorption, slow recognition by immune system, slow blood clearance from body and can constantly diffuse and deposit throughout the physiological pH. PMID:25005075

  4. Europium complexes with trifluoroacetic acid

    International Nuclear Information System (INIS)

    Synthesis conditions and spectra-luminescent properties of different-ligand europium complexes of the composition Eu (TFA)2x2D, where TFA = anion of trifluoroacetic acid, D = 1,10-phenanthroline, 2,2-dipyridyl, triphenylphosphinoxide, hexamethyl-phosphotriamide, were studied. The compounds prepared have been characterized by the methods of elementary chemical analysis, IR and luminescence spectroscopy. It is shown that in the complex compounds two methods of coordination of the acid residue functional groups are realized, i.e. monodentate and bridge functions. The compounds were tested for resistance to UV light effect and to heating in the air. Complex with 2,2-dipyridyl proved the most thermally stable complex in the series studied, its decomposition temperature being 240 deg C

  5. Spectrophotometric kinetic and determination of quinones and barbiturates

    Science.gov (United States)

    Medien, H. A. A.; Zahran, A. A.

    2001-10-01

    The kinetics of 1,3-dimethylbarbituric acid with some quinones, namely 1,4-benzoquinone, 1,4-naphthoquinone and p-chloranil in 50% methyl alcohol-water mixture have been investigated spectrophotometrically at 30-50°C. The reaction follows overall second-order kinetics, first order each in reactant. From the dependence of the rate constants on temperature, activation parameters have been calculated. A plot of Δ H# versus Δ S# for the reaction gave a good straight line with an isokinetic temperature of 387.66 K. The rate of reaction increases with increasing dielectric constant of the medium. Based on this reaction, a spectrophotometric determination method of quinones is described. Beer's law was obeyed within the concentration range 2.7-61.5 μg ml -1 quinone. The method was applied for determination of barbituric, thiobarbituric and 1,3-dimethylbarbituric acids with 1,4-naphthoquinone within a concentration range of 3.2-39.5 μg ml -1 barbiturate. The reaction mechanism and reactivity have been discussed.

  6. Cyanoacetamide based Barbiturates, Thiobarbiturates and their Biological Studies

    International Nuclear Information System (INIS)

    Various cyanoacetamide based Knoevenagel adducts were coupled with barbituric acid / thiobarbituric acid and triethylorthoformate via a one pot three component reaction in 2-butanol availing the desired compound in excellent yields. All the synthesized compounds (2-15) were extensively characterized by 1H-NMR, 13C-NMR, Mass spectrometry and elemental analysis and were screened for antibacterial, antiurease, antioxidant, cytotoxicity and chymotrypsin inhibition studies. In case of antibacterial studies 2 was found appreciably active against the six selected strains whereas the rest of the compounds were moderately active. The urease inhibition studies revealed compound 5 and 12 as potent whereas the rest were found inactive where thiourea was used as control. Antioxidant activity results exhibited with 2 as the most active and rest of compounds showed good activity. In case of chymotrypsin inhibition studies all the synthesized compounds were found inactive with the exception of 6 which was moderately active. (author)

  7. Recognition of anesthetic barbiturates by a protein binding site: a high resolution structural analysis.

    Directory of Open Access Journals (Sweden)

    Simon Oakley

    Full Text Available Barbiturates potentiate GABA actions at the GABA(A receptor and act as central nervous system depressants that can induce effects ranging from sedation to general anesthesia. No structural information has been available about how barbiturates are recognized by their protein targets. For this reason, we tested whether these drugs were able to bind specifically to horse spleen apoferritin, a model protein that has previously been shown to bind many anesthetic agents with affinities that are closely correlated with anesthetic potency. Thiopental, pentobarbital, and phenobarbital were all found to bind to apoferritin with affinities ranging from 10-500 µM, approximately matching the concentrations required to produce anesthetic and GABAergic responses. X-ray crystal structures were determined for the complexes of apoferritin with thiopental and pentobarbital at resolutions of 1.9 and 2.0 Å, respectively. These structures reveal that the barbiturates bind to a cavity in the apoferritin shell that also binds haloalkanes, halogenated ethers, and propofol. Unlike these other general anesthetics, however, which rely entirely upon van der Waals interactions and the hydrophobic effect for recognition, the barbiturates are recognized in the apoferritin site using a mixture of both polar and nonpolar interactions. These results suggest that any protein binding site that is able to recognize and respond to the chemically and structurally diverse set of compounds used as general anesthetics is likely to include a versatile mixture of both polar and hydrophobic elements.

  8. 5,5-Dihydroxybarbituric acid 1,4-dioxane hemisolvate

    Directory of Open Access Journals (Sweden)

    Thomas Gelbrich

    2010-05-01

    Full Text Available The asymmetric unit of the title compound,, C4H4N2O5·0.5C4H8O2, contains one molecule of 5,5-dihydroxybarbituric acid with a nearly planar barbiturate ring and half a molecule of 1,4-dioxane. The geometry of the centrosymmetric dioxane molecule is close to an ideal chair conformation. The crystal structure exhibits a complex three-dimensional hydrogen-bonded network. Barbiturate molecules are connected to one another via N—H...O=C, O—H...O=C and N—H...O(hydroxy interactions, while the barbituric acid molecule is linked to dioxane by an O—H...O contact.

  9. Complexes of salicylic acid and its derivatives

    International Nuclear Information System (INIS)

    A generalization and systematization have been made of literature data on complexing of various elements, including beryllium, cadmium, boron, indium, rare-earth elements, actinides, and transition elements with salicylic acid and it derivatives (amino-, nitro- and halosalicylic acids). The effect of the position and nature of the substitute, in the case of salicylic acid derivatives, on the complexing process is discussed. Certain physicochemical properties of the complexes under consideration are described along with data indicative of their stability

  10. Simultaneous effect of organic modifier and physicochemical parameters of barbiturates on their retention on a narrow-bore PGC column.

    Science.gov (United States)

    Forgács, Esther; Cserháti, Tibor; Miksik, Ivan; Echardt, Adam; Deyl, Zdenek

    2004-02-01

    The retention time of 22 barbituric acid derivatives was measured on a narrow-bore porous graphitized carbon (PGC) column using water-dioxane mixtures as mobile phases. The capacity factor (k), theoretical plate number (N), and asymmetry factor (AF) were calculated for each solute in each mobile phase. The relationships between chromatographic characteristics and physicochemical parameters of solutes were elucidated by stepwise regression analysis (SRA). SRA indicated that the binding of barbiturates to the PGC surface is of mixed character electrostatic and apolar interactive forces are equally involved. Sterical correspondence between the surface of the stationary phase and the solutes also exert a significant influence on the retention behavior. PMID:14698263

  11. Ruthenium nitrosyl complexes in nitric acid solutions

    International Nuclear Information System (INIS)

    Nine nitrosyl ruthenium complexes have been separated and identified in aqueous solutions of nitric acid. The separation method was low temperature, gradient elution, reverse phase partition chromatography using tri-n-butyl phosphate on a kiesel gel 60 support using 106Ru labelled complexes in the nitric acid phase. The identification of the complexes was deduced from the relationships between the products of aquation and nitration and paper chromatography using both methyl-iso-propyl ketone and nitric acid-acetone elutions. The proportion of each complex at equilibrium in various concentrations of nitric acid have been measured. The rates of nitration in 10 M nitric acid, and of aquation in 0.45 M nitric acid have been determined at 00C. (author)

  12. Complexation of americium with humic acid

    International Nuclear Information System (INIS)

    As a part of the interlaboratory comparison exercise for the complexation of humic acid and colloid generation (COCO-Club activities) in the CEC project MIRAGE-II, the complexation of americium with humic acid has been studied in our laboratory. Two humic acids were used for the study: Aldrich-HA(H+) which is a reference humic acid of the COCO-Club and Bradford-HA(H+) from Lake Bradford, Florida. A wide concentration range of humic acid and different ratios of Am to humic acid have been investigated between pH 5 and 6 with the ionic strength of 0.1 M and 1.0 M. The complexation has been studied by UV-spectroscopy, Laser-induced Photoacoustic Spectroscopy (LPAS) and ultrafiltration. LPAS is used for the submicromolar concentration range where the sensitivity of UV spectroscopy is not accessible. Ultrafiltration is used for low Am to humic acid ratios where both spectroscopic methods are not applicable. Varying the humic acid concentration over three orders of magnitude, only a 1:1 type of binding is observed. No significant variation of the stability constant is found in the investigated range of pH and ionic strength. However, the precipitation tendency and the loading capacity of humic acid are found to depend sensitively on pH and ionic strength. The complexation study provides a deep insight into the influence of humic acid on the migration behaviour of fission products and actinides in the geosphere. (orig.)

  13. Chemical speciation and equilibria of some nucleic acid compounds and their iron(III) complexes

    Science.gov (United States)

    Masoud, Mamdouh S.; Abd El-Kaway, Marwa Y.; Hindawy, Ahmed M.; Soayed, Amina A.

    The pH effect on electronic absorption spectra of some biologically active nucleic acid constituents have been studied at room temperature and the mechanism of ionization was explained. These compounds are of two categories (pyrimidines: [barbital; 5,5'-diethyl-barbituric acid], [SBA; 4,6-dihydroxy-2-mercapto-pyrimidin], [NBA; 5-nitro-2,4,6(1H,3H,5H)-pyrimidine trione] and [TU; 2,3-dihydro-2-thioxo-pyrimidin-4(1H)-one]) and (purines: [adenine; 6-amino purine], its [Schiff bases derived from adenine-acetylacetone; (Z)-4-(7H-purin-6-ylimino)pentan-2-one) and adenine-salicylaldehyde; 2-((7H-purin-6-ylimino) methyl) phenol] and its [Azo derived from adenine-resorcinol; 4-((7H-purin-6-yl)-diazenyl) benzene-1,3-diol]. The phenomena of tautomerization assigned different tautomers. Different spectrophotometric methods are applied to evaluate the pK's values that explained with their molecular structures. The interaction of Fe3+ with some selected pyrimidines (barbital, NBA and SBA) was explained using familiar six spectrophotometric methods. The data typified the existence of different absorbing species with the different stoichiometries 1:1, 1:2, 1:3 and 2:3. The stability constant of the complexes was computed. More approach was deduced to assign the existence of different species applying the distribution diagrams.

  14. Spectroscopic studies on some azo compounds and their cobalt, copper and nickel complexes

    Science.gov (United States)

    Masoud, Mamdouh. S.; Khalil, Ekram A.; Hindawy, Ahmed M.; Ali, Alaa E.; Mohamed, Eman F.

    2004-10-01

    Synthesis and characterization of [ o-carboxy phenylazo] moiety of barbituric acid, thiobarbituric acid, thiouracil, citrazinic acid, and disodium chromotropate and their complexes derived from cobalt (II), nickel (II), and copper (II) salts were done. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, NMR, UV-Vis, IR and ESR. The dissociation constants of the free azo ligands are evaluated by spectrophotometric methods.

  15. Characterization and complexation of humic acid

    International Nuclear Information System (INIS)

    This paper summarizes the research contributions to the CEC project MIRAGE II, particularly the research area: complexation and colloids (COCO). The first part of the paper comprises the characterization of humic and fulvic acids from different origins: a commercial product from Aldrich Co. used as a reference humic acid and site specific humic acids from Gorleben (FRG), Boom Clay (B) and Fanay Augeres (F) aquifer systems. The second part includes the complexation of trivalent actinides: Am(III) and Cm(III) with various humic acids. A number of different methods have been applied for the complexation study: spectrophotometry, ultrafiltration, laser-indused photoacoustic spectroscopy (LPAS) and time resolved laser fluorescence spectroscopy (TRLFS). The evaluation process of complexation constant is discussed extensively and the well consolidated results are presented, which can be directly used for the geochemical modelling of the radionuclide migration. (orig.)

  16. Synthesis and Evaluation of Changes Induced by Solvent and Substituent in Electronic Absorption Spectra of New Azo Disperse Dyes Containig Barbiturate Ring

    Directory of Open Access Journals (Sweden)

    Hooshang Hamidian

    2013-01-01

    Full Text Available Six azo disperse dyes were prepared by diazotizing 4-amino hippuric acid and coupled with barbituric acid and 2-thiobarbituric acid. Then, the products were reacted with aromatic aldehyde, sodium acetate, and acetic anhydride, and oxazolone derivatives were formed. Characterization of the dyes was carried out by using UV-Vis, FT-IR, 1H NMR and 13C NMR, and mass spectroscopic techniques. The solvatochromic behavior of azo disperse dyes was evaluated in various solvents. The effects of substituents of aromatic aldehyde, barbiturate, and thiobarbiturate ring on the color of dyes were investigated.

  17. Allyl m-Trifluoromethyldiazirine Mephobarbital: An Unusually Potent Enantioselective and Photoreactive Barbiturate General Anesthetic

    Energy Technology Data Exchange (ETDEWEB)

    Savechenkov, Pavel Y.; Zhang, Xi; Chiara, David C.; Stewart, Deirdre S.; Ge, Rile; Zhou, Xiaojuan; Raines, Douglas E.; Cohen, Jonathan B.; Forman, Stuart A.; Miller, Keith W.; Bruzik, Karol S. (Harvard-Med); (Mass. Gen. Hosp.); (UIC)

    2012-12-10

    We synthesized 5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (14), a trifluoromethyldiazirine-containing derivative of general anesthetic mephobarbital, separated the racemic mixture into enantiomers by chiral chromatography, and determined the configuration of the (+)-enantiomer as S by X-ray crystallography. Additionally, we obtained the {sup 3}H-labeled ligand with high specific radioactivity. R-(-)-14 is an order of magnitude more potent than the most potent clinically used barbiturate, thiopental, and its general anesthetic EC{sub 50} approaches those for propofol and etomidate, whereas S-(+)-14 is 10-fold less potent. Furthermore, at concentrations close to its anesthetic potency, R-(-)-14 both potentiated GABA-induced currents and increased the affinity for the agonist muscimol in human {alpha}1{beta}2/3{gamma}2L GABA{sub A} receptors. Finally, R-(-)-14 was found to be an exceptionally efficient photolabeling reagent, incorporating into both {alpha}1 and {beta}3 subunits of human {alpha}1{beta}3 GABAA receptors. These results indicate R-(-)-14 is a functional general anesthetic that is well-suited for identifying barbiturate binding sites on Cys-loop receptors.

  18. Complex coacervates of hyaluronic acid and lysozyme

    DEFF Research Database (Denmark)

    Water, Jorrit J.; Schack, Malthe M.; Velazquez-Campoy, Adrian;

    2014-01-01

    Complex coacervates of hyaluronic acid and lysozyme, a model protein, were formed by ionic interaction using bulk mixing and were characterized in terms of binding stoichiometry and protein structure and stability. The complexes were formed at pH 7.2 at low ionic strength (6 mM) and the binding...... stoichiometry was determined using solution depletion and isothermal titration calorimetry. The binding stoichiometry of lysozyme to hyaluronic acid (870 kDa) determined by solution depletion was found to be 225.9 ± 6.6 mol, or 0.1 bound lysozyme molecules per hyaluronic acid monomer. This corresponded well...... with that obtained by isothermal titration calorimetry of 0.09 bound lysozyme molecules per hyaluronic acid monomer. The complexation did not alter the secondary structure of lysozyme measured by Fourier-transform infrared spectroscopy overlap analysis and had no significant impact on the Tm of...

  19. Simultaneous detection of morphine and barbiturates in urine by radioimmunoassay

    International Nuclear Information System (INIS)

    This report describes a radioimmunoassay for the simultaneous detection of morphine and barbiturates. Morphine and barbiturate antibodies, obtained from goats, were mixed with 125I-labeled antigens. By adjusting concentrations of the morphine and barbiturate antibodies and radiolabeled antigens, closely superimposed standard curves for the two drugs would be obtained. As a consequence, similar response curves were obtained for urine specimens containing morphine or barbiturates. Although concentrations as low as 25 μg/liter could be measured, to ensure against false positive reactions the test should be performed at the 100 μg/liter concentration. Unknown samples positive by the dual assay were confirmed by separately testing the specimens with the individual radioimmunoassay specific for morphine or barbiturate. Equivalency tests of urines positive for morphine, positive for barbiturates, or negative for both demonstrated complete correlation between the single and dual assays. The mixed reagent retained its sensitivity and specificity for at least three months when stored at 4 or 250C. The dual radioimmunoassay is a rapid, simple procedure that can be adapted to automated processes and that is suitable for large- and small-scale screening

  20. Pyrole-substituted barbituric derivatives as pharmaceutically significant compounds and intermediates

    International Nuclear Information System (INIS)

    Pyrrole- and indolecarbaldehydes are condensed with 5-unsubstituted barbituric acids targeting 16 new heterocyclic structures with a prospective pharmacological profile. So 1H-2-pyrrolecarbaldehyde, diethyl 5-formyl-3-methyl-1H-2,4-pyrroledicarboxylate, ethyl 5-formy 1-2,4-dimethyl-l.fl'-3-pyrrolecarboxylate, ethyl 4-formyl-3,5-dimethyl-1H-2-pyrrolecarboxylate, ethyl 4-formyl-2,5-dimethyl-1H-3-pyrrolecarboxylate and l-acetyl-1H-3-indolecarbaldehyde have been condensed in a molar ratio with hexahydro-2,4,6-pyrimidinetrione (barbituric acid) and its 1,3-dimethyl-, 1,3-diphenyl- and 1,3-dicyclohexyl- derivatives. The synthesis takes place in ethanol (or in ethanol/water in the cases of unsubstituted barbituric acid) within several hours at 200 - 600 C in the absence of any catalyst with yields in the range of 70-95%. An insufficient carbonyl activity of N-unsubstituted indole-3-carbaldehyde has been observed and overcome by a preliminary N-acethylation avoiding the inactive vinylene-carboxamide form. In addition to their pharmaceutical significance based on the interaction of two heterocyclic pharmacophores, the condensation products could also be useful as versatile intermediates for further synthesis of new heterocyclic systems. The synthesis of 5-[(4-acetyl-3,5-dimethyl-1H-2-pyrrolyl)(l-acetyl-1H-3-indolyl)methyl] hexahydr= o-2,4,6-pyrimidinetrione (60% in enol-form according to 1H-NMR) by refluxing of [(1-acetyl-1H-3-indolyl) methylene]hexahydro-2,4,6-pyrimidinetrione] and 3-acethyl-2,4-dimethylpyrrole for 6 h in CH3CN illustrates their capability to add C-nucleophiles to the double bound bridging 3 heterocyclic units together. The new 17 products are TLC pure and their structures are proved by 1H-NMR/IR-spectra which interpretation is displayed. (authors)

  1. A Complexity View of Acid Deposition

    Institute of Scientific and Technical Information of China (English)

    朱建林; 方见树

    2003-01-01

    We show that acid deposition is analogous to complex systems composed of a series of interconnected components.Frequency-size distributions of weekly hydrogen deposition (WHD) of precipitation are consistent with double power-law in two different regimes separated by a crossover WHD. The distribution of variations in acid deposition over a week interval is remarkably symmetrical, with long tail extending over eight orders of magnitude. The acid deposition fluctuations exhibit fractal Brown motion with two different temporal scaling regimes and long-range correlation exists in the series. The power-laws in the acid deposition dynamics are considered to be indicators of seff-organization of atmosphere under environmental pollution stress.

  2. Nucleobase-based barbiturates: their protective effect against DNA damage induced by bleomycin-iron, antioxidant, and lymphocyte transformation assay.

    Science.gov (United States)

    Dhorajiya, Bhaveshkumar D; Dholakiya, Bharatkumar Z; Ibrahim, Ahmed S; Badria, Farid A

    2014-01-01

    A number of nucleobase-based barbiturates have been synthesized by combination of nucleic acid bases and heterocyclic amines and barbituric acid derivatives through green and efficient multicomponent route and one pot reaction. This approach was accomplished efficiently using aqueous medium to give the corresponding products in high yield. The newly synthesized compounds were characterized by spectral analysis (FT-IR, (1)H NMR, (13)C NMR, HMBC, and UV spectroscopy) and elemental analysis. Representative of all synthesized compounds was tested and evaluated for antioxidant, bleomycin-dependent DNA damage, and Lymphocyte Transformation studies. Compounds TBC > TBA > TBG showed highest lymphocyte transformation assay, TBC > TBA > BG showed inhibitory antioxidant activity using ABTS methods, and TBC > BPA > BAMT > TBA > 1, 3 -TBA manifested the best protective effect against DNA damage induced by bleomycin. PMID:24900997

  3. Identifying barbiturate binding sites in a nicotinic acetylcholine receptor with [3H]allyl m-trifluoromethyldiazirine mephobarbital, a photoreactive barbiturate.

    Science.gov (United States)

    Hamouda, Ayman K; Stewart, Deirdre S; Chiara, David C; Savechenkov, Pavel Y; Bruzik, Karol S; Cohen, Jonathan B

    2014-05-01

    At concentrations that produce anesthesia, many barbituric acid derivatives act as positive allosteric modulators of inhibitory GABAA receptors (GABAARs) and inhibitors of excitatory nicotinic acetylcholine receptors (nAChRs). Recent research on [(3)H]R-mTFD-MPAB ([(3)H]R-5-allyl-1-methyl-5-(m-trifluoromethyldiazirinylphenyl)barbituric acid), a photoreactive barbiturate that is a potent and stereoselective anesthetic and GABAAR potentiator, has identified a second class of intersubunit binding sites for general anesthetics in the α1β3γ2 GABAAR transmembrane domain. We now characterize mTFD-MPAB interactions with the Torpedo (muscle-type) nAChR. For nAChRs expressed in Xenopus oocytes, S- and R-mTFD-MPAB inhibited ACh-induced currents with IC50 values of 5 and 10 µM, respectively. Racemic mTFD-MPAB enhanced the equilibrium binding of [(3)H]ACh to nAChR-rich membranes (EC50 = 9 µM) and inhibited binding of the ion channel blocker [(3)H]tenocyclidine in the nAChR desensitized and resting states with IC50 values of 2 and 170 µM, respectively. Photoaffinity labeling identified two binding sites for [(3)H]R-mTFD-MPAB in the nAChR transmembrane domain: 1) a site within the ion channel, identified by photolabeling in the nAChR desensitized state of amino acids within the M2 helices of each nAChR subunit; and 2) a site at the γ-α subunit interface, identified by photolabeling of γMet299 within the γM3 helix at similar efficiency in the resting and desensitized states. These results establish that mTFD-MPAB is a potent nAChR inhibitor that binds in the ion channel preferentially in the desensitized state and binds with lower affinity to a site at the γ-α subunit interface where etomidate analogs bind that act as positive and negative nAChR modulators. PMID:24563544

  4. Complex Pharmacology of Free Fatty Acid Receptors

    DEFF Research Database (Denmark)

    Milligan, Graeme; Shimpukade, Bharat; Ulven, Trond;

    2016-01-01

    G protein-coupled receptors (GPCRs) are historically the most successful family of drug targets. In recent times it has become clear that the pharmacology of these receptors is far more complex than previously imagined. Understanding of the pharmacological regulation of GPCRs now extends beyond...... pharmacology have shaped understanding of the complex pharmacology of receptors that recognize and are activated by nonesterified or "free" fatty acids (FFAs). The FFA family of receptors is a recently deorphanized set of GPCRs, the members of which are now receiving substantial interest as novel targets for...... the treatment of metabolic and inflammatory diseases. Further understanding of the complex pharmacology of these receptors will be critical to unlocking their ultimate therapeutic potential....

  5. Comparative Actions of Barbiturates Studied by Pollen Grain Germination.

    Science.gov (United States)

    Kordan, Herbert A.; Mumford, Pauline M.

    1979-01-01

    Describes a simple experimental system whereby the comparative actions of long, medium, and short-acting barbiturates can be demonstrated in a relatively short period of time under optical microscopy using pollen grains as the biological test or assay system. (Author/HM)

  6. Biotransformation of plutonium complexed with citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Francis, A.J.; Dodge, C.J.; Gillow, J.B. [Environmental Sciences Department, Brookhaven National Laboratory, Upton, New York, 11973 (United States)

    2005-07-01

    Full text of publication follows: The presence of organic ligands in radioactive wastes is a major concern because of the potential for increasing the transport of radionuclides from disposal sites. Microorganisms present in radioactive wastes can affect the long-term stability of radionuclides associated with organic ligands. Biotransformation of radionuclides complexed with organic ligands should result in the precipitation of the radionuclides and retard their migration. In this study we investigated the biotransformation of {sup 242}Pu{sup 4+} (10{sup -8} to 10{sup -5} M) in the presence of equimolar and excess citric acid by Pseudomonas fluorescens. Analysis of {sup 242}Pu-citrate by electro-spray ionization-mass spectrometry (ESI-MS) indicated the presence of a bi-ligand Pu-cit{sub 2} complex. Analysis of Th-citrate complex, an analog for Pu-citrate, indicated the formation of a 2:3 complex. Citric acid under aerobic conditions was metabolized by P. fluorescens at a rate of 4.9 {mu}M/h, and decreased to 4.0 and 3.8 {mu}M/h in the presence of 10{sup -8} and 10{sup -6} M of Pu, respectively. The pH of the medium containing citric acid alone increased from 6.5 to 7.1, while the pH of the samples containing Pu increased from 6.8 to 7.9. The high ionic strength (0.9 M) of the medium reduced citric acid metabolism by 50% in comparison to 0.1 M ionic strength. Initially, Pu added to the growth medium as Pu-citrate remained in solution as Pu{sup 4+}. Selective solvent extraction by thenyl-tri-fluoro-acetone (TTA) as well as micro-filtration (0.03 {mu}m) of the medium after biodegradation studies indicated that Pu was present as the polymeric form. The Pu polymer formation was dependent on the Pu:citrate ratio as well as the extent of citrate metabolism. The high ionic strength solution containing 10{sup -5} M 1:1 Pu-citrate complex showed only 27% citrate degradation but had the highest percentage ({approx}80%) of polymer formation, suggesting the Pu was soluble only

  7. Biotransformation of plutonium complexed with citric acid

    International Nuclear Information System (INIS)

    Full text of publication follows: The presence of organic ligands in radioactive wastes is a major concern because of the potential for increasing the transport of radionuclides from disposal sites. Microorganisms present in radioactive wastes can affect the long-term stability of radionuclides associated with organic ligands. Biotransformation of radionuclides complexed with organic ligands should result in the precipitation of the radionuclides and retard their migration. In this study we investigated the biotransformation of 242Pu4+ (10-8 to 10-5 M) in the presence of equimolar and excess citric acid by Pseudomonas fluorescens. Analysis of 242Pu-citrate by electro-spray ionization-mass spectrometry (ESI-MS) indicated the presence of a bi-ligand Pu-cit2 complex. Analysis of Th-citrate complex, an analog for Pu-citrate, indicated the formation of a 2:3 complex. Citric acid under aerobic conditions was metabolized by P. fluorescens at a rate of 4.9 μM/h, and decreased to 4.0 and 3.8 μM/h in the presence of 10-8 and 10-6 M of Pu, respectively. The pH of the medium containing citric acid alone increased from 6.5 to 7.1, while the pH of the samples containing Pu increased from 6.8 to 7.9. The high ionic strength (0.9 M) of the medium reduced citric acid metabolism by 50% in comparison to 0.1 M ionic strength. Initially, Pu added to the growth medium as Pu-citrate remained in solution as Pu4+. Selective solvent extraction by thenyl-tri-fluoro-acetone (TTA) as well as micro-filtration (0.03 μm) of the medium after biodegradation studies indicated that Pu was present as the polymeric form. The Pu polymer formation was dependent on the Pu:citrate ratio as well as the extent of citrate metabolism. The high ionic strength solution containing 10-5 M 1:1 Pu-citrate complex showed only 27% citrate degradation but had the highest percentage (∼80%) of polymer formation, suggesting the Pu was soluble only in the presence of excess citric acid. However, the extensive

  8. Synthesis and Evaluation of Changes Induced by Solvent and Substituent in Electronic Absorption Spectra of New Azo Disperse Dyes Containig Barbiturate Ring

    OpenAIRE

    Hooshang Hamidian; Najmeh Zahedian; Dadkhoda Ghazanfari; Samieh Fozooni

    2013-01-01

    Six azo disperse dyes were prepared by diazotizing 4-amino hippuric acid and coupled with barbituric acid and 2-thiobarbituric acid. Then, the products were reacted with aromatic aldehyde, sodium acetate, and acetic anhydride, and oxazolone derivatives were formed. Characterization of the dyes was carried out by using UV-Vis, FT-IR, 1H NMR and 13C NMR, and mass spectroscopic techniques. The solvatochromic behavior of azo disperse dyes was evaluated in various solvents. The effects of substitu...

  9. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nicotinamide-ascorbic acid complex. 172.315 Section... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed...

  10. Complex formation of calcium with humic acid and polyacrylic acid

    International Nuclear Information System (INIS)

    In order to understand the migration behavior of radionuclides in the underground, it is also important to estimate the effect of the competing cations originally present in the groundwater. In this connection, the complexation of Ca(II) with Aldrich humic acid has been examined. For the study at trace concentrations (∝ 10-10 M) of Ca(II), the solvent extraction of 45Ca with TTA and TOPO in cyclohexane has been used. At macro concentrations (10-4 M) of Ca(II), the measurement of the free Ca2+ ion concentration with a calcium selective electrode has been conducted. To estimate the polyelectrolyte effect of humic acid separately from its heterogeneous composition effect, polyacrylic acid ([-CH2CH(COOH)-]n) has been selected as a representative of the homogeneous polymeric weak acids and its complexation with Ca(II) has also been examined. The values of log βα have been obtained at pH 5 ∝ 7 in 0.1, 0.4 and 1.0 M NaCl, where βα is the apparent formation constants defined by βα = [ML]/([M][R]). In this definition, [ML] and [M] are the concentrations of bound and free Ca2+ respectively, [R] is the concentration of dissociated proton exchanging sites. log βα of humate decreases from 2.19 ∝ 2.92 (depending on pH and ionic strength 1.0 α of polyacrylate (1.36 ∝ 3.24 for I = 0.1 ∝ 1.0). For both humate and polyacrylate, log βα decreases linearly with log[Na+], where [Na+] is the bulk concentration of sodium ion. Their dependences of log βα on ionic strength are stronger than those of log β of monomeric carboxylates such as oxalate and EDTA, indicating the large electrostatic effect of crowded negative charges on the macromolecules of humic or polyacrylic acid. (orig.)

  11. Evidence against the Bm1P1 protein as a positive transcription factor for barbiturate-mediated induction of cytochrome P450BM-1 in bacillus megaterium.

    Science.gov (United States)

    Shaw, G C; Sung, C C; Liu, C H; Lin, C H

    1998-04-01

    The Bm1P1 protein was previously proposed to act as a positive transcription factor involved in barbiturate-mediated induction of cytochrome P450BM-1 in Bacillus megaterium. We now report that the bm1P1 gene encodes a protein of 217 amino acids, rather than the 98 amino acids as reported previously. In vitro gel shift assays indicate that the Bm1P1 protein did not interact with probes comprising the regulatory regions of the P450BM-1 gene. Moreover, disruption of the bm1P1 gene did not markedly affect barbiturate induction of P450BM-1 expression. A multicopy plasmid harboring only the P450BM-1 promoter region could increase expression of the chromosome-encoded P450BM-1. The level of expression is comparable with that shown by a multicopy plasmid harboring the P450BM-1 promoter region along with the bm1P1 gene. These results strongly suggest that the Bm1P1 protein is unlikely to act as a positive regulator for barbiturate induction of P450BM-1 expression. Finally, deletion of the Barbie box did not markedly diminish the effect of pentobarbital on expression of a reporter gene transcriptionally fused to the P450BM-1 promoter. This suggests that the Barbie box is unlikely to be a key element in barbiturate-mediated induction of P450BM-1. PMID:9525898

  12. Ni(II) complexes of dithiophosphonic acids

    Indian Academy of Sciences (India)

    Afshin Saadat; Alireza Banaee; Patrick McArdle; Karim Zare; Khodayar Gholivand; Ali Asghar Ebrahimi Valmoozi

    2014-07-01

    The reaction of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson reagent) with isobutanol, cyclohexylamine and phenylethylamine produced (4-methoxy-phenyl)-phosphonodithioic acid o-isobutyl ester HS2P(p-C6H4OMe) (OCH2CH(CH3)2) (I), [S2P(C6H11NH)(p-C6H4OMe) H3N+C6H11] (II) and [S2P(phCH2CH2NH) (p-C6H4OMe)H3N+CH2CH2ph] (III), respectively. The reaction of alcohol with Lawesson reagent produced neutral product (I) while that with amines led to an ion pair (II, III). Furthermore, reaction of I, II and III with NiCl2.6H2O in methanol produced novel complexes: IV, V and VI. The compounds were characterized by 1H, 13C and 31P NMR, IR spectroscopy and elemental analysis. The single crystal X-ray structures of IV and V showed that the nickel complexes are square planar. Compound V formed a three-dimensional supramolecular structure via intermolecular P-O…H-N hydrogen bonds. The Xray crystallography of V showed that those three hydrogens of +NH3 cation produced three hydrogen bonds with different distances. The new compounds were additionally tested in view of their anti-bacterial properties. The ligands containing amine substituents exhibited more activity toward tested bacteria than their alcohol substituents, while the Ni(II) complexes including alcohol substituents exhibited high potential.

  13. Application of thermoresponsive HPLC to forensic toxicology: determination of barbiturates in human urine

    OpenAIRE

    Kanno, Sanae; Watanabe, Kanako; Hirano, Seishiro; Yamagishi, Itaru; Gonmori, Kunio; Minakata, Kayoko; Suzuki, Osamu

    2009-01-01

    A high-performance liquid chromatography (HPLC) method has been developed for the assays of five barbiturates in human urine using a new thermoresponsive polymer separation column, which is composed of N-isopropylacrylamide polymer. According to elevating the column temperature from 10 ℃ to 50 ℃, five barbiturates, such as metharbital, primidone, phenobarbital, mephobarbital and pentobarbital, became well separated by this method. Five barbiturates showed good linearity in the range of 0.2-10...

  14. Sm(II)-Mediated Electron Transfer to Carboxylic Acid Derivatives: Development of Complexity-Generating Cascades.

    Science.gov (United States)

    Just-Baringo, Xavier; Procter, David J

    2015-05-19

    Reductive electron transfer (ET) to organic compounds is a powerful method for the activation of substrates via the formation of radicals, radical anions, anions, and dianions that can be exploited in bond-cleaving and bond-forming processes. Since its introduction to the synthetic community in 1977 by Kagan, SmI2 has become one of the most important reducing agents available in the laboratory. Despite its widespread application in aldehyde and ketone reduction, it was widely accepted that carboxylic acid derivatives could not be reduced by SmI2; only recently has our work led to this dogma being overturned, and the reduction of carboxylic acid derivatives using SmI2 can now take its place alongside aldehyde/ketone reduction as a powerful activation mode for synthesis. In this Account, we set out our studies of the reduction of carboxylic acid derivatives using SmI2, SmI2-H2O, and SmI2-H2O-NR3 and the exploitation of the unusual radical anions that are now accessible in unprecedented carbon-carbon bond-forming processes. The Account begins with our serendipitous discovery that SmI2 mixed with H2O is able to reduce six-membered lactones to diols, a transformation previously thought to be impossible. After the successful development of selective monoreductions of Meldrum's acid and barbituric acid heterocyclic feedstocks, we then identified the SmI2-H2O-NR3 reagent system for the efficient reduction of a range of acyclic carboxylic acid derivatives that typically present a significant challenge for ET reductants. Mechanistic studies have led us to propose a common mechanism for the reduction of carboxylic acid derivatives using Sm(II), with only subtle changes observed as the carboxylic acid derivative and Sm(II) reagent system are varied. At the center of our postulated mechanism is the proposed reversibility of the first ET to the carbonyl of carboxylic acid derivatives, and this led us to devise several strategies that allow the radical anion intermediates to be

  15. Mixed-metal hydroxycarboxylic acid complexes

    International Nuclear Information System (INIS)

    Formation constants for mixed-metal complexes, Kmmc, between uranium(VI), as the central metal ion, and each one of the metal ions, iron(III), aluminium(III), indium(III) and copper(II) have been determined using data from potentiometric measurements. In each case one of the hydroxycarboxylic acids, citric, tartaric or malic, was used as a ligand. At 298.15 K the values of -log Kmmc for the investigated systems are uranyl iron(II) citrate, 2.45; uranyl iron(III) malate, 7.37; uranyl aluminium(III) citrate, 8.21; uranyl aluminium(III) tartarate, >12; uranyl aluminium(III) malate, 8.06; uranyl indium(III) citrate, 11.3; uranyl indium(III) tartarate, 7.88; uranyl indium(III) malate, 7.45; uranyl copper(II) citrate -1.41; uranyl copper(II) tartarate, -1.17; and uranyl copper(II) malate, -1.11. (author)

  16. Simultaneous Effect of Organic Modifier and Physicochemical Parameters of Barbiturates on their Retention on a Narrow-Bore PGC Column. Part 2

    OpenAIRE

    Cserháti, Tibor; Szőgyi, Maria

    2011-01-01

    The retention time of 23 barbituric acid derivatives was determined on an narrow-bore porous graphitized carbon (PGC) column employing water-dioxane mixtures as mobile phases. The retention fac-tor (k), theoretical plate number (N), and asymmetry factor (AF) were computed for each analyte in each mobile phase. Quantitative structure-retention relationship (QSRR) calculations using stepwise regression analysis (SRA) demonstrated the binding of analytes to the surface of PGC stationary phase is...

  17. Chemodynamics of soft nanoparticulate complexes: Cu(II) and Ni(II) complexes with fulvic acids and aquatic humic acids

    NARCIS (Netherlands)

    Town, R.M.; Leeuwen, van H.P.; Buffle, J.

    2012-01-01

    The dynamics of metal complexation by small humic substances (fulvic acid and aquatic humic acid, collectively denoted as "fulvic-like substance", FS) are explored within the framework of concepts recently developed for soft nanoparticulate complexants. From a comprehensive collection of published e

  18. Photodissociation spectroscopy of the Mg+-acetic acid complex

    International Nuclear Information System (INIS)

    We have studied the structure and photodissociation of Mg+-acetic acid clusters. Ab initio calculations suggest four relatively strongly bound ground state isomers for the [MgC2H4O2]+ complex. These isomers include the cis and trans forms of the Mg+-acetic acid association complex with Mg+ bonded to the carbonyl O atom of acetic acid, the Mg+-acetic acid association complex with Mg+ bonded to the hydroxyl O atom of acetic acid, or to a Mg+-ethenediol association complex. Photodissociation through the Mg+-based 3p+, MgOH+, Mg(H2O)+, CH3CO+, and MgCH3+. At low energies the dominant reactive quenching pathway is through dehydration to Mg(H2O)+, but additional reaction channels involving C-H and C-C bond activation are also open at higher energies

  19. Complexes of low oxidated /sup 99/Tc with salicylic acid

    International Nuclear Information System (INIS)

    While several complexes of technetium with hydroxycarboxylic acids in solution are well known, little has been done about complexes of technetium with phenolcarboxylic acids. M.A. Kayssi suggested the use of sulphosalicylic acid as a reagent for the quantitative determination of technetium. The resulting complex shows a spectrophotometric maximum at 460 nm; the author supposes that the complex could contain technetium in the (V) oxidation state. In this paper the reaction between technetium and salicylic acid at concentrations between 10/sup -4/ and 5 x 10/sup -2/ M, in a pH range of 2 to 4.5, has been studied. The pH does not seem to influence the reaction, while the salicylic acid concentration is particularly significant

  20. Flotation extraction of rhodanide indium complexes from acidic solutions

    International Nuclear Information System (INIS)

    Principle possibility of flotation extraction of indium rhodanide complexes from acid solutions (H2SO4, HCl, HBr, HF, HNO3, HI, H3PO4, CH3COOH, HClO4) is shown. Optimum conditions for their extraction are created in the range of moderate (0.01-0.1 g-eq./l acid in solution) acidity when using quaternary compounds, containing from 13 to 18 carbon atoms in the alkyl part as collectors. It is established experimentally that indium is extracted from weakly acidic solutions in the form of mixed complex anions according to ion exchange mechanism, from strong acidic ones - mainly in the form of acid complexes similar to addition reactions

  1. Studies On Some Acid Divalent-Metal Nitrilotriacetate Complexes

    Directory of Open Access Journals (Sweden)

    N. E. Milad

    2000-10-01

    Full Text Available IR and 1H-NMR studies on nitrilotriacetic acid (H3NTA suggest that the acid exists in the zwitterion form, which allows the existence of intermolecular hydrogen bonding. A tetrahedral structure is established for eleven (1:1 anhydrous acid-metal (II nitrilotriacetates complexes. The ten Dq values for the colored complexes were determined spectrophotometrically. The pKa values for the eleven acid metal complexes [M(HNTA].(OH23] were determined and compared with the corresponding pKa values of the [M(OH2n]+2 ions and also with the log β1 values of the corresponding [M(NTA]- complexes. X-ray diffraction studies on the ligand and on eight of these complexes are described.

  2. Spectral, magnetic, and thermal properties of some thiazolylazo complexes

    Energy Technology Data Exchange (ETDEWEB)

    Masoud, M. S.; Mohamed, G. B.; Abdulrazek, Y. H.; Ali, A. E. [Alexandria Univ., Alexandria (Egypt); Khairy, F. N. [Ahfad Univ. for Women, Omderman (Sudan)

    2002-04-01

    The thiazolylazo compounds and their Co(II), Ni(II) and Cu(II) complexes of barbituric acid, uracil, thiouracil, citrazinic acid, chromotropic acid, gallic acid, pyrogallol and salicylic acid were prepared and characterized by {sup 1}H NMR, IR and the effect of pH on the electronic absorption spectra. The mode of ionization, the electronic transitions and the dissociation constants were discussed. The stoichiometries of the complexed were of 1:1, 2:1 and 3:2 (M:L). The copper complexes are of isotropic ESR spectra (except that of gallic acid which showed a complicated one) and are of magnetically diluted behavior with orbital contribution. Detailed DTA data were obtained and discussed.

  3. Starch-lipid complexes: Interesting material and applications from amylose-fatty acid salt inclusion complexes

    Science.gov (United States)

    Aqueous slurries of high amylose starch can be steam jet cooked and blended with aqueous solutions of fatty acid salts to generate materials that contain inclusion complexes between amylose and the fatty acid salt. These complexes are simply prepared on large scale using commercially available steam...

  4. Characterization and complexation of humic acids. Part 1

    International Nuclear Information System (INIS)

    This paper summarizes the research contributions to the CEC Mirage II project, particularly the research area on complexation and colloids (COCO). The first part of the paper comprises the characterization of humic and fulvic acids from different origins: a commercial product from the Aldrich Co. used as a reference humic acid and site-specific humic acids from Gorleben (Germany), Boom Clay (Belgium) and Fanay Augeres (France) aquifer systems. The second part includes the complexation of trivalent actinides: Am(III) and Cm(III) with various humic acids. A number of different methods have been applied for the complexation study: spectrophotometry, ultrafiltration, laser-induced photo-acoustic spectroscopy (LPAS) and time-resolved laser fluorescence spectroscopy (TRLFS). The evaluation process of complexation constant is discussed extensively and the well consolidated results are presented, which can be directly used for the geochemical modelling of the radionuclide migration

  5. Investigation of neodymium complexes with hydroxyethyliminodiacetic acid by spectrography

    International Nuclear Information System (INIS)

    The electron absorption spectra of NdCl3 solution in the presence of oxyethylimidinodiacetic acid (H2L) in a wide range of pH (1.35-11) were studied. It is shown by the isomolar series method that neodymium forms mono-, di- and sesquialteral complexes with H2L. The absorption spectra of the corresponding solid and dissolved complexes of neodymium with oxyethyliminodiacetic acid were investigated

  6. Composition of nitrosyl ruthenium complexes in nitric acid

    International Nuclear Information System (INIS)

    The composition of nitrosyl ruthenium complexes in nitric acid has been determined. The analysis was carried out by low temperature, gradient elution, reversed-phase partition chromatography. Paper chromatography, using methyl isopropyl ketone and nitric acid-acetone, were also carried out to obtain complementary data. (author)

  7. Stability constant of the lanthanum complex with humic acid

    International Nuclear Information System (INIS)

    The work described here is a study on the formation of trivalent lanthanum complex with humic acid. Commercial humic acid was purified and then characterized by various analytical techniques. The stability constant determined by a radiochemical method has a worth of log βLa,AHA = 13.6. (Author)

  8. Uranyl complexes of n-alkanediaminotetra-acetic acids

    International Nuclear Information System (INIS)

    The uranyl complexes of n-propanediaminetetra-acetic acid, n-butanediaminetetra-acetic acid and n-hexanediaminetetra-acetic acid have been studied by potentiometry, with computer evaluation of the titration data by the MINIQUAD program. Stability constants of the 1:1 and 2:1 metal:ligand chelates have been determined as well as the respective hydrolysis and polymerization constants at 25 deg in 0.10M and 1.00M KNO3. The influence of the length of the alkane chain of the ligands on the complexes formed is discussed. (author)

  9. Investigation into neodymium complexes with methylmalonic acid by spectrography

    International Nuclear Information System (INIS)

    Complexes of neodymium with methylmalonic acid have been studied spectrographically. It has been shown that aquoion and three dimeric complexes of the composition approximately 1:1 coexist in the pH region 3.5-6.5 when the ratio between the components is equimolar. When there is an excess of the ligand, polymeric complexes of the composition 1:2 are found in the solution in addition to the complexes 1:1. The stability constants of the complexes have been determined and the data on their structure have been obtained

  10. Acrylic acid obtaining from methanol and acetic acid in the presence of complex oxide catalysts

    OpenAIRE

    Небесний, Роман Володимирович; Піх, Зорян Григорович; Шпирка, Ірина Іванівна; Івасів, Володимир Васильович; Небесна, Юлія Віталіївна; Фуч, Уляна Василівна

    2015-01-01

    The purpose of this work is to research process of single-stage acrylic acid obtaining from methanol and acetic acid, namely: to develop effective catalysts for the process of methanol oxidation to formaldehyde with its further aldol condensation with acetic acid to acrylic acid, and to determine optimum conditions for the process. Complex oxide catalysts consisting of oxides of boron, phosphorus, tungsten and vanadium supported on the silica gel have been investigated. The effect of vanadium...

  11. Respiratory depression in rats induced by alcohol and barbiturate and rescue by ampakine CX717

    OpenAIRE

    Ren, Jun; Ding, Xiuqing; Greer, John J

    2012-01-01

    Barbiturate use in conjunction with alcohol can result in severe respiratory depression and overdose deaths. The mechanisms underlying the additive/synergistic actions were unresolved. Current management of ethanol-barbiturate-induced apnea is limited to ventilatory and circulatory support coupled with drug elimination. Based on recent preclinical and clinical studies of opiate-induced respiratory depression, we hypothesized that ampakine compounds may provide a treatment fo...

  12. Simultaneous detection of morphine and barbiturates in urine by radioimmunoassay. [/sup 125/I

    Energy Technology Data Exchange (ETDEWEB)

    Usategui-Gomez, M.; Heveran, J.E.; Cleeland, R.; McGhee, B.; Telischak, Z.; Awdziej, T.; Grunberg, E.

    1975-09-01

    This report describes a radioimmunoassay for the simultaneous detection of morphine and barbiturates. Morphine and barbiturate antibodies, obtained from goats, were mixed with /sup 125/I-labeled antigens. By adjusting concentrations of the morphine and barbiturate antibodies and radiolabeled antigens, closely superimposed standard curves for the two drugs would be obtained. As a consequence, similar response curves were obtained for urine specimens containing morphine or barbiturates. Although concentrations as low as 25 ..mu..g/liter could be measured, to ensure against false positive reactions the test should be performed at the 100 ..mu..g/liter concentration. Unknown samples positive by the dual assay were confirmed by separately testing the specimens with the individual radioimmunoassay specific for morphine or barbiturate. Equivalency tests of urines positive for morphine, positive for barbiturates, or negative for both demonstrated complete correlation between the single and dual assays. The mixed reagent retained its sensitivity and specificity for at least three months when stored at 4 or 25/sup 0/C. The dual radioimmunoassay is a rapid, simple procedure that can be adapted to automated processes and that is suitable for large- and small-scale screening. (auth)

  13. Complex forming properties of natural organic acids. Pt. 2

    International Nuclear Information System (INIS)

    An ultrafiltration technique combined with ion-selective-electrode and atomic absorption methods have been employed to obtain information on the complex forming properties of fulvic acid with iron and calcium. A model for interpreting complexation of metal ions to fulvic acid at any pH, medium ionic strength and metal to fulvic acid ratio developed earlier has been used in an attempt to predict the nature of iron and calcium interaction to Armadale Horizon Bh fulvic acid. Binding of calcium to fulvic acid which is enhanced at pHs greater than 6.0 has reasonably been predicted by the model taking into consideration complications due to the polyelectrolyte nature and the heterogeneity of the fulvic acid. The lack of agreement observed between the model predicted binding behavior and the experimentally observed results for the fulvic acid-iron system has been attributed to the formation of metal-induced aggregation. Reduction of Fe(III) to Fe(II) by the fulvic acid as reported by other workers is corroborated. (orig.)

  14. Phase Chemistry of the Complexes of RE Amino Acids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Forty-three phase diagrams of ternary system concerning rare earth salts, α-amino acids and water, which were constructed by phase equilibrium methods, were expounded. The influences of the factors such as cations, anions, the structure of amino acids, temperature on the phase diagrams were discussed. Under the guidance of phase equilibrium results, over 150 new solid complexes were prepared. IR, reflecting, UV, FS, and Raman spectra for these complexes were investigated and the regularity of “tripartite effect”, “tetrad effect”, “Nephelanxetic effect”, “Oddo-Harkins” was observed. Thermal decomposition processes of the complexes were confirmed. Based on the comparison with the known crystal structures of rare earth-amino acid-complexes, an estimation method for predicting the crystal structure data of series complexes was founded. The constant volume combustion energies of the complexes were determined by RBC-1 type rotating bomb calorimeter. The standard enthalpies of combustion and standard enthalpies of formation were calculated for these complexes.

  15. Formation constants of mixed ligand complexes of oxovanadium(IV) with salicylic acid/5-sulphosalicylic acid/8-hydroxyquinoline-5-sulphonic acid and hippuric acid

    International Nuclear Information System (INIS)

    Equilibrium studies are described on the interaction of oxovanadium(IV) with salicylic acid (SA)/5-sulphosalicylic acid (SSA)/8-hydroxyquinoline-5-sulphonic acid (HQSA) in presence of hippuric acid. The formation of 1:1:1 mixed ligand complexes and their hydroxo derivatives inferred from the pH-metric titration curves and formation constants of 1:1:1 ternary complexes have been evaluated at 30 +- 0.5deg (μ = 0.1 M KNO3). The order of stability of ternary complexes has been found to be the same as that of 1:1 binary complexes involving hydroxy acids. (author)

  16. Spectrographic investigation of neodymium complexing with hexamethylenediaminetetraacetic acid

    International Nuclear Information System (INIS)

    Complex formation between neodymium and hexamethylenediamine-tetraacetic acid (HMTA, H2L) in aqueous solution has been studied by high-resolution spectrography. Formation of NdHL, Hd(HL)23-, Nd(HL)36- complexes has been proved, their values of formation constants (lg Csub(form)) being equal to 5.63+-0.45, 4.20+-0.15, 2.63+-0.15, respectively

  17. Complexation of the uranyl ion with aquatic humic acid

    International Nuclear Information System (INIS)

    The complexation of the uranyl(VI) ion with aquatic humic acid from Gorleben groundwater (Gohy-573) is studied in 0.1 M NaClO4 at pH 4 under argon atmosphere. The concentration range investigated is from 1 x 10-7 to 1 x 10-5 mol/l for the uranyl ion and from 1 x 10-6 to 1.12 x 10-5 mol/l for the humic acid. Three different experimental methods are applied to separate the uncomplexed uranyl ion from the uranyl humate complex, using differences of the two species in size by ultrafiltration at the pore size of about 1 nm, in charge by anion exchange separation and in spectroscopic properties by time resolved laser fluorescence spectroscopy (TRLFS). No reduction of U(VI) to U(IV) is observed in the course of the humate complexation process. The experimental results confirm that the prevailing complexation reaction is charge neutralization of the UO2+2 ion with two proton exchanging sites of humic acid. At pH 4 in 0.1 M NaClO4, where the hydrolysis of the uranyl ion appears negligible, the fraction of proton exchanging sites of the humic acid that can be occupied by the uranyl ion (called the loading capacity (LC) of the uranyl ion) is determined to be 0.185±0.003. The complexation constant evaluated by taking the loading capacity into account is found to be logβ = 6.16±0.13, which is a grand average of all values determined by the three experimental procedures under consideration. This value is valid for the humate complexation of the non-hydrolyzed uranyl ion, being independent of pH and ionic strength. (orig.)

  18. Protactinium(V) complexation by oxalic and diethylenetriaminepentaacetic acids

    International Nuclear Information System (INIS)

    The present work is devoted to complexation of Pa(V) with oxalic acid and DTPA. Structural data on the limiting complex have been collected by combining X-ray absorption Spectroscopy, Capillary Electrophoresis (CE-ICP-MS) and DFT calculations. Thermodynamic data have been deduced from solvent extraction experiments. XAS data registered on samples of Pa(V) in oxalic acid have revealed the presence of one single Pa-O oxo bond and 3 oxalate in a bidentate mode in the complex of maximum order. The structure optimization, performed through DFT calculations indicate that 2 oxalate lie in the equatorial plane of the Pa=O bond, whereas one oxygen of the third oxalate goes in the prolongation of the oxo bond. Stability constants of the three successive complexes were determined by solvent extraction in the TTA/toluene/H2O/Pa(V)/NaClO4/HClO4/H2C2O4 system at different temperatures and 3M ionic strength. The stability of the complexes was proved to increase with their order. CE-ICP-MS measurements on Pa/DTPA samples have indicated the formation of a neutral (1:1)limiting complex. This complex can therefore be written as Pa(DTPA). The optimized structure determined by DFT calculations allowed one to conclude that all eight donor atoms (5 O and 3 N) of the DTPA ligand are involved in the coordination of protactinium. The formation constant of this complex has been determined for different values of ionic strength and temperature. The complexation reaction of Pa(V) with DTPA was proved to be entropy controlled. (author)

  19. The complexation behavior of neptunium and plutonium with nitrilotriacetic acid

    International Nuclear Information System (INIS)

    The first stability constant of NpO2+ with nitrilotriacetic acid (NTA) was determined at four ionic strengths (I = 0.5, 1.0, 2.0, 3.0 M) by using spectrophotometry. Nonlinear least-squares data fitting identified the complex as NpO2NTA2-. The specific ion interaction (SIT) theory approximation method was used to determine the stability constants at infinite dilution. In this paper first results on Pu4+ and PuO22+ complexation with NTA are reported. The stability constant for the Pu(NTA)+ complex at I = 0.1 M is given. From results for PuO22+ complexation with NTA (I = 1 M) at pH 2-NTA-. At pH > 3, NTA partially reduced PuO22+ to PuO2+

  20. Scandium and zirconium ion complexing with salicylic acid

    International Nuclear Information System (INIS)

    A study has been made of the extraction of complexes containing scandium and zirconium compounds and salicylic acid by using benzene, nitrobenzene, chloroform and isoamyl alcohol. It is shown that in the metal concentration range 10-5-10-3 mole/l scandium forms mononuclear complexes composed of Sc(HSal)3 (pH2 (pH>4), zirconium - polynuclear complexes Zrsub(x)(OH)sub(y)(HSal)sub(n), where the x:n ratio varies from 0.5 to 1.5. Stability constants have been calculated for the salicylate scandium complexes in aqueous solution, equal to β1=(3+-1)x102; β2=(5.0+-0.6)x104; β3=(5.3+-0.3)x106

  1. Pharmacology of bile acid receptors: Evolution of bile acids from simple detergents to complex signaling molecules.

    Science.gov (United States)

    Copple, Bryan L; Li, Tiangang

    2016-02-01

    For many years, bile acids were thought to only function as detergents which solubilize fats and facilitate the uptake of fat-soluble vitamins in the intestine. Many early observations; however, demonstrated that bile acids regulate more complex processes, such as bile acids synthesis and immune cell function through activation of signal transduction pathways. These studies were the first to suggest that receptors may exist for bile acids. Ultimately, seminal studies by many investigators led to the discovery of several bile acid-activated receptors including the farnesoid X receptor, the vitamin D receptor, the pregnane X receptor, TGR5, α5 β1 integrin, and sphingosine-1-phosphate receptor 2. Several of these receptors are expressed outside of the gastrointestinal system, indicating that bile acids may have diverse functions throughout the body. Characterization of the functions of these receptors over the last two decades has identified many important roles for these receptors in regulation of bile acid synthesis, transport, and detoxification; regulation of glucose utilization; regulation of fatty acid synthesis and oxidation; regulation of immune cell function; regulation of energy expenditure; and regulation of neural processes such as gastric motility. Through these many functions, bile acids regulate many aspects of digestion ranging from uptake of essential vitamins to proper utilization of nutrients. Accordingly, within a short time period, bile acids moved beyond simple detergents and into the realm of complex signaling molecules. Because of the important processes that bile acids regulate through activation of receptors, drugs that target these receptors are under development for the treatment of several diseases, including cholestatic liver disease and metabolic syndrome. In this review, we will describe the various bile acid receptors, the signal transduction pathways activated by these receptors, and briefly discuss the physiological processes that

  2. Corrosion Inhibition of Mild Steel in Hydrochloric Acid Solution by Amino Acid Complexes

    OpenAIRE

    K. Kiruthikajothi; G. Chandramohan

    2015-01-01

    Using the amino acids methionine and serine reduced Schiff base and their copper(II) complexes were synthesized. The inhibition effect of these copper (II) complexes on the corrosion of mild steel in 1 M HCl solution was investigated. The corrosion inhibition action is studied through weight loss method. Among the tested complexes [CuCl(SMet)PPh3.H2O] exhibited better corrosion inhibition at 3 mmol concentration. The adsorption of the complexes on the metal surface obeys Langmuir’s adsorption...

  3. Nucleic Acid-Peptide Complex Phase Controlled by DNA Hybridization

    Science.gov (United States)

    Vieregg, Jeffrey; Lueckheide, Michael; Leon, Lorraine; Marciel, Amanda; Tirrell, Matthew

    When polyanions and polycations are mixed, counterion release drives formation of polymer-rich complexes that can either be solid (precipitates) or liquid (coacervates) depending on the properties of the polyelectrolytes. These complexes are important in many fields, from encapsulation of industrial polymers to membrane-free segregation of biomolecules such as nucleic acids and proteins. Condensation of long double-stranded DNA has been studied for several decades, but comparatively little attention has been paid to the polyelectrolyte behavior of oligonucleotides. We report here studies of DNA oligonucleotides (10 - 88 nt) complexed with polylysine (10 - 100 aa). Unexpectedly, we find that the phase of the resulting complexes is controlled by the hybridization state of the nucleic acid, with double-stranded DNA forming precipitates and single-stranded DNA forming coacervates. Stability increases with polyelectrolyte length and decreases with solution salt concentration, with complexes of the longer double-stranded polymers undergoing precipitate/coacervate/soluble transitions as ionic strength is increased. Mixing coacervates formed by complementary single-stranded oligonucleotides results in precipitate formation, raising the possibility of stimulus-responsive material design.

  4. Thermochemical properties of rare earth complexes with salicylic acid

    International Nuclear Information System (INIS)

    Fourteen rare earth complexes with salicylic acid RE(HSal)3.nH2O (HSal = C7H5O3; RE = La-Sm, n = 2; RE = Eu-Lu, n = 1) were synthesized and characterized by elemental analysis, and their thermal decomposition mechanism were studied with TG-DTG technology. The constant-volume combustion energies of complexes, ΔcU, were determined by a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHm0, and standard molar enthalpies of formation, ΔfHmo, were calculated

  5. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    International Nuclear Information System (INIS)

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid–base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for 1H, and 31P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min

  6. Ionic products of metal complexes with dithiocarbonic acid derivatives

    International Nuclear Information System (INIS)

    Ionic products of the complexes of certain sulfide-forming metal ions (In, Cd, Te, etc.) with alkyl derivates of dithiocarbonic acid have been defined. The possibility to use ionic products of alkyl xanthates for predicting the practicability of employing alkyl xanthates as analytic reagents in titrimetric methods of analysis, in extractional methods of separation and determination of elements, increase in the determination selectivity, is shown. 11 refs., 1 fig., 1 tab

  7. Technology of complex cleaning of mine acidic waters

    International Nuclear Information System (INIS)

    It is shown, that problem of complex use of mine waters includes two tasks: its cleaning and use of these waters in capacity of hydro-mineral raw. The floatation-extraction technology of mine acidic waters reprocessing is developed. The possibility of extraction processing of foam products of floatation with purpose of selective isolation of valuable components (Co, Ni, Sc, numerous of rare elements) is considered, optimum modes of metal extraction are defined. (author)

  8. Effect of inclusion complex on nitrous acid reaction with flavonoids

    Science.gov (United States)

    Khalafi, Lida; Rafiee, Mohammad; Sedaghat, Sajjad

    2011-10-01

    The kinetic of the nitrous acid reactions with quercetin and catechin has been studied using spectrophotometric method in aqueous solution. The results show that these antioxidants participate in oxidation reactions with nitrous acid which is derived from protonation of nitrite ion in mild acidic conditions. Corresponding o-quinones as relatively stable products were detected by spectrophotometric techniques. pH dependence of the reactions has been examined and the rate constants of reactions were obtained by non-linear fitting of kinetic profiles. The effect of β-cyclodextrin on the oxidation pathway was another object of this study. It is shown that β-cyclodextrin has an inhibitory effect on the oxidation reaction. The rate constants of oxidation reactions for complexed forms and their stability constants were obtained based on changes in the reaction rates as a function of β-cyclodextrin concentration.

  9. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants.

    Science.gov (United States)

    Morris, Robert H

    2014-02-01

    A simple equation (pKa(THF) = ∑AL + Ccharge + Cnd + Cd6) can be used to obtain an estimate of the pKa of diamagnetic transition metal hydride and dihydrogen complexes in tetrahydrofuran, and, by use of conversion equations, in other solvents. It involves adding acidity constants AL for each of the ligands in the 5-, 6-, 7-, or 8-coordinate conjugate base complex of the hydride or dihydrogen complex along with a correction for the charge (Ccharge = -15, 0 or 30 for x = +1, 0 or -1 charge, respectively) and the periodic row of the transition metal (Cnd = 0 for 3d or 4d metal, 2 for 5d metal) as well as a correction for d(6) octahedral acids (Cd6 = 6 for d(6) metal ion in the acid, 0 for others) that are not dihydrogen complexes. Constants AL are provided for 13 commonly occurring ligand types; of these, nine neutral ligands are correlated with Lever's electrochemical ligand parameters EL. This method gives good estimates of the over 170 literature pKa values that range from less than zero to 50 with a standard deviation of 3 pKa units for complexes of the metals chromium to nickel, molybdenum, ruthenium to palladium, and tungsten to platinum in the periodic table. This approach allows a quick assessment of the acidity of hydride complexes found in nature (e.g., hydrogenases) and in industry (e.g., catalysis and hydrogen energy applications). The pKa values calculated for acids that have bulky or large bite angle chelating ligands deviate the most from this correlation. The method also provides an estimate of the base strength of the deprotonated form of the complex. PMID:24410025

  10. Quantification of Acidic Compounds in Complex Biomass-Derived Streams

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Eric M.; Nimlos, Claire T.; Deutch, Steve; Salvachua, Davinia; Cywar, Robin M.; Beckham, Gregg T.

    2016-09-07

    Biomass-derived streams that contain acidic compounds from the degradation of lignin and polysaccharides (e.g. black liquor, pyrolysis oil, pyrolytic lignin, etc.) are chemically complex solutions prone to instability and degradation during analysis, making quantification of compounds within them challenging. Here we present a robust analytical method to quantify acidic compounds in complex biomass-derived mixtures using ion exchange, sample reconstitution in pyridine and derivatization with BSTFA. The procedure is based on an earlier method originally reported for kraft black liquors and, in this work, is applied to identify and quantify a large slate of acidic compounds in corn stover derived alkaline pretreatment liquor (APL) as a function of pretreatment severity. Analysis of the samples is conducted with GCxGC-TOFMS to achieve good resolution of the components within the complex mixture. The results reveal the dominant low molecular weight components and their concentrations as a function of pretreatment severity. Application of this method is also demonstrated in the context of lignin conversion technologies by applying it to track the microbial conversion of an APL substrate. Here too excellent results are achieved, and the appearance and disappearance of compounds is observed in agreement with the known metabolic pathways of two bacteria, indicating the sample integrity was maintained throughout analysis. Finally, it is shown that this method applies more generally to lignin-rich materials by demonstrating its usefulness in analysis of pyrolysis oil and pyrolytic lignin.

  11. Chloroform extraction of ethyl xanthate complexes from sulphuric acid media

    International Nuclear Information System (INIS)

    The chloroform extraction of 30 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Ce) from 0.1 to 8 M sulphuric acid in the presence of potassium ethyl xanthate has been studied. Pd(II), Bi, As(III), Sb(III), Se(IV) and Te(IV) are completely extracted and Au(III) is largely extracted over the range of acid concentration investigated. Fe(II), Tl(I), Rh(III) and Cr(VI) are only slightly extracted and Se(VI), Te(VI), Ru(III), Cr(III), Mn(II), Zn, Ce(IV), Ir(IV) and Ge(IV) are not extracted at all. Depending on the acid concentration, the remaining elements are all partly extracted. Results are compared with those obtained in an earlier study of the extraction of xanthate complexes from hydrochloric acid media. The processes involved in the formation of some xanthate complexes and potential analytical separations are discussed. (author)

  12. complex formation of americium (III) with humic acid

    International Nuclear Information System (INIS)

    The presence of humic substances in natural waters will modify the migration behavior of actinides in the geosphere due to the strong reaction properties of these ligands with actinides. Therefore, the possible reactions of humic acid with actinides have been studied widely in recent years. The complex formation of Am(III) with humic acid is studied with solvent extraction technique. The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 mol/kg NaClO4 solution at ambient temperature. Experimental results show that the complex formation constants of Am(III) with humic acid are varied with the variation of pH value in solution. 1:2 complex is obtained in the experiments and the complex formation constants determined at each pH are: lgβ1 = 6.56 +- 0.05, lgβ2 = 10.77 +- 0.31 at pH 4.0. lgβ1 = 7.94 +- 0.11, lgβ2 = 11.80 +- 0.21 at pH = 5.0. lgβ1 = 10.74 +- 0.28, lgβ2 = 12.88 +- 0.49 at pH = 6.0. lgβ1 = 12.85 +- 0.30, lgβ2 = 14.80 +- 0.62 at pH = 7.0. lgβ1 = 14.88 +- 0.48, lgβ2 = 15.65 +- 0.69 at pH = 8.0, respectively. The dependence of the complex formation constant on pH is: lgβ1 = 2.16 (+-0.98)pH-2.34(+-0.93),lgβ2 1.28(+-1.04)pH+5.52(+-1.21), respectively

  13. Psycho-pharmacotherapy for anxiety and obsessive-compulsive disorder: the issue of prolonged barbiturate retention.

    Science.gov (United States)

    Feldmann, Robert E; Kranz, Gottfried; Praschak-Rieder, Nicole; Kasper, Siegfried

    2009-09-01

    The authors report the case of a 32-year-old man who had been treated for anxiety and obsessive-compulsive disorder and had received 800 mg methylphenobarbital (MPB). After switching to a barbiturate-free schedule, his condition continued to be unstable for more than 21 MPB half-lives (approx. 30 days) and did not stabilize until MPB-metabolites dropped below their urinary detection limit. Considering that this article provides findings from a single patient, the authors use this experience to discuss and emphasize the importance of clinical control of barbiturates in psychiatry. PMID:19630487

  14. The analytical application of the osmium(VIII) reaction with thiobarbituric acid and its imide

    International Nuclear Information System (INIS)

    Osmium(VIII) forms complexes with thiobarbituric acid and its imide having a metal-ligand molar ratio of 1:2. The dissociation constants for the osmium-thiobarbituric acid complex are pK=3.03 and for the osmium-thiobarbiturimide complex, pK=3.30. A new spectrophotometric method for determination of thiobarbituric acid in a concentration range of 2.0 to 4.0 μg·ml-1 and thiobarbiturimide in a range of 1.0 to 2.0 μg·ml-1 has been developed. By this method, thiobarbituric acid can be determined in the presence of a ten-fold excess of barbituric acid. This method has been applied for determination of thiobarbiturates in physiological solutions, water and in drug (thiopental sodium). (author). 15 refs, 2 figs, 5 tabs

  15. Barbiturate-like actions of the propanediol dicarbamates felbamate and meprobamate.

    Science.gov (United States)

    Rho, J M; Donevan, S D; Rogawski, M A

    1997-03-01

    Felbamate and meprobamate are structurally related propanediol dicarbamates that possess distinct pharmacological profiles. Felbamate is a minimally sedative, broad-spectrum anticonvulsant, whereas meprobamate is a strong sedative-anxiolytic agent. Previously, we reported that felbamate potentiates gamma-aminobutyric acid(A) (GABA(A)) receptor Cl- currents and inhibits N-methyl-D-aspartate (NMDA) receptor currents. Here we further characterized the interaction of the two dicarbamates with GABA(A) receptors to determine the basis for their pharmacological differences. In whole-cell voltage-clamp recordings from cultured rat hippocampal neurons, meprobamate enhanced GABA-evoked responses in a concentration-dependent manner and, at high concentrations (>1 mM), exhibited a separate channel-blocking effect that limited the magnitude of GABA(A) receptor potentiation. At equivalent concentrations, meprobamate produced substantially greater potentiation than did felbamate. Furthermore, meprobamate (but not felbamate), in the absence of GABA, directly activated Cl- currents that could be attenuated by the GABA(A) receptor antagonists bicuculline and picrotoxin. The mean deactivation time constant of whole-cell currents evoked by 10 mM meprobamate (110 ms) or 1 and 3 microM GABA (180 ms) were faster than the deactivation time constant of 10 mM meprobamate (490 ms) or 3 mM felbamate (470 ms) in the presence of GABA. Meprobamate and felbamate prolonged the mean burst duration of GABA-activated unitary currents in excised outside-out membrane patches. In addition, at high (supratherapeutic) concentrations, meprobamate blocked NMDA-activated currents. We conclude that felbamate and meprobamate have barbiturate-like modulatory actions on GABA(A) receptors, but meprobamate has greater activity and, unlike felbamate, is able to directly activate the receptor. PMID:9067327

  16. Complexes of carborane acids linked by strong hydrogen bonds: acidity scales.

    Science.gov (United States)

    Grabowski, Sławomir J

    2016-06-28

    Carborane acids, currently known as the strongest acis, are analyzed and compared with other species classified as superacids as well as with selected mineral acids and carbocations. Calculations (B3LYP/6-311++G(d,p) level) on these moieties as well as on their conjugate bases were performed to evaluate corresponding proton affinities. In addition, the complexes of these species with the CHB11F11(-) anion and the complexes of the conjugate bases with the trimethylammonium cation were analyzed. The scales, based on spectroscopic results, DFT energies and on the topological QTAIM (Quantum Theory of Atoms in Molecules) parameters, are introduced and discussed to order the acidity of the species analyzed here. The properties of the bond critical points corresponding to the intermolecular contacts are discussed. The majority of the results show that HCHB11F11 carborane acid is the strongest in agreement with the previous experimental studies of Reed and coworkers. Very often the abovementioned acidity scales show that carborane acids are able to protonate hydrocarbons. PMID:27253195

  17. One barbiturate and two solvated thiobarbiturates containing the triply hydrogen-bonded ADA/DAD synthon, plus one ansolvate and three solvates of their coformer 2,4-diaminopyrimidine.

    Science.gov (United States)

    Hützler, Wilhelm Maximilian; Egert, Ernst; Bolte, Michael

    2016-09-01

    A path to new synthons for application in crystal engineering is the replacement of a strong hydrogen-bond acceptor, like a C=O group, with a weaker acceptor, like a C=S group, in doubly or triply hydrogen-bonded synthons. For instance, if the C=O group at the 2-position of barbituric acid is changed into a C=S group, 2-thiobarbituric acid is obtained. Each of the compounds comprises two ADA hydrogen-bonding sites (D = donor and A = acceptor). We report the results of cocrystallization experiments of barbituric acid and 2-thiobarbituric acid, respectively, with 2,4-diaminopyrimidine, which contains a complementary DAD hydrogen-bonding site and is therefore capable of forming an ADA/DAD synthon with barbituric acid and 2-thiobarbituric acid. In addition, pure 2,4-diaminopyrimidine was crystallized in order to study its preferred hydrogen-bonding motifs. The experiments yielded one ansolvate of 2,4-diaminopyrimidine (pyrimidine-2,4-diamine, DAPY), C4H6N4, (I), three solvates of DAPY, namely 2,4-diaminopyrimidine-1,4-dioxane (2/1), 2C4H6N4·C4H8O2, (II), 2,4-diaminopyrimidine-N,N-dimethylacetamide (1/1), C4H6N4·C4H9NO, (III), and 2,4-diaminopyrimidine-1-methylpyrrolidin-2-one (1/1), C4H6N4·C5H9NO, (IV), one salt of barbituric acid, viz. 2,4-diaminopyrimidinium barbiturate (barbiturate is 2,4,6-trioxopyrimidin-5-ide), C4H7N4(+)·C4H3N2O3(-), (V), and two solvated salts of 2-thiobarbituric acid, viz. 2,4-diaminopyrimidinium 2-thiobarbiturate-N,N-dimethylformamide (1/2) (2-thiobarbiturate is 4,6-dioxo-2-sulfanylidenepyrimidin-5-ide), C4H7N4(+)·C4H3N2O2S(-)·2C3H7NO, (VI), and 2,4-diaminopyrimidinium 2-thiobarbiturate-N,N-dimethylacetamide (1/2), C4H7N4(+)·C4H3N2O2S(-)·2C4H9NO, (VII). The ADA/DAD synthon was succesfully formed in the salt of barbituric acid, i.e. (V), as well as in the salts of 2-thiobarbituric acid, i.e. (VI) and (VII). In the crystal structures of 2,4-diaminopyrimidine, i.e. (I)-(IV), R2(2)(8) N-H...N hydrogen-bond motifs are preferred and, in two

  18. Complex formation of americium (III) with humic acid

    International Nuclear Information System (INIS)

    The presence of humic substances in natural waters will modify the migration behavior of actinides in the geosphere due to the strong reaction properties of these ligands with actinides. Therefore, the possible reactions of humic acid with actinides have been studied widely in recent years. The complex formation of Am (III) with humic acid is studied with solvent extraction technique in this paper. The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 M NaClO4 solution at ambient temperature. Experimental results show that the complex formation constants of Am (III) with humic acid are varied with the variation of pH value in solution. 1:2 complex is obtained in the experiments and the complex formation constants determined at each pH are: lgβ1=6.56±0.05, lgβ2=10.77±0.31 at pH=4.0; lgβ1=7.94±0.11, lgβ2=11.80±0.21 at pH=5.0; lgβ1=10.74±0.28, lgβ2=12.88±0.49 at pH=6.0; lgβ1=12.85±0.30, lgβ2=14.80±0.62 at pH=7.0; lgβ1=14.88±0.48, lgβ2=15.65±0.69 at pH=8.0, respectively. The dependence of the complex of the complex formation constant on pH is: lgβ1=2.16(±0.98)pH-2.34(±1.03), lgβ2=1.28(±1.04)pH+5.52(±1.21), respectively. (author)

  19. From ligand to complexes: inhibition of HIV-1 Integrase by beta-diketo acid metal complexes

    OpenAIRE

    Sechi, Mario; BACCHI, Alessia; Carcelli, Mauro; Fisicaro, Emilia; Rogolino, Dominga; Gates, Paul; Derudas, Marco; Al-Mawsawi, Laith Q.; Neamati, Nouri

    2006-01-01

    Recently, a class of compounds bearing a β-diketo acid moiety have emerged as the most promising lead in anti-HIV-1 IN drug discovery. It is believed that the β-diketo acid pharmacophoric motif could be involved in a functional sequestration of one or both divalent metal ions, which are critical cofactors at the enzyme catalytic site. This would subsequently block the transition state of the IN-DNA complex. In this scenario, it is of paramount importance to acquire information ...

  20. Spectrophotometric study of lanthanoid complexes with antipyrine and salicylic acid

    International Nuclear Information System (INIS)

    The extraction-spectrophotometric method has been used to study lanthanoid ion complexing (Pr, Nd, Ho and Er) with antipyrine (Ant) and salicylic acid (Sal). The component relationship in different-ligand compounds Ln:Aut:Sal=2:3:6 and solvate number equal to 5 are determined; molar extinction coefficients of binary and different-ligand compounds are calculated. Oscillator strengths of absorption bands corresponding to supersensitive transitions of neodymium, holmium, erbium and some most intensive praseodymium bands are calculated. The study of IR spectra of investigated compounds allows to conclude on formation of coordination bonds of the central atom with the antipyrine molecule through the oxygen of the carbonyl group as well as on carboxyl group hydrogen substitution for metal and formation of coordination bond with OH group in salicylic acid molecules

  1. Complementary hydrogen bonding of a carboxylato-barbiturate with urea and acetamide: Experimental and theoretical approach

    Czech Academy of Sciences Publication Activity Database

    Hasan, Md. A.; Seshaditya, A.; Záliš, Stanislav; Mishra, L.

    2011-01-01

    Roč. 83, č. 1 (2011), s. 532-539. ISSN 1386-1425 Institutional research plan: CEZ:AV0Z40400503 Keywords : barbiturate derivative * binding study * 1H-NMR titration Subject RIV: CG - Electrochemistry Impact factor: 2.098, year: 2011

  2. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

  3. Structure and function analysis of protein–nucleic acid complexes

    Science.gov (United States)

    Kuznetsova, S. A.; Oretskaya, T. S.

    2016-05-01

    The review summarizes published data on the results and achievements in the field of structure and function analysis of protein–nucleic acid complexes by means of main physical and biochemical methods, including X-ray diffraction, nuclear magnetic resonance spectroscopy, electron and atomic force microscopy, small-angle X-ray and neutron scattering, footprinting and cross-linking. Special attention is given to combined approaches. The advantages and limitations of each method are considered, and the prospects of their application for wide-scale structural studies in vivo are discussed. The bibliography includes 145 references.

  4. Complexation behavior of Np(IV) and humic acid

    International Nuclear Information System (INIS)

    Complexation behavior between humic acid (HA), which is one of the natural organic matter in groundwater, and tetravalent neptunium (Np(IV)) was investigated by batch type complexation experiments and solvent extraction by TTA xylene, focused on the effect of concentration and molecular weight of HA. In addition, proton dissociation behavior from HA was evaluated by acid-base titration and its results was used for the calculation of stability constant of Np(IV) and HA complex. The results of titration of HA was analysed based on NICA-Donnan model and parameters used for evaluation of proton dissociation behavior were calculated. The charge density of HA in pH 8, which is necessary for calculation of stability constant, was evaluated as -4.35 meq/g. The complexation experiments were carried out under the conditions as follows; 1x10-5 mol/l of initial Np concentration, from 5 to 500 mg/l of HA concentration, pH 8, in the 0.1 mol/l NaClO4, and 0.05 mol/l Na2S2O4 as reductant to keep Np as tetravalent. As a result, in the presence of 5 mg/l of HA, total concentration of Np was increased at least one order of magnitude higher than in the case without HA. All added Np existed as soluble species in the presence of more than 50 mg/l of HA. Np in the solution was fractionated by solvent extraction using TTA-xylene as follows; 1) extractable Np into the organic phase, 2) non-extractable Np remained in the inorganic phase, and 3) precipitated Np. These were considered as 1) free Np(VI) or weakly binded Np(IV) and 3) strongly binded Np(IV), while 2) Np(IV)-fulvic acid complex could be suggested. Consequently, stability constant, log βα=26.31, was obtained. In addition, compared with Am(III) or Np(V), accessible site in the HA for Np(IV) seems to be quite limited. (author)

  5. Influencing of resorption and side-effects of salicylic acid by complexing with β-cyclodextrin

    International Nuclear Information System (INIS)

    After oral administration of 14C-labelled salicylic acid and its β-cyclodextrin complex to rats, the radioactivity level of the blood reached its maximum during the first 2 h. The blood level obtained with the complex is somewhat but not significantly lower than with free acid. Since the resorption of cyclodextrin is a considerably slower process, it is very likely that the resorption of salicylic acid takes place in the form of free acid after dissociation of the complex. The urinary excretion cumulative curves showed that the free salicylic acid was completely excreted, while about 10% of the salicylic acid administered in the form of complex is lost. The cyclodextrin complex formation increased the pK values of all hydroxybenzoic acids. Direct observations revealed that complex formation decreased the stomach-irritating effect of salicylic acid. The ratio of radioactivity was nearly the same in the organs of animals treated by both free salicylic and cyclodextrin complex. (author)

  6. Investigation of molecular interactions in the complex formation of tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn- thesizing new chiral resolving agents.

  7. Investigation of molecular interactions in the complex formation of tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid

    Institute of Scientific and Technical Information of China (English)

    TAN Bin; ZHAI Zheng; LUO GuangSheng; WANG JiaDing

    2008-01-01

    The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn-thesizing new chiral resolving agents.

  8. α-Lactalbumin:Oleic Acid Complex Spontaneously Delivers Oleic Acid to Artificial and Erythrocyte Membranes.

    Science.gov (United States)

    Wen, Hanzhen; Strømland, Øyvind; Halskau, Øyvind

    2015-09-25

    Human α-lactalbumin made lethal to tumor cells (HAMLET) is a tumoricidal complex consisting of human α-lactalbumin and multiple oleic acids (OAs). OA has been shown to play a key role in the activity of HAMLET and its related complexes, generally known as protein-fatty acid (PFA) complexes. In contrast to what is known about the fate of the protein component of such complexes, information about what happens to OA during their action is still lacking. We monitored the membrane, OA and protein components of bovine α-lactalbumin complexed with OA (BLAOA; a HAMLET-like substance) and how they associate with each other. Using ultracentrifugation, we found that the OA and lipid components follow each other closely. We then firmly identify a transfer of OA from BLAOA to both artificial and erythrocyte membranes, indicating that natural cells respond similarly to BLAOA treatment as artificial membranes. Uncomplexed OA is unable to similarly affect membranes at the conditions tested, even at elevated concentrations. Thus, BLAOA can spontaneously transfer OA to a lipid membrane. After the interaction with the membrane, the protein is likely to have lost most or all of its OA. We suggest a mechanism for passive import of mainly uncomplexed protein into cells, using existing models for OA's effect on membranes. Our results are consistent with a membrane destabilization mediated predominantly by OA insertion being a significant contribution to PFA cytotoxicity. PMID:26297199

  9. Dual Fatty Acid Elongase Complex Interactions in Arabidopsis.

    Science.gov (United States)

    Morineau, Céline; Gissot, Lionel; Bellec, Yannick; Hematy, Kian; Tellier, Frédérique; Renne, Charlotte; Haslam, Richard; Beaudoin, Frédéric; Napier, Johnathan; Faure, Jean-Denis

    2016-01-01

    Very long chain fatty acids (VLCFAs) are involved in plant development and particularly in several cellular processes such as membrane trafficking, cell division and cell differentiation. However, the precise role of VLCFAs in these different cellular processes is still poorly understood in plants. In order to identify new factors associated with the biosynthesis or function of VLCFAs, a yeast multicopy suppressor screen was carried out in a yeast mutant strain defective for fatty acid elongation. Loss of function of the elongase 3 hydroxyacyl-CoA dehydratase PHS1 in yeast and PASTICCINO2 in plants prevents growth and induces cytokinesis defects. PROTEIN TYROSIN PHOSPHATASE-LIKE (PTPLA) previously characterized as an inactive dehydratase was able to restore yeast phs1 growth and VLCFAs elongation but not the plant pas2-1 defects. PTPLA interacted with elongase subunits in the Endoplasmic Reticulum (ER) and its absence induced the accumulation of 3-hydroxyacyl-CoA as expected from a dehydratase involved in fatty acid (FA) elongation. However, loss of PTPLA function increased VLCFA levels, an effect that was dependent on the presence of PAS2 indicating that PTPLA activity repressed FA elongation. The two dehydratases have specific expression profiles in the root with PAS2, mostly restricted to the endodermis, while PTPLA was confined in the vascular tissue and pericycle cells. Comparative ectopic expression of PTPLA and PAS2 in their respective domains confirmed the existence of two independent elongase complexes based on PAS2 or PTPLA dehydratase that are functionally interacting. PMID:27583779

  10. Oral absorption of hyaluronic acid and phospholipids complexes in rats

    Institute of Scientific and Technical Information of China (English)

    Si-Ling Huang; Pei-Xue Ling; Tian-Min Zhang

    2007-01-01

    AIM: To prepare a complex of hyaluronic acid (HA) and phospholipids (PL), and study the improvement effect of PL on the oral absorption of HA.METHODS: The complex of HA-PL (named Haplex) was prepared by film dispersion and sonication method, its physico-chemical properties were identified by infrared spectra and differential scanning calorimetry (DSC). The oral absorption of Haplex was studied. Thirty-two healthy rats were divided into 4 groups randomly: (1) a normal saline (NS) control group; (2) an HA group; (3) a mixture group and (4) a Haplex group. After intragastric administration, the concentration of HA in serum was determined.RESULTS: The physico-chemical properties of Haplex were different from HA or PL or their mixture. After Haplex was administered to rats orally, the serum concentration of HA was increased when compared with the mixture or HA control groups from 4 h to 10 h (P < 0.05). The ΔAUCo-12 h of Haplex was also greater than that of the other three groups (P < 0.05).CONCLUSION: The method of film dispersion and sonication can prepare HA and PL complex, and PL can enhance the oral absorption of exogenous HA.

  11. Syntheses,characteristics,and fluorescence properties of complexes of europium with benzoic acid and its derivatives

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhongcheng; SHU Wangen; RUAN Jianming; HUANG Boyun; LIU Younian

    2004-01-01

    The binary complexes of europium with benzoic acid and its derivatives (phthalic acid, m-phthalic acid,o-aminobenzoic acid, salicylic acid, and sulfosalicylic acid) were synthesized and their compositions were identified by elemental analyses. UV and IR of the complexes have been investigated. The UV spectra indicated that the complexes' ultraviolet absorption were mainly the ligands' absorption. The IR spectra showed that the IR spectra of complexes are different from those of free ligands. The fluorescence properties of them were investigated by using luminescence spectroscopy, the results showed that only three complexes appear as better luminescence, they were Eu-benzoic acid,Eu-m-phthalic acid and Eu-phthalic acid, while the others exhibited the ligands' wideband emission.

  12. Effects of humic acid-metal complexes on hepatic carnitine palmitoyltransferase, carnitine acetyltransferase and catalase activities

    Energy Technology Data Exchange (ETDEWEB)

    Fungjou Lu; Youngshin Chen (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Biochemistry); Tienshang Huang (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Medicine)

    1994-03-01

    A significant increase in activities of hepatic carnitine palmitoyltransferase and carnitine acetyltransferase was observed in male Balb/c mice intraperitoneally injected for 40 d with 0.125 mg/0.1 ml/d humic acid-metal complexes. Among these complexes, the humic acid-As complex was relatively effective, whereas humic acid-25 metal complex was more effective, and humic acid-26 metal complex was most effective. However, humic acid or metal mixtures, or metal such as As alone, was not effective. Humic acid-metal complexes also significantly decreased hepatic catalase activity. A marked decrease of 60-kDa polypeptide in liver cytoplasm was also observed on SDS-polyacrylamide gel electrophoresis after the mice had been injected with the complexes. Morphological analysis of a histopathological biopsy of such treated mice revealed several changes in hepatocytes, including focal necrosis and cell infiltration, mild fatty changes, reactive nuclei, and hypertrophy. Humic acid-metal complexes affect activities of metabolic enzymes of fatty acids, and this results in accumulation of hydrogen peroxide and increase of the lipid peroxidation. The products of lipid peroxidation may be responsible for liver damage and possible carcinogenesis. Previous studies in this laboratory had shown that humic acid-metal complex altered the coagulation system and that humic acid, per se, caused vasculopathy. Therefore, humic acid-metal complexes may be main causal factors of not only so-called blackfoot disease, but also the liver cancer prevailing on the southwestern coast of Taiwan.

  13. Decrease in white blood cell counts after thiopentone barbiturate therapy for refractory intracranial hypertension: A common complication

    OpenAIRE

    Shin Yi Ng; Ki Jinn Chin; Tong Kiat Kwek

    2013-01-01

    Background: Leucopenia has been reported after induction of thiopentone barbiturate therapy for refractory intracranial hypertension. However, the incidence and characterisitics are not well described. Aims: We performed a retrospective review to describe the incidence and characteristics of leucopenia after induction of thiopentone barbiturate therapy. Setting and Design: Our centre is a national referral centre for neurotrauma and surgery in a tertiary medical institution. Materials and Met...

  14. Complex formation of Eu(III) with polyacrylic acid

    International Nuclear Information System (INIS)

    For the quantitative description of the interaction of metal ions with humic substances, it is necessary to clarify the effects of both polyelectrolyte and heterogeneous nature of humic substances. To estimate the polyelectrolyte effect separately, polyacrylic acid (MW = 90 000) has been selected as a representative of well-defined, homogeneous polymeric weak acids, and its interaction with Eu(III) has been investigated by a solvent extraction method using 152Eu (∝ 10-8 M) with TTA and TBP in xylene. By defining the apparent complex formation constant as βα = [ML]/([M][R]), where [M] = [Eu3+], [ML] is the concentration of Eu(III) associated with polyacrylic acid and [R] = CRα (CR is a total concentration of proton exchanging sites and α is a degree of dissociation determined by potentiometric titration), the apparent constants have been obtained at several pcH and ionic strength (0.1 M and 1.0 M NaClO4). The constants increased with pcH and decreased with an increase of ionic strength, that is, the values of log βα varied from 6.0 (at pcH = 4.7) to 7.6 (pcH = 5.5) at 0.1 M NaClO4 and from 4.8 (pcH = 4.4) to 6.5 (pcH = 5.4) at 1.0 M. The plots of log βα versus log α revealed almost linear relationship both at 0.1 and 1.0 M NaClO4. (orig.)

  15. Synthesis and spectroscopic characterization of fluorescent solid rare earth complexes with hydroxamic acids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The complexes RE2(DHYA)3 .nH2O in the title bar were synthesized through some reactions oftrivalent rareearth ions. In the process of synthesis, dihydroxamic acids were taken as ligands while the alcohol was taken as a solvent.The ligands included adipylhydroxamic acid (ADHA), p-phthalichydroxamic acid (PPHA), oxalohydroxamic acid (OXHA), butadihydroxamic acid (BDHA), o-phthalichydroxamic acid (OPHA), benzoylhydroxamic acid (BHA), etc.Measured at 25 ℃, the molar conductances in various modes are 13.00-21.05 S. cm2. mol-1, which shows that rare-earth complexes are nonelectrolytes and the hydroxamino groups of the complexes have taken part in bonding. Infrared spectra, ultraviolet spectra, nuclear magnetic resonance (1HNMR) spectra, and fluorescence spectra were used to investigate the complexes. Experiments have proved that the complexes of Eu3+ and Tb3+ with aromatic hydroxamic acids have good fluorescent characteristics.

  16. Transition Metal–α-Amino Acid Complexes with Antibiotic Activity against Mycobacterium spp.

    OpenAIRE

    Karpin, George W.; Merola, Joseph S.; Joseph O. Falkinham

    2013-01-01

    Synthetic iridium-, rhodium-, and ruthenium-amino acid complexes with hydrophobic l-amino acids have antibiotic activity against Mycobacterium spp., including Mycobacterium bovis BCG and the rapidly growing species Mycobacterium abscessus and Mycobacterium chelonae. Concentrations of transition metal-amino acid complexes demonstrating hemolysis or cytotoxicity were 10- to 25-fold higher than were the MICs.

  17. Solid-phase extraction and GC/MS confirmation of barbiturates from human urine.

    Science.gov (United States)

    Pocci, R; Dixit, V; Dixit, V M

    1992-01-01

    A highly selective and sensitive procedure has been developed for isolating and identifying barbiturates in human urine. With a new disposable bonded silica gel solid-phase extraction (SPE) column and hexobarbital as an internal standard (IS), amobarbital, butabarbital, pentobarbital, phenobarbital, secobarbital, and methaqualone were selectively isolated from endogenous urine components. Capillary gas chromatography/ion trap mass spectrometry (GC/MS) analysis of the extracts generated a full mass spectrum for the detection, identification, and quantitation of barbiturates. Linear quantitative response curves for the drugs have been generated over a concentration range of 20-500 ng/mL. Overall extraction efficiencies for drugs averaged greater than 90%, and the quantitative response curves exhibited correlation coefficients of 0.996 to 0.999. PMID:1353548

  18. Kinetics and mechanism of reduction of iron (III) kojic acid complex by ascorbic acid

    International Nuclear Information System (INIS)

    Kinetics of reduction of iron (III) kojic acid complex by ascorbic acid has been carried out using photodiode array spectrophotometer over the ranges: 4.0<=pH<=5.5 and 5.0<=T<=25.0 degree C at ionic strength 0.2 M under pseudo-first order conditions by stopped-flow technique. Rate of the reaction was found to be pH dependent. The redox reaction followed the saturation kinetics. The rate law is deduced as follows: Rate = (k/sub 3/k/sub eq(H/sup +/)(HAsc/sup -/)(Fe(KA)/sub 3/) / (HKA) + K/sub eq/(H/sup +/)(HAsc/sup -/) The activation parameters of this reaction were determined. A mechanism consistent with this rate law has been proposed. (author)

  19. Refractory hypokalemia during barbiturate coma therapy used for treating refractory intracranial hypertension in traumatic brain injury

    OpenAIRE

    WAN HASSAN, Wan Mohd Nazaruddin; Najid, Nazuha Mohd; Muslim, Halimatun Sa’adiah; Izaini Ghani, Abdul Rahman

    2015-01-01

    Barbiturate coma therapy (BCT) is a choice treatment for refractory intracranial hypertension after all surgical or medical managements have failed to control the intracranial pressure (ICP). It helps to reduce cerebral blood flow, cerebral metabolic rate of oxygen consumption and ICP. However, this therapy can also cause many complications. One of the underreported, but life-threatening complications is refractory hypokalemia, which can lead to subsequent rebound hyperkalemia after sudden ce...

  20. Complex Formation of Selected Radionuclides with Ligands Commonly Found in Ground Water: Low Molecular Organic Acids

    DEFF Research Database (Denmark)

    Jensen, Bror Skytte; Jensen, H.

    1985-01-01

    A general approach to the analysis of potentiometric data on complex formation between cations and polybasic amphoteric acids is described. The method is used for the characterisation of complex formation between Cs+, Sr2+, Co2+, La 3+, and Eu3+ with a α-hydroxy acids, tartaric acid and citric acid......, and with the α-amino acids, aspartic acid and L-cysteine. The cations have been chosen as typical components of reactor waste, and the acids because they are often found as products of microbial activity in pits or wherever organic material decays...

  1. Complexation of metal ions with humic acid: metal ion charge neutralization model

    International Nuclear Information System (INIS)

    The humic acid complexation reaction presented in this work is based on the concept of metal ion charge neutralization upon complexation to humic acid functional groups. Experimental results from the complexation of UO22+, Am3+, and Cm3+ with humic acids of different origin are presented to demonstrate and validate the proposed model. By introducing the operational humic acid concentration and the loading capacity, the complexation constants are derived, which are independent of the metal ion concentration, pH, and origin of humic acid. The loading capacity is an operational term needed for the intercomparison of stability constants and is the mole fraction of the maximum available complexing sites of humic acid under a given set of experimental conditions. The metal ion charge neutralization model adequately describes the thermodynamic equilibrium reaction of metal ions with humic acid and allows a direct application of the resulting stability constants for geochemical modeling of actinide migration at an environmentally relevant pH. (orig.)

  2. Complex formation of Eu(III) with humic acid and polyacrylic acid

    International Nuclear Information System (INIS)

    With the intention of estimating the effect of the heterogeneous composition in the humic acid separately from its polyelectrolyte effect, comparative study on the interaction of Eu(III) with humic acid and polyacrylic acid has been carried out by the solvent extraction method with 10-3 M TTA and 10-3 M TBP in xylene at various total concentrations of Eu(III) (10-8 M to 10-5 M), pcH (5.0 to 5.5) and ionic strengths (0.02 to 1.0 M NaClO4). The interaction has been discussed in terms of the apparent complex formation constants, βα = [ML]/([M][R]), where [M] and [ML] are the concentrations of free and bound Eu3+ ion and [R] is the concentration of dissociated proton exchanging site. For both humate and polyacrylate, log βα increased with pcH or the degree of ionization and decreased with ionic strength. The Eu3+ ion concentration had no appreciable influence on the complex formation of Eu(III)-polyacrylate, and the values of log βα were obtained to be 7.57 ± 0.05 (I = 0.1, pcH = 5.53), 7.13 ± 0.04 (I = 0.1, pcH = 5.20), 6.68 ± 0.04 (I = 1.0, pcH = 5.54) and 5.61 ± 0.09 (I = 1.0, pcH = 4.73). On the other hand, log βα of humate remarkably decreased with the Eu3+ ion concentration; from 9.32 ([Eu3+] = 10-11.9 M) to 7.20 ([Eu3+] = 10-7.5 M) at pcH = 5.53 in 0.02 M NaClO4, from 8.63 ([Eu3+] = 10-12.5 M) to 6.35 ([Eu3+] = 10-7.2 M) at pcH = 5.53 in 0.1 M and from 7.59 ([Eu3+] = 10-10.7 M) to 5.20 ([Eu3+] = 10-7.0 M) at pcH = 5.52 in 1.0 M. The observed dependence of log βα of humate on the concentration of metal ion strongly suggests the heterogeneity of the complexing sites (the coexistence of weak and strong binding sites) in the humic acid. (orig.)

  3. Optical Absorption, Stability and Structure of NpO2+ Complexes with Dicarboxylic Acids

    International Nuclear Information System (INIS)

    Complexation of NpO2+ with oxalic acid (OX),2,2'-oxydiacetic acid (ODA), 2,2'-iminodiacetic acid (IDA) and 2,2'-thiodiacetic acid (TDA), has been studied using spectrophotometry in1 M NaClO4. Both the position and the intensity of the absorption band of NpO2+ at 980 nm are affected by the formation of NpO2+/dicarboxylate complexes, providing useful information on the complexation strength, the coordination mode and the structure of the complexes

  4. Quantum chemical prediction of paramagnetic NMR spectra of lanthanide complexes with salicylic acid in water solution

    International Nuclear Information System (INIS)

    17O and 13C paramagnetic NMR (PNMR) shifts have been calculated for Gd complexes with salicylic acid in water solution. These complexes served us as model compounds for simulation of more complicated lanthanide complexes with humic acids. The obtained data demonstrate that paramagnetic NMR spectra are very sensitive to the bonding details of the ligand. Our calculations suggest that formation of Gd(III) complex with salicylic acid in water solution via carboxyl group with uni-dentate coordination is preferable. New experimental studies with the enriched 17O and 13C nuclei of carboxylate groups of the salicylic and humic acids are extremely desirable

  5. Influence of humic acid size on actinide complexation

    International Nuclear Information System (INIS)

    The complexation of Am(III) and Eu(III) with humic acid of different molecular sizes was measured and the data for the ≥300kD and ≥10kD sized HA at pcH 4.0 and 6.0 was analyzed by the Charge Neutralization Model (CNM) and the Polyelectrolyte Model (PM). For the PM, solvent extraction was used to obtain the stability constants of 241Am at tracer concentration. For the CNM, ultrafiltration was used to determine the loading capacity and the stability constants for Eu(III) at macro concentrations. There was a difference of 1-2 orders of magnitude in the stability constants from the two models. The 5D0-7F0 excitation spectra of Eu(III) as a function of loading of HA was found to have a shift in wavenumbers of the peak maximum, indicating that the coordination environment of Eu(III) varied with pH, presumably due to variation in the number of functional groups of the humate bound to the metal ion

  6. Complex modulation of androgen responsive gene expression by methoxyacetic acid

    Directory of Open Access Journals (Sweden)

    Stanley Kerri A

    2011-03-01

    Full Text Available Abstract Background Optimal androgen signaling is critical for testicular development and spermatogenesis. Methoxyacetic acid (MAA, the primary active metabolite of the industrial chemical ethylene glycol monomethyl ether, disrupts spermatogenesis and causes testicular atrophy. Transcriptional trans-activation studies have indicated that MAA can enhance androgen receptor activity, however, whether MAA actually impacts the expression of androgen-responsive genes in vivo, and which genes might be affected is not known. Methods A mouse TM3 Leydig cell line that stably expresses androgen receptor (TM3-AR was prepared and analyzed by transcriptional profiling to identify target gene interactions between MAA and testosterone on a global scale. Results MAA is shown to have widespread effects on androgen-responsive genes, affecting processes ranging from apoptosis to ion transport, cell adhesion, phosphorylation and transcription, with MAA able to enhance, as well as antagonize, androgenic responses. Moreover, testosterone is shown to exert both positive and negative effects on MAA gene responses. Motif analysis indicated that binding sites for FOX, HOX, LEF/TCF, STAT5 and MEF2 family transcription factors are among the most highly enriched in genes regulated by testosterone and MAA. Notably, 65 FOXO targets were repressed by testosterone or showed repression enhanced by MAA with testosterone; these include 16 genes associated with developmental processes, six of which are Hox genes. Conclusions These findings highlight the complex interactions between testosterone and MAA, and provide insight into the effects of MAA exposure on androgen-dependent processes in a Leydig cell model.

  7. Substituent electrophilicities in the NMR spectra of barbituric derivatives.

    Science.gov (United States)

    Rezende, Marcos Caroli; Almodovar, Iriux

    2012-04-01

    Comparison of the (1) H and (13)  C NMR spectra of a series of substituted 5-benzylidene-N,N'-dimethylbarbituric acids (1) revealed chemical-shift variations of different centers that correlated with the theoretical electrophilicities or with the substituent electrophilic constant σ(ω) , in an example of the usefulness of these DFT-based indices. PMID:22415981

  8. Synthesis, Characterization of α-Oxopentanedioic Acid-Isonicotinoyl Hydrazone Rare Earth-Complexes and Relaxivity of Gd-complex

    Institute of Scientific and Technical Information of China (English)

    杨正银; 杨汝栋

    2004-01-01

    α-Oxopentanedioic acid isonicotinoyl hydrazone (H2L) and its five rare earth complexes were synthesized with a view to further investigating MRI activities of the polycarboxylic Schiff base complexes. The complexes were characterized on the basis of elemental analyses, IR, UV, 1H NMR spectra and thermal analyses. The general formula of the complexes is [Ln(HL)(H2O)2]Cl2·H2O (where Ln(Ⅲ)=La, Pr, Nd, Eu and Gd). In addition, the relaxivity (R1) of the Gd-complex was determined by INVREC Au program.

  9. Study of Complexes of Lanthanum with Amino Acids by Titration Calorimeter

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The stability constants and thermodynamic functions for complexes of lanthanum with eight kind of amino acids according to 1:1 and 1:2 in proportion have been determined by titration calorimeter at 298. 15 K. The enthalpy change makes a predominant contribution to the stability of these complexes. The ring in amino acid associated with lanthanum ion helps to enhance the stability of complexes. Steric effectsbetween rings in complexes leads to that the equilibrium constants of reaction of the complexes (1:2) ismuch less than that of the complexes (l:1).

  10. Peptide Nucleic Acids Complexes of Two Peptide Nucleic Acid Strands and One

    DEFF Research Database (Denmark)

    1999-01-01

    Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest...

  11. Investigation of lanthanum and lutetium complexing with 5-sulfosalicylic acid by the NMR method

    International Nuclear Information System (INIS)

    The study of the lanthanum-5-sulfosalicylic acid and lutetium-5-sulfosalicylic acid systems is carried out using the method of NMR spectroscopy. Participation of ionized phenol hydroxyl and carboxylic group of 5-sulfosalicylic acid in complexing with lanthanum and lutetium is shown. pH value at which phenol proton splitting out occurs is found and the constant of acid dissociation of phenol hydroxyl in the complex, pK of which has the value 6.82+-0.04, is calculated dissociation of phenol hydroxyl in the complex, pK of which has the value 6.82+-0.04, is calculated dissociation of phen

  12. Spectrophotometric study into complexing of vanadium(3) with salicylic acid derivatives

    International Nuclear Information System (INIS)

    Complexing of vanadium (3) with 5 amino-salicylic acid and amide of salicylhydroxamic acid has been studied. It has been shown that in acidic medium V3+ forms yellow complexes of the composition 1:1 with instability constants 2.2x10-19, 7.8x10-11, and 2.2x10-12, respectively. Complexes of V3+ with derivatives of salicylic acid can be used for determining V(3) content in the presence of V(4)

  13. Syntheses and characterizations of three acid-base supramolecular complexes

    International Nuclear Information System (INIS)

    Three acid-base compounds with supramolecular architectures, namely, (1,2-H2bdc)(dmt) (1), (trans-1,4-H2ccdc)0.5(phdat) (2) and (1,3-H2bdc)(phdat) (3) (1,2-H2bdc = 1,2-benzenedicarboxylic acid, trans-1, 4-H2ccdc = trans-1, 4-cyclohexanedicarboxylic acid, 1,3-H2bdc = 1,3-benzenedicarboxylic acid, dmt = 2,4-diamino-6-methyl-s-triazine, phdat = 2,4-diamino-6-phenyl-s-triazine) have been synthesized and characterized by IR spectra, elemental analyses, single-crystal X-ray diffractions and TGA. (author)

  14. Study on complex formation of cadmium (II) ions, 9. Formation constants on cadmium (II) complexes with dicarboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Haruo (Government Industrial Research Inst., Nagoya (Japan))

    1984-03-01

    Formation constants of cadmium (11) complexes with dicarboxylic acids such as oxalic, malonic, methylmalonic, succinic, and glutaric acids were determined in aqueous solutions containing 3 mol.dm/sup -3/ LiClO/sub 4/ as a constant ionic medium at 25/sup 0/C by potentiometric titrations. It was reported in the previous works that cadmium (11)- aspartic acid complexes contained two chelate rings. However, a problem remained whether the second chelate ring could be formed by six membered-ring containing -O-Cd-N- bond or by seven membered-ring containing -O-Cd-O- bond. The results of the present work suggested that it would be formed by a six membered ring. Cadmium (11) ions were coordinated with a carboxylic group of the dicarboxylic acids studied, and formed no chelate ring within the complexes. The white precipitate appeared in the solution containing cadmium (11) ion and oxalic acid, in the pH range below 3.0, therefore, the chelate formation was not ascertained in this case. The formation constants, log ..beta..sub(pr)= log((Cdsub(p)Lsub(r)sup((2p-2r)+))/((Cd/sup 2 +/)sup(p)(L/sup 2 -/)sup(r))), of the complexes were: log ..beta../sub 11/ = 1.98, log ..beta../sub 12/ = 3.05 for cadmium (11)-malonic acid; log ..beta../sub 11/ = 2.28, log ..beta../sub 12/ = 3.06 for cadmium (11)-methylmalonic acid; log ..beta../sub 11/ = 1.78, log ..beta../sub 12/ = 3.08 for cadmium (11)-succinic acid; log ..beta../sub 11/ = 1.85, log ..beta../sub 12/ = 3.28 for cadmium (11)-glutaric acid complexes.

  15. Fluorescence of complexes of Eu( Ⅱ ) with aromatic carboxylic acid-1, 1O-phenanthroline

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The 1, 10-phenanthroline-aromatic carboxylic acid (benzoic acid and o-phthalic acid) binary and ternary complexes of europium were synthesized. The fluorescence and FT-IR spectroscopy, elemental analysis, UV spectroscopic studies on these complexes were also performed. These complexes can emit strong red fluorescence of Eu( m ) excited by UV light. At the same excited wavelength, the fluorescence spectra of the complexes were also studied. The results indi cated that the fluorescence intensities of ternary complexes are stronger than that of binary complexes. The reason is that phenanthroline has higher electron density and higher orbit scope in the conjugated system and consequently an easier ener gy transfer to the europium ion, which makes the fluorescence intensity of ternary complexes be stronger than that of bi nary complexes.

  16. Influence of heterogeneity of binding sites of humic acid on its complexation with actinyl ions

    International Nuclear Information System (INIS)

    The influence of heterogeneity of binding sites of humic acid was investigated using three different experimental approaches. 1) Complexation with UO22+ was studied by fluorescence spectroscopy. Considering the quenching phenomena, the apparent stability constants of complexation of humic acid with UO22+ were evaluated and compared with the values reported in the literature. 2) Complexation kinetics of NpO2+ with humic acid and fulvic acid was investigated by kinetic spectra. The complexation kinetics was found to be controlled by the heterogeneity of binding sites. 3) The migration of humic acid-NpO2+ complexes was discussed experimentally by column experiments and analytically by a migration model. The concentration profile of NpO2+ in the column was qualitatively simulated. (author)

  17. Sorption of small quantities of silver on silicic acid under the conditions of complex formation

    International Nuclear Information System (INIS)

    Present article is devoted to sorption of small quantities of silver on silicic acid under the conditions of complex formation. Study of precipitation of small quantities of silver (4.2·10-5mg/l) from the solutions of oxalic, tartaric and citric acids depending on ph showed that under these conditions the precipitation does not occur. This is due to formation of stable and soluble in the water silver complex compounds with oxalic, tartaric and citric acids.

  18. Nonlinear optical properties of p-substituted benzalbarbituric acids

    Science.gov (United States)

    Kondo, K.; Ochiai, S.; Takemoto, K.; Irie, M.

    1990-02-01

    A number of p-substituted benzalbarbituric acid derivatives were synthesized by the reaction of p-substituted benzaldehyde with barbituric acid, and their nonlinear optical properties were investigated by using the Kurtz powder test. p-acetamidobenzalbarbituric acid derivatives were found to exhibit the relatively high second-harmonic intensity and have the higher thermal stability.

  19. Stability of cadmium complex with octaphenyltetrazaporphin and its solvoprotolytic dissociation in pyridine-acetic acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, B.D.; Khelevina, O.G. (Ivanovskij Khimiko-Tekhnologicheskij Inst. (USSR))

    1982-01-01

    Solvoprotolytic dissociation of octaphenyltetrazaporphin cadmium complex in acetic acid solutions in pyridine is investigated. It is stated that its dissociation is obeyed submitted the first order by the complex and the second order by solvated proton. Comparison with cadmium complexes of other porphyrins is carried out.

  20. Syntheses,characteristics and fluorescence properties of complexes of terbium with benzoic acid and its derivatives

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhong-cheng; SHU Wan-gen; RUAN Jian-ming; HUANG Bai-yun; LIU You-nian

    2005-01-01

    The binary complexes of terbium with benzoic acid and its derivatives (phthalic acid,iso-phthalic acid,oaminobenzoic acid,salicylic acid,sulfosalicylic acid) were synthesized and their compositions were identified by elemental analyses.UV,IR of the complexes were investigated.The UV spectra indicate that the complexes'ultraviolet absorption is mainly the ligands' absorption,but the location of peak drifts.The IR spectra show that the IR spectra of complexes are different from those of free ligands,and the band at 400-500 cm-1,due to the stretching vibration of Tb-O,is absent for free ligands.The fluorescence properties were investigated by using luminescence spectroscope,the results show that all the six complexes of terbium exhibit excellent luminescence,due to the transition from the lowest excited state 5D4 to 7F ground state manifold,the complexes of terbium with sulfosalicylic acid have the strongest fluorescence intensity,and is stronger than o-aminobenzoic acid-terbium,whose fluorescence intensity is regarded as the strongest one in the literature,and even stronger than some phosphor of terbium.

  1. Neodymium(3) complexing with bischloromethylphosphinic acid in aqueous solution

    International Nuclear Information System (INIS)

    High resolution spectrography is used to study Nd3+ complexing with (ClCH2)2POOH(HL) in aqueous solution. NdL2+ complex (lg Kstab = 0.44±0.04) with the corresponding absorption band with a maximum at λ=4283 A is formed in a system

  2. Design of stereoelectronically promoted super lewis acids and unprecedented chemistry of their complexes.

    Science.gov (United States)

    Foroutan-Nejad, Cina; Vicha, Jan; Marek, Radek

    2014-09-01

    A new family of stereoelectronically promoted aluminum and scandium super Lewis acids is introduced on the basis of state-of-the-art computations. Structures of these molecules are designed to minimize resonance electron donation to central metal atoms in the Lewis acids. Acidity of these species is evaluated on the basis of their fluoride-ion affinities relative to the antimony pentafluoride reference system. It is demonstrated that introduced changes in the stereochemistry of the designed ligands increase acidity considerably relative to Al and Sc complexes with analogous monodentate ligands. The high stability of fluoride complexes of these species makes them ideal candidates to be used as weakly coordinating anions in combination with highly reactive cations instead of conventional Lewis acid-fluoride complexes. Further, the interaction of all designed molecules with methane is investigated. All studied acids form stable pentavalent-carbon complexes with methane. In addition, interactions of the strongest acid of this family with very weak bases, namely, H2, N2, carbon oxides, and noble gases were investigated; it is demonstrated that this compound can form considerably stable complexes with the aforementioned molecules. To the best of our knowledge, carbonyl and nitrogen complexes of this species are the first hypothetical four-coordinated carbonyl and nitrogen complexes of aluminum. The nature of bonding in these systems is studied in detail by various bonding analysis approaches. PMID:25055748

  3. Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex.

    Science.gov (United States)

    Pastrana-Rios, Belinda; Del Valle Sosa, Liliana; Santiago, Jorge

    2015-07-01

    Trifluoroacetic acid (TFA) may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient). Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I'/I'* band for the components and the ternary complex. Melittin (MLT) was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence. PMID:26798810

  4. Improvement on stability of square planar rhodium (Ⅰ) complexes for carbonylation of methanol to acetic acid

    Institute of Scientific and Technical Information of China (English)

    蒋华; 潘平来; 袁国卿; 陈新滋

    1999-01-01

    A series of square planar cis-dicarbonyl polymer coordinated rhodium complexes with uncoordinated donors near the central rhodium atoms for carbonylation of methanol to acetic acid are reported. Data of IR, XPS and thermal analysis show that these complexes are very stable. The intramolecular substitution reaction is proposed for their high stability. These complexes show excellent catalytic activity, selectivity and less erosion to the equipment for the methanol carbonylation to acetic acid. The distillation process may be used instead of flash vaporization in the manufacture of acetic acid, which reduces the investment on the equipment.

  5. E.E.G. and multiple unit activity during ketamine and barbiturate anaesthesia.

    Science.gov (United States)

    Tamásy, V; Korányi, L; Tekeres, M

    1975-12-01

    Cortical e.e.g. and multiple unit activity (m.u.a.) of the mesencephalic reticular formation, the anterior hypothalamic area, the basal nuclear group of the amygdala and the dorsal hippocampus were studied before and following i.p. injection of different doses of ketamine hydrochloride and a barbiturate in cats with chronically implanted electrodes. Barbiturate administration resulted in a rapid decrease in m.u.a. in the mesencephalic reticular formation which was accompanied by a significant decrease of activity in the limbic structures. No m.u.a. response was observed to visual, acoutic or somatosensory stimulation or to pain. The m.u.a. of the mesencephalic reticular formation and limbic structures increased gradually following ketamine injection. Intermittent or continuous hypersynchronous activity was characteristic in the cortical e.e.g. During the hypersynchronous activity the responsiveness of m.u.a. in the mesencephalic reticular formation, to visual and acoustic stimuli, was blocked. Somatosensory and painful stimulation, however, resulted in a significant increase in the activity both of the mesencephalic reticular formation and of the limbic neuronal pools. PMID:1218162

  6. Synthesis and complex forming property of phosphor acid derivatives

    International Nuclear Information System (INIS)

    Full text:With the aim to get new effective and selective extra gents of noble and non-ferrous metals from acid solution and industrial sewage, research of the dependence of 'structure effectiveness' the various phosphor acid derivatives with logical changeable structure (thio phosphor acids, derivatives of dialkoxythiophosphor, O-alkyl-methylphosphon, alkylphenylphosphon, diphenylphosphine acids also 4 methyl-1,3,2 dioxaphosphorinane) which contain different functional groups, the remains of heterocyclic amines and alkaloids, new derivatives of some analytical reagents were synthesized. The structure of synthesized compounds is approved by the results of IR-, PMR-, mass-spectrum analyze. Researching mass-spectrum decay of synthesized phosphor acid derivatives we defined that differing from O-dihexyl-S-propargyl-benzylthio phosphat, mass spectrum decay of O-dialkyl-S-(piperdynobutin-2-il)thio phosphat is characterized by the appearing [M-H]+ ions and during the decay ions with high intensiveness are formed. Fragmentation of M+ O-alkyl-O-(aminoalkyl)phenylphosphonate proceeds in various directions and characterized with the great number of phosphor containing ions, the possession of the second phenyl radical in the molecule of diphenylphosphon acid derivatives changes the fragmentation of molecular ion of diphenylphosphon acid derivatives. The process of extraction of noble (Au, Ag, Pt, Pd, Os) metals from hydrochloric-sulphur-nitrogen acid medium was analyzed by radioactive indicator's method. It was noticed that structure, strength, conformation of compounds, the temperature, of acid medium (0,1-10 M) and the nature of acids (HCL, H2SO4, HNO3) could have strong influence to the effectiveness of metal extraction. During the research of metals extraction from pure solutions we can see the followings: 1) There are such substances, which can be used as effective group reagent towards the Au, Ag and Pd. 2) Derivatives with acetylene extract ions of gold from medium of

  7. Concentration of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) of Asian catfish oil by urea complexation: optimization of reaction conditions

    OpenAIRE

    Pornpisanu Thammapat; Sirithon Siriamornpun; Patcharin Raviyan

    2016-01-01

    Optimization of the concentrating conditions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) extracted from Asian catfish oil was studied to obtain a maximum concentration. The crude fish oil was extracted from the belly flap and adipose tissue of Asian catfish, and the extracted oil was used as fresh crude oil. The EPA and DHA were concentrated by the urea complexation method. A hexagonal rotatable design was applied to examine the effects of crystallization temperatur...

  8. Transition Metal Complexes of Phosphinous Acids Featuring a Quasichelating Unit: Synthesis, Characterization, and Hetero-bimetallic Complexes.

    Science.gov (United States)

    Allefeld, Nadine; Bader, Julia; Neumann, Beate; Stammler, Hans-Georg; Ignat'ev, Nikolai; Hoge, Berthold

    2015-08-17

    Diorganophosphane oxides were employed as preligands for the synthesis of catalytically active transition metal complexes of the phosphinous acids (CF3)2POH and (C2F5)2POH. Their reactions with solid PtCl2 and PdCl2 led to the formation of mononuclear phosphinous acid complexes [Cl2M{P(R(f))2OH}2] (M = Pd, Pt; R(f) = C2F5, CF3), which can be crystallized, for example, as its pyridinium salts, 2[HPy](+)[Cl2Pd{P(CF3)2O}2](2-). In vacuo HCl is liberated from the neutral palladium complexes affording mixtures of di- and polynuclear complexes. Moreover, (C2F5)2POH was reacted with several β-diketonato complexes of palladium, platinum, and nickel yielding air- and moisture-stable complexes [(acac)M{[P(R(f))2O]2H}], featuring a quasichelating phosphinous acid phosphinito unit {P(R(f))2O···H···O(R(f))2P}(-). Treatment of [Ni(Cp)2] (Cp = cyclopentadienyl) and [(cod)RhCl]2 (cod = 1,5-cyclooctadiene) with (C2F5)2POH leads to the substitution of one Cp or chloro ligand by a quasichelating unit. The novel coordination compounds were characterized by NMR and IR spectroscopies, mass spectrometry, and X-ray diffraction analysis. The platinum complex [(acac)Pt{[P(C2F5)2O]2H}] (acac = acetylacetonato) was used for the construction of hetero-bimetallic complexes by the treatment with [(cod)RhCl]2 and [Ni(Cp)2]. The trinuclear bimetallic complex [{(acac)Pt[P(C2F5)2O]2}2Ni] is the first structurally characterized hetero-bimetallic species containing a bis(perfluoroalkyl)phosphinito bridge. PMID:26242286

  9. Solution structures of lipoyl domains of the 2-oxo acid dehydrogenase complexes from Azotobacter vinelandii. Implications for molecular recognition.

    OpenAIRE

    Berg, A.

    1997-01-01

    The 2-oxo acid dehydrogenase complexes are large multienzyme complexes that catalyse the irreversible oxidative decarboxylation of a specific 2-oxo acid to the corresponding acyl-CoA derivative. The pyruvate dehydrogenase complex (PDHC) converts the product of the glycolysis, pyruvate, to acetyl-CoA, which enters the tricarboxylic acid cycle. The 2-oxoglutarate dehydrogenase complex (OGDHC functions in the tricarboxylic acid cycle itself by converting 2-oxoglutarate to succinyl-CoA. The branc...

  10. Complexation of lanthanides and actinides with humic acids. Appendix II

    International Nuclear Information System (INIS)

    Natural waters are the main transport medium for radionuclides in the geosphere in case of an accidental release of radioactivity from a nuclear waste disposal. Complexation studies of radionuclides with natural organic substances present in aquifers are important to perform in order to predict their behaviour in natural systems. Interactions of two trivalent elements, curium and dysprosium, representative respectively for actinides and lanthanides, have been investigated by Time-Resolved Laser-Induced Spectrofluorometry (TRLIS) allowing to work at low concentrations of cations (10-6 M-10-8 M). By using a 'Fluorescence titration' method, complexing capacities and interaction constants are obtained over a broad pH range (4 to 7) at a constant ionic strength (0.1 M). The complexing behaviour of Cm and Dy is analysed. Data are discussed and compared with existing literature data. (orig.)

  11. Complexation and biodistribution study of 111In complexes of bifunctional phosphinic acid analogues of H4DOTA

    Czech Academy of Sciences Publication Activity Database

    Forsterová, Michaela; Zimová, Jana; Petrík, M.; Lázníček, M.; Lázníčková, A.; Hermann, P.; Melichar, František

    2007-01-01

    Roč. 2, č. 337 (2007), s. 34-34. ISSN 1619-7070 R&D Projects: GA AV ČR 1QS100480501 Institutional research plan: CEZ:AV0Z10480505 Keywords : bifunctional H4DOTA ligands * phosphinic acid analogues, * complexation of 111In Subject RIV: FR - Pharmacology ; Medidal Chemistry

  12. Simultaneous effect of organic modifier and physicochemical parameters of barbiturates on their retention on a narrow-bore PGC column

    Czech Academy of Sciences Publication Activity Database

    Forgács, E.; Cserháti, T.; Mikšík, Ivan; Eckhardt, Adam; Deyl, Zdeněk

    2004-01-01

    Roč. 800, č. 1-2 (2004), s. 259-262. ISSN 1570-0232 Grant ostatní: CZ - HU(CZ) Cooperation programme Institutional research plan: CEZ:AV0Z5011922 Keywords : barbiturates * porous graphitized carbon Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.176, year: 2004

  13. Complexation and extraction of series 4f, 5f and 4d ions by dialkyldithiophosphoric acids

    International Nuclear Information System (INIS)

    A study was carried out on the complexing and extracting properties of various dialkyldithiophosphoric acids towards ions of the 4f, 5f and 4d series. Sulphurated donors complex and extract ions of the 4f and 5f series less strongly than their oxygenated homologues. However the affinity of trivalent actinide ions for dialkythiophosphate ions is shown to be greater than that of lanthanides. The conditions of ruthenium extraction from nitric acid are defined

  14. Determination of aminoglycoside antibiotics using complex compounds of chromotropic acid bisazoderivatives with rare earth ions

    International Nuclear Information System (INIS)

    Studies of complex formation of bisazo derivatives of chromotropic acid with rare earth ions and aminoglycoside antibiotics have made it possible to choose carboxyarsenazo, orthanyl R and carboxynitrazo as highly sensitive reagents for determining aminoglycoside antibiotics. Conditions have been found for the formation of precipitates of different-ligand complexes containing rare earth ions, bisazo derivatives of chromotropic acid and aminogylcoside antibiotics. A procedure has been worked out of determining the antibiotics in biological samples with carboxyarsenazo

  15. FT-IR spectroscopic studies of fulvic acid from weathered coal and its complexes

    International Nuclear Information System (INIS)

    FT-IR spectrum of fulvic acid from wheathered coal of Gongxian is determined using second derivative spectroscopy and the spectroscopic resolution is enhanced. Moreover, FT-IR spectra of the complexes of fulvic acid with Ca2+, Ba2+, Cu2+, Pb2+ and UO22+ under different pH are determined and the nature of the coordination of these complexes is discussed

  16. Water-free Alkaline Polymer-inorganic Acid Complexes with High Conductivity at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    O.V.Chervakov; M.V.Andriianova; V.V.Riabenko; A.V.Markevich; E.M.Shembel; D.Meshri

    2007-01-01

    1 Results Recently increased interest is shown to proton conducting materials based on the alkaline polymer-inorganic acid complexes that is caused by a possibility of their application as the high-temperature electrolyte systems for various electrochemical devices (fuel cells,sensors,lithium power sources etc.).Complexes of inorganic acids with the alkaline polymers (polybenzimidazoles[1],polyvinylpyridines[2]) are characterized by high ionic conductivity at ambient temperatures (up to 10-2 Ω-1·cm-1) a...

  17. Metal ion complexation properties of fulvic acids extracted from composted sewage sludge as compared to a soil fulvic acid.

    Science.gov (United States)

    Esteves da Silva, Joaquim C G; Oliveira, César J S

    2002-07-01

    Complexation properties of an anthropogenic fulvic acid (FA) extracted from a composted sewage sludge (csFA) for Cu(II), Pb(II) and Cd(II) were studied at pH=6 and at a concentration of 25 mg L(-1). For the case of Cu(II), a particular analysis of the complexation phenomena was done at pH values of 3, 4, 5 and 6 and at aqueous FA concentrations of 25, 50 and 100 mg L(-1) by synchronous excitation molecular fluorescence spectroscopy (SyF). Potentiometric titrimetry with Cu(II), Pb(II), Cd(II) and H+ ion-selective electrodes and acid-base conductimetric titrations were used to obtain experimental information about the acid properties and complexation phenomena. A comparison of the results obtained for csFA with a natural soil FA (sFA) was made. Differences have been detected in the structural composition of the two samples and in the structure of the binding sites. In the csFA, binding site structures containing nitrogen probably play an important role in the complexation, besides oxygen containing structures. Complexation by sFA is mainly due to carboxylic and phenolic structures. Nevertheless, this work shows that csFA have macroscopic complexation properties (magnitude of the conditional stability constant and binding sites concentration) somewhat similar to the natural sFA samples. PMID:12188141

  18. Contribution to the study of pertechnetate (sup(99m)Tc) stannous citrate - citric acid complexation

    International Nuclear Information System (INIS)

    Pertechnetate/citric acid/stannous citrate complexation carried out from a lyophilisate of stannous citrate in citric medium at pH5 leads to the formation of separable compounds. These compounds are tin-free technetium citrates. Similar results have been described in the case of complexation reactions with glycolic, thioglycolic and thiomalic acids and with other carboxylates such as dimercaptosuccinic acid. These processes include the reduction of Tcsup(VIII) by Snsup(II) in the presence of thiomalic acid under conditions similar to our own: stannous thiomalate in thiomalic medium to which is added the pertechnetate solution producing Tc-thiomalate complexes variable with the reaction pH. Also worth considering is the possible complexation between pertechnetate and the same acid in the absence of reducing ion, following a special procedure (heating). The complexes described here contain the oxotechnetium bond (terminal oxygen-technetium) and a strong probability exists in favour of dimerisation. Their stability, for a reaction in acid solution: pH 5.0/5.5, becomes satisfactory if: the solution is concentrated enough; bubbling by an inert gas is carried out; room temperature is not exceeded. The development takes place through a partial reoxidation characterised by colour change. An original interaction between reduced states of Tc and citric acid may be claimed with certainty under our experimental conditions. The difficulty then lies in the passage to the tracer stage when the isotope sup(99m)Tc is used

  19. The properties of solid Zn(II)-amino acid complexes in the form of suspensions.

    Science.gov (United States)

    Dolińska, B

    2001-10-01

    An investigation was made into the experimental conditions for the formation of poorly soluble complexes of the divalent Zinc(II) combined with the following selected amino acids: tyrosine, tryptophan, cysteine, histidine, and alanine, in the form of suspensions for parenteral administration. The number of Zn(II)-binding sites in the amino acid (n) as well as the amino acid affinity to Zn(II) (Ka), were determined. Cysteine was found to have the highest number of Zn(II)-binding sites--3, whereas alanine the lowest--1. In the conditions described herein, Zn(II) amino acid complexes of diverse stability (durability) were obtained. The analysis of the kinetics of the binding revealed that the most stable complexes were those formed by Zn(II) in combination with tryptophan (Ka = 405.78 microM(-1) +/- 12.17), and with tyrosine (Ka = 343.88 microM +/- 22.35); whereas the least stable complexes were those formed by Zn(II) in combination with histidine (Ka = 29.90 microM +/- 4.78), and with alanine (Ka = 13.0 microM(-1) +/- 1.04). Cysteine formed complexes of intermediate stability (Ka = 168.53 microM(-1) +/- 12.36). The stability ofthe Zn(II) amino acid complexes obtained was conditioned by both the molecular weight (P = 0.033) of the amino acid and its isoelectric point (P < 0.001). PMID:11718265

  20. A study on dissociation and complexation of fuivic acid from weathered coal using potentiometric titration

    International Nuclear Information System (INIS)

    The dissociation and complexation of fulvic acid from weathered coal (from Gong Xian, Henan Province) are studied by means of potentiometric titrations. The effects of salt concentration and functional group heterogeneity on the apparent dissociation constants are characterized. Some characteristics of the binding of the ions Cu(II), Th(IV) and La(III) on this fulvic acid are determined

  1. Metals complexation with humic acids in surface water of different natural–climatic zones

    Directory of Open Access Journals (Sweden)

    Dinu M. I.

    2013-04-01

    Full Text Available Humic acids extracted from different soils. The stability constants of metal humates and acid dissociation constant humic acids were calculated. Forms of metals in natural waters was determined with use account their chemical composition and content and properties of organic matter. We assessed metals speciation in water objects with account for competitive reactions resulting in formation of hydroxide, hydrocarbonate, sulfate, and chloride metal complexes and obtained a competitive series of metal activity in natural waters of the zones considered.

  2. Retention of ruthenium-nitrosyl complexes in 30% TBP-kerosene-laurohydroxamic acid

    International Nuclear Information System (INIS)

    The degradation products of diluent cause RuNO complexes to be retained in the irradiated organic solvent. The Ru retention in 30% TBP-kerosene-laurohydroxamic acid increases with hydroxamic acid concentration, aging temperature and aging time of loaded organic phase. For U concentrations in the aqueous phase above 30 g/l, Ru retention is not influenced by NaNO2, although NaNO2, can destroy the hydroxamic acid. (orig.)

  3. Metal complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid and benzohydroxamic acid. Crystal and molecular structure of [Cu(phen)2(Cl)]Cl x H2Sha, a model for a peroxidase-inhibitor complex.

    Science.gov (United States)

    O'Brien, E C; Farkas, E; Gil, M J; Fitzgerald, D; Castineras, A; Nolan, K B

    2000-04-01

    Stability constants of iron(III), copper(II), nickel(II) and zinc(II) complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid (HAha) and benzohydroxamic acid (HBha) have been determined at 25.0 degrees C, I=0.2 mol dm(-3) KCl in aqueous solution. The complex stability order, iron(III) > copper(II) > nickel(II) approximately = zinc(II) was observed whilst complexes of H2Sha were found to be more stable than those of the other two ligands. In the preparation of ternary metal ion complexes of these ligands and 1,10-phenanthroline (phen) the crystalline complex [Cu(phen)2(Cl)]Cl x H2Sha was obtained and its crystal structure determined. This complex is a model for hydroxamate-peroxidase inhibitor interactions. PMID:10830846

  4. Barbiturate ingestion in three adult captive tigers (Panthera tigris and concomitant fatal botulism of one : clinical communication

    Directory of Open Access Journals (Sweden)

    J. H. Williams

    2011-05-01

    Full Text Available Zoo animals, including tigers, have been reported to suffer from barbiturate intoxication, with pentabarbitone being most commonly recorded. Clinical signs range from mild ataxia to general anaesthesia with recovery over hours to days with several factors affecting hepatic barbiturate metabolism and tissue partitioning. Botulism is an often fatal intoxication in man, animals, birds and certain fish. The occurrence in carnivores is uncommon to rare, with only 2 reports found of botulism in felids. This report relates to 3 adult captive cohabiting tigers that simultaneously developed signs of abdominal discomfort, progressive ataxia, recumbency and comatose sleep resembling stage 2 anaesthesia, alternating with periods of distracted wakefulness and ataxic movements. These signs occurred 4 days after being fed the carcass of a horse that had ostensibly died of colic and not been euthanased. The male tiger that was the dominant animal in the feeding hierarchy was worst affected and had to be given intravenous fluids. The female that was lowest in hierarchy was unaffected. After 48-72 hours of treatment at the Onderstepoort Veterinary Academic Hospital the females could eat and made an uneventful recovery. The male tiger showed partial recovery but died during the night a few hours after drinking water on his return to the owner. Necropsy revealed severe oesophageal dilation and impaction with decaying grass; some of this material and water were present in the pharynx and trachea, and had been aspirated causing acute widespread bronchopneumonia. Colon content tested negative for common pesticides but, together with liver, tested positive for barbiturate. Serum taken on the day of admission had tested negative for barbiturate and the residual serum from the 3 animals later tested negative for botulinum toxin. Colon and oesophageal content from the male at necropsy were positive for Clostridium botulinum toxin type C by the mouse bioassay

  5. A new approach to study cadmium complexes with oxalic acid in soil solution

    International Nuclear Information System (INIS)

    This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH2) were observed. In order to verify the possible formation of complexes with OAH2, aqueous solutions of OAH2 with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cdn(X,Y)(2n+1)]-, where n is the number of cadmium atoms, X = Cl-, and Y = OAH-. Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions.

  6. Studies on photolysis of nitrosyl ruthenium complexes in nitric acid media

    International Nuclear Information System (INIS)

    The photolysis of nitrosyl ruthenium complexes in nitric acid media has been investigated in detail using low pressure mercury lamp (254 nm). The UV spectra of nitrosyl ruthenium complexes is also studied. The experimental results show that the photolysis of nitrosyl ruthenium in nitric acid media obeys pseudo-first order kinetics. The rate constant is affected by the concentration of nitric acid and has a maximum at 2 mol/L HNO3. In temperature range from 10 degree C to 40 degree C, the rate constant decreases with the increasing of the temperature

  7. Oxidation of aromatic alcohols on zeolite-encapsulated copper amino acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Teixeira Florencio, J.M. [Kaiserslautern Univ. (Germany). Dept. of Chemistry, Chemical Technology

    1998-12-31

    Copper complexes of the amino acids histidine, arginine and lysine have been introduced into the supercages of zeolite Y and, for the first time, into the large intracrystalline cavities of zeolites EMT and MCM-22. The resulting host/guest compounds are characterized by X-ray powder diffraction, UV/VIS-spectroscopy in the diffuse reflectance mode and by catalytic tests in the liquid-phase oxidation of aromatic alcohols (viz. benzyl alcohol, 2- and 3-methylbenzyl alcohol and 2,5-dimethylbenzyl alcohol) with tertiary-butylhydroperoxide as oxidant. It was observed that intracrystalline copper-amino acid complexes possess remarkable catalytic activity, yielding the corresponding aromatic aldehydes and acids. (orig.)

  8. 异烟酸巴比妥酸流动注射法测定水中总氰化物%Measurement of the total cyanide with Isonicotinic/Barbituric bv flow iniection analysis

    Institute of Scientific and Technical Information of China (English)

    郭少维; 孟祖君; 姜鑫; 陈杨虹

    2011-01-01

    Objective to establish a method of using flow injection in-line cyanide distillation to determine total cyanide in water and wastewater.This method uses sonicotinic acid and barbituric acid as the color reagent.Samples are first mixed with phosphoric acid,and then introduced into an in-line cyanide distillation unit.Then samples passed over a heater and a UV lamp.Then CN-re-leased from complexes during the heating and irradiation combines with protons to form HCN.The HCN diffuses across a Teflon membrane and is trapped as CN- in a sodium hydroxide solution.The CN- is first converted to cyanogens chloride.Then react with color reagent and form a colored product that is measured at 600 nm.Results Detection range as 2 ~ 200 μg · L-1.Detection limit was 0.15 μg · L-1.The sample recovery was 90% to 105%.RSD was less than 3.0%.Conclusion The method is simple and sensitive compared with standard method.%建立了新的流动注射在线蒸馏测定水和废水中总氰化物的方法.该方法采用异烟酸-巴比妥酸为显色剂,将含氰样品与磷酸混合,进入在线氰消解蒸馏系统,通过加热与紫外辐射,CN-从化合物中释放形成气态的HCN并流过膜组件,其中的CN-被氢氧化钠吸收,将其转换为氯化氰,加入显色剂后可在600 nm波长下比色测定总氰化物浓度.结果表明:方法测量范围为2 ~ 200 μg·L-1,最低检出限为0.15μg·L-1,水样测量的回收率为90% ~ 105%,精密度RSD小于3.0%.方法操作简便,灵敏度高,优于标准方法.

  9. Structural, spectroscopic and computational studies of the 2:1 complex of nipecotic acid with squaric acid

    International Nuclear Information System (INIS)

    Highlights: • Centrosymmetric complex of nipecotic acid with squaric acid. • N–H⋯O hydrogen bonds are dominant in a supromolecular structure. • Isolated 2:1 complexes are optimized by the B3LYP/6-311G(d, p) approach. • NMR spectra suggest the same conformation of piperidinium ring in crystal and solution. • FTIR spectrum confirms a medium strong H-bonds in the solid state. - Abstract: The 2:1 centrosymmetric complex of protonated (R) and (S)-nipecotic acids (piperidinium-3-carboxylic acid) with the squarate dianion (3,4-dihydroxy-3-cyclobuten-1,2-dione) (1), has been synthesized and characterized by single-crystal X-ray analysis, FTIR and NMR spectroscopy. Crystals are monoclinic, space group C2/c, Z′ = 0.5. The squarate dianion lays at the center of symmetry. It is surrounded by six stereoisomers of (R) and (S)-nipecotinium acid cations. The molecules are linked by N–H⋯O and COOH⋯O hydrogen bonds of 2.759(2) and 2.619(2) Å, respectively. The piperidine ring adopts a chair conformation with the carboxylic group in equatorial position. The FTIR spectrum shows a broad and intense absorption in the 3400–2000 cm−1 region, typical of medium–strong N–H⋯O and O–H⋯O hydrogen bonds. The 1H and 13C NMR spectra of the investigated complex confirm the structure of 1 in aqueous solution. Two models of the isolated 2:1 complexes (2 and 3) have been optimized at B3LYP/6-311G(d, p) level of theory to predict the more energetically stable structure. In 2 the molecules are linked by the O–H⋯N and O–H⋯O hydrogen bonds, while in 3 by the N–H⋯O and O–H⋯N hydrogen bonds

  10. Spectroscopic study of the Eu3+, Tb3+ and Gd3+ complexes with ligands derived from dicarboxylic acids

    International Nuclear Information System (INIS)

    Complexes of Eu3+, Tb3+ and Gd3+ with dipicolinic acid, chelidamic acid and chelidonic acid have been synthesized in order to study the effect of the substituent groups on the luminescence of the lanthanide complexes. The luminescence of the Eu3+ and Tb3+ complexes was quantified by quantum yield measurements. The complexes of Gd3+ have been used to determine the energies of the triplet states of the ligands. The Tb3+ complex synthesized with dipicolinic acid presented the highest quantum yield due to the energy difference between the triplet state of the dipicolinic acid and the emitting level of the Tb3+ ion. (author)

  11. Studies on some simple and mixed ligated oxovanadium(V) complexes of hydroxamic acids

    International Nuclear Information System (INIS)

    Some simple and mixed ligands complexes of oxovanadium(V) with benzo-, and salicyl-hydroxamic acids as primary ligands and 2,2-bipyridine and 1,10-phenanthroline as secondary ligands have been prepared and characterised. The structures of the complexes have been assigned on the basis of electronic and infra red spectral data. The IR spectra of the simple complexes reveal the bidentate nature of the primary ligands, whereas in the mixed complexes these ligands exhibit monodentate nature. Magnetic moment studies show that the complexes are diamagnetic. (author). 13 refs., 1 tab., 1 fig

  12. Database of amino acid-nucleotide contacts in the DNA complexes with homeodomain family proteins

    International Nuclear Information System (INIS)

    The analysis of amino acid-nucleotide contacts in interfaces of the protein-DNA complexes, intended to find consistencies in the protein-DNA recognition, is a complex problem that requires analysis of the physicochemical characteristics of these contacts, of the positions of the participating amino acids and nucleotides in the chains of the protein and the DNA, respectively, as well as conservatism of these contacts. Thus, those heterogeneous data should be systematized. For this purpose we have developed a database of amino acid-nucleotide contacts ANTPC (Amino acid Nucleotide Type Position Conservation) following the archetypal example of the proteins in the homeodomain family. We show that it can be used for comparison and classification of interfaces of the protein-DNA complexes

  13. Novel rhenium(V) complexes with thiosemicarbazones of pyruvic or phenylglyoxylic acids

    International Nuclear Information System (INIS)

    New rhenium(V) complexes with thiosemicarbazones of pyruvic (L') or phenylglyoxylic (L'') acids were synthesized and isolated in solid state in aqueous solutions of concentrated hydrohalic acids. By the method of elementary analysis formation of complexes, featuring the following composition [ReOL'Cl3]·2H2O, [ReOL''2Br]Br2·2H2O, [ReOL'Br2(OH)]·2H2O, [ReOL''2(OH)]Cl·2H2O, [Re2O3L'2Cl4]·2H2O, was ascertained. Solubility of the complexes in organic solvents was determined

  14. State and dissociation mechanisms of mixed-ligand acidoporphyrin complexes of metals in sulfuric acid solutions

    International Nuclear Information System (INIS)

    Dissociation of indium complexes with tetraphenylporphyrin (H2 TPP) and complexes (Cl)In TPP(X)4, where TPP(X)42--dianion of TPP substituted in para-positions of phenyls with OCH3, Br, NO2 groups, in sulfuric acid solutions has been studied by spectrophotometric method. It is shown that complex (Cl)In TPP associated with proton of the solvent dissociates by multistage mechanism, protolytic dissociation of metalloporphyrin under the effect of sulfuric acid molecules being the limiting stage of the process. Proton associated with metalloporphyrin produces inhibiting effect on dissociation

  15. Characterization of folic acid/native cyclodextrins host-guest complexes in solution

    Science.gov (United States)

    Ceborska, Magdalena; Zimnicka, Magdalena; Wszelaka-Rylik, Małgorzata; Troć, Anna

    2016-04-01

    The complexation of folic acid (FA) with native cyclodextrins was studied and this process was used for the comparison of 1H NMR, ITC and ESIMS for the evaluation of association constants. The stability increases in the series: α-cyclodextrin/FA complexes. The dimerization of FA in water was also studied, as well as its impact on the process of complexation with native cyclodextrins.

  16. Hydrolytic activity of -alkoxide/acetato-bridged binuclear Cu(II) complexes towards carboxylic acid ester

    Indian Academy of Sciences (India)

    Weidong Jiang; Bin Xu; Zhen Xiang; Shengtian Huang; Fuan Liu; Ying Wang

    2013-09-01

    Two -alkoxide/acetate-bridged small molecule binuclear copper(II) complexes were synthesized, and used to promote the hydrolysis of a classic carboxylic acid ester, -nitrophenyl picolinate (PNPP). Both binuclear complexes exhibited good hydrolytic reactivity, giving rise to . 15547- and 17462-fold acceleration over background value for PNPP hydrolysis at neutral conditions, respectively. For comparing, activities of the other two mononuclear analogues were evaluated, revealing that binuclear complexes show approximately 150- and 171-fold kinetic advantage over their mononuclear analogues.

  17. Reactions of certain acids with ammoniac 1,2,4-triazole complexes of rhenium (5)

    International Nuclear Information System (INIS)

    The process of interaction of formic, acetic, hydrofluoric and sulfuric acids with ammoniac-1,2,4-triazole complexes of rhenium (5) was studied. The complexes [Re2O3(OH)2L2X2(H2O)2], where X=CH3COO, HCOO, F; L=1,2,4-triazole, and [Re2O2(SO4)3L2(H2O)2] were synthesized. The properties of the complexes prepared were characterized by physicochemical methods

  18. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    Institute of Scientific and Technical Information of China (English)

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  19. Characterization of humic acids and humate complexation of Am(III)

    International Nuclear Information System (INIS)

    The characterization of selected humic acids and the humate complexation behaviour of Am(III) are described. The commercial humic acid (Na salt) from Aldrich Co. is purified to a protonated form and used as a reference material. Humic and fulvic acids extracted and purified from Gorleben groundwaters (FRG) are taken as site specific materials. The characterization of the reference and site specific materials shows that they have very similar chemical properties and represent typical humic acids as known in the literature. By considering the humic acids as ion-exchangers and taking their loading capacity into account, the complexation constant of Am(III) is determined. The thus determined constant is found to be independent of pH and ionic strength. (orig.)

  20. Metal complexation inhibits the effect of oxalic acid in aerosols as cloud condensation nuclei (CCN

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2010-11-01

    Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to cancel the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play a key role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is one of the major components of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan with fractionation based on particle size using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid can act as CCN because of its hygroscopic properties, while metal complexes are not hygroscopic, and so cannot be CCN. Based on the concentration of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not act as CCN in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is possible that the cooling effect of organic aerosols assumed in various climate modeling studies is overestimated because of the lack of information on metal oxalate complexes in aerosols.

  1. Determination of stability constants of the Co(II) complexes with weathered coal fulvic acid

    International Nuclear Information System (INIS)

    The stability constants of Co(II) complexes with weathered coal fulvic acid are determined by both Schubert method and Stevenson method at pH = 5.3 +- 0.2, I = 0.001-1.0 mol/kg and (30 +- 1) degree C. The modified Schubert method is also used to estimate the stability constants of Co(II) complexes with the fulvic acid. It is shown that the trend of forming poly nuclei complexes of Co(II)-fulvic acid increases with increasing ionic strength in the solution and that 1:1 and 2:1 type complexes, respectively, are formed at different ionic strength. A comparison between the values of lg β obtained by different methods is made

  2. A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex

    International Nuclear Information System (INIS)

    A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 μg ml-1. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C

  3. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes

    Science.gov (United States)

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M. Arif

    2016-05-01

    We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

  4. Respiratory depression in rats induced by alcohol and barbiturate and rescue by ampakine CX717.

    Science.gov (United States)

    Ren, Jun; Ding, Xiuqing; Greer, John J

    2012-10-01

    Barbiturate use in conjunction with alcohol can result in severe respiratory depression and overdose deaths. The mechanisms underlying the additive/synergistic actions were unresolved. Current management of ethanol-barbiturate-induced apnea is limited to ventilatory and circulatory support coupled with drug elimination. Based on recent preclinical and clinical studies of opiate-induced respiratory depression, we hypothesized that ampakine compounds may provide a treatment for other types of drug-induced respiratory depression. The actions of alcohol, pentobarbital, bicuculline, and the ampakine CX717, alone and in combination, were measured via 1) ventral root recordings from newborn rat brain stem-spinal cord preparations and 2) plethysmographic recordings from unrestrained newborn and adult rats. We found that ethanol caused a modest suppression of respiratory drive in vitro (50 mM) and in vivo (2 g/kg ip). Pentobarbital induced an ∼50% reduction in respiratory frequency in vitro (50 μM) and in vivo (28 mg/kg for pups and 56 mg/kg for adult rats ip). However, severe life-threatening apnea was induced by the combination of the agents in vitro and in vivo via activation of GABA(A) receptors, which was exacerbated by hypoxic (8% O(2)) conditions. Administration of the ampakine CX717 alleviated a significant component of the respiratory depression in vitro (50-150 μM) and in vivo (30 mg/kg ip). Bicuculline also alleviated ethanol-/pentobarbital-induced respiratory depression but caused seizure activity, whereas CX717 did not. These data demonstrated that ethanol and pentobarbital together caused severe respiratory depression, including lethal apnea, via synergistic actions that blunt chemoreceptive responses to hypoxia and hypercapnia and suppress central respiratory rhythmogenesis. The ampakine CX717 markedly reduced the severity of respiratory depression. PMID:22837171

  5. Crystal structure of 5-hy-droxy-5-propyl-barbituric acid.

    Science.gov (United States)

    Gelbrich, Thomas; Griesser, Ulrich J

    2015-11-01

    Mol-ecules of the title compound, C7H10N2O4, systematic name 5-hy-droxy-5-propyl-pyrimidine-2,4,6(1H,3H,5H)-trione, form a hydrogen-bonded framework which is based on three independent hydrogen bonds, N-H⋯O(carbon-yl), N-H⋯O(hy-droxy) and O-H⋯O(carbon-yl). This framework has the topology of the 5-connected nov net. Each mol-ecule is linked to five other mol-ecules via six hydrogen bonds, and the descriptor of the hydrogen-bonded structure is F65[4(4).6(6)-nov]. The crystal packing is isostructural with that of the previously reported 5-hy-droxy-5-ethyl analogue. PMID:26594498

  6. Crystal structure of 5-hy­droxy-5-propyl­barbituric acid

    Science.gov (United States)

    Gelbrich, Thomas; Griesser, Ulrich J.

    2015-01-01

    Mol­ecules of the title compound, C7H10N2O4, systematic name 5-hy­droxy-5-propyl­pyrimidine-2,4,6(1H,3H,5H)-trione, form a hydrogen-bonded framework which is based on three independent hydrogen bonds, N—H⋯O(carbon­yl), N—H⋯O(hy­droxy) and O—H⋯O(carbon­yl). This framework has the topology of the 5-connected nov net. Each mol­ecule is linked to five other mol­ecules via six hydrogen bonds, and the descriptor of the hydrogen-bonded structure is F65[44.66-nov]. The crystal packing is isostructural with that of the previously reported 5-hy­droxy-5-ethyl analogue. PMID:26594498

  7. Amino acid detection using fluoroquinolone–Cu2+ complex as a switch-on fluorescent probe by competitive complexation without derivatization

    International Nuclear Information System (INIS)

    In this work, we describe the use of fluoroquinolone–Cu2+ complex as a competitive switch-on fluorescence probe for amino acid determination without derivatization. The fluorescence intensity of this probe, which has been reduced due to effective quenching by Cu2+ ion, increases drastically by an addition of amino acid (glycine, phenylalanine, sarcosine, aspargine, alanine, proline, arginine, aspartic acid, glutamic acid, lysine, leucine and isoleucine). The overall stability constants of Cu2+ ion complexes with amino acids were determined by fluorometric titration of fluoroquinolone-Cu2+ complex with the amino acid solution. Furthermore, the probe shows high calibration sensitivity toward aspartic acid. The fluorescence signal depends linearly on the amino acid concentration within the range of concentration from 1.2×10−7 to 1.1×10−5 mol L−1 for aspartic acid. The detection limit was found 2.7×10−8 mol L−1 with the relative standard deviation (RSD%) about 2.1% (five replicate). -- Highlights: • Amino acids are detected by using fluoroquinolone–Cu2+ complex as fluorescent probe. • Amino acids were detected based on a competitive complexation reaction. • Probe has been able to recognize amino acids through switch-on fluorescence behavior. • Ultra-trace level of aspartic and glutamic acid is determined without derivatization

  8. Amino acid detection using fluoroquinolone–Cu{sup 2+} complex as a switch-on fluorescent probe by competitive complexation without derivatization

    Energy Technology Data Exchange (ETDEWEB)

    Farokhcheh, Alireza; Alizadeh, Naader, E-mail: alizaden@modares.ac.ir

    2014-01-15

    In this work, we describe the use of fluoroquinolone–Cu{sup 2+} complex as a competitive switch-on fluorescence probe for amino acid determination without derivatization. The fluorescence intensity of this probe, which has been reduced due to effective quenching by Cu{sup 2+} ion, increases drastically by an addition of amino acid (glycine, phenylalanine, sarcosine, aspargine, alanine, proline, arginine, aspartic acid, glutamic acid, lysine, leucine and isoleucine). The overall stability constants of Cu{sup 2+} ion complexes with amino acids were determined by fluorometric titration of fluoroquinolone-Cu{sup 2+} complex with the amino acid solution. Furthermore, the probe shows high calibration sensitivity toward aspartic acid. The fluorescence signal depends linearly on the amino acid concentration within the range of concentration from 1.2×10{sup −7} to 1.1×10{sup −5} mol L{sup −1} for aspartic acid. The detection limit was found 2.7×10{sup −8} mol L{sup −1} with the relative standard deviation (RSD%) about 2.1% (five replicate). -- Highlights: • Amino acids are detected by using fluoroquinolone–Cu{sup 2+} complex as fluorescent probe. • Amino acids were detected based on a competitive complexation reaction. • Probe has been able to recognize amino acids through switch-on fluorescence behavior. • Ultra-trace level of aspartic and glutamic acid is determined without derivatization.

  9. Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

    International Nuclear Information System (INIS)

    The pseudotetrahedral complexes of [Cu(PPh3)2(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88 ms (frozen DCM solution up to 6.7 ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. - Highlights: • Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands. • Very long lived phosphorescent copper(I) complexes. • [Cu(PPh3)2(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9 ms). • In frozen MeOH:EtOH solution lifetime increases to 7 ms. • Quantum efficiency equal to 4.7%

  10. Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, Jan G., E-mail: gmalecki@us.edu.pl [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Łakomska, Iwona, E-mail: iwolak@chem.umk.pl [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Maroń, Anna [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Szala, Marcin [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland); Fandzloch, Marzena [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Nycz, Jacek E., E-mail: jacek.nycz@us.edu.pl [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland)

    2015-05-15

    The pseudotetrahedral complexes of [Cu(PPh{sub 3}){sub 2}(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88 ms (frozen DCM solution up to 6.7 ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. - Highlights: • Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands. • Very long lived phosphorescent copper(I) complexes. • [Cu(PPh{sub 3}){sub 2}(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9 ms). • In frozen MeOH:EtOH solution lifetime increases to 7 ms. • Quantum efficiency equal to 4.7%.

  11. A complex of equine lysozyme and oleic acid with bactericidal activity against Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Emily A Clementi

    Full Text Available HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize

  12. Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex

    Directory of Open Access Journals (Sweden)

    Belinda Pastrana-Rios

    2015-07-01

    Full Text Available Trifluoroacetic acid (TFA may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient. Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I'/I'* band for the components and the ternary complex. Melittin (MLT was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence.

  13. Water Soluble Usnic Acid-Polyacrylamide Complexes with Enhanced Antimicrobial Activity against Staphylococcus epidermidis

    Directory of Open Access Journals (Sweden)

    Iolanda Francolini

    2013-04-01

    Full Text Available Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly dissolved in water and possessed a greater antimicrobial activity against Staphylococcus epidermidis than both the free drug and the polymer alone. The best results were obtained with the complex based on the lowest molecular weight polymer and containing a low drug content. Such a complex showed a larger inhibition zone of bacterial growth and a lower minimum inhibitory concentration (MIC with respect to usnic acid alone. This improved killing effect is presumably due to the reduced size of the complexes that allows an efficient cellular uptake of the antimicrobial complexes. The killing effect extent seems to be not significantly dependent on usnic acid content in the samples.

  14. Copper Complexes of Nicotinic-Aromatic Carboxylic Acids as Superoxide Dismutase Mimetics

    Directory of Open Access Journals (Sweden)

    Virapong Prachayasittikul

    2008-12-01

    Full Text Available Nicotinic acid (also known as vitamin B3 is a dietary element essential for physiological and antihyperlipidemic functions. This study reports the synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids (phthalic, salicylic and anthranilic acids. The tested copper complexes exhibited superoxide dismutase (SOD mimetic activity and antimicrobial activity against Bacillus subtilis ATCC 6633, with a minimum inhibition concentration of 256 μg/mL. Copper complex of nicotinic-phthalic acids (CuNA/Ph was the most potent with a SOD mimetic activity of IC50 34.42 μM. The SOD activities were observed to correlate well with the theoretical parameters as calculated using density functional theory (DFT at the B3LYP/LANL2DZ level of theory. Interestingly, the SOD activity of the copper complex CuNA/Ph was positively correlated with the electron affinity (EA value. The two quantum chemical parameters, highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO, were shown to be appropriate for understanding the mechanism of the metal complexes as their calculated energies show good correlation with the SOD activity. Moreover, copper complex with the highest SOD activity were shown to possess the lowest HOMO energy. These findings demonstrate a great potential for the development of value-added metallovitamin-based therapeutics.

  15. Rare earth(III) complexes with an amino acid derived from isonicotinic acid hydrazide: synthesis, characterization and antifungal activities

    Energy Technology Data Exchange (ETDEWEB)

    Shen, X.; Shi, X.F.; Liu, Y.S.; Yao, T.M. [Department of Chemistry, Tongji University, Shanghai (China); Xie, Y.Y. [Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China)

    1998-12-31

    Rare earth(III) complexes, RE{sub 2}(CPI){sub 3}{center_dot}nH{sub 2}O (RE = La, Ce, Pr, Sm, Gd, Tb, Dy, Er, Yb, Sc, n =3; RE = Nd, Eu, n = 4; H{sub 2}CPI 1-[(N-carboxymethyl-N-phenyl) amino] [acetylisonicotinic acid hydrazide]), have been synthesized and characterized by IR, UV and {sup 1}H NMR spectroscopy, magnetic susceptibility, elemental analysis, molar conductivity and TGA measurement. Preliminary pharmaceutical tests showed that these complex exhibit definite inhibition activities against S. Sake Yake and C. Albicans (Robin) Berkh 50. (author) 16 refs, 4 figs, 3 tabs

  16. Rare earth(III) complexes with an amino acid derived from isonicotinic acid hydrazide: synthesis, characterization and antifungal activities

    International Nuclear Information System (INIS)

    Rare earth(III) complexes, RE2(CPI)3·nH2O (RE = La, Ce, Pr, Sm, Gd, Tb, Dy, Er, Yb, Sc, n =3; RE = Nd, Eu, n = 4; H2CPI 1-[(N-carboxymethyl-N-phenyl)amino]acetylisonicotinic acid hydrazide], have been synthesized and characterized by IR, UV and 1H NMR spectroscopy, magnetic susceptibility, elemental analysis, molar conductivity and TGA measurement. Preliminary pharmaceutical tests showed that these complex exhibit definite inhibition activities against S. Sake Yake and C. Albicans (Robin) Berkh 50. (author)

  17. The Synergistic Biologic Activity of Oleanolic and Ursolic Acids in Complex with Hydroxypropyl-γ-Cyclodextrin

    Directory of Open Access Journals (Sweden)

    Codruţa Soica

    2014-04-01

    Full Text Available Oleanolic and ursolic acids are natural triterpenic compounds with pentacyclic cholesterol-like structures which gives them very low water solubility, a significant disadvantage in terms of bioavailability. We previously reported the synthesis of inclusion complexes between these acids and cyclodextrins, as well as their in vivo evaluation on chemically induced skin cancer experimental models. In this study the synergistic activity of the acid mixture included inside hydroxypropyl-gamma-cyclodextrin (HPGCD was monitored using in vitro tests and in vivo skin cancer models. The coefficient of drug interaction (CDI was used to characterize the interactions as synergism, additivity or antagonism. Our results revealed an increased antitumor activity for the mixture of the two triterpenic acids, both single and in complex with cyclodextrin, thus proving their complementary biologic activities.

  18. Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes

    Science.gov (United States)

    Gu, Quanli; Tang, Zhen; Su, Peifeng; Wu, Wei; Yang, Zhijun; Trindle, Carl O.; Knee, Joseph L.

    2016-08-01

    The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red. For 9HFCA—H2O, a substantial decrease of the repulsive frozen energy in cation further shifts the IP toward red. For 9HFCA—HCOOH, the increase of the frozen energy actually occurs in the cation and shifts the IP toward blue. Consistent with the experimental measurements, our analysis provides new, non-intuitive perspectives on multiple hydrogen bonds interactions in carboxylic acids and water complexes.

  19. Sequence and structural features of binding site residues in protein-protein complexes: comparison with protein-nucleic acid complexes

    Directory of Open Access Journals (Sweden)

    Selvaraj S

    2011-10-01

    Full Text Available Abstract Background Protein-protein interactions are important for several cellular processes. Understanding the mechanism of protein-protein recognition and predicting the binding sites in protein-protein complexes are long standing goals in molecular and computational biology. Methods We have developed an energy based approach for identifying the binding site residues in protein–protein complexes. The binding site residues have been analyzed with sequence and structure based parameters such as binding propensity, neighboring residues in the vicinity of binding sites, conservation score and conformational switching. Results We observed that the binding propensities of amino acid residues are specific for protein-protein complexes. Further, typical dipeptides and tripeptides showed high preference for binding, which is unique to protein-protein complexes. Most of the binding site residues are highly conserved among homologous sequences. Our analysis showed that 7% of residues changed their conformations upon protein-protein complex formation and it is 9.2% and 6.6% in the binding and non-binding sites, respectively. Specifically, the residues Glu, Lys, Leu and Ser changed their conformation from coil to helix/strand and from helix to coil/strand. Leu, Ser, Thr and Val prefer to change their conformation from strand to coil/helix. Conclusions The results obtained in this study will be helpful for understanding and predicting the binding sites in protein-protein complexes.

  20. Oxidation of formic acid on platinum surfaces decorated with cobalt(III) macrocyclic complexes

    Science.gov (United States)

    Stevanović, S.; Babić-Samardžija, K.; Sovilj, S. P.; Tripković, A.; Jovanović, V. M.

    2009-09-01

    Platinum electrode decorated with three different mixed-ligand cobalt(III) complexes of the general formula [Co(Rdtc)cyclam](ClO4)2 [cyclam = 1,4,8,11-tetraazacyclotetradecane, Rdtc- = morpholine-(Morphdtc), piperidine-(Pipdtc), and 4-methylpiperidine-(4-Mepipdtc) dithiocarbamates, respectively] was used to study oxidation of formic acid in acidic solution. The complexes were adsorbed on differently prepared Pt surfaces, at open circuit potential. The preliminary results show increased catalytic activity of Pt for formic acid oxidation with complex ion adsorbed on the polycrystalline surfaces. The increase in catalytic activity depends on the structure of the complex applied and follows the order of metal-coordinated bidentate ligand as Morphdtc > Pipdtc > 4-Mepipdtc. Based on IR and NMR data, the main characteristics of the Rdtc ligands do not vary dramatically, but high symmetry of the corresponding complexes decreases in the same order. Accordingly, the complexes are distinctively more mobile, causing chemical interactions to occur on the surface with appreciable speed and enhanced selectivity. The effect of the complexes on catalytic activity presumably depends on structural changes on Pt surfaces caused by their adsorption.

  1. Luminescent polymethacrylate composite nanofibers containing a benzoic acid rare earth complex: Morphology and luminescence properties

    International Nuclear Information System (INIS)

    Highlights: • We synthesize PMMA composite nanofibers containing benzoic acid rare earth complex. • We investigate the effects of nanofiber morphology on luminescence properties. • Nanofibers with different morphologies had different luminescence characteristics. • Fluorescence intensity and emission lifetime of porous nanobeads were the highest. • Nanofibers with a porous structure showed the stronger fluorescent recognition ability. - Abstract: In this study, we systematically investigated the morphologies and luminescence properties of luminescent polymethacrylate composite nanofibers containing a benzoic acid rare earth complex. The analysis results indicated that the benzoic acid rare earth complex, Tb(4-methylbenzoic acid)3phen, was distributed uniformly in the polymethacrylate nanofibers, which were fabricated by electrostatic spinning. The Tb(4-methylbenzoic acid)3phen content in the polymethacrylate nanofibers was as high as 20% (mass%). The emission peaks of the as-prepared polymethacrylate composite nanofibers corresponded to the characteristic 5D4–7F6,5,4,3 transitions of Tb3+ ions. The highest emission peak was observed at 548 nm and corresponded to the 5D4–7F5 transition. When the Tb(4-methylbenzoic acid)3phen content was less than 1%, even a 0.2% increase in the content increased the fluorescence intensity markedly. The thermal stability of the rare earth complex was higher in the as-prepared nanofibers; the initial decomposition temperature of the polymethacrylate composite nanofiber reached 291 °C. Composite nanofibers with different morphologies exhibited different luminescence characteristics. The fluorescence intensity and emission lifetime of porous nanobeads were nine and two times higher, respectively, than those of smooth nanofibers. The better morphological and luminescence properties exhibited by the synthesized luminescent polymethacrylate composite nanofibers should result in the use of benzoic acid rare earth complexes in

  2. Luminescent polymethacrylate composite nanofibers containing a benzoic acid rare earth complex: Morphology and luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Fulai [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Tianjin Polytechnic University, 300387 Tianjin (China); Xi, Peng, E-mail: xpsyq0007@sina.com [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Tianjin Polytechnic University, 300387 Tianjin (China); State Key laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, 100080 Beijing (China); Xia, Haiying; Wang, Chaohua; Gao, Li [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Tianjin Polytechnic University, 300387 Tianjin (China); Cheng, Bowen, E-mail: Bowen@tjpu.edu.cn [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Tianjin Polytechnic University, 300387 Tianjin (China)

    2015-08-25

    Highlights: • We synthesize PMMA composite nanofibers containing benzoic acid rare earth complex. • We investigate the effects of nanofiber morphology on luminescence properties. • Nanofibers with different morphologies had different luminescence characteristics. • Fluorescence intensity and emission lifetime of porous nanobeads were the highest. • Nanofibers with a porous structure showed the stronger fluorescent recognition ability. - Abstract: In this study, we systematically investigated the morphologies and luminescence properties of luminescent polymethacrylate composite nanofibers containing a benzoic acid rare earth complex. The analysis results indicated that the benzoic acid rare earth complex, Tb(4-methylbenzoic acid){sub 3}phen, was distributed uniformly in the polymethacrylate nanofibers, which were fabricated by electrostatic spinning. The Tb(4-methylbenzoic acid){sub 3}phen content in the polymethacrylate nanofibers was as high as 20% (mass%). The emission peaks of the as-prepared polymethacrylate composite nanofibers corresponded to the characteristic {sup 5}D{sub 4}–{sup 7}F{sub 6,5,4,3} transitions of Tb{sup 3+} ions. The highest emission peak was observed at 548 nm and corresponded to the {sup 5}D{sub 4}–{sup 7}F{sub 5} transition. When the Tb(4-methylbenzoic acid){sub 3}phen content was less than 1%, even a 0.2% increase in the content increased the fluorescence intensity markedly. The thermal stability of the rare earth complex was higher in the as-prepared nanofibers; the initial decomposition temperature of the polymethacrylate composite nanofiber reached 291 °C. Composite nanofibers with different morphologies exhibited different luminescence characteristics. The fluorescence intensity and emission lifetime of porous nanobeads were nine and two times higher, respectively, than those of smooth nanofibers. The better morphological and luminescence properties exhibited by the synthesized luminescent polymethacrylate composite

  3. Studies on beryllium complexes. V. Chelation of Be2+ ions by anthranilic acid

    International Nuclear Information System (INIS)

    After having determined the formation constants of anthranilic acid, the anthranilic acid-Be2+ - H2O system (0.5 M NaClO3 and t=25 deg C) has been studied. The complex BeA+ and the hydroxylated species Be2(OH)A2+, Be3(OH)3A2+, Be3(OH)3A2+ have been identified

  4. Effect of ionic strength on complexation of Pu(IV) with humic acid

    OpenAIRE

    Szabo, G; Guczi, J.; Reiller, Pascal; Miyajima, T.; Bulman, R.,

    2010-01-01

    Successful geochemical modelling of the migration of radioactive materials, such as the transuranic elements, from nuclear waste repositories is dependent upon an understanding of their interaction with biogeopolymers such as humic acids, the most likely complexing agents in groundwaters. An established silica/humic acid composite has been evaluated as a model substrate for naturally occurring humate-coated minerals that are likely to be present in the vicinity of the repositories. The bindin...

  5. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II

    OpenAIRE

    Koenitzer, Jeffrey R; Gustavo Bonacci; Woodcock, Steven R.; Chen-Shan Chen; Nadiezhda Cantu-Medellin; Kelley, Eric E.; Schopfer, Francisco J.

    2016-01-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the s...

  6. Electrocatalytic and simultaneous determination of isoproterenol, uric acid and folic acid at molybdenum (VI) complex-carbon nanotube paste electrode

    Energy Technology Data Exchange (ETDEWEB)

    Beitollahi, Hadi, E-mail: h.beitollahi@yahoo.com [Environment Department, Research Institute of Environmental Sciences, International Center for Science, High Technology and Environmental Sciences, Kerman (Iran, Islamic Republic of); Sheikhshoaie, Iran [Department of Chemistry, Faculty of Science, Shahid Bahonar University of Kerman, Kerman 76175-133 (Iran, Islamic Republic of)

    2011-11-30

    Highlights: > A molybdenum (VI) complex-carbon nanotube paste electrode have been fabricated. > This electrode reduced the oxidation potential of isoproterenol by about 175 mV. > It resolved the voltammetric waves of isoproterenol, uric acid and folic acid. - Abstract: This paper describes the development, electrochemical characterization and utilization of a novel modified molybdenum (VI) complex-carbon nanotube paste electrode for the electrocatalytic determination of isoproterenol (IP). The electrochemical profile of the proposed modified electrode was analyzed by cyclic voltammetry (CV) that showed a shift of the oxidation peak potential of IP at 175 mV to less positive value, compared with an unmodified carbon paste electrode. Differential pulse voltammetry (DPV) in 0.1 M phosphate buffer solution (PBS) at pH 7.0 was performed to determine IP in the range from 0.7 to 600.0 {mu}M, with a detection limit of 35.0 nM. Then the modified electrode was used to determine IP in an excess of uric acid (UA) and folic acid (FA) by DPV. Finally, this method was used for the determination of IP in some real samples.

  7. Asymmetric epoxidation of allylic alcohols catalyzed by vanadium-binaphthylbishydroxamic Acid complex.

    Science.gov (United States)

    Noji, Masahiro; Kobayashi, Toshihiro; Uechi, Yuria; Kikuchi, Asami; Kondo, Hisako; Sugiyama, Shigeo; Ishii, Keitaro

    2015-03-20

    A vanadium-binaphthylbishydroxamic acid (BBHA) complex-catalyzed asymmetric epoxidation of allylic alcohols is described. The optically active binaphthyl-based ligands BBHA 2a and 2b were synthesized from (S)-1,1'-binaphthyl-2,2'-dicarboxylic acid and N-substituted-O-trimethylsilyl (TMS)-protected hydroxylamines via a one-pot, three-step procedure. The epoxidations of 2,3,3-trisubstituted allylic alcohols using the vanadium complex of 2a were easily performed in toluene with a TBHP water solution to afford (2R)-epoxy alcohols in good to excellent enantioselectivities. PMID:25714329

  8. Co(II) complexes of amino acids and peptides in aqueous solution studied by 170 NMR

    International Nuclear Information System (INIS)

    Structural, dynamic and kinetic 170 NMR investigations of the complexation of metal ions with amino acids and peptides were performed in Glicine, proling cyclo(Ala '1'70-Ala), cyclo-(Gly170-Pro) and cyclo(Pro170-Gly). The 170 carboxyl and carbonylsignals of paramagnetic complexes with amino acids were observed and allowed for the determinatio, in several cases, of the stoichiometry of the ocmplexes formed and the kinetic and thermodynamic parameters characterizing ligand exchange. It was found that the paramagnetic ions bind to the oxygen of the peptide carboxyl group. (H.W.). 25 refs.; 10 figs.; 3 tabs

  9. Mononuclear metal complexes of organic carboxylic acid derivatives: Synthesis, spectroscopic characterization, thermal investigation and antimicrobial activity

    Science.gov (United States)

    Abd El-Wahab, Zeinab H.

    2007-05-01

    Two Schiff base ligands bearing organic acid moiety, vis., N-(2-thienylmethylidene)-2-amino-4-chlorobenzoic acid (HL 1) and N-(2-hydroxybenzylidene)-2-amino-4-chlorobenzoic acid (H 2L 2) have been synthesized by the interaction of 2-thiophenecarboxaldehyde and 2-hydroxybenzaldehyde with 2-amino-4-chlorobenzoic acid. Co(II), Ni(II), Cu(II) and Zn(II) complexes of these ligands have been prepared. They are characterized on the basis of analytical data, molar conductance, IR, 1H NMR, UV-vis, mass spectra, magnetic measurements, thermal analysis and X-ray powder diffraction technique. The molar conductance data reveal that these complexes are non-electrolytes. The ligands are coordinated to the metal ions in a terdentate manner with ONO/ONS donor sites of the carbonyl oxygen, azomethine nitrogen and phenolic oxygen or thiophenic sulphur. An octahedral structure is proposed for the prepared metal complexes and some ligand field parameters ( Dq, B and β) in addition to CFSE were calculated. The thermal stability of the metal complexes is evaluated. The Schiff base ligands and their metal complexes have been tested against four species of bacteria as well as four species of fungi and the results have been compared with some known antibiotics.

  10. Recognition of amino acids and anions by a Zn(Ⅱ)-methylazacalix[4]pyridine complex

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    As a powerful macrocyclic host molecule with unique conformation and cavity structure that are fine-tuned by the bridging nitrogen atoms, methylazacalix[4]pyridine (MACP-4) has been shown to selectively recognize Zn2+ and form stable Zn(Ⅱ)-MACP-4 complexes both in solid state and solution with an association constant up to 5.97 (logKs). The molecular recognition of Zn(Ⅱ)-MACP-4 complexes towards various amino acids and anions with different geometry was investigated by using the spectral titration methods and X-ray analysis. The Zn(Ⅱ)-MACP-4 complex was found to recognize the 17 amino acids tested with the association constant up to 3.97 (logKs). On the other hand, the Zn(Ⅱ)-MACP-4 complex selectively interacted with anions and the maximum association constant of 3.9 (logKs) was obtained.

  11. Functionalization of conducting polymer with novel Co(II) complex: Electroanalysis of ascorbic acid

    International Nuclear Information System (INIS)

    We report for the first time the functionalization of a conducting polymer with a metal complex in order to develop a new type of catalytic material exhibiting better electronic communication through their delocalized π electrons. The Co(II) complex having hydroxyl group as functional moiety is chemically coupled with carboxyl group of polyanthranilic acid which itself is a self doped conducting polymer. The covalent linkage between Co(II) and -OH group is confirmed using UV-vis, FT-IR and NMR spectroscopic techniques. The Co(II) complex functionalized polymer does exhibit excellent redox behavior and stability with mixed properties of Co(II) complex and π-conjugated polymer. The material possesses potential benefits in sensors/biosensor applications and it is demonstrated for the electroanalysis of ascorbic acid at a level of nano molar concentration.

  12. Oxidation of saturated hydrocarbons with peroxyacetic acid catalyzed by vanadium complexes

    OpenAIRE

    Gonzalez Cuervo, Laura; Kozlov, Yuriy N.; Süss-Fink, Georg; Shul’pin, Georgiy B.

    2009-01-01

    Peroxyacetic acid (PAA) oxidizes alkanes in acetonitrile or acetic acid at 60 °C if a soluble vanadium(V) salt, n-Bu4NVO3 (1), is used as a catalyst. Corresponding ketones, alcohols and alkyl hydroperoxides are the main products. Methane, ethane, propane, cyclohexane, and other higher alkanes were substrates in the oxidations. The proposed mechanism involves the formation of a complex between (1) and PAA with equilibrium constants 3.3 and 6.8 dm3 mol−1 for acetonitrile and acetic acid as solv...

  13. Synthesis and evaluation of 3-acyl-tetronic acid-containing metal complexing agents

    International Nuclear Information System (INIS)

    Potential metal chelators containing one or several acyl-tetronic acid moieties were prepared from cyclic or acyclic amines and polyamines, and from bis(phenols) by reaction with 1-4 equiv of 3 bromoacetyl-tetronic acid in the presence of potassium carbonate. The affinity constants of the chelating agents for toxic metallic cations Cd2+, Cs+, and Pb2+ and for dimethylarsinic acid were measured, at pH 7.5 and 9.3. Compound 4, an acyclic triamine containing four acyl-tetronic moieties, was found to complex efficiently all the tested species. (authors)

  14. Hydrogen bonding in oxalic acid and its complexes: A database study of neutron structures

    Indian Academy of Sciences (India)

    R Chitra; Amit Das; R R Choudhury; M Ramanadham; R Chidambaram

    2004-08-01

    The basic result of carboxylic group that the oxygen atom of the –OH never seems to be a hydrogen bond acceptor is violated in the cases, namely urea oxalic acid and bis urea oxalic acid complexes, where the hydroxyl oxygen atom is an acceptor of a weak N–H... O hydrogen bond. The parameters of this hydrogen bond, respectively in these structures are: hydrogen acceptor distance 2.110 Å and 2.127 Å and the bending angle at hydrogen, 165.6° and 165.8°. The bond strength around the hydroxyl oxygen is close to 1.91 valence units, indicating that it has hardly any strength left to form hydrogen bonds. These two structures being highly planar, force the formation of this hydrogen bond. As oxalic acid is the common moiety, the structures of the two polymorphs, -oxalic acid and -oxalic acid, also were looked into in terms of hydrogen bonding and packing.

  15. Comb-like ionic complexes of hyaluronic acid with alkyltrimethylammonium surfactants

    OpenAIRE

    Tolentino, Ainhoa; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián

    2013-01-01

    Stoichiometric complexes of hyaluronic acid with alkyltrimethylammonium surfactants bearing octadecyl, eicosyl and docosyl groups were prepared by ionic coupling in aqueous solution. The complexes were non soluble in water but soluble in organic solvents. In the solid state they self-assembled in a biphasic layered structure with the alkyl side chains forming a separate phase that melted in the 50–60 °C range. They were stable to heating up to above 200 °C.

  16. NMR study of reactions between Pd, Ru, and Rh nitrite complexes and sulfamic acid

    International Nuclear Information System (INIS)

    Interaction of Pd, Ru and Rh nitrite complexes with sulfamic acid was studied by the method of 14N, 15N and 17O NMR. Reference of chemical shifts was made, prevailing complex forms being ascertained. It was established that cis-nitroaquacomplexes are products of the interaction at room temperature. Coordination of sulfaminate-ion during long-term allowance to stand or during heating of the solutions was revealed

  17. Study of molecular complexation of glycyrrhizic acid with chloramphenicol by electrospray ionization mass spectrometry

    OpenAIRE

    Vetrova, Elena V.; Lekar, Anna V.; Filonova, Olga V.; Borisenko, Sergey N.; Maksimenko, Elena V.; Borisenko, Nikolay I.

    2015-01-01

    Context: Glycyrrhizic acid (GA) is a triterpene glycoside representing the main active component of licorice root extract obtained from plants of the Glycyrrhiza glabra L. and widely used as a complex-forming agent for the synthesis of new transport forms of the well-known drugs. Aims: For the first time, the complexation of GA with chloramphenicol antibiotic (ChlA) was investigated by electrospray ionization mass spectrometry (ESI MS). Subjects and Methods: ESI MS was utilized in order to de...

  18. Synthesis and spectroscopic studies of iron (III) complex with a quinolone family member (pipemidic acid)

    Science.gov (United States)

    Skrzypek, D.; Szymanska, B.; Kovala-Demertzi, Dimitra; Wiecek, Joanna; Talik, E.; Demertzis, Mavroudis A.

    2006-12-01

    The interaction of iron (III) with pipemidic acid, Hpipem, afforded the complex [Fe (pipem) (HO)2 (H2O)]2. The new complex has been characterised by elemental analyses, infra-red, EPR and XPS spectroscopies. The monoanion, pipem, exhibits O, O ligation through the carbonyl and carboxylato oxygen atoms. Six coordinate dimer distorted octahedral configuration has been proposed for [Fe (pipem) (HO)2 (H2O)]2.

  19. Therapeutic Potentials of Silver Nanoparticle Complex of α-Lipoic Acid

    OpenAIRE

    Lakshmy Ramachandran; Cherupally Krishnan Krishnan Nair

    2011-01-01

    Silver (SN) nanoparticles were re‐dispersed in aqueous solution of Pluronic F127 and complexed with the antioxidant, alpha‐ Lipoic acid (LA). The nanoparticle ‐ LA complex (SN‐LA) was characterized using SEM. SN‐ LA exhibited DPPH radical scavenging activity in vitro and anti‐ inflammatory activity against acute and chronic paw models of edema in mice. SN‐LA protected mice from whole body gamma radiation induced body weight losses and mortality reveal...

  20. Arsenic speciation and identification of monomethylarsonous acid and monomethylthioarsonic acid in a complex matrix.

    Science.gov (United States)

    Yathavakilla, Santha Ketavarapu V; Fricke, Michael; Creed, Patricia A; Heitkemper, Douglas T; Shockey, Nohora V; Schwegel, Carol; Caruso, Joseph A; Creed, John T

    2008-02-01

    Anion-exchange chromatography was utilized for speciation of arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA(V)), monomethylarsonic acid (MMA(V)), monomethylarsonous acid (MMA(III)), and the new As species monomethylthioarsonic acid (MMTA), using inductively coupled plasma mass spectrometric (ICPMS) detection. MMA(III) and MMTA were identified for the first time in freeze-dried carrot samples that were collected over 25 years ago as part of a joint U.S. EPA, U.S. FDA, and USDA study on trace elements in agricultural crops. The discovery of MMA(III) and MMTA in terrestrial foods necessitated the analytical characterization of synthetic standards of both species, which were used for standard addition in carrot extracts. The negative ion mode, high-resolution electrospray mass spectrometry (HR-ESI-MS) data produced molecular ions of m/z 122.9418 and 154.9152 for MMA(III) and MMTA, respectively. However, ESI-MS was not sensitive enough to directly identify MMA(III) and MMTA in the carrot extracts. Therefore, to further substantiate the identification of MMA(III) and MMTA, two additional separations using an Ion-120 column were developed using the more sensitive ICPMS detection. The first separation used 20 mM tetramethylammonium hydroxide at pH 12.2 with MMA(III) eluting in less than 7 min. In the second separation, MMTA eluted at 11.2 min by utilizing 40 mM ammonium carbonate at pH 9.0. Oxidation of MMA(III) and MMTA to MMA(V) with hydrogen peroxide was observed for standards and carrot extracts alike. Several samples of carrots collected from local markets in 2006 were also analyzed and found to contain low levels of inorganic arsenic species. PMID:18181583

  1. Determination of complex formation constants by phase sensitive alternating current polarography: Cadmium-polymethacrylic acid and cadmium-polygalacturonic acid.

    Science.gov (United States)

    Garrigosa, Anna Maria; Gusmão, Rui; Ariño, Cristina; Díaz-Cruz, José Manuel; Esteban, Miquel

    2007-10-15

    The use of phase sensitive alternating current polarography (ACP) for the evaluation of complex formation constants of systems where electrodic adsorption is present has been proposed. The applicability of the technique implies the previous selection of the phase angle where contribution of capacitive current is minimized. This is made using Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) in the analysis of ACP measurements at different phase angles. The method is checked by the study of the complexation of Cd by polymethacrylic (PMA) and polygalacturonic (PGA) acids, and the optimal phase angles have been ca. -10 degrees for Cd-PMA and ca. -15 degrees for Cd-PGA systems. The goodness of phase sensitive ACP has been demonstrated comparing the determined complex formation constants with those obtained by reverse pulse polarography, a technique that minimizes the electrode adsorption effects on the measured currents. PMID:19073101

  2. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport

    OpenAIRE

    Richard J Naftalin; Cunningham, Philip; Afzal-Ahmed, Iram

    2004-01-01

    Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide...

  3. Stability constants of mixed ligand complexes of lanthanide(III) and yttrium(III) with complexone and substituted salicylic acids

    International Nuclear Information System (INIS)

    Salicylic acid and substituted salicylic acids are potential antimicrobial agents. Binary complexes of salicylic acid and its substituted derivatives with lanthanide(III) and yttrium(III) metal ions have been reported. There are reports on the ternary metal complexing equilibria with some lanthanide(III) and yttrium(III) metal ions involving aminopolycarboxylic acid as one ligand and salicylic acid (SA) and other related compounds as the second ligands. Ethylene glycol bis(2-aminoethylether)- N, N, N', N'-tetraacetic acid (EGTA) is an important member of aminopolycarboxylic acid and finds many applications in medicine and biology. Recently, few ternary complexes have been reported using EGTA as ligand. In view of biological importance of simple and mixed ligand complexes EGTA, SA and DNSA (3,5-dinitrosalicylic acid), a systematic study has been undertaken for the determination of stability constant and the results are reported. (author). 6 refs., 1 fig., 2 tabs

  4. Effect of complex amino acid imbalance on growth of tumor in tumor-bearing rats

    Institute of Scientific and Technical Information of China (English)

    Yin-Cheng He; Yuan-Hong Wang; Jun Cao; Ji-Wei Chen; Ding-Yu Pan; Ya-Kui Zhou

    2003-01-01

    AIM: To investigate the effect of complex amino acid imbalance on the growth of tumor in tumor-bearing (TB) rats.METHODS: Sprague-Dawlley (SD) rats underwent jejunostomy for nutritional support. A suspension of Walker256 carcinosarcoma cells was subcutaneously inoculated.TB rats were randomly divided into groups A, B, C and D according to the formula of amino acids in enteral nutritional solutions, respectively. TB rats received jejunal feedings supplemented with balanced amino acids (group A),methionine-depleted amino acids (group B), valine-depleted amino acids (group C) and methionine- and valine-depleted complex amino acid imbalance (group D) for 10 days. Tumor volume, inhibitory rates of tumor, cell cycle and life span of TB rats were investigated.RESULTS: The G0/G1 ratio of tumor cells in group D (80.5±9.0) % was higher than that in groups A, B and C which was 67.0±5.1 %, 78.9±8.5 %, 69.2±6.2 %, respectively (P<0.05). The ratio of S/G2M and PI in group D were lower than those in groups A, B and C. The inhibitory rate of tumor in groups B, C and D was 37.2 %, 33.3 % and 43.9 %,respectively (P<0.05). The life span of TB rats in group D was significantly longer than that in groups B, C, and A.CONCLUSION: Methionine/valine-depleted amino acid imbalance can inhibit tumor growth. Complex amino acids of methionine and valine depleted imbalance have stronger inhibitory effects on tumor growth.

  5. Potential cerebral perfusion agents: synthesis and evaluation of a radioiodinated vinylalkylbarbituric acid analogue

    International Nuclear Information System (INIS)

    A new iodinated barbiturate has been prepared. Treatment of 5-chloropentyne and propargyl bromide with diethyl 2-ethyl-2-sodiomalonate (DESM) provided diethyl 2-ethyl-2-(1-pentyn-5-yl)malonate (3) and diethyl 2-ethyl-2-propargylmalonate (4), respectively. Similar condensation of DESM with (E)-(5-iodo-1-penten-1-yl)boronic acid (9) or the reaction of catecholborane with 3 provided diethyl (E)-2-ethyl-2-(1-borono-1-penten-5-yl)malonate (8). The direct sodium iodide-chloramine-T iodination of 8 or the treatment of (E)-1,5-diiodo-1-pentene (10) with DESM provided diethyl (E)-2-ethyl-2-(1-iodo-1-penten-5-yl)malonate (11). The condensation of functionalized malonates 3, 4, and 11 with urea in the presence of a base provided the corresponding barbiturates, 5-ethyl-5-(1-pentyn-5-yl)-(5), 5-ethyl-5-propargyl- (6), and (E)-5-ethyl-5-(1-iodo-1-penten-5-yl)barbituric acid (12), respectively. (E)-6-(Ethoxycarbonyl)-1-iodo-1-octene-6-carboxylic acid (13) was isolated as the hydrolytic byproduct of 11. Compound 13 decarboxylated under vacuum to provide ethyl (E)-1-iodo-1-octene-6-carboxylate (14). The 125I-labeled congeners of 12 and 13 were synthesized in the same manner and evaluated in rats. The barbiturate 12 exhibited significant brain uptake (approximately 1% dose after 5 min), demonstrating that iodinated barbiturates freely cross the intact blood-brain barrier

  6. Potential cerebral perfusion agents: synthesis and evaluation of a radioiodinated vinylalkylbarbituric acid analogue

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, P.C.; Callahan, A.P.; Cunningham, E.B.; Knapp, F.F. Jr.

    1983-05-01

    A new iodinated barbiturate has been prepared. Treatment of 5-chloropentyne and propargyl bromide with diethyl 2-ethyl-2-sodiomalonate (DESM) provided diethyl 2-ethyl-2-(1-pentyn-5-yl)malonate (3) and diethyl 2-ethyl-2-propargylmalonate (4), respectively. Similar condensation of DESM with (E)-(5-iodo-1-penten-1-yl)boronic acid (9) or the reaction of catecholborane with 3 provided diethyl (E)-2-ethyl-2-(1-borono-1-penten-5-yl)malonate (8). The direct sodium iodide-chloramine-T iodination of 8 or the treatment of (E)-1,5-diiodo-1-pentene (10) with DESM provided diethyl (E)-2-ethyl-2-(1-iodo-1-penten-5-yl)malonate (11). The condensation of functionalized malonates 3, 4, and 11 with urea in the presence of a base provided the corresponding barbiturates, 5-ethyl-5-(1-pentyn-5-yl)-(5), 5-ethyl-5-propargyl- (6), and (E)-5-ethyl-5-(1-iodo-1-penten-5-yl)barbituric acid (12), respectively. (E)-6-(Ethoxycarbonyl)-1-iodo-1-octene-6-carboxylic acid (13) was isolated as the hydrolytic byproduct of 11. Compound 13 decarboxylated under vacuum to provide ethyl (E)-1-iodo-1-octene-6-carboxylate (14). The /sup 125/I-labeled congeners of 12 and 13 were synthesized in the same manner and evaluated in rats. The barbiturate 12 exhibited significant brain uptake (approximately 1% dose after 5 min), demonstrating that iodinated barbiturates freely cross the intact blood-brain barrier.

  7. Studies on vanadium salicyl hydroxamic acid complexes - a 1:4 metal-ligand system

    International Nuclear Information System (INIS)

    Vanadium reacts with salicyl hydroxamic acid to form a blue-violet coloured complex with lambdasub(max) at 475 nm at pH 3.3. The metal-ligand ratio in the complex is 1:4. The step-wise formation constants of the complexes have been evaluated by Yatsimirskii's and Leden's graphical extrapolation methods from extractive photometric data. The values from log K1, log K3 and log K2, and log K4 are 3.65 +- 0.05, 2.50 +- 0.05, 2.30 +- 0.05 and 2.15 +- 0.05 respectively. (author)

  8. Decomposition Reaction of Zn-MPA(3-Mercaptopropionic Acid) Complex Under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    JIAN Wen-ping; LIU Sheng; LI Jun; YANG Wen-sheng

    2008-01-01

    The thermal decomposition of Zn-MPA complex was investigated under microwave irradiation. ZnO and ZnS nanocrystals could be obtained by decomposing Zn-MPA(3-mercaptopropionic acid) complex under different reaction conditions. It was found that both the pH value of the solution and the molar ratio of Zn2+ and MPA can play an important role in the formation of ZnO and ZnS nanocrystals. MPA mainly acts as an S source or as a complexing agent.This study provides a new route for the controllable preparation of semiconductor nanocrystals.

  9. Synthesis and structural studies of some trivalent lanthanide complexes of isonicotinic acid hydrazide

    International Nuclear Information System (INIS)

    Trivalent lanthanides have been found to form complexes with isonicotinic acid hydrazide (INH) of the type M(INH)3X3 [X=Cl, SCN; M=La(III), Pr(III), Nd(III), Sm(III) and Gd(III)]. The complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectral studies. The nephelauxetic ratio (β), covalency (δ) and bonding parameter (b1/1) have been calculated from the electronic spectra. Infrared spectral studies reveal that INH acts as a neutral bidentate chelating ligand in all the complexes and that thiocyanate is N-bonded. (author)

  10. Structural organization of films based on polyaniline/polysulfonic acid complexes depending on the synthesis method

    International Nuclear Information System (INIS)

    The optical properties and morphology of complexes based on polyaniline (PANI) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), depending on their synthesis conditions, have been characterized by UV-visible spectroscopy and atomic force microscopy. The dependence of the electron absorption spectra of PANI/PAMPS complexes and the surface topography of their films on the initiation way of PANI formation (chemical and enzymatic) and the use of promoters of aniline polymerization has been investigated. The aniline polymerization kinetics with and without polymerization promoters has been studied. All PANI/PAMPS complexes are found to have a nanocomposite time-stable structure.

  11. [The favorable effect of humic acid based complex micro-element preparations in cadmium exposure].

    Science.gov (United States)

    Hudák, A; Náray, M; Nagy, I; Molnár, M; Gömöry, I; Ungváry, G

    1997-06-01

    The authors have studied the effect of consumption of a humic acid based complex microelement preparation (potassium, magnesium, iron, zinc, manganese, copper, vanadium, cobalt, molibden, selenium bound to humic acids) for six weeks (10 ml daily) on the biological exposure indices (blood and urine cadmium levels) and clinical laboratory parameters (liver and kidney tests, blood picture) of men (n = 18; 39.7 +/- 10.4 years of age;) working in cadmium exposure for 8.3 +/- 5.0 years. The initial mean blood and urine cadmium levels of the non-smoking subjects was twice higher than that of the non-smoking male controls living in the same urban area (n = 35), and significantly correlated with the length of exposure. Their mean serum alanin-aminotransferase, gamma-glutamyl-transferase, creatinine, uric acid and urinary N-acetyl-beta-D-glucosaminidase levels were significantly higher than that of the controls. After the six-week treatment blood cadmium level, activity of serum alanin-aminotransferase, serum uric acid and urinary protein concentrations decreased significantly, the abnormal serum iron levels normalized. According to this results, the absorption of cadmium decreased on the effect of the complex microelement supplementation and the adverse laboratory changes attributable partly to cadmium exposure improved. Therefore humic acid based complex microelement supplementation is recommended as an effective tool for prevention and health protection in occupational cadmium exposure as well as for smokers known to be considerably burdened by cadmium. PMID:9254361

  12. Activity of Picolinic Acid in Combination with the Antiprotozoal Drug Quinacrine against Mycobacterium avium Complex

    OpenAIRE

    Shimizu, Toshiaki; Tomioka, Haruaki

    2006-01-01

    We studied the in vitro and in vivo antimicrobial activities of picolinic acid (PA) in combination with the antiprotozoal drug quinacrine against intramacrophage Mycobacterium avium complex (MAC). Quinacrine significantly potentiated the anti-MAC activity of PA, suggesting the usefulness of this combination in the clinical control of MAC infection.

  13. Oxalic acid complexes: Promising draw solutes for forward osmosis (FO) in protein enrichment

    KAUST Repository

    Ge, Qingchun

    2015-01-01

    Highly soluble oxalic acid complexes (OACs) were synthesized through a one-pot reaction. The OACs exhibit excellent performance as draw solutes in FO processes with high water fluxes and negligible reverse solute fluxes. Efficient protein enrichment was achieved. The diluted OACs can be recycled via nanofiltration and are promising as draw solutes.

  14. Influence of solvent on proton transport in complexes of pyridine alkalines with trifluoroacetic acid

    International Nuclear Information System (INIS)

    The influence of solvent on proton transport in complexes of pyridine alkalines with trifluoroacetic acid was studied by nuclear magnetic resonance. The values of proton chemical shift are given. The influence of solution strength on chemical shift is also presented. (A.S.)

  15. Synthesis and Spectroscopic studies on cadmium halide complexes of isonicotinic acid

    International Nuclear Information System (INIS)

    In this study infrared spectra (4000-400cm-1) are reported for the cadmium(II) halide isonicotinic acid complexes. Vibrational assignments are given for all observed bands. Some structure spectra correlations and frequency shifts were found. It's found the frequency shifts depends on the halogen for a given metal. Certain chemical formulas were determined using elemental analysis results

  16. Zirconium complexes with lactic acid in the solution and solid states

    Science.gov (United States)

    Demkowicz, Paul Andrew

    Lactic acid complexes of zirconium are used in a great number of industrial applications. Among these is their use as crosslinking agents for hydraulic fracturing fluids used in secondary oil recovery operations. Because of a poor understanding of zirconium lactate complex chemistry and crosslinking reactions, however, the design of superior fluid systems is often not guided by sound chemical principles and leads to empirical guesswork. Zirconium lactate solutions were characterized using Fourier transform infrared (FT-IR) spectroscopy, 1H, 13C, and 17O nuclear magnetic resonance (NMR) spectroscopy, and potentiometry. The results indicate that lactic acid is coordinated bidentate to zirconium via the alcohol and carboxylate groups. The average number of lactate ligands per zirconium ion is approximately 2 and is demonstrated to be relatively constant from pH 4--9. The lability of the lactate complexes increases as the pH is decreased. The NMR data reveal that there are both large and small complex molecules present in solution, with the size of the complex depending on the extent of zirconium hydrolysis. Large complexes consist of lactic acid coordinated to polynuclear zirconium hydroxy ions. The molecular size of these complexes is sufficient to hinder their tumbling in solution and cause broadening of the measured NMR signals. Small complexes involve lactic acid coordinated to hydroxylated species containing fewer zirconium ions, such that the rotational motion in solution is sufficiently rapid to result in narrow NMR signals. Zirconium lactate complexes were precipitated from solution and analyzed in the solid state using FT-IR spectroscopy, 13C magic angle spinning (MAS) NMR spectroscopy, elemental analysis, thermal gravitational analysis, and x-ray diffraction. Two distinct types of crystalline compounds were synthesized with four lactate ligands per zirconium ion. The coordination of lactic acid to zirconium is different in the two compounds, with one showing

  17. Surface complexation modeling of uranium (Vi) retained onto zirconium diphosphate in presence of organic acids

    International Nuclear Information System (INIS)

    In the field of nuclear waste disposal, predictions regarding radionuclide migration through the geosphere, have to take account the effects of natural organic matter. This work presents an investigation of interaction mechanisms between U (Vi) and zirconium diphosphate (ZrP2O7) in presence of organic acids (citric acid and oxalic acid). The retention reactions were previously examined using a batch equilibrium method. Previous results showed that U (Vi) retention was more efficient when citric acid or oxalic acid was present in solid surface at lower ph values. In order to determine the retention equilibria for both systems studied, a phosphorescence spectroscopy study was carried out. The experimental data were then fitted using the Constant Capacitance Model included in the FITEQL4.0 code. Previous results concerning surface characterization of ZrP2O7 (surface sites density and surface acidity constants) were used to constraint the modeling. The best fit for U (Vi)/citric acid/ZrP2O7 and U (Vi)/oxalic acid/ZrP2O7 systems considered the formation of a ternary surface complex. (Author)

  18. Methods of staining target chromosomal DNA employing high complexity nucleic acid probes

    Science.gov (United States)

    Gray, Joe W.; Pinkel, Daniel; Kallioniemi, Ol'li-Pekka; Kallioniemi, Anne; Sakamoto, Masaru

    2006-10-03

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML), retinoblastoma, ovarian and uterine cancers, and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  19. Investigation of complexing reactions of terbium(3) ions with anions of salicylic and 5-sulfosalicylic acids in aqueous solutions

    International Nuclear Information System (INIS)

    Complexing of terbium(3) ions with anions of salicylic and 5-sulfosalicylic acids was investigated by luminescence-kinetic method. Values of stability and dissociation constants of formed complexes were obtained

  20. Investigation of neodymium complex with acid chrome blue K by beta-correction spectrophotometry

    International Nuclear Information System (INIS)

    The neodymium complex with acid chrome blue K (ACBK) at pH 10 has been studied in detail by beta-correction spectrophotometry. The cationic surfactant, cetyltrimethylammonium bromide (CTAB) is useful for increasing the sensitivity and solubility of ligand and complex. The characteristic factors of complex are calculated, for example, complex ratio and stability constant. Results show that Nd(ACBK)3 is formed and its real not apparent molar absorptivity is the first to be determined as follows : ε520 Nd(ACBK)3 = 5.54 x 104 dm3 mol-1 cm-1 at pH 10. In addition, the cumulative stability constant of complex Nd(ACBK)3 is still computed to be 1.72 x 1016 in ionic strength 0.1 M and at temperature 15 deg. (author)

  1. Probing inclusion complexes of cyclodextrins with amino acids by physicochemical approach.

    Science.gov (United States)

    Roy, Mahendra Nath; Roy, Aditi; Saha, Subhadeep

    2016-10-20

    Formations of host-guest inclusion complexes of two natural amino acids, viz., l-Leucine and l-Isoleucine as guests with α and β-cyclodextrins have been investigated which include diverse applications in modern science such as controlled delivery in the field of pharmaceuticals, food processing etc. Surface tension and conductivity studies establish the formation of inclusion complexes with 1:1 stoichiometry. The interactions of cyclodextrins with amino acids have been supported by density, viscosity, refractive index, hydration and solvation number measurements indicating higher degree of inclusion in case of α-cyclodextrin. l-Leucine interacts more with the hydrophobic cavity of cyclodextrin than its isomer. With the help of stability constant by NMR titration, hydrophobic effect, H-bonds and structural effects the formations of inclusion complexes have been explained. PMID:27474589

  2. Synthesis and physicochemical study of rhenium(V) complexes with phenylglyoxylic acid thiosemicarbazone

    International Nuclear Information System (INIS)

    With high yield (75-93 %) rhenium(V) complexes were prepared with thiosemicarbazone of phenylglyoxylic acid (L) of the composition [ReOLX3]·2H2O, [ReOL2X]X2·2H2O, [ReOLX2(OH)]·2H2O, [ReOL2(OH)]X2 (X = Cl, Br). The compounds prepared were characterized by the methods of elementary and thermal analyses, IR spectroscopy and conductometry. It was ascertained that depending on synthesis conditions, initial concentration of hydrohalic acid first of all, rhenium(V) complexes are formed with different number of ligands in the inner sphere. In all the complexes studied ligand L is coordinated by rhenium atom in bidentate way via sulfur and nitrogen atoms of hydrazine fragment, forming a five-member chelate node

  3. Competition effect of some metal ions on the complexation of strontium with humic acid. Vol. 4

    International Nuclear Information System (INIS)

    Interaction of radioactive strontium with humic acid present in water streams is of main importance to learn about the fate of strontium in case of accidental release. In this work, formation of Sr-humate precipitate was studied radiometrically and colorimetric at different PH's. The investigations indicated that formation of the precipitated complex increases with increasing strontium concentration till saturation. The competition effect of other cations in solution such as Ca, Mg, Ba, and Ni was investigated. The humate complexes of these cations were studied colorimetric, and the competition behaviour was investigated using the radiotracer of strontium. The results indicated that presence of Ba, Mg and Ni decreases the Sr-humate complex, while increasing Ca concentration enhances precipitation of Sr with humic acid. 10 figs

  4. Separation of glycols from dilute aqueous solutions via complexation with boronic acids

    Energy Technology Data Exchange (ETDEWEB)

    Randel, L.A.; King, C.J.

    1991-07-01

    This work examines methods of separating low molecular weight glycols from dilute aqueous solution. Extraction into conventional solvents is generally not economical, since, in the literature reviewed, distribution ratios for the two- to four-carbon glycols are all less than one. Distribution ratios can be increased, however, by incorporating into the organic phase an extracting agent that will complex with the solute of interest. The extracting agent investigated in this work is 3-nitrophenylboronic acid (NPBA). NPBA, a boric acid derivative, reversibly complexes with many glycols. The literature on complexation of borate and related compounds with glycols, including mechanistic data, measurement techniques, and applications to separation processes, provides information valuable for designing experiments with NPBA and is reviewed herein. 88 refs., 15 figs., 24 tabs.

  5. Peat humic acids and their complex forming properties as influenced by peat humification

    Science.gov (United States)

    Dudare, D.; Klavins, M.

    2012-04-01

    To study paleoenvironmental changes of importance is understanding of processes of organic matter diagenesis, especially changes of refractory part of natural organic substances - humic substances. Studies of the living organic matter humification process are also essential for understanding of the carbon biogeochemical cycle. The aim of this study was to analyze peat organic matter diagenesis: changes of properties of humic acids, relations between the humification process, properties of peat, peat humic acids, their ability to interact with metal ions, as well ability to accumulate metals. The analysis were carried out on samples of humic substances preparatively extracted from three ombrotrophic bog peat profiles to identify the links between peat age, decomposition and humification degree, botanical composition and properties of peat humic acids elemental (C, H, N, O), functional (-COOH, -OH) composition, structural characteristics - UV, fluorescence, FTIR. The found variability of peat properties is less significant than differences in the properties of peat-forming living matter, thus revealing the dominant impact of humification process on the properties of peat. Correspondingly, composition of peat humic acids is little affected by differences in the properties of precursor living organic material, and such indicators as decomposition degree, humification degree, humic acid elemental ratio and concentrations of acidic functional groups are the best descriptors of changes in organic matter during the process of organic matter diagenesis and humification. Peat ability to accumulate major and trace elements depends on the character of element supply, potency of metal ions to bind functionalities in the peat, with an emphasis on the structure of peat humic acid, pH reaction, oxygen presence, presence of complexing compounds, inorganic ions and many other factors. Major and trace element presence in peat is of importance as an indicator of peat genesis and

  6. Concentration of eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA of Asian catfish oil by urea complexation: optimization of reaction conditions

    Directory of Open Access Journals (Sweden)

    Pornpisanu Thammapat

    2016-04-01

    Full Text Available Optimization of the concentrating conditions of eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA extracted from Asian catfish oil was studied to obtain a maximum concentration. The crude fish oil was extracted from the belly flap and adipose tissue of Asian catfish, and the extracted oil was used as fresh crude oil. The EPA and DHA were concentrated by the urea complexation method. A hexagonal rotatable design was applied to examine the effects of crystallization temperature and urea-to-fatty acid ratio on the total content of EPA and DHA (Y1 and the liquid recovery yield (Y2 . The second order polynomial regression models for Y1 and Y2 were employed to generate the response surfaces. Under the optimum conditions of -20 °C and a urea-to-fatty acid ratio of 4 (w/w, the total concentration of EPA and DHA could be increased by up to 88%, while a liquid recovery yield of 26% was obtained.

  7. Solid-phase synthesis of europium and terbium complexes of quinolinic acid

    International Nuclear Information System (INIS)

    The regularities of mechanochemical synthesis and spectral-luminescent properties of europium and terbium compounds with dicarboxylic quinoline acid were studied. The compounds Ln2(XH)3D · 2H2O, Ln = Eu3+, Tb3+, XH - quinoline acid anion, D - 1,10-phenanthroline, 2,2'-dipyridyl, diphenyl guanidine, benzotriazole were prepared. The synthesis of the europium and terbium complexes aqueous solutions was also conducted for comparison by the reaction of the rare earth chlorides(nitrates) with alcohol solution of the acid and neutral ligand. The data of element analysis and X-ray diffraction are given. IR-spectra and luminescence spectra of europium and quinoline acid synthesized as mechanochemically, so traditional method, are identical to each other

  8. Complexes of molybdenum (6) and tungsten (6) with amino- and pyridine carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V.I.; Mozgin, S.V.; Felin, M.G.; Subbotina, N.A.; Ajzenberg, M.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

    1984-01-01

    By interaction of Na/sub 2/MO/sub 4/ with amino acid excess in muriatic medium the complexes Mo/sub 2/O/sub 4/ (OH)/sub 3/L (LH-anthranilic, nicotinic acids, histidine), Mo/sub 2/O/sub 5/ (OH)L' (L'H-..cap alpha..- and ..beta..-alanine, valine, isonicotinic acid), W/sub 3/O/sub 8/ (OH) (H/sub 2/O)/sub 4/ L'' (L'H-nicotinic, isonicotinic acids, histidine) are isolated. On the basis of the data of elementary analysis, IR spectroscopy and thermogravimetry assumptions on their composition and structure have been suggested.

  9. Effect of environmental factors on the complexation of iron and humic acid

    Institute of Scientific and Technical Information of China (English)

    Kai Fang; Dongxing Yuan; Lei Zhang; Lifeng Feng; Yaojin Chen; Yuzhou Wang

    2015-01-01

    A method of size exclusion chromatography coupled with ultraviolet spectrophotometry and off-line graphite furnace atomic absorption spectrometry was developed to assess the complexation properties of iron (Fe) and humic acid (HA) in a water environment.The factors affecting the complexation of Fe and HA,such as ionic strength,pH,temperature and UV radiation,were investigated.The Fe-HA complex residence time was also studied.Experimental results showed that pH could influence the deprotonation of HA and hydrolysis of Fe,and thus affected the complexation of Fe and HA.The complexation was greatly disrupted by the presence of NaCl.Temperature had some influence on the complexation.The yield of Fe-HA complexes showed a small decrease at high levels of UV radiation,but the effect of UV radiation on Fe-HA complex formation at natural levels could be neglected.It took about 10 hr for the complexation to reach equilibrium,and the Fe-HA complex residence time was about 20 hr.Complexation of Fe and HA reached a maximum level under the conditions of pH 6,very low ionic strength,in the dark and at a water temperature of about 25℃,for 10 hr.It was suggested that the Fe-HA complex could form mainly in freshwater bodies and reach high levels in the warm season with mild sunlight radiation.With changing environmental parameters,such as at lower temperature in winter or higher pH and ionic strength in an estuary,the concentration of the Fe-HA complex would decrease.

  10. Fluorescence and Judd-Ofelt analysis of rare earth complexes with maleic anhydride and acrylic acid

    Institute of Scientific and Technical Information of China (English)

    WEN Shipeng; ZHANG Xiaoping; HU Shui; ZHANG Liqun; LIU Li

    2008-01-01

    Two kinds of Eu-complexes, Eu(TTA)2(Phen)(AA) and Eu(TTA)2(Phen)(MA) (HTFA=2-Thenoyltrifluoroacetone, Phen=1,10-phenanthroline, AA=acrylic acid, MA=Maleic anhydride), which combined the excellent fluorescence properties of Eu(TTA)2(Phen)(H2O) and the reactivity of acrylic acid and maleic anhydride with radicals, were synthesized. The two complexes were characterized by elemental analysis, infrared (IR) spectra, and X-ray photoelectron spectroscopy (XPS). Based on the data shown from the fluorescent spectra of the Eu-MA and Eu-AA complexes, the Ωλ (λ=2 and 4) experimental intensity parameters were calculated. The results demonstrated that the Ω2 intensity parameters for the two complexes were smaller than those for the Eu(TTA)2(Phen)(H2O) complex, indicating that a less symmetri-cal chemical environment existed in the complexes. It implied that the radiative efficiency of the 5D0 of these two complexes could be en-hanced by ligand of MA and AA, respectively. The luminescent lifetime of the Eu-AA (τ=7.26×10-4 s) or Eu-MA complex (τ=-8.12×10-4 s) was higher than that of the Eu(TTA)2(Phen)(H2O) complex, which was attributed to the substitution of the water molecule (H2O) in Eu(TTA)2(Phen)(H2O) by the MA or AA ligand.

  11. A study of the metal binding capacity of saccharinic acids formed during the alkali catalysed decomposition of cellulosic materials: nickel complexation by glucoisosaccharinic acids and xyloisosaccharinic acids.

    Science.gov (United States)

    Almond, Michael; Belton, Daniel; Humphreys, Paul N; Laws, Andrew P

    2016-06-01

    The stoichiometry of the metal complexes formed between nickel and the ligand β-glucoisosaccharinic acid (β-GISA) and a racemic mixture of enantiomers of xyloisosaccharinic acid (XISA) has been determined at both neutral and alkaline pHs. Bjerrum plots, Job's plots and conductance measurements indicated that for each of the systems one to one Ni(ligand) complexes were formed at near neutral pHs (13) sparingly soluble Ni2(ligand)(OH)4 complexes were formed. The stability constants for the Ni(β-GISA), Ni(α-GISA) and Ni(XISA) complexes formed at neutral pH were determined under identical conditions using polarographic studies. The measured stability constants for Ni(β-GISA) (log10 β = 1.94 ± 0.15) and for Ni(α-GISA)(log10 β = 2.07 ± 0.13) are very similar; the value measured for the Ni(XISA) complex (log10 β = 0.83) was an order of magnitude smaller. The stability constants for the Ni2(Ligand)(OH)4 complexes formed at highly alkaline pHs were determined using the Schubert method. The measured stability constant for Ni2(β-GISA)(OH)4 (log10 β = 30.6 ± 0.5) was an order of magnitude bigger than the value for Ni2(α-GISA)(OH)4 (log10 β = 29.0 ± 0.5) measured under identical conditions. Attempts to measure the stability constant for Ni2(XISA)(OH)4 were unsuccessful; Ni2(XISA)(OH)4 complexes were not present in significant amounts at high pH to allow the log10β value to be determined by the Schubert method. PMID:27107221

  12. Potentiometric studies on ternary complexes involving some divalent transition metal ions, gallic acid and biologically abundant aliphatic dicarboxylic acids in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Abdelatty Mohamed Radalla

    2015-06-01

    Full Text Available Formation of binary and ternary complexes of the divalent transition metal ions, Cu2+, Ni2+, Co2+ and Zn2+ with gallic acid and the biologically important aliphatic dicarboxylic acids (adipic, succinic, malic, malonic, maleic, tartaric and oxalic acids were investigated by means of the potentiometric technique at 25 °C and I = 0.10 mol dm−3 NaNO3. The acid-base properties of the ligands were investigated and discussed. The acidity constants of gallic acid and aliphatic dicarboxylic acids were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the above experimental conditions. The formation of the different 1:1 and 1:2 binary complexes and 1:1:1 ternary complexes are inferred from the corresponding potentiometric pH-metric titration curves. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The values of Δ log K, percentage of relative stabilization (%R.S. and log X were evaluated and discussed. The concentration distribution of the various complex species formed in solution was evaluated and discussed. The mode of chelation of ternary complexes formed was ascertained by conductivity measurements.

  13. Complexation of the actinides (III, IV and V) with organic acids

    International Nuclear Information System (INIS)

    A thorough knowledge of the chemical properties of actinides is now required in a wide variety of fields: extraction processes involved in spent fuel reprocessing, groundwater in the vicinity of radioactive waste packages, environmental and biological media in the case of accidental release of radionuclides. In this context, the present work has been focused on the complexation of Am(III), Cm(III), Cf(III), Pu(IV) and Pa(V) with organic ligands: DTPA, NTA and citric acid. The complexation of pentavalent protactinium with citric and nitrilotriacetic acids was studied using liquid-liquid extraction with the element at tracer scale (CPa ≤ 10-10M). The order and the mean charge of each complex were determined from the analysis of the systematic variations of the distribution coefficient of Pa(V) as function of ligand and proton concentration. Then, the apparent formation constants related of the so-identified complexes were calculated. The complexation of trivalent actinides with DTPA was studied by fluorescence spectroscopy (TRLFS) and capillary electrophoresis (CE-ICP-MS). The coexistence of the mono-protonated and non-protonated complexes (AnHDTPA- and AnDTPA2-) in acidic media (1.5 ≤ pH ≤ 3.5) was shown unambiguously. Literature data have been reinterpreted by taking into account both complexes and a consistent set of formation constants of An(III)-DTPA has been obtained. The experimental study was completed by theoretical calculations (DFT) on Cm-DTPA system. The coordination geometry of Cm in CmDTPA2- and CmHDTPA- including water molecules in the first coordination sphere has been determined as well as interatomic distances. Finally, a study on the complexation of Pu(IV) with DTPA was initiated in order to more closely mimic physiological conditions. A three-step approach was proposed to avoid plutonium hydrolysis: i/ complexation of Pu(IV) with (NTA) in order to protect Pu(IV) from hydrolysis (at low pH) ii/ increase of pH toward neutral conditions and iii

  14. Improving cyclodextrin complexation of a new antihepatitis drug with glacial acetic acid

    OpenAIRE

    Johnson, Jennifer L. H.; He, Yan; Jain, Akash; Yalkowsky, Samuel H.

    2006-01-01

    The purpose of this study was to develop and evaluate a solid nonaqueous oral dosage form for a new hepatitis C drug, PG301029, which is insoluble and unstable in water. Hydroxypropyl-β-cyclodextrin (HPβCD) and PG301029 were dissolved in glacial acetic acid. The acetic acid was removed by rotoevaporation such that the drug exists primarily in the complexed form. The stability of formulated PG301029 was determined upon dry storage and after reconstitution in simulated intestinal fluid (SIF), s...

  15. Kinetic stability of indium(3) complexes with azaporphyrins in aqueous sulfuric acid

    International Nuclear Information System (INIS)

    Kinetic stability of octaphenyltetraazaporphynatochloroindium(3) and 3,7,13,17-tetramethyl-2,8,12,18-tetrabutyl-5,15-diazaporphynatochloroindium (3)= (ClInDAP) in aqueous 90-98% sulfuric acid was studied by the method of spectrophotometric titration. Kinetic parameters of solvo-protolytic dissociation of indium complexes were determined, the reaction mechanism being suggested. The state of ClInDAP in proton-donor medium was studied by the method of absorption spectroscopy and it was shown that two mesoatoms of nitrogen enter the interaction in series. Dissociation constants of the acid forms formed were determined

  16. Biosynthesis of caffeic acid in Escherichia coli using its endogenous hydroxylase complex

    Directory of Open Access Journals (Sweden)

    Lin Yuheng

    2012-04-01

    Full Text Available Abstract Background Caffeic acid (3,4-dihydroxycinnamic acid is a natural phenolic compound derived from the plant phenylpropanoid pathway. Caffeic acid and its phenethyl ester (CAPE have attracted increasing attention for their various pharmaceutical properties and health-promoting effects. Nowadays, large-scale production of drugs or drug precursors via microbial approaches provides a promising alternative to chemical synthesis and extraction from plant sources. Results We first identified that an Escherichia coli native hydroxylase complex previously characterized as the 4-hydroxyphenylacetate 3-hydroxylase (4HPA3H was able to convert p-coumaric acid to caffeic acid efficiently. This critical enzymatic step catalyzed in plants by a membrane-associated cytochrome P450 enzyme, p-coumarate 3-hydroxylase (C3H, is difficult to be functionally expressed in prokaryotic systems. Moreover, the performances of two tyrosine ammonia lyases (TALs from Rhodobacter species were compared after overexpression in E. coli. The results indicated that the TAL from R. capsulatus (Rc possesses higher activity towards both tyrosine and L-dopa. Based on these findings, we further designed a dual pathway leading from tyrosine to caffeic acid consisting of the enzymes 4HPA3H and RcTAL. This heterologous pathway extended E. coli native tyrosine biosynthesis machinery and was able to produce caffeic acid (12.1 mg/L in minimal salt medium. Further improvement in production was accomplished by boosting tyrosine biosynthesis in E. coli, which involved the alleviation of tyrosine-induced feedback inhibition and carbon flux redirection. Finally, the titer of caffeic acid reached 50.2 mg/L in shake flasks after 48-hour cultivation. Conclusion We have successfully established a novel pathway and constructed an E. coli strain for the production of caffeic acid. This work forms a basis for further improvement in production, as well as opens the possibility of microbial synthesis

  17. Polarographic study of mixed-ligand complexes of cadmium(II) with L-amino acid and vitamin B5

    International Nuclear Information System (INIS)

    A survey of literature shows that ternary complexes of CdII with L-amino acids and vitamin B5 have not been studied so far. The present communication reports the formation of mixed-ligand complexes of CdII with L-amino acids as primary ligands and vitamin B5 as secondary ligand, studied by polarographic technique. (author)

  18. Fractionation of SWNT/nucleic acid complexes by agarose gel electrophoresis

    International Nuclear Information System (INIS)

    We show that aqueous dispersions of single-walled carbon nanotubes (SWNTs), prepared with the aid of nucleic acids (NAs) such as RNA or DNA, can be separated into fractions using agarose gel electrophoresis. In a DC electric field, SWNT/NA complexes migrate in the gel in the direction of positive potential to form well-defined bands. Raman spectroscopy as a function of band position shows that nanotubes having different spectroscopic properties possess different electrophoretic mobilities. The migration patterns for SWNT/RNA and SWNT/DNA complexes differ. Parallel elution of the SWNT/NA complexes from the gel during electrophoresis and subsequent characterization by AFM reveals differences in nanotube diameter, length and curvature. The results suggest that fractionation of nanotubes can be achieved by this procedure. We discuss factors affecting the mobility of the nanotube complexes and propose analytical applications of this technique

  19. Ruthenium(II) multi carboxylic acid complexes: chemistry and application in dye sensitized solar cells.

    Science.gov (United States)

    Shahroosvand, Hashem; Nasouti, Fahimeh; Sousaraei, Ahmad

    2014-04-01

    Novel ruthenium multi carboxylic complexes (RMCCs) have been synthesized by using ruthenium nitrosyl nitrate, 1,2,4,5-benzenetetracarboxylic acid (H4btec) and 4,7-diphenyl-1,10-phenanthroline (BPhen) as photosensitizers for titanium dioxide semiconductor solar cells. The complexes were characterized by (1)H-NMR, FT-IR, UV-Vis, ICP and CHN analyses. The reaction details and features were then described. SEM analysis revealed that the penetration of dyes into the pores of the nanocrystalline TiO2 surface was improved by increasing the number of btec units. The solar energy to electricity conversion efficiency of complexes shows that the number of attached carboxylates on a dye has an influence on the photoelectrochemical properties of the dye-sensitized electrode. An incident photon-to-current conversion efficiency (IPCE) of 13% at 510 nm was obtained for ruthenium complexes with three btec units. PMID:24500312

  20. Fractionation of SWNT/nucleic acid complexes by agarose gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Vetcher, Alexandre A [Institute of Biomedical Sciences and Technology and Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083 (United States); Srinivasan, Srimeenakshi [Institute of Biomedical Sciences and Technology and Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083 (United States); Vetcher, Ivan A [Institute of Biomedical Sciences and Technology and Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083 (United States); Abramov, Semen M [NanoTech Institute, University of Texas at Dallas, Richardson, TX 75083 (United States); Kozlov, Mikhail [NanoTech Institute, University of Texas at Dallas, Richardson, TX 75083 (United States); Baughman, Ray H [NanoTech Institute, University of Texas at Dallas, Richardson, TX 75083 (United States); Levene, Stephen D [Institute of Biomedical Sciences and Technology and Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083 (United States)

    2006-08-28

    We show that aqueous dispersions of single-walled carbon nanotubes (SWNTs), prepared with the aid of nucleic acids (NAs) such as RNA or DNA, can be separated into fractions using agarose gel electrophoresis. In a DC electric field, SWNT/NA complexes migrate in the gel in the direction of positive potential to form well-defined bands. Raman spectroscopy as a function of band position shows that nanotubes having different spectroscopic properties possess different electrophoretic mobilities. The migration patterns for SWNT/RNA and SWNT/DNA complexes differ. Parallel elution of the SWNT/NA complexes from the gel during electrophoresis and subsequent characterization by AFM reveals differences in nanotube diameter, length and curvature. The results suggest that fractionation of nanotubes can be achieved by this procedure. We discuss factors affecting the mobility of the nanotube complexes and propose analytical applications of this technique.

  1. NMR studies of inclusion complexes formed by (R)-α-lipoic acid with α-, β-, and γ-cyclodextrins

    International Nuclear Information System (INIS)

    The structures of inclusion complexes of (R)-α-lipoic acid with α-, β-, and γ-cyclodextrin (CD) were constructed using restraints derived from ROESY spectra and MMFF94 molecular mechanics calculations. (R)-α-lipoic acid and α-CD generate a single stable inclusion complex, in which the 1,2-dithiolane ring of the (R)-α-lipoic acid is oriented toward the secondary hydroxy side of the α-CD. NMR data suggests that β-CD produces two kinds of inclusion complexes with α-lipoic acid. Finally, γ-CD yields 1:1 and 1:2 host/guest complexes with (R)-α-lipoic acid. The estimated structure of the 1:1 γ-CD inclusion complex has the 1,2-dithiolane ring oriented toward the primary hydroxy side of the γ-CD. (author)

  2. Antimicrobial and Thermal Properties of Metal Complexes of Grafted Fabrics with Acrylic Acid by Gamma Irradiation

    International Nuclear Information System (INIS)

    Cotton, cotton/PET blend and PET fabrics were treated against microbial effect by radiation - induced grafting of acrylic acid followed by metal complexation with some divalent transition metal ions Co (II), Ni (II) and Cu (II). The microbial resistance was evaluated by testing the mechanical properties of the treated fabrics after burring for one and two weeks in a moist soil reach with microorganisms. Also, the growth of microorganisms was examined by scanning electron microscope (SEM). Moreover, the effect of this treatment on the thermal decomposition behavior was investigated by thermogravimetric analysis (TGA). On the basis of microbial studies, it was found that the metal complexation of the grafted fabrics with acrylic acid enhanced the antimicrobial resistance of the fabrics and the antimicrobial resistance could be arranged according to the metal ions as follows: copper> nickel> cobalt. Also, the thermal stability of different fabrics could be arranged as follow: grafted fabrics complexed with Cu (II) > grafted fabrics complexed with Ni (II) > grafted fabrics complexed with Co (II)

  3. Thermal properties of some pyrimidine, purine, amino-acid and mixed ligand complexes

    Energy Technology Data Exchange (ETDEWEB)

    Masoud, Mamdouh S. [Department of Chemistry, Faculty of Science, Alexandria University, Alexandria (Egypt); Ramadan, Ahmed M., E-mail: dramramadan@yahoo.com [Department of Chemistry, Faculty of Science, Alexandria University, Alexandria (Egypt); Chemistry Department, Faculty of Science, King Khalid University (Saudi Arabia); El-Ashry, Ghada M. [Central Laboratory for Food and Feed, Agriculture Research Centre, Ministry of Agriculture (Egypt)

    2013-01-10

    Highlights: Black-Right-Pointing-Pointer Synthesis of novel complexes from barbital, thiouracil, adenine, amino acids. Black-Right-Pointing-Pointer We examine their thermal stability using DTA and TG techniques. Black-Right-Pointing-Pointer The thermodynamic parameters of the decomposition reaction were evaluated. Black-Right-Pointing-Pointer We proposed mechanisms for the decomposition processes. - Abstract: Mn(II), Fe(III), Co(II), Ni(II), Zn(II) and Cd(II) complexes of barbital, thiouracil, adenine, amino acids, beside mixed metals and mixed ligands were prepared. The structures of the complexes are of Oh, distorted Oh, Td and distorted Td geometries. Differential thermal (DTA) and thermogravimetric analysis (TG) of the complexes pointed to their stability. The change of entropy values, {Delta}S{sup numbersign}, showed that the transition states are more ordered than the reacting complexes. The fractions appeared in the calculated order of the thermal reactions, n, confirmed that the thermal reactions proceed in complicated mechanisms where the bond between the central metal ion and the ligands dissociates after losing small molecules such as H{sub 2}O. In most cases, the free radical species of the ligands are assigned to exist through decomposition mechanisms.

  4. Inhibition of acid, alkaline, and tyrosine (PTP1B) phosphatases by novel vanadium complexes.

    Science.gov (United States)

    McLauchlan, Craig C; Hooker, Jaqueline D; Jones, Marjorie A; Dymon, Zaneta; Backhus, Emily A; Greiner, Bradley A; Dorner, Nicole A; Youkhana, Mary A; Manus, Lisa M

    2010-03-01

    In the course of our investigations of vanadium-containing complexes for use as insulin-enhancing agents, we have generated a series of novel vanadium coordination complexes with bidentate ligands. Specifically we have focused on two ligands: anthranilate (anc(-)), a natural metabolite of tryptophan, and imidizole-4-carboxylate (imc(-)), meant to mimic naturally occurring N-donor ligands. For each ligand, we have generated a series of complexes containing the V(III), V(IV), and V(V) oxidation states. Each complex was investigated using phosphatase inhibition studies of three different phosphatases (acid, alkaline, and tyrosine (PTP1B) phosphatase) as prima facia evidence for potential use as an insulin-enhancing agent. Using p-nitrophenyl phosphate as an artificial phosphatase substrate, the levels of inhibition were determined by measuring the absorbance of the product at 405nm using UV/vis spectroscopy. Under our experimental conditions, for instance, V(imc)(3) appears to be as potent an inhibitor of alkaline phosphatase as sodium orthovanadate when comparing the K(cat)/K(m) term. VO(anc)(2) is as potent an inhibitor of acid phosphatase and tyrosine phosphatase as the Na(3)VO(4). Thus, use of these complexes can increase our mechanistic understanding of the effects of vanadium in vivo. PMID:20071031

  5. Spectroscopic Study on the Ternary Complex Formation of U(VI) with Salicylic Acid

    International Nuclear Information System (INIS)

    From the nuclear chemical point of view, ternary complex formation of actinide ions with ligands has attracted attention for understanding radionuclides' migration in the environment. There are various ligands in natural aquatic systems which can form stable ternary actinide complexes. Humic substance in a near-neutral groundwater is one of them and carboxylic groups in a humic substance are considered as the most likely functional group which interacts with actinides. In this work, the formation of the ternary complex of U(VI) with salicylic acid (SAH2) was investigated by two different laser-based spectroscopic methods, i.e., laser-induced breakdown detection (LIBD) and time-resolved laser fluorescence spectroscopy (TRLFS). The notable features are as follows: (i) the breakdown probability increases slightly, (ii) the absorbance of U(VI) increases, whereas the fluorescence intensity decreases with increasing salicylic acid concentration. The increase of the breakdown probability indicates that insoluble species are formed due to the complexation of U(VI) with SAH2. The decrease of the fluorescence intensity is due to the quenching effect of the SAH2 in the complexes. With regards to the instrumentation, the characteristics of a newly developed LIBD system adopting a probe beam deflection method are presented. We report also on the improved speciation sensitivity (∼10-9M for UO22+) of the TRLFS system

  6. Spectroscopy of charge transfer complexes of four amino acids as organic two-dimensional conductors

    Energy Technology Data Exchange (ETDEWEB)

    Padhiyar, Ashvin; Patel, A J; Oza, A T [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388 120, Gujarat (India)

    2007-12-05

    It is found in this study that four amino acids, namely asparagine, arginine, histidine and glutamine form two-dimensional conducting systems which are charge transfer complexes (CTCs) with organic acceptors like TCNQ, TCNE, chloranil, DDQ, TNF and iodine. It is verified using optical absorption edges that these are 2d conductors like transition metal dichalcogenides obeying absorption functions different from 1d and 3d conductors. This 2d nature is related to the network of intermolecular H-bonding in these complexes, which leads to a global H-bonded network resulting in the absence of local deformation due to the relaxation of strain.

  7. STRUCTURE AND REDOX TRANSFORMATIONS OF IRON(III COMPLEXES WITH SOME BIOLOGICALLY IMPORTANT INDOLE-3-ALKANOIC ACIDS IN AQUEOUS SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Krisztina Kovács

    2007-06-01

    Full Text Available Interactions of a series of indole-3-alkanoic acids (with n-alkanoic acid side-chains from C1 to C4 with iron(III in acidic aqueous solutions have been shown to comprise two parallel processes including complexation and redox transformations giving iron(II hexaaquo complexes. The structure and composition of the reaction products are discussed, as analysed using a combination of instrumental techniques including 57Fe Mössbauer, vibrational and HNMR spectroscopies.

  8. Complexation of americium(III) with humic acid by cation exchange and solvent extraction

    International Nuclear Information System (INIS)

    Complexation of Am(III) with humic acid was studied at various pHs in 0.1M NaClO4. The stability constants of the Am(III)-humate complexes were determined by a cation-exchange method. The values of logβ1 and logβ2 increased slightly with increases of pH from 4 to 6 and were found to be 6.9 and 11.6, respectively, at a pH of 5. Markedly larger values than these were obtained by a solvent extraction method. This discrepancy was also revealed by summarizing data from several literature sources. It is very likely that this can be ascribed to decreases in either humic acid and/or the extractant from the extraction system due to humate interactions at the aqueous-organic interface. (author)

  9. Luminescence spectral properties of europium(3) and terbium(3) complexes with cinnamic acid

    International Nuclear Information System (INIS)

    The different-ligand europium and terbium complexes with cinnamic acid of the Ln(Cor)3 · xH2O composition, where Ln = Eu3+, Tb3+; Cor - cinnamic acis anion (C6H5CH=CHCOO-); D - 1,10 - phenanthroline, 2,2'-dipyridyl, benzotriazole (n = 2, x = 0), triphenylphosphine oxide (n 1, x = 2), H2O (n = 0, 1; x = 0), are synthesized. The compounds were characterized by element analysis, infrared and luminescence spectroscopies. Stark structure of the 5D0-7Fj (j = 0, 1, 2) electron transfers were analyzed in low temperature luminescence spectra of europium complexes. IR-spectroscopic investigation showed that cinnamic acid anion was coordinated by bidentate in the obtained compounds

  10. Inorganic-organic hybrid silica based tin complex as a novel, highly efficient and recyclable heterogeneous catalyst for the one-pot preparation of spirooxindoles in water.

    Science.gov (United States)

    Ghahremanzadeh, Ramin; Rashid, Zahra; Zarnani, Amir-Hassan; Naeimi, Hossein

    2014-11-14

    In the present study, a tin complex immobilized on silica gel as a novel, green, highly efficient and heterogeneous reusable catalyst was synthesized by grafting 2-amino benzamide onto the silica gel surface as a result of the reaction between isatoic anhydride and 3-aminopropyl-functionalized silica gel, followed by complexing with tin chloride. The resulting organic-inorganic hybrid material was evaluated in the one-pot three-component synthesis of spiro[indoline-pyrazolo[4',3':5,6]pyrido[2,3-d]pyrimidine]trione derivatives in water via the condensation reaction of isatins, barbituric acids, and 1H-pyrazol-5-amines. All the reactions were completed in short reaction times and all the products were obtained in high to excellent yields with high purity. In addition, the synthesized novel catalyst could be separated from the reaction mixture by simple filtration and can be reused up to seven runs without significant loss in activity. PMID:25215454

  11. Thermodynamics of Np(IV) complexes with gluconic acid under alkaline conditions. Sorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, H.; Garcia-Gutierrez, M.; Missana, T. [CIEMAT, Madrid (Spain). Sorption, Migration and Colloids Lab.; Tits, J.; Wieland, E. [Paul Scherrer Institut, Villigen (Switzerland). Lab. for Waste Management; Gaona, X. [Karlsruhe Institute of Technology, Karlsruhe (Germany). Inst. fuer Nukleare Entsorgung

    2013-05-01

    The complexation of Np(IV) with gluconic acid (GLU) under alkaline conditions was investigated in the absence of Ca by carrying out a series of sorption experiments. The decrease of Np(IV) sorption on the sorbing material at increasing concentrations of GLU was interpreted as the formation of Np(IV)-GLU aqueous complexes. The modelling of experimental data according to the Schubert method [1] confirmed the formation of a complex with a Np:GLU ratio 1: 1. The stoichiometry of the complex Np(OH){sub 4}GLU{sup -} was proposed based on the experimental observation that no proton exchange occurred during the course of the complexation reaction and that Np(OH){sub 4}(aq) was the predominant hydrolysis product in the absence of GLU. A log *{beta}{sup 0}{sub 1,4,1} = -2.92 {+-} 0.30 for the formation reaction Np{sup 4+} + 4H{sub 2}O + GLU{sup -} <=> Np(OH){sub 4}GLU{sup -} + 4H{sup +} was calculated based on the conditional stability constants determined from sorption experiments and using the Np(IV) thermodynamic data selected in the NEA reviews [2]. Linear free energy relationships (LFER) confirmed that the stoichiometry and stability of the Np(IV)-GLU complex characterized in this work are consistent with data available for Th(IV)-, U(IV)- and Pu(IV)-GLU complexes. (orig.)

  12. Antibacterial activity of chitosan and the interpolyelectrolyte complexes of poly(acrylic acid-chitosan

    Directory of Open Access Journals (Sweden)

    Hortensia Ortega-Ortiz

    2010-06-01

    Full Text Available The antimicrobial activity of chitosan and water soluble interpolyelectrolyte complexes of poly(acrylic acid-chitosan was studied. Chitosans of two different molecular weights were tested at different concentration for 0.5 to 5 g·L-1 as antimicrobial agents against P. aeruginosa and P. oleovorans. In both cases, the best microbial inhibition was obtained with the concentration of 5 g·L-1. However, the interpolyelectrolyte complexes of poly(acrylic acid-chitosan with composition φ =2 produced higher antibacterial activity than the two chitosans at the concentration of 0.5 g·L-1. The NPEC2 complex was more effective than chitosans. This could be attributed to the number of moles of the amino groups of chitosan and the carboxylic acid groups of the interpolyelectrolyte complexes poly(acrylic acid.A atividade antimicrobiana de quitosana e complexos interpolieletrolíticos hidrossoluvéis de poli(ácido acrílico-quitosana foi estudada. Quitosanas de dois diferentes pesos moleculares foram testados em diferentes concentrações, 0,5 a 5 g • L-1, como agentes antimicrobianos nas P. aeruginosa e P. oleovorans. Em ambos os casos, obteu-se a melhor inibição microbiana com a concentração de 5 g • L-1, no entanto os complexos interpolieletrolíticos de poli (ácido acrílico-quitosana com composição φ = 2 apresentaram maior atividade antibacteriana do que os dois quitosans na concentração de 0,5 g • L-1. O complexo NPEC2 foi mais eficaz do que as quitosanas, sendo que o resultado pode ser atribuído ao número de moles dos grupos aminos da quitosana e aos grupos carboxílicos dos complexos de poli(ácido acrílico.

  13. Local Solvent Acidities in β-Cyclodextrin Complexes with PRODAN Derivatives

    OpenAIRE

    Naughton, Hannah R.; Christopher J. Abelt

    2013-01-01

    The local solvent acidities (SA scale) of six 6-carbonyl-2-aminonaphthalene derivatives as β-cyclodextrin complexes in water are determined through fluorescence quenching. The local polarities (ETN scale) are determined through the shift of the emission center-of-mass. The apparent SA values reflect the solvent structure surrounding the guest’s carbonyl group, whereas the apparent ETN values reveal the net polarity of the entire guest molecule. Comparison of these values affords greater insig...

  14. Design and evaluation of Lumefantrine – Oleic Acid Self Nanoemulsifying Ionic Complex for Enhanced Dissolution

    Directory of Open Access Journals (Sweden)

    Pradeep Vavia

    2013-03-01

    Full Text Available Background:Lumefantrine, an antimalarial molecule has very low and variable bioavailability owing to its extremely poor solubility in water. It is recommended to be taken with milk to enhance its solubility and bioavailability. The aim of present study was to develop a Self Nanoemulsifying Delivery system (SNEDs of lumefantrine (LF to achieve rapid and complete dissolution independent of food-fat and surfactant in dissolution media.Methods:Solubility of LF in oil, co-solvent/co-surfactant and surfactant solution and emulsification efficiency of surfactant were analyzed to optimize the LF loaded self nanoemulsifying preconcentrate. Effect of LF-oleic acid complexation on emulsification, droplet size, zeta potential and dissolution were investigated. Effect of milk concentration and fat content on saturation solubility and dissolution of LF was investigated. Dissolution of marketed formulation and LF-SNEDs was carried out in pH 1.2 and pH 6.8 phosphate buffer.Results:LF exhibited very high solubility in oleic acid owing to complexation between tertiary amine of LF and carboxyl group of oleic acid (OA. Cremophore EL and medium chain monoglyceride were selected surfactant and co-surfactant, respectively. Significantly smaller droplet size (37 nm, shift in zeta potential from negative to positive value, very high drug loading in lipid based system (> 10%, no precipitation after dissolution are the major distinguish characteristics contributed by LF-OA complex in the SNED system. Saturation solubility and dissolution study in milk containing media pointed the significant increment in solubility of LF in the presence of milk-food fat. LF-SNEDs showed > 90% LF release within 30 min in pH 1.2 while marketed tablet showed almost 0% drug release.Conclusion:Self nanoemulsification promoting ionic complexation between basic drug and oleic acid hold great promise in enhancing solubility of hydrophobic drugs.

  15. The Effect of the Serum Amino Acid Levels Thiosemicarbazone Derivatives and its Metal Complexes on Rats

    OpenAIRE

    Karatepe, Mustafa; Kaman, Dilara

    2013-01-01

    Advers biological activities of Thiosemicarbazone (TSC) and Schiff base (SB) derivatives have been widely studied in rats and in other animal species using different doses, times and routes of administration. To date, no attempt has been made to study alterations occurring in the amino acid profile in the effects of the thiosemicarbazone derivative and its metal complexes on the rats. At this study, the rats were injected subcutaneously with a new thiosemicarbazone and its LH-Zn and LH-Cu com...

  16. End-labeling of peptide nucleic acid with osmium complex. Voltammetry at carbon and mercury electrodes

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Trefulka, Mojmír; Fojta, Miroslav

    2009-01-01

    Roč. 11, č. 2 (2009), s. 359-362. ISSN 1388-2481 R&D Projects: GA AV ČR(CZ) KAN400310651; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : peptide nucleic acid end-labeling * osmium tetroxide complexes * electroactive labels Subject RIV: BO - Biophysics Impact factor: 4.243, year: 2009

  17. Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows

    OpenAIRE

    Pessione, Enrica

    2012-01-01

    Lactic Acid Bacteria (LAB) are ancient organisms that cannot biosynthesize functional cytochromes, and cannot get ATP from respiration. Besides sugar fermentation, they evolved electrogenic decarboxylations and ATP-forming deiminations. The right balance between sugar fermentation and decarboxylation/deimination ensures buffered environments thus enabling LAB to survive in human gastric trait and colonize gut. A complex molecular cross-talk between LAB and host exists. LAB moonlight proteins ...

  18. Improved DNA Electrophoresis in Conditions Favoring Polyborates and Lewis Acid Complexation

    OpenAIRE

    Singhal, Hari; Ren, Yunzhao R.; Kern, Scott E.

    2010-01-01

    Spatial compression among the longer DNA fragments occurs during DNA electrophoresis in agarose and non-agarose gels when using certain ions in the conductive buffer, impairing the range of fragment sizes resolved well in a single gel. Substitutions using various polyhydroxyl anions supported the underlying phenomenon as the complexation of Lewis acids to DNA. We saw significant improvements using conditions (lithium borate 10 mM cations, pH 6.5) favoring the formation of borate polyanions an...

  19. Copper complexation by fulvic acid affects copper toxicity to the larvae of the polychaete

    OpenAIRE

    Qiu, Jian-Wen; Tang, Xiao; Zheng, Chuanbo; Li, Yan; Huang, Yanliang

    2007-01-01

    Copper complexation by fulvic acid affects copper toxicity to the larvae of the polychaete Hydroides elegans correspondence: Corresponding author. Tel.: +852 34117055; fax: +852 34115995. (Qiu, Jian-Wen) (Qiu, Jian-Wen) Department of Biology, Hong Kong Baptist University - HONG KONG, CHINA (Qiu, Jian-Wen) CHINA (Qiu, Jian-Wen) Department of Biology, Hong Kong Baptist University - HONG KONG, CHINA (Tang, Xiao) Insti...

  20. Calcium-acidic phospholipid-phosphate complexes in human hydroxyapatite-containing pathologic deposits.

    OpenAIRE

    Boskey, A. L.; Bullough, P. G.; Vigorita, V.; Di Carlo, E

    1988-01-01

    The deposition of calcium-containing crystals in tissues is due to a combination of factors: elevation in the concentrations of precipitating ions, formation of specific nucleators, and removal of macromolecules that inhibit crystal deposition. This study tested the hypothesis that calcium acidic phospholipid phosphate complexes, which promote hydroxyapatite deposition both in vitro and in vivo, are associated only with hydroxyapatite deposits, and furthermore, that the presence of these comp...

  1. Phosphine and thiophene cyclopalladated complexes: hydrolysis reactions in strong acidic media.

    Science.gov (United States)

    García, Begoña; Hoyuelos, Francisco J; Ibeas, Saturnino; Muñoz, María S; Navarro, Ana M; Peñacoba, Indalecio A; Leal, José M

    2010-12-01

    The mechanisms for the hydrolysis of organopalladium complexes [Pd(CNN)R]BF(4) (R=P(OPh)(3), PPh(3), and SC(4)H(8)) were investigated at 25 °C by using UV/Vis absorbance measurements in 10 % v/v ethanol/water mixtures containing different sulphuric acid concentrations in the 1.3-11.7 M range. In all cases, a biphasic behavior was observed with rate constants k(1obs), which corresponds to the initial step of the hydrolysis reaction, and k(2obs), where k(1obs)>k(2obs). The plots of k(1obs) and k(2obs) versus sulfuric acid concentration suggest a change in the reaction mechanism. The change with respect to the k(1obs) value corresponds to 35 %, 2 %, and 99 % of the protonated complexes for R=PPh(3), P(OPh)(3), and SC(4)H(8), respectively. Regarding k(2obs), the change occurred in all cases at about 6.5 M H(2)SO(4) and matched up with the results reported for the hydrolysis of the 2-acetylpyridinephenylhydrazone (CNN) ligand. By using the excess acidity method, the mechanisms were elucidated by carefully looking at the variation of k(i),(obs) (i=1,2) versus cH+. The rate-determining constants, k(0,A-1), k(0,A-2), and k(0,A-SE2) were evaluated in all cases. The R=P(OPh)(3) complex was most reactive due to its π-acid character, which favors the rupture of the trans nitrogen-palladium bond in the A-2 mechanism and also that of the pyridine nitrogen-palladium bond in the A-1 mechanism. The organometallic bond exerts no effect on the relative basicity of the complexes, which are strongly reliant on the substituent. PMID:21125574

  2. Effect of denaturants on the speciation of dicarboxylic acids: uranium(VI) complexes of oxalic acid in micellar media

    International Nuclear Information System (INIS)

    A computer assisted pH-metric investigation has been carried out on the effect of micelles on the complexes of uranium(VI) with oxalic acid. Approximate formation constants have been calculated with the computer program SCPHD utilizing the experimental data obtained by monitoring H+ ion concentration. The formation constants thus obtained are refined with the computer program MINIQUAD75. Selection of the best-fit chemical model is based on the statistical parameters and residual analysis. The major complexes formed are [UO2(C2O4)2]2-, UO2(C2O4) and [UO2(C2O4)2OH]3-. The distribution patterns of the different species with pH show that [UO2(C2O4)2]2- is the predominant species. Influence of the micelles on the speciation is discussed based on the distribution of the various species in the Stern layer and in bulk solvent. The probable structures of the complexes are also given. (author)

  3. Tandem Catalytic Depolymerization of Lignin by Water-Tolerant Lewis Acids and Rhodium Complexes.

    Science.gov (United States)

    Jastrzebski, Robin; Constant, Sandra; Lancefield, Christopher S; Westwood, Nicholas J; Weckhuysen, Bert M; Bruijnincx, Pieter C A

    2016-08-23

    Lignin is an attractive renewable feedstock for aromatic bulk and fine chemicals production, provided that suitable depolymerization procedures are developed. Here, we describe a tandem catalysis strategy for ether linkage cleavage within lignin, involving ether hydrolysis by water-tolerant Lewis acids followed by aldehyde decarbonylation by a Rh complex. In situ decarbonylation of the reactive aldehydes limits loss of monomers by recondensation, a major issue in acid-catalyzed lignin depolymerization. Rate of hydrolysis and decarbonylation were matched using lignin model compounds, allowing the method to be successfully applied to softwood, hardwood, and herbaceous dioxasolv lignins, as well as poplar sawdust, to give the anticipated decarbonylation products and, rather surprisingly, 4-(1-propenyl)phenols. Promisingly, product selectivity can be tuned by variation of the Lewis-acid strength and lignin source. PMID:27440544

  4. Silver nanoparticle glycyrrhizic acid complex: prospects as an adjuvant in radiotherapy

    International Nuclear Information System (INIS)

    Radiotherapy is one of the most common modality for the treatment of cancer. To obtain optimum results, the tumour tissues should receive maximum radiation inflicted damage while the normal tissues are to be protected. There are several reports that indicate the possibility of cancer induction because of exposure to radiation during therapeutic and diagnostic radiation exposures. Thus, the role of radioprotective compounds is very important in clinical radiotherapy. 'Radiopharmaceuticals' are drugs that are described to sensitize tumor cells to radiotherapy or to protect normal tissues from radiation-induced injuries. The present study is aimed to evaluate differential radioprotecting ability of silver nanoparticle complex of glycyrrhizic acid (SN-GLY) in solid tumor bearing Swiss albino mice. Silver nanoparticle complex of glycyrrhizic acid (SN-GLY) was evaluated for its differential radioprotecting ability. DLA tumor was transplanted subcutaneously the hind limbs of mice and when the tumor size reached approximately 1 cm3, the animals was administered po with Silver nanoparticle-glycyrrhizic acid complexes (SN-GLY) and exposed to a single dose of whole body 4 Gy a-radiation. Radiation induced damages in cellular DNA of tumour and normal tissues were analyzed by alkaline comet assay and the extent of apoptosis was investigated. The extent of tumor regression in the animals was also monitored

  5. Thermodynamics and Structure of Actinide(IV) Complexes with Nitrilotriacetic Acid

    International Nuclear Information System (INIS)

    Nitrilotriacetic acid, commonly known as NITA (N(CH2CO2H)3), can be considered a representative of the polyamino-carboxylic family. The results presented in this paper describe the thermodynamical complexation and structural investigation of An(IV) complexes with NTA in aqueous solution. In the first part, the stability constants of the An(IV) complexes (An = Pu, Np, U, and Th) have been determined by spectrophotometry. In the second part, the coordination spheres of the actinide cation in these complexes have been described using extended X-ray absorption fine structure spectroscopy and compared to the solid-state structure of (Hpy)2[U(NTA)2].H2O. These data are further compared to quantum chemical calculations, and their evolution across the actinide series is discussed. In particular, an interpretation of the role of the nitrogen atom in the coordination mode is proposed. These results are considered to be model behavior of polyamino-carboxylic ligands such as diethylenetriamine pentaacetic acid, which is nowadays the best candidate for a chelating agent in the framework of actinide decorporation for the human body. (authors)

  6. Scandium(3) complexing with di-(2-ethylhexyl)phosphoric acid during solvent extraction from sulfuric acid solutions from 31P and 45Sc NMR data

    International Nuclear Information System (INIS)

    The structure of scandium complexes with di-(2-ethylhexyl)phosphoric acid forming in the organic phase during the extraction from aqueous 0.5-9.0M H2SO4 solutions is studied. It is shown that the composition of extracts does not include mineral acid anions while the increase of water phase activity brings about the dominating extraction of forms in the coordination sphere of the complex

  7. Barbiturates inhibit ATP-K+ channels and voltage-activated currents in CRI-G1 insulin-secreting cells.

    OpenAIRE

    Kozlowski, R. Z.; Ashford, M. L.

    1991-01-01

    1. Patch-clamp recording techniques were used to examine the effects of barbiturates upon the ATP-K+ channel, and voltage-activated channels present in the plasma membrane of CRI-G1 insulin-secreting cells. 2. Thiopentone inhibited ATP-K+ channel activity when applied to cell-attached patches or the intracellular or extracellular surface of cell-free patches. Secobarbitone and pentobarbitone were also effective inhibitors of ATP-K+ channels in cell-free patches, whereas phenobarbitone was ine...

  8. Study of equilibrium complexing reactions of uranomolybdic acid with REE3+ ions

    International Nuclear Information System (INIS)

    Equilibria in aqueous solutions, containing REE ions (La-Lu, Y, Sc) and uranomolybdic acid H8(UMo12O42) with 1:1 molar ratio and in the case with Sc-with 1:1 and 2:1 ratio are described by mathematical modelling method based on pH-metric titration data LiOH solution is used as titrant. Evaluations of complex form series production constants are obtained by a non-linear least squaretit. It is ascertained, that with an increase of REE ordinal number models and complexing constant evaluations do not change sufficiently. A possibility of polymer inert complex formation in the case with La3+ and Ce3+ is demonstrated using 17O, 95Mo, 139La NMR spectroscopy

  9. Electron transfer reactions of osmium(II) complexes with phenols and phenolic acids

    Science.gov (United States)

    Rajeswari, Angusamy; Ramdass, Arumugam; Muthu Mareeswaran, Paulpandian; Velayudham, Murugesan; Rajagopal, Seenivasan

    2016-07-01

    Three [Os(NN)3]2+ complexes (NN = polypyridine) with ligands of varying hydrophobicity were synthesized and characterized by NMR spectral techniques. The geometry of the molecules are optimized by DFT calculations. The interaction between [Os(NN)3]2+ complexes and phenolate ion in ground state is confirmed by absorption spectral study and the binding constant values are in the range of 3-740 M-1. The photoinduced electron transfer reaction of these [Os(NN)3]2+ complexes with phenols and phenolic acids at pH 12.5 leads to the formation of phenoxyl radical confirmed through transient absorption spectral study. Binding constants and electron transfer rate constants within the [Os(NN)3]2+-phenolate ion adduct account for the change for the overall quenching constant with the change of structure of reactants.

  10. Electrochemiluminescence Study of Europium (III Complex with Coumarin3-Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Tomasz Grzyb

    2008-10-01

    Full Text Available The europium (III complex of coumarin-3-carboxylic acid (C3CA has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence spectroscopy. The synthesised complex having a formula Eu(C3CA2(NO3(H2O2 was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET in the generated ECL.

  11. Synthesis and Crystal Structure of a Complex of Melamine with Benzoic Acid

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiu-lian

    2008-01-01

    A new complex of melamine(MA) with benzoic acid(HBA) was prepared,affording [(HMA+)(BA-)]·2H2O.Each HBA molecule is deprotonated and one triazine nitrogen atom of MA is protonated,The adjacent HMA+ cations are hydrogen bonded to alternate sides of the (HMA+)∞ ribbons to generate indention 1D tapes,which are extended into the hydrogen bond present in the complex are anion/water and amino/water tape structures,The hydrogen-bonding patterns consist of alternate 6,10-membered rings sharing two edges,Infrared(IR) spectroscopy conforms that proton transfer has taken place in the complex.

  12. Complex formation of trivalent americium with salicylic acid at very low concentrations

    International Nuclear Information System (INIS)

    For the first time, the complexation of americium(III) with salicylic acid was studied at trace metal concentrations using a 2.0 m Long Path Flow Cell for UV-vis spectroscopy. The detection limit of Am(III) in aqueous solution at pH 3.0 was found to be 5 x 10-9 M. Two Am(III)-salicylate complexes were formed at pH 5.0 in 0.1 M NaClO4, indicated by a clear red shift of the absorption maximum. The absorption spectra obtained from spectrophotometric titration were analyzed by means of factor analysis and complex stabilities were calculated to be log β110 = 2.56 ± 0.08 and log β120 = 3.93 ± 0.19. (author)

  13. Complexes of rare-earth perchlorates with ditbutyl amides of di, tri and tetraglycolic acids

    OpenAIRE

    Premlatha, C; Soundararajan, S

    1981-01-01

    New complexes of lanthanide perchlorates with di-t-butyl amides of di, tri and tetraglycolic acids have been synthesised. The complexes have the general formula Ln(DiGA)3(ClO4)3; Ln(TriGA)2 (ClO4)3 and Ln(TetGA)2 (C1O4)3, where Ln = La-Yb and Y and DiGA = N,N′, di-t-butyl diglycolamide, TriGA N,N′, di-t-butyl triglycolamide and TetGA = N,N′ di-t-butyl tetraglycolamide, respectively. The complexes have been characterized by analysis, electrolytic conductance, infrared,1H and13C nuclear magneti...

  14. Lipid-Nucleic Acid Supramolecular Complexes: Lipoplex Structure and the Kinetics of Formation

    Directory of Open Access Journals (Sweden)

    Nily Dan

    2015-06-01

    Full Text Available The need for synthetic gene therapy or gene silencing vehicles that can insert therapeutic nucleic acids (DNA or siRNA into cells (so-called transfection has focused interest on lipid-nucleic acid assemblies (lipoplexes. This paper reviews the kinetics pathways leading to lipoplex formation and structure. The process is qualitatively comparable to those of cluster nucleation and growth and to the adsorption of polyelectrolytes on colloidal particles: Initially is a rapid stage where the nucleic acid binds onto the surface of the cationic lipid aggregate (adsorption, or nucleation. This is followed by an intermediate step where the lipid/nucleic acid complexes flocculate to form larger structures (growth. The last and final step involves internal rearrangement, where the overall global structure remains constant while local adjustment of the nucleic acid/lipid organization takes place until the equilibrium lipoplex characteristics are obtained. This step can require unusually long time scales of order hours or longer. Understanding the kinetics of lipoplex formation is not only of fundamental interest as a multi-component, multi-length scale and multi-time scale process, but also has significant implications for the utilization of lipoplexes as carriers for gene delivery and gene silencing agents.

  15. DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes

    Science.gov (United States)

    Raman, N.; Sobha, S.; Selvaganapathy, M.; Mahalakshmi, R.

    2012-10-01

    Few transition metal complexes of tetradentate N2O2 donor Schiff base ligands containing 2-hydroxybenzylidene-4-aminoantipyrine and amino acids (alanine/valine) abbreviated to KHL1/KHL2 have been synthesized. All the metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The Schiff bases KHL1/KHL2 are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around the metal ions. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through minor groove binding mode. The studies on mechanism of photocleavage reveal that singlet oxygen (1O2) and superoxide anion radical (O2rad -) may play an important role in the photocleavage. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae and antifungal activities against Aspergillus niger, Fusarium solani, Culvularia lunata, Rhizoctonia bataicola and Candida albicans by MIC method.

  16. Influence of Humic Acid Complexation with Metal Ions on Extracellular Electron Transfer Activity

    Science.gov (United States)

    Zhou, Shungui; Chen, Shanshan; Yuan, Yong; Lu, Qin

    2015-11-01

    Humic acids (HAs) can act as electron shuttles and mediate biogeochemical cycles, thereby influencing the transformation of nutrients and environmental pollutants. HAs commonly complex with metals in the environment, but few studies have focused on how these metals affect the roles of HAs in extracellular electron transfer (EET). In this study, HA-metal (HA-M) complexes (HA-Fe, HA-Cu, and HA-Al) were prepared and characterized. The electron shuttle capacities of HA-M complexes were experimentally evaluated through microbial Fe(III) reduction, biocurrent generation, and microbial azoreduction. The results show that the electron shuttle capacities of HAs were enhanced after complexation with Fe but were weakened when using Cu or Al. Density functional theory calculations were performed to explore the structural geometry of the HA-M complexes and revealed the best binding sites of the HAs to metals and the varied charge transfer rate constants (k). The EET activity of the HA-M complexes were in the order HA-Fe > HA-Cu > HA-Al. These findings have important implications for biogeochemical redox processes given the ubiquitous nature of both HAs and various metals in the environment.

  17. Mn(II) complexes with bipyridine, phenanthroline and benzoic acid: Biological and catalase-like activity

    Indian Academy of Sciences (India)

    Ibrahim Kani; Özlem Atlier; Kiymet Güven

    2016-04-01

    Five mononuclear Mn(II) complexes, [Mn(phen)2(ClO4)2] (1), [Mn(phen)3](ClO4)2(H2CO3)2(2), [Mn(bipy)2(ClO4)2] (3), [Mn(bipy)3](ClO4)2) (4), and Mn(phen)2(ba)(H2O)](ClO4)(CH3OH) (5), where bipy = 2,2’-bipyridine, phen = 1,10-phenanthroline, and ba = benzoic acid were prepared and characterized by Xray, IR and UV-Vis spectroscopies, and their catalase-like and biological activities were studied. The presence of two different types and the number of chelating NN-donor neutral ligands allowed for analysis of their effects on the catalase and biological activities. It was observed that the presence and number of phen ligands improved the activity more than the bipy ligand. Complexes 1 and 2, which contain more basic phen ligands, disproportionate H2O2 faster than complexes 3 and 4, which contain less basic bipy ligands. The in vitro antimicrobial activities of all the complexes were also tested against seven bacterial strains by microdilution tests. All the bacterial isolates demonstrated sensitivity to the complexes and the antifungal (anticandidal) activities of the Mn(II) complexes were remarkably higher than the reference drug ketoconazole.

  18. Structure and dynamics studies of the short strong hydrogen bond in the 3,5-dinitrobenzoic acid-nicotinic acid molecular complex.

    OpenAIRE

    Ford, Samantha J.; McIntyre, Garry J.; Johnson, Mark R.; Evans, Ivana Radosavljevic

    2013-01-01

    The molecular complex between 3,5-dinitrobenzoic acid and nicotinic acid (35DBNA) has been studied by variable temperature single crystal X-ray and neutron diffraction (30 to 300 K) and ab initio molecular dynamics, in order to investigate the dynamics and any proton migration in this system, which exhibits structural similarities with the well-known proton migration material 3,5-dicarboxylic acid. The refined structures clearly indicate a significant degree of proton transfer in ...

  19. Synthesis of amino acid rare earth complexes and its application in agriculture

    International Nuclear Information System (INIS)

    Full text: The application of rare-earth compounds in agriculture has been widely reported. So far, most rare-earth compounds used in agriculture were inorganic salt and they were difficult to be absorbed by croup. The synthesis method and structure of amino acid rare-earth complexes have been reported. In this paper, we reported the preparation of mixed amino acids rare-earth complexes and their application in agriculture. The mixed amino acids were obtained by hydrolysis of waste natural protein. Rare earth was lanthanum oxide(99%). Mixed amino acids lanthanum complexes(MALa) was prepared according to the previous method. Investigation to the effect of croup by MALa, we have make tests of citrus, rice and mung bean. The results show as follows: 1) When the experiment group citrus was sprinkled twice 400ppm MALa at bouquet stage and young fruit stage, the sugar, morose, sucrose, soluble solid matter and vitamin C of fruit were increased 21%, 20%, 22%, 22% and 6% as compared to the control group, respectively. The area of leaf and foliage branch in Spring were also increased 4.6% and 2.2%. 2) When the rice was sprinkled 300ppm MALa at early tillering stage, the productively of rice was addition to 10-15%, and the relative effect of prevention was 45.61% for sheath and culm blight of rice. 3) In the test of mungbean growth, the low consistency of MALa (250ppm) retain from sprouting seed. As the same time, it was similar action to seeding growth. Preliminary results indicated MLAa could used as the plant growth regulation agent on the croup. Investigation to the effect of MALa on other croup and the mechanism of biological effect on the croup are still going on

  20. STUDY ON POLYMER-RARE EARTH METAL ION COMPLEXES I. FLUORESCENT PROPERTIES OF POLY(ACRYLIC ACID-CO-4-VINYLPYRIDINE)-RARE EARTH METAL COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    LU Hong; FANG Shibi; JIANG Yingyan

    1987-01-01

    A kind of copolymer of acrylic acid and vinylpyridine was synthesized and the fluorescent properties of the complexes of the copolymer with Eu3+ or Tb3+ were studied. It was found that the fluorescence intensity of the complexes of the copolymer with Eu3+ was 20 times as high as that of the complexes of polyacrylic acid with Eu3+ and twice as high as that of the complexes of polyvinylpyridine with Eu3+. The effects of the composition of the copolymer and the content of Eu3+ or Tb3+ in the complexes were studied.The fluorescence lifetime of the complexes was measured and it was found that two or more kinds of energy transfer mechanism existed.

  1. ESR study of irradiated single crystals of the cocrystalline complex of cytidine: Salicylic acid

    International Nuclear Information System (INIS)

    Irradiation at 77 K of single crystals of the 1:1 complex of cytidine and salicylic acid produces a phenoxyl radical formed by oxidation of the salicylic acid. Anisotropic hyperfine coupling tensors have been determined for this radical which are associated with the para and ortho hydrogens. No cytidine oxidation products (alkoxy or hydroxyalkyl radicals) were observed at 77 K. Following the decay of the phenoxyl radical at room temperature, four radicals were detected. These include the cytosine 5--yl and 6--yl radicals, formed by H addition to the cytosine ring, and an anisotropic doublet. By UV irradiation at room temperature, it is possible to convert a significant fraction of 6-yl radicals into 5-yl radicals. Hyperfine coupling and g tensors determined for the anisotropic doublet indicate that this radical is formed in the C/sub 1'/-C/sub 2'/ region of the sugar moiety. These results indicate a shift in radiation damage away from the salicylic acid upon warming, and show that the radiation chemistry of the cocrystalline complex is different from that of the isolated bases

  2. Synthesis and biodistribution of six novel 99mTc complexes of 2-hydroxybenzaldehyde-amino acid Schiff bases

    International Nuclear Information System (INIS)

    For the purpose of developing novel diagnostic pharmaceuticals of 99mTc-labeled small-size complexes, six novel complexes of 99mTc-2-hydroxybenzaldehyde-amino acid Schiff bases were designed and synthesized, and their biodistributions in mice were investigated. All the compounds were obtained in radiochemical yields higher than 90% at optimal conditions, and poor uptakes in muscle, brain, heart and tumor were commonly observed with rapid blood clearance. Potentiality was revealed of good kidney imaging by 2-hydroxybenzaldehyde-alanine (L2) complex within 40 min post-injection. Good bone uptake of 2-hydroxybenzaldehyde-histidine (L4) and 2-hydroxybenzaldehyde-aspartic acid (L5) complexes, high spleen accumulation of 2-hydroxybenzaldehyde-glycine (L1) and 2-hydroxybenzaldehyde-cysteine (L3) complexes, and non-specific biodistribution of 2-hydroxybenzaldehyde-glutamic acid (L6) complex were demonstrated

  3. Fluorometric Investigation of the Acid-Base and Complexation Behaviour of Tetracycline and Oxytetracycline

    Institute of Scientific and Technical Information of China (English)

    LI, Hong-Xia(李红霞); ZHANG, Jun-Jie(张俊杰); HE, Xi-Wen(何锡文); LI, Guo-Jiang(李国江)

    2004-01-01

    The widely used antibiotics tetracyclines have been effectively used for ailing heart attack, ulcer cure and gene therapy. The actual mechanism of their activity has been proposed to link with the complexes with many metal ions. However, the sites at which complex formation takes place are not well established. In the present work, the deprotonation sequence of tetracycline (TC) and oxytetracycline (OTC), and their specific group used to bind europium ion were investigated by examining the character of fluorescence of TC and OTC as well as that of their complexes. It was concluded that the site of complexation is coordinated with the deprotonation sequence changing with the acidity/basicity of the solution. And it was inferred that five hydrogens in TC and OTC could be dissociated. The deprotonation sequence is as follows: C(3) hydroxy, C(10) phenol, C(4) dimethylamine, C(12) hydroxy and C(12a) hydroxy. The corresponding complexation site changed with pH increase in solution as follows: C(2) acylamino and C(3) hydroxy moiety, C(10)-C(11) ketophenol moiety, C(4) dimethylamine and C(3) hydroxy moiety, C(11)-C(12) β-diketone moiety, C(12) hydroxy and C(12a) hydroxy moiety, and C(12) hydroxy and C(1) ketone moiety respectively.

  4. β-Cyclodextrin Inclusion Complex to Improve Physicochemical Properties of Pipemidic Acid: Characterization and Bioactivity Evaluation

    Directory of Open Access Journals (Sweden)

    Gaetano Malgieri

    2013-06-01

    Full Text Available The aptitude of cyclodextrins (CDs to form host-guest complexes has prompted an increase in the development of new drug formulations. In this study, the inclusion complexes of pipemidic acid (HPPA, a therapeutic agent for urinary tract infections, with native β-CD were prepared in solid state by kneading method and confirmed by FT-IR and 1H NMR. The inclusion complex formation was also characterized in aqueous solution at different pH via UV-Vis titration and phase solubility studies obtaining the stability constant. The 1:1 stoichiometry was established by a Job plot and the inclusion mechanism was clarified using docking experiments. Finally, the antibacterial activity of HPPA and its inclusion complex was tested on P. aeruginosa, E. coli and S. aureus to determine the respective EC50s and EC90s. The results showed that the antibacterial activity of HPPA:β-CD against E. coli and S. aureus is higher than that of HPPA. Furthermore, HPPA and HPPA:β-CD, tested on human hepatoblastoma HepG2 and MCF-7 cell lines by MTT assay, exhibited, for the first time, antitumor activities, and the complex revealed a higher activity than that of HPPA. The use of β-CD allows an increase in the aqueous solubility of the drug, its bioavailability and then its bioactivity.

  5. Trimethylglycine complexes with carboxylic acids and HF: solvation by a polar aprotic solvent.

    Science.gov (United States)

    Guo, Jing; Koeppe, Benjamin; Tolstoy, Peter M

    2011-02-14

    A series of strong H-bonded complexes of trimethylglycine, also known as betaine, with acetic, chloroacetic, dichloroacetic, trifluoroacetic and hydrofluoric acids as well as the homo-conjugated cation of betaine with trifluoroacetate as the counteranion were investigated by low-temperature (120-160 K) liquid-state NMR spectroscopy using CDF(3)/CDF(2)Cl mixture as the solvent. The temperature dependencies of (1)H NMR chemical shifts are analyzed in terms of the solvent-solute interactions. The experimental data are explained assuming the combined action of two main effects. Firstly, the solvent ordering around the negatively charged OHX region of the complex (X = O, F) at low temperatures, which leads to a contraction and symmetrisation of the H-bond; this effect dominates for the homo-conjugated cation of betaine. Secondly, at low temperatures structures with a larger dipole moment are preferentially stabilized, an effect which dominates for the neutral betaine-acid complexes. The way this second contribution affects the H-bond geometry seems to depend on the proton position. For the Be(+)COO(-)···HOOCCH(3) complex (Be = (CH(3))(3)NCH(2)-) the proton displaces towards the hydrogen bond center (H-bond symmetrisation, O···O contraction). In contrast, for the Be(+)COOH···(-)OOCCF(3) complex the proton shifts further away from the center, closer to the betaine moiety (H-bond asymmetrisation, O···O elongation). Hydrogen bond geometries and their changes upon lowering the temperature were estimated using previously published H-bond correlations. PMID:21132169

  6. Stability constants of some complexes of Argentine humic acids and micronutrients

    International Nuclear Information System (INIS)

    One of the main aims in the study of the complexes of humic substances and plant mineral nutrients in the soil is to obtain thermodynamic data which, compared with known systems, can give the necessary information to calculate the element activity in solution. This information is essential for predicting the dynamics of such nutrients in the soil solution, since the latter is one of the main locations of fundamental reactions related to soil genesis and fertility. The distribution of radioactive 65Zn and non-radioactive Cu between a cation exchange resin and the humic systems was used to calculate the stability constants of these elements and the humic acids (HA) extracted from various Argentine soils. On the basis of these stability constants, the following conclusions were obtained: (1) Copper was more strongly complexed than zinc by the humic acid of a Solod soil. Copper had also almost the same value of the logarithm of the stability constant for several soils (8.1 to 9.1); (2) The value of the stability constant of the Zn-HA complex was higher for a Chestnut soil (Petrocalcic Paleustoll) than for the other soils studied; (3) Since HA is an important insoluble fraction in normal soil conditions, it is suggested that the mobility of Cu is low in the soil solution of these soils. Therefore, a Cu deficiency may be predicted or expected. (author)

  7. Inclusion complex of ellagic acid with β-cyclodextrin: Characterization and in vitro anti-inflammatory evaluation

    Science.gov (United States)

    Bulani, Vipin D.; Kothavade, Pankaj S.; Kundaikar, Harish S.; Gawali, Nitin B.; Chowdhury, Amrita A.; Degani, Mariam S.; Juvekar, Archana R.

    2016-02-01

    Freeze-dried inclusion complex of ellagic acid/β-cyclodextrin (EACD) was investigated both in solution and solid state by means of aqueous solubility, in vitro dissolution, absorption, fluorescence, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and molecular modeling methods. The phase solubility study showed that ellagic acid formed 1:2 stoichiometric inclusion complex with β-cyclodextrin (β-CD). The FTIR study indicates that carbonyl group of ellagic acid interact with β-CD. The NMR results demonstrate that ellagic acid was partly included into the β-CD from the wider side of the cavity. Molecular modeling studies revealed that hydrogen bonding interactions played an important role in the inclusion process and higher negative values for the complexation energies imply that 1:2 complex was more stable than 1:1 complex. The solubility and in vitro dissolution of ellagic acid was significantly enhanced by complexation with β-CD as compared to the free ellagic acid. Additionally, the complexation of EACD positively influences it's in vitro anti-inflammatory activity by protecting from protein denaturation and lysis of erythrocyte membrane.

  8. Chlorogenic acid ameliorates intestinal mitochondrial injury by increasing antioxidant effects and activity of respiratory complexes.

    Science.gov (United States)

    Zhou, Yan; Zhou, Lili; Ruan, Zheng; Mi, Shumei; Jiang, Min; Li, Xiaolan; Wu, Xin; Deng, Zeyuan; Yin, Yulong

    2016-05-01

    Dietary polyphenols are thought to be beneficial for human health by acting as antioxidants. Chlorogenic acid (CGA) is abundant in plant-based foods as an ester of caffeic acid and quinic acid. In this study, we investigated the effects of CGA on mitochondrial protection. Our results demonstrated that pretreatment with CGA ameliorated the intestinal mitochondrial injury induced by H2O2; membrane potential was increased, mitochondrial swelling, levels of reactive oxygen species, contents of 8-hydroxy-2-deoxyguanosine, and cytochrome c released were decreased. The beneficial effects of CGA were accompanied by an increase in antioxidant and respiratory-chain complex I, IV, and V activities. In trinitrobenzene-sulfonic acid-induced colitic rats indicated that CGA supplementation improved mitochondria ultrastructure and decreased mitochondrial injury. Our results suggest a promising role for CGA as a mitochondria-targeted antioxidant in combating intestinal oxidative injury. Daily intake of diets containing CGA, such as coffee and honeysuckle, may be useful for prevention of intestinal diseases. PMID:26824685

  9. A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex

    Energy Technology Data Exchange (ETDEWEB)

    Arya, S. P.; Mahajan, M. [Haryana, Kurukshetra Univ. (India). Dept. of Chemistry

    1998-05-01

    A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 {mu}g ml{sup -1}. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C. [Italiano] Si propone un rapido e semplice metodo spettrofotometrico per la determinazione dell`acido ascorbico. L`acido ascorbico riduce il ferro(III) a ferro(II) che forma con la dimetilgliossima, in presenza di piridina, un complesso colorato in rosso. L`assorbanza della soluzione risultante e` misurata a 514 nm e si ottiene una relazione lineare tra assorbanza e concentrazione dell`acido ascorbico fino a 14 {mu}g ml{sup -1}. Si sono condotti studi sugli interferenti usualmente associati all`acido ascorbico ed e` stata valutata l`applicabilita` del metodo all`analisi di preparati farmaceutici di vitamina C.

  10. Self-assembled ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates for targeted gene delivery.

    Science.gov (United States)

    Liang, Kun; Bae, Ki Hyun; Lee, Fan; Xu, Keming; Chung, Joo Eun; Gao, Shu Jun; Kurisawa, Motoichi

    2016-03-28

    Nanosized polyelectrolyte complexes are attractive delivery vehicles for the transfer of therapeutic genes to diseased cells. Here we report the application of self-assembled ternary complexes constructed with plasmid DNA, branched polyethylenimine and hyaluronic acid-green tea catechin conjugates for targeted gene delivery. These conjugates not only stabilize plasmid DNA/polyethylenimine complexes via the strong DNA-binding affinity of green tea catechin, but also facilitate their transport into CD44-overexpressing cells via receptor-mediated endocytosis. The hydrodynamic size, surface charge and physical stability of the complexes are characterized. We demonstrate that the stabilized ternary complexes display enhanced resistance to nuclease attack and polyanion-induced dissociation. Moreover, the ternary complexes can efficiently transfect the difficult-to-transfect HCT-116 colon cancer cell line even in serum-supplemented media due to their enhanced stability and CD44-targeting ability. Confocal microscopic analysis demonstrates that the stabilized ternary complexes are able to promote the nuclear transport of plasmid DNA more effectively than binary complexes and hyaluronic acid-coated ternary complexes. The present study suggests that the ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates can be widely utilized for CD44-targeted delivery of nucleic acid-based therapeutics. PMID:26855049

  11. IMMOBILIZATION OF GLUCOSE OXIDASE AND CELLULASE BY CHITOSAN-POLYACRYLIC ACID COMPLEX

    Institute of Scientific and Technical Information of China (English)

    WANG Lingzhi; JIANG Yingyan; ZHANG Changde; HUANG Dexiu

    1990-01-01

    This study is concerned with chitosan-polyacrylic acid complex as a carrier to immobilize glucose oxidase (GOD) and cellulase. The optimum temperature of the immobilized GOD (IG) was determined to be 60 ℃ which is higher than that of the native GOD about 40 ℃ . The optimum temperature of the immobilized cellulase (IC) was determined to be about 30 ℃ higher than that of native cellulase. Both of the optimum pH of IG and IC shifted one pH unit to acid. Immobilized enzyme may be used in more wide pH range. Their storage life are much longer compared with their native states. Both of them can be reused at least 12 times.

  12. One-Step Assembly of Phytic Acid Metal Complexes for Superhydrophilic Coatings.

    Science.gov (United States)

    Li, Longbiao; Zhang, Guangyu; Su, Zhaohui

    2016-07-25

    While of immense scientific interest, superhydrophilic surfaces are usually difficult to prepare, and preparation methods are typically substrate specific. Herein, a one-step coating method is described that can endow superhydrophilicity to a variety of substrates, both inorganic and organic, using the coordination complexes of natural phytic acid and Fe(III) ions. Coating deposition occurs in minutes, and coatings are ultrathin, colorless, and transparent. Superhydrophilicity is attributed, in part, to the high density of phosphonic acid groups. The ease, rapidness, and mildness of the assembly process, which is also cost-effective and environmental-friendly, points towards potential applications, such as self-cleaning, oil/water separation, antifogging. PMID:27377349

  13. Synthesis and Characteristic Study on Complexes of Europium(Ⅲ) and Maleic Acid Doped with Non-Fluorescent Ions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Complex of europium (Ⅲ) with maleic acid, and binuclear complexes of europium(Ⅲ)with maleic acid doped with non-fluorescent ions gadolinium, lanthanum and yttrium, were synthesized. The compositions and structures of complexes were characterized with elemental analysis, single crystal X-ray diffraction, IR and DSC-TG. Fluorescent properties were studied with fluorescence spectrum. The results indicated that the strongest fluorescent complexes were obtained when the ratio of europium and non-fluorescent ion was 8: 2. The order of Eu3+ fluorescence strengthened by three doped rare earths was Gd3+>La3+>Y3+.

  14. Anion-π interactions in complexes of proteins and halogen-containing amino acids.

    Science.gov (United States)

    Borozan, Sunčica Z; Zlatović, Mario V; Stojanović, Srđan Đ

    2016-06-01

    We analyzed the potential influence of anion-π interactions on the stability of complexes of proteins and halogen-containing non-natural amino acids. Anion-π interactions are distance and orientation dependent and our ab initio calculations showed that their energy can be lower than -8 kcal mol(-1), while most of their interaction energies lie in the range from -1 to -4 kcal mol(-1). About 20 % of these interactions were found to be repulsive. We have observed that Tyr has the highest occurrence among the aromatic residues involved in anion-π interactions, while His made the least contribution. Furthermore, our study showed that 67 % of total interactions in the dataset are multiple anion-π interactions. Most of the amino acid residues involved in anion-π interactions tend to be buried in the solvent-excluded environment. The majority of the anion-π interacting residues are located in regions with helical secondary structure. Analysis of stabilization centers for these complexes showed that all of the six residues capable of anion-π interactions are important in locating one or more of such centers. We found that anion-π interacting residues are sometimes involved in simultaneous interactions with halogens as well. With all that in mind, we can conclude that the anion-π interactions can show significant influence on molecular organization and on the structural stability of the complexes of proteins and halogen-containing non-natural amino acids. Their influence should not be neglected in supramolecular chemistry and crystal engineering fields as well. PMID:26910415

  15. Influence of the chemical properties of technetium complexes with hydroxycarboxylic acid ligands on the biodistribution in the rat

    International Nuclear Information System (INIS)

    A comparison of the biodistribution of chemically defined 99Tc-hydroxycarboxylic acid chelats and the respective sup(99m)Tc-compounds showed that, with the exception of the tartrate derivatives, the sup(99m)Tc-Radiopharmaceuticals have the structure of Tc(V)-complexes. Kidney trapping is related to the oxidation state Tc(V), but is otherwise practically independent of charge, size and structure of the respective hydroxycarboxylic acid complexes. In contrast to Tc(IV)-complexes the Tc(V)-derivatives reveal rapid ligand exchange with SH-containing ligands such as dimercaptosuccinic acid. As a likely mechanism for kidney trapping, the exchange of Tc(V)-hydroxycarboxylic acid complexes with SH-containing proteins of the kidney cortex is proposed. (orig.)

  16. Effects of alkaline earth metal ion complexation on amino acid zwitterion stability: Results from infrared action spectroscopy

    NARCIS (Netherlands)

    Bush, M. F.; Oomens, J.; Saykally, R. J.; Williams, E. R.

    2008-01-01

    The structures of isolated alkaline earth metal cationized amino acids are investigated using infrared multiple photon dissociation (IRMPD) spectroscopy and theory. These results indicate that arginine, glutamine, proline, serine, and valine all adopt zwitterionic structures when complexed with diva

  17. New complexes of samarium(III), terbium(III) and holmium (III) with quercetin-5'-sulfonic acid

    International Nuclear Information System (INIS)

    New solid complexes of samarium(III), terbium (III), and holmium (III) with quercetin-5'-sulfonic acid were obtained. Their composition and physicochemical properties were investigated. Ultraviolet, visible and infrared spectroscopy methods were used to determine their structure. (author)

  18. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    Science.gov (United States)

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers. PMID:27040215

  19. Structural plasticity and dynamic selectivity of acid sensing ion channel–toxin complexes

    OpenAIRE

    Baconguis, Isabelle; Gouaux, Eric

    2012-01-01

    Acid sensing ion channels (ASICs) are voltage-independent, amiloride-sensitive channels implicated in diverse physiological processes ranging from nociception to taste. Despite the importance of ASICs in physiology, we know little about the mechanism of channel activation. Here we show that psalmotoxin activates non- and sodium-selective currents in chicken ASIC1a at pH 7.25 and 5.5, respectively. Crystal structures of ASIC1a – psalmotoxin complexes map the toxin binding site to the extracell...

  20. Fluorescence of lanthanide(3) complexes with aminopolyacetic acids in aqueous solutions

    International Nuclear Information System (INIS)

    The fluorescence of Eu(3), Gd(3), Tb(3) and Dy(3) ions complexed with aminopolyacetic acids was investigated. The influence of temperature and the dimensions of the ligand molecules and of their electric charge on the intensity of the emission bands is discussed as well as the ratio of the hypersensitive (forbidden) band to the allowed band intensity. On the basis of the fluorescence measurements a simple theoretical model is discussed and certain generalizations concerning the fluorescence of the lanthanides group are derived. (Author)

  1. The effect of Gcmaf complexed with oleic acid on multiple myeloma cultures

    OpenAIRE

    Smith, R.J.; Ward, E.; J.J.V. Branca; Ruggiero, M; G.Morucci; S. Pacini

    2014-01-01

    Abstract: Deglycosylated vitamin D-binding protein-derived macrophage-activating factor (GcMAF) is known to be a strong immune stimulatory natural molecule. Data in literature demonstrate that GcMAF has a direct role in decreasing cell proliferation of different cancer cell lines. In this study we evaluate the direct effect of GcMAF complexed with oleic acid (OA-GcMAF) on human multiple myeloma cells (KMS-12- BM), as well as the effect on the same cell line of human macrophages (CRL9853) prev...

  2. Crystal structure of the 1:2 molecular complex of tetrafluoroboric acid with triphenylphosphine oxide

    International Nuclear Information System (INIS)

    Crystalline molecular complex of tetrafluoroboric acid with triphenylphosphine oxide of Ph3PO·0.5HBF4 (1) is prepared and studied by means of x-ray diffraction method. HBF4 molecule is situated near crystallographic axis 2 and is statistically disordered relatively this axis. All the atoms of the molecule have positions of population density equal 0.5. Boron atom has distorted tetrahedral coordination. B-F(H) bond is significantly more lengthy then other three B-F bonds and is donor-acceptor one. HBF4 molecule is bonded with Ph3PO molecule by strong asymmetrical hydrogen bond with 50 % probability

  3. Fatty acid ethanolamide levels are altered in borderline personality and complex posttraumatic stress disorders.

    Science.gov (United States)

    Schaefer, Carola; Enning, Frank; Mueller, Juliane K; Bumb, J Malte; Rohleder, Cathrin; Odorfer, Thorsten M; Klosterkötter, Joachim; Hellmich, Martin; Koethe, Dagmar; Schmahl, Christian; Bohus, Martin; Leweke, F Markus

    2014-08-01

    Borderline personality (BPD) and complex posttraumatic stress disorders (PTSD) are both powerfully associated with the experience of interpersonal violence during childhood and adolescence. The disorders frequently co-occur and often result in pervasive problems in, e.g., emotion regulation and altered pain perception, where the endocannabinoid system is deeply involved. We hypothesize an endocannabinoid role in both disorders. We investigated serum levels of the endocannabinoids anandamide and 2-arachidonoylglycerol and related fatty acid ethanolamides (FAEs) in BPD, PTSD, and controls. Significant alterations were found for both endocannabinoids in BPD and for the FAE oleoylethanolamide in PTSD suggesting a respective link to both disorders. PMID:24253425

  4. Complexes of fulvic acid on the surface of hematite, goethite, and akaganeite: FTIR observation.

    Science.gov (United States)

    Fu, Hongbo; Quan, Xie

    2006-04-01

    The present work extended our knowledge on the binding and complexation of a fulvic acid (FA) derived from leonardite and the iron oxides (hematite, goethite and akaganeite) by Fourier transform infrared spectroscopy (FTIR). As a prerequisite, the iron oxides were firstly prepared and characterized by transmission electron micrograph (TEM). All iron phases were single and well-described crystalloid. The FTIR data obtained by two different sampling preparation methods gave the consisting evidences that under our experimental conditions the interaction mechanism was to the ligand-exchange involving carboxylic functional groups of the FA and the surfaces sites of both hematite and goethite, while no complexation can be evidenced in the case of akaganeite, only surface adsorption. In general, the binding affinities of the iron oxides with the FA was in the order of hematite>goethite>akaganeite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in the field of the humic chemistry. PMID:16293289

  5. Methanofullerene-Based Palladium Bis(amino)aryl Complexes and Applications in Lewis Acid Catalysis

    OpenAIRE

    van Koten, G.; Meijer, M.D.; Ronde, N.; Vogt, D.; van Klink, G.P.M.

    2001-01-01

    Synthetic routes have been developed for the attachment of palladium(II) bis(amino)aryl (NCN or C6H2{CH2NMe2}2-2,6)- complexes to C60. Using diazo and Bingel addition reactions, various methanofullerene NCN-SiMe3 compounds (C60-L-NCN-SiMe3, L = C(Me), C(CO2Et)CO2CH2, and C(Me)C6H4CC) have been prepared and characterized. Electrophilic palladation of these ligands was achieved with Pd(OAc)2, leading to the corresponding C60-L-NCN·PdCl complexes. These were converted into active Lewis acid cata...

  6. Therapeutic Potentials of Silver Nanoparticle Complex of α-Lipoic Acid

    Directory of Open Access Journals (Sweden)

    Lakshmy Ramachandran

    2011-10-01

    Full Text Available Silver (SN nanoparticles were re‐dispersed in aqueous solution of Pluronic F127 and complexed with the antioxidant, alpha‐ Lipoic acid (LA. The nanoparticle ‐ LA complex (SN‐LA was characterized using SEM. SN‐ LA exhibited DPPH radical scavenging activity in vitro and anti‐ inflammatory activity against acute and chronic paw models of edema in mice. SN‐LA protected mice from whole body gamma radiation induced body weight losses and mortality revealing its radioprotecting capacity. Meanwhile, SN‐LA administration to tumour‐ bearing mice prior to whole body gamma radiation exposure, aided in better tumour growth delay. The results suggest the feasibility in using SN‐LA as a therapeutic adjuvant during cancer radiotherapy.

  7. Regulation of Fatty Acid Oxidation in Mouse Cumulus-Oocyte Complexes during Maturation and Modulation by PPAR Agonists

    OpenAIRE

    Dunning, Kylie R.; Anastasi, Marie R.; Zhang, Voueleng J.; Russell, Darryl L.; Robker, Rebecca L.

    2014-01-01

    Fatty acid oxidation is an important energy source for the oocyte; however, little is known about how this metabolic pathway is regulated in cumulus-oocyte complexes. Analysis of genes involved in fatty acid oxidation showed that many are regulated by the luteinizing hormone surge during in vivo maturation, including acyl-CoA synthetases, carnitine transporters, acyl-CoA dehydrogenases and acetyl-CoA transferase, but that many are dysregulated when cumulus-oocyte complexes are matured under i...

  8. Determination of dissociation constants of chloride complex acids of bivalent cobalt, zinc, copper and cadmium in TBP from extraction data

    Energy Technology Data Exchange (ETDEWEB)

    Prokuev, V.A.; Belousov, E.A. (Leningradskij Tekhnologicheskij Inst. (USSR); Petrozavodskij Gosudarstvennyj Univ. (USSR))

    1980-12-01

    The calculated method of determining constants of dissociation complex acids of a number of metals (cobalt, copper, zinc and cadmium) in TBP on the basis of known values of element distribution coefficients and degrees of formation of extractive complexes in aqeuous solutions of hydrochloric acid at 25 deg C is suggested. The results of calculations are presented in a table. For H/sub 2/CdCl/sub 4/ the dissociation constant is (10sup(3)Ksub(D)=1.3).

  9. Determination of the thermodynamic quantities of complexation between Eu(III) and carboxylic acids by microcalorimetry

    International Nuclear Information System (INIS)

    Potentiometric and microcalorimetric titration techniques were applied to determine the Gibbs free energies and enthalpies of the protonation of some carboxylic acids (acetic, glycolic, malonic and malic acids) and their complexation with Eu(III) in 1.0 M NaClO4 solution at 25 C, where Eu(III) was used as a chemical analogue of radiologically important Am(III). By using the values of ΔG determined by potentiometric titrations, the results of calorimetric titrations were analyzed to give the values of ΔH and ΔS. To support the discussion on the obtained thermodynamic quantities, the hydration numbers of Eu(III) in the complexes were obtained by TRLFS measurement, where the luminescence lifetime of Eu(III) excited by 394 nm laser was measured. A few to several kJ/mol of enthalpies were determined for the reactions within the uncertainties of ±0.01 to ±0.4. These enthalpy values indicated that the protonation of these carboxylates were entropy-driven, that is, vertical stroke - TΔS vertical stroke >> vertical stroke ΔH vertical stroke in ΔG = ΔH - TΔS. The complexations of Eu(III) were also shown to be controlled mainly by entropy term. The results of TRLFS measurement revealed that the number of dehydrated water molecule increased with the degree of complexation. A linear relation was found between total entropy change of the system (ΔST) and the net number of released molecules from the central Eu(III) ion. However, the values of ΔST for the hydroxy-carboxylates were smaller than that for simple carboxylates at the same net number of molecules released from Eu(III), suggesting that the dehydration occurred not only in the cation but also in the anion. (orig.)

  10. Nanoparticles formed by complexation of poly-gamma-glutamic acid with lead ions

    International Nuclear Information System (INIS)

    The present investigation describes the preparation and characterization of novel biodegradable nanoparticles based on complexation of poly-gamma-glutamic acid (γ-PGA) with bivalent lead ion. The prepared nano-systems were stable in aqueous media at low pH, neutral and mild alkaline conditions. The particle size and the size of the complexes were identified by dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. It was found that the size of the complexes depended on the pH and concentrations of γ-PGA and lead ions. Particle sizes measured by TEM revealed that at low concentrations, nanosized particles were formed, however, at high concentrations of γ-PGA and lead ions, the formation of large aggregates with a broad size distribution was promoted. The size of individual particles was in the range of 40-100 nm measured by TEM. The results from the DLS measurements showed that the low and high pH values in mixtures with high concentrations of γ-PGA and Pb2+ ions favored the growth of large complexes. The γ-PGA nanoparticles, composed of a biodegradable biomaterial with high flocculating and heavy metal binding activity, may be useful for various water treatment applications

  11. Nanoparticles formed by complexation of poly-gamma-glutamic acid with lead ions

    Energy Technology Data Exchange (ETDEWEB)

    Bodnar, Magdolna [Departments of Colloid and Environmental Chemistry, University of Debrecen, H-4010 Debrecen (Hungary); Kjoniksen, Anna-Lena [Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo (Norway); Molnar, Reka M. [Departments of Colloid and Environmental Chemistry, University of Debrecen, H-4010 Debrecen (Hungary); Hartmann, John F. [ElizaNor Polymer LLC, Princeton Junction, NJ 08550 (United States); Daroczi, Lajos [Solid State Physics, University of Debrecen, H-4010 Debrecen (Hungary); Nystroem, Bo [Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo (Norway); Borbely, Janos [Departments of Colloid and Environmental Chemistry, University of Debrecen, H-4010 Debrecen (Hungary); BBS Nanotechnology Ltd., P.O. Box 12, H-4225 Debrecen 16 (Hungary)], E-mail: jborbely@delfin.unideb.hu

    2008-05-30

    The present investigation describes the preparation and characterization of novel biodegradable nanoparticles based on complexation of poly-gamma-glutamic acid ({gamma}-PGA) with bivalent lead ion. The prepared nano-systems were stable in aqueous media at low pH, neutral and mild alkaline conditions. The particle size and the size of the complexes were identified by dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. It was found that the size of the complexes depended on the pH and concentrations of {gamma}-PGA and lead ions. Particle sizes measured by TEM revealed that at low concentrations, nanosized particles were formed, however, at high concentrations of {gamma}-PGA and lead ions, the formation of large aggregates with a broad size distribution was promoted. The size of individual particles was in the range of 40-100 nm measured by TEM. The results from the DLS measurements showed that the low and high pH values in mixtures with high concentrations of {gamma}-PGA and Pb{sup 2+} ions favored the growth of large complexes. The {gamma}-PGA nanoparticles, composed of a biodegradable biomaterial with high flocculating and heavy metal binding activity, may be useful for various water treatment applications.

  12. Preparation and characterization of aqueous dispersions of high amylose starch and conjugated linoleic acid complex.

    Science.gov (United States)

    Seo, Tae-Rang; Kim, Hee-Young; Lim, Seung-Taik

    2016-11-15

    Crystalline starch-CLA complexes were prepared by blending an alcoholic solution of conjugated linoleic acid (CLA) in an aqueous high-amylose maize starch dispersion. Recovery yield of CLA in the precipitates obtained by centrifuging the dispersion was dependent on reaction conditions such as temperature, time and pH. The CLA recovery reached a maximum when the reaction was performed at 90°C for 6h at neutral pH, with 67.7% of the initial CLA being co-precipitated with starch. The precipitates contained amylose-CLA complex exhibiting a V6I-type crystalline structure under X-ray diffraction analysis and a type II polymorph under DSC analysis. Ultrasonic treatment for the re-dispersed starch-CLA complex in water resulted in the reduction of hydrodynamic diameter of the complex particles to 201.5nm. The dispersion exhibited a zeta potential of -27.0mV and remained stable in an ambient storage without forming precipitates for more than 4weeks. PMID:27283663

  13. Synthesis and characterization of tin(II) complexes of fluorinated Schiff bases derived from amino acids

    Science.gov (United States)

    Singh, Har Lal

    2010-07-01

    New tin(II) complexes of general formula Sn(L) 2 (L = monoanion of 3-methyl-4-fluoro-acetophenone phenylalanine L 1H, 3-methyl-4-fluoro-acetophenone alanine L 2H, 3-methyl-4-fluoro acetophenone tryptophan L 3H, 3-methyl-4-fluoro-acetophenone valine L 4H, 3-methyl-4-fluoro-acetophenone isoleucine L 5H and 3-methyl-4-fluoro-acetophenone glycine L 6H) have been prepared. It is characterized by elemental analyses, molar conductance measurements and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance ( 1H, 13C, 19F and 119Sn NMR) spectral studies. The ligands act as bidentate towards metal ions, via the azomethine nitrogen and deprotonated oxygen of the respective amino acid. Elemental analyses and NMR spectral data of the ligands with their tin(II) complexes agree with their proposed square pyramidal structures. A few representative ligands and their tin complexes have been screened for their antibacterial activities and found to be quite active in this respect.

  14. Thermal Behaviour of Some New Polyoxometalate Complexes of Ciprofloxacin with Keggin-type Heteropoly Acids

    Institute of Scientific and Technical Information of China (English)

    WANG Dun-jia; FANG Zheng-dong; HAN De-yan

    2005-01-01

    Four polyoxometalate complexes, (CPFX·HCl)3H4SiW12O40, (CPFX·HCl)3H3PW12O40, (CPFX·HCl)3H3PMo12O40 and (CPFX·HCl)4H4SiMo12O40, were prepared from ciprofloxacin hydrochloride(CPFX·HCl) reacting with HnXM12O40·nH2O(X=P,Si; M=W,Mo) in an aqueous solution, and characterized by elemental analysis, IR spectrometry and TG-DTA. The IR spectrum confirms the presence of Keggin-type anions of heteropoly acids and the characteristic functional groups of ciprofloxacin. The TG/DTA curves show that their thermal decomposition is a multi-step process including simultaneous collapse of the Keggin-type structure. At first, these compounds had a mass loss of water molecules, then several other mass losses occurred due to the decomposition of ciprofloxacin hydrochloride and its fragments with the degradation of Keggin anions. The end product of decomposition is the mixture of WO3(or MoO3) and SiO2(or P2O5), identified by X-ray diffraction and IR spectroscopy. The possible thermal decomposition mechanisms of these complexes are proposed. This study exemplified that the thermal stability of the complexes containing tungsten is much better than that of the complexes containing molybdenum.

  15. Differentiation of Species Combined into the Burkholderia cepacia Complex and Related Taxa on the Basis of Their Fatty Acid Patterns

    OpenAIRE

    Krejčí, Eva; Kroppenstedt, Reiner M.

    2006-01-01

    Using the established commercial system Sherlock (MIDI, Inc.), cellular fatty acid methyl ester analysis for differentiation among Burkholderia cepacia complex species was proven. The identification key based on the diagnostic fatty acids is able to discern phenotypically related Ralstonia pickettii and Pandoraea spp. and further distinguish Burkholderia pyrrocinia, Burkholderia ambifaria, and Burkholderia vietnamiensis.

  16. Synthesis of new monosubstituted methanediphosphonic acids and in vivo study in animals of their metal complexes with technetium 99m

    International Nuclear Information System (INIS)

    A new class of monosubstituted methanediphosphonic acids has been synthesized and their acidic constants were determined by potentiometry. Metal complexes with technetium 99m have been prepared and analysed by paper chromatography. In vivo study of their behaviour has been tested on to the animal. These compounds, inorganic pyrophosphate analogues, are potential bone seeking agents

  17. Use of Chromophoric Ligands to Visually Screen Co-crystals of Putative Protein-Nucleic Acid Complexes

    OpenAIRE

    Jiang, Xiaohua; Egli, Martin

    2011-01-01

    Distinguishing between crystals of protein-nucleic acid complexes and those containing protein alone is a common problem in structural studies of protein-nucleic acid interactions. Currently there are several methods available for detecting nucleic acid in crystals, including gel electrophoresis, SYBR Gold fluorescence dye staining and methyl violet staining. However, they require either that the crystals be sacrificed or access to a fluorescence microscope. In this protocol, we describe an a...

  18. A NOVEL COPOLYMER-BOUND CIS- DICARBONYLRHODIUM COMPLEX FOR THE CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE

    Institute of Scientific and Technical Information of China (English)

    YUAN Guoqing; CHEN Yuying; CHEN Rongyao

    1989-01-01

    A series of porous microspheres of linear and ethylene diacrylate (M ') cross-linked copolymers of 2 - vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol - acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.

  19. Reliability of self-reported use of amphetamine, barbiturates, benzodiazepines, cannabinoids, cocaine, methadone, and opiates among acutely hospitalized elderly medical patients

    DEFF Research Database (Denmark)

    Glintborg, B.; Olsen, L.; Poulsen, H.;

    2008-01-01

    Undisclosed use of illicit drugs and prescription controlled substances is frequent in some settings. The aim of the present study was to estimate the reliability of self-reported use of amphetamine, barbiturates, benzodiazepines, cannabinoids, cocaine, methadone, and opiates among acutely...... hospitalized medical patients....

  20. Intra- and intermolecular hydrogen bonding in formohydroxamic acid complexes with water and ammonia: infrared matrix isolation and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    SaIdyka, Magdalena [Faculty of Chemistry, University of WrocIaw, Joliot-Curie 14, 50-383 WrocIaw (Poland); Mielke, Zofia [Faculty of Chemistry, University of WrocIaw, Joliot-Curie 14, 50-383 WrocIaw (Poland)]. E-mail: zm@wchuwr.chem.uni.wroc.pl

    2005-01-10

    The complexes of formohydroxamic acid with water and ammonia have been studied using FTIR matrix isolation spectroscopy and MP2 calculations with a 6-311++G(2d,2p) basis set. The analysis of the experimental spectra of the HCONHOH/H{sub 2}O(NH{sub 3})/Ar matrixes indicates formation of strongly hydrogen-bonded complexes in which the NH group of formohydroxamic acid acts as a proton donor toward the oxygen atom of water or the nitrogen atom of ammonia. The NH stretching vibration of formohydroxamic acid exhibits 150 cm{sup -1} red shift in the complex with water and 443 cm{sup -1} red shift in the complex with ammonia as compared to the NH stretch of the HCONHOH monomer. The theoretical calculations indicate stability of five isomers for the water complex and three isomers for the ammonia complex. The most stable are the cyclic structures in which the water or ammonia molecules are inserted within the intramolecular hydrogen bond of the formohydroxamic acid molecule and act as proton donors for the CO group and proton acceptors for the OH group of the formohydroxamic acid molecule. In spite of their stability the cyclic structures have not been observed in the matrixes which indicates high energy barrier for their formation, the reaction of complex formation is under kinetic and not thermodynamic control.

  1. Use of the ion exchange method for the determination of stability constants of trivalent metal complexes with humic and fulvic acids--Part I: Eu3+ and Am3+ complexes in weakly acidic conditions

    International Nuclear Information System (INIS)

    The conditional stability constants for tracer concentrations of Eu(III) and Am(III) with a red earth humic acid (REHA), a red earth fulvic acid (REFA) and a fulvic acid from weathered coal (WFA) were determined at pH 5.2-6.4 (such values are similar to those in non-calcareous soils) in the presence of HAc/NaAc or NaNO3 by using the cation exchange method. It was found that 1 : 1 complexes were predominately formed in weakly acidic conditions. The total exchangeable proton capacities and the degrees of dissociation of these humic substances were determined by using a potentiometric titration method. The key parameters necessary for the experimental determination of the conditional stability constants of metal ions with humic substances in weakly acidic conditions by using the cation exchange method were discussed. The conditional stability constants of 1 : 1 complexes obtained in this paper were compared with the literature data of Am(III) determined by using the ion exchange method and the solvent extraction method and with the stability constants of 1 : 1 complexes of UO22+ and Th4+ with the same soil humic substances. These results indicate the great stability of bivalent UO22+, trivalent Eu3+, Am3+ and tetravalent Th4+ complexes with humic and fulvic acids in weakly acidic conditions

  2. Depolarization-induced release of amino acids from the vestibular nuclear complex.

    Science.gov (United States)

    Godfrey, Donald A; Sun, Yizhe; Frisch, Christopher; Godfrey, Matthew A; Rubin, Allan M

    2012-04-01

    There is evidence from immunohistochemistry, quantitative microchemistry, and pharmacology for several amino acids as neurotransmitters in the vestibular nuclear complex (VNC), including glutamate, γ-aminobutyrate (GABA), and glycine. However, evidence from measurements of release has been limited. The purpose of this study was to measure depolarization-stimulated calcium-dependent release of amino acids from the VNC in brain slices. Coronal slices containing predominantly the VNC were prepared from rats and perfused with artificial cerebrospinal fluid (ACSF) in an interface chamber. Fluid was collected from the chamber just downstream from the VNC using a microsiphon. Depolarization was induced by 50 mM potassium in either control calcium and magnesium concentrations or reduced calcium and elevated magnesium. Amino acid concentrations in effluent fluid were measured by high performance liquid chromatography. Glutamate release increased fivefold during depolarization in control calcium concentration and twofold in low calcium/high magnesium. These same ratios were 6 and 1.5 for GABA, 2 and 1.3 for glycine, and 2 and 1.5 for aspartate. Differences between release in control and low calcium/high magnesium ACSF were statistically significant for glutamate, GABA, and glycine. Glutamine release decreased during and after depolarization, and taurine release slowly increased. No evidence for calcium-dependent release was found for serine, glutamine, alanine, threonine, arginine, taurine, or tyrosine. Our results support glutamate and GABA as major neurotransmitters in the VNC. They also support glycine as a neurotransmitter and some function for taurine. PMID:22147284

  3. The Complex Role of Branched Chain Amino Acids in Diabetes and Cancer

    Directory of Open Access Journals (Sweden)

    Thomas M. O'Connell

    2013-10-01

    Full Text Available The obesity and diabetes epidemics are continuing to spread across the globe. There is increasing evidence that diabetes leads to a significantly higher risk for certain types of cancer. Both diabetes and cancer are characterized by severe metabolic perturbations and the branched chain amino acids (BCAAs appear to play a significant role in both of these diseases. These essential amino acids participate in a wide variety of metabolic pathways, but it is now recognized that they are also critical regulators of a number of cell signaling pathways. An elevation in branched chain amino acids has recently been shown to be significantly correlated with insulin resistance and the future development of diabetes. In cancer, the normal demands for BCAAs are complicated by the conflicting needs of the tumor and the host. The severe muscle wasting syndrome experience by many cancer patients, known as cachexia, has motivated the use of BCAA supplementation. The desired improvement in muscle mass must be balanced by the need to avoid providing materials for tumor proliferation. A better understanding of the complex functions of BCAAs could lead to their use as biomarkers of the progression of certain cancers in diabetic patients.

  4. Capillary zone electrophoresis of lanthanoid elements after complexation with aminopolycarboxylic acids

    International Nuclear Information System (INIS)

    Capillary zone electrophoresis was applied to the separation of the lanthanoid elements chelated with aminopolycarboxylic acids. Several aminopolycarboxylic reagents (ethylenediaminetetraacetic acid and chemically similar analogues) were varied in an effort to optimize the separation resolution. By varying the pH and concentration of the electrophoretic buffer, it was also possible to manipulate the migration times, efficiency and detectability. Optimum resolution and analysis time (within 12 min) for lanthanoids(III), and also scandium(III) and yttrium(III), was achieved with cyclohexane-1,2-diaminetetraacetic acid (CDTA) and simple electrolytes such as a borate buffer (20 mmol 1-1, pH 11.0) containing 1 mmol 1-1 CDTA. Determination of the lanthanoid complexes was performed by direct UV detection at 214 nm. The calibration graphs were linear (r > 0.99) over at least two orders of magnitude of concentration. The detection limits were at the mid-ppb level and the relative standard deviation was about 2.8% at the mid-calibration range. The method appeared to be feasible to determining the lanthanoid elements in nuclear fuel waste, and may also be recommended for assessing lanthanoid impurities in nuclear field. (author)

  5. Influence of humic-acid complexing on the mobility of Americium in the soil aquatic environment

    International Nuclear Information System (INIS)

    Diffusion data indicate the Am, Cm and Np migrate 1.2, 0.8, and 26 centimeters, respectively, in a thousand years. Thus, excluding mass transport by moving water or wind, actinide elements, such as Cm, Am, and Np that find their way to the soil-aquatic environment are relatively immobile. Measured diffusion coefficients, corrected for distribution between the aqueous and soil phases, tortuosity, negative absorption, and relative fluidity are in reasonable agreement with aqueous diffusion coefficients. However, agreement depends strongly on measurement method used to determine distribution ratios. Two sets of experiments with 241Am and 152Eu tracers have been done to measure distribution ratios as a function of the aqueous humic acid concentration. In the first experiments the solid phase was kaolinite and in the second series of distribution ratios were measured with Burbank sandy loam. Both of these experiments indicated that Am(III) and Eu(III) form very strong humic acid complexes with formation constants of approximately 105. Additional experiments are being done to establish the average number of Am(III)s or Eu(III)s bound to the humic acid polymer

  6. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    DEFF Research Database (Denmark)

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested as...

  7. Cobalt (II)-EDTA complex as a new reductant for phosphomolybdic acid used for the assay of trazodone

    Indian Academy of Sciences (India)

    A V S S Prasad; C S P Sastry

    2003-02-01

    A new spectrophotometric method for the assay of trazodone (TZ) has been described. TZ forms a complex in stoichiometric proportions with phosphomolybdic acid. The released phosphomolybdic acid from the complex with acetone is reduced with a new reductant (cobalt nitrate-ethylenediamine tetra acetic acid) to molybdenum blue, which has maximum absorption at 840 nm. Beer's law limits, precision and accuracy of the methods are checked by the UV reference method. This method is found to be suitable for the assay of TZ in the presence of other ingredients that are usually present in tablets. Recoveries are almost quantitative.

  8. Interaction of antitumor alpha-lactalbumin-oleic acid complexes with artificial and natural membranes.

    Science.gov (United States)

    Zherelova, Olga M; Kataev, Anatoly A; Grishchenko, Valery M; Knyazeva, Ekaterina L; Permyakov, Sergei E; Permyakov, Eugene A

    2009-06-01

    The specific complexes of human alpha-lactalbumin (alpha-LA) with oleic acid (OA), HAMLET and LA-OA-17 (OA-complexes), possess cytotoxic activity against tumor cells but the mechanism of their cell penetration remains unclear. To explore the molecular mechanisms underlying interaction of the OA-complexes with the cell membrane, their interactions with small unilamellar dipalmitoylphosphatidylcholine (DPPC) vesicles and electroexcitable plasma membrane of internodal native and perfused cells of the green alga Chara corallina have been studied. The fractionation (Sephadex G-200) of mixtures of the OA-complexes with the vesicles shows that OA-binding increases the affinity of alpha-LA to DPPC vesicles. Calcium association decreases protein affinity to the vesicles; the effect being less pronounced for LA-OA-17. The voltage clamp technique studies show that LA-OA-17, HAMLET, and their constituents produce different modifying effects on the plasmalemmal ionic channels of the Chara corallina cells. The irreversible binding of OA-complexes to the plasmalemma is accompanied by changes in the activation-inactivation kinetics of developing integral transmembrane currents, suppression of the Ca(2+) current and Ca(2+)-activated Cl(-) current, and by increase in the nonspecific K(+) leakage currents. The latter reflects development of nonselective permeability of the plasma membrane. The HAMLET-induced effects on the plasmalemmal currents are less pronounced and potentiated by LA-OA-17. The control experiments with OA and intact alpha-LA show their qualitatively different and much less pronounced effects on the transmembrane ionic currents. Thus, the modification of alpha-LA by OA results in an increase in the protein association with the model lipid bilayer and in drastic irreversible changes in permeability of several types of the plasmalemmal ionic channels. PMID:19588235

  9. Deciphering the binding patterns and conformation changes upon the bovine serum albumin-rosmarinic acid complex.

    Science.gov (United States)

    Peng, Xin; Wang, Xiangchao; Qi, Wei; Huang, Renliang; Su, Rongxin; He, Zhimin

    2015-08-01

    Rosmarinic acid (RA) is an importantly and naturally occurring polyphenol from plants of the mint family with potent biological activities. Here, the in vitro interaction of RA with bovine serum albumin (BSA) has been investigated using various biophysical approaches as well as molecular modeling methods, to ascertain its binding mechanism and conformational changes. The fluorescence results demonstrated that the fluorescence quenching of BSA by RA was mainly the result of the formation of a ground state BSA-RA complex, and BSA had one high affinity RA binding site with a binding constant of 4.18 × 10(4) mol L(-1) at 298 K. Analysis of thermodynamic parameters revealed that hydrophobic and hydrogen bond interactions were the dominant intermolecular force in the complex formation. The primary binding site of RA in BSA (site I) had been identified by site marker competitive experiments. The distance between RA and the tryptophan residue of BSA was evaluated at 3.12 nm based on Förster's theory of non-radiation energy transfer. The UV-vis absorption, synchronous fluorescence, three-dimensional fluorescence, 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectra confirmed that the conformation and structure of BSA were altered in the presence of RA. Moreover, the nuclear magnetic spectroscopy showed that the aromatic groups of RA took part in the binding reaction during the BSA-RA complexation. In addition, the molecular picture of the interaction mechanism between BSA and RA at the atomic level was well examined by molecular docking and dynamics studies. In brief, RA can bind to BSA with noncovalent bonds in a relatively stable way, and these findings will be beneficial to the functional food research of RA. PMID:26146359

  10. Solid-State Synthesis, Characterization, and Biological Activity of the Bioinorganic Complex of Aspartic Acid and Arsenic Triiodide

    Directory of Open Access Journals (Sweden)

    Guo-Qing Zhong

    2013-01-01

    Full Text Available The bioinorganic complex of aspartic acid and arsenic triiodide was synthesized by a solid-state reaction at room temperature. The formula of the complex is AsI3[HOOCCH2CH(NH2COOH]2.5. The crystal structure of the complex belongs to monoclinic system with lattice parameters: a=1.0019 nm, b=1.5118 nm, c=2.1971 nm, and β=100.28°. The infrared spectra can demonstrate the complex formation between the arsenic ion and aspartic acid, and the complex may be a dimer with bridge structure. The result of primary biological test indicates that the complex possesses better biological activity for the HL-60 cells of the leukemia than arsenic triiodide.

  11. Equilibrium, thermoanalytical and spectroscopic studies to characterize phytic acid complexes with Mn(II) and Co(II)

    International Nuclear Information System (INIS)

    Potentiometric studies were carried out to determine the binding degree of phytic acid with Co(II) and Mn(II) ions, in the absence of dioxygen. Equilibrium constants for all major complexes formed are reported, and the results are presented in the form of distribution diagrams showing the concentrations of individual complexes as a function of pH. The formation constants of the complexes show higher values for the species in which the ligand was more deprotonated. Potentiometric data indicates that the species [MH4L]6-, was totally formed at pH 7.0 and the complexes were synthesized from this data. A solid state complex of Mn(II) and Co(II) with phytic acid was synthesized. Thermogravimetry, differential scanning calorimetry, and infrared spectroscopy were used to investigate and characterize the thermal behavior of these compounds. The results led to information on the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes. (author)

  12. Investigation of the Ionic conductivity and dielectric measurements of poly (N-vinyl pyrrolidone)-sulfamic acid polymer complexes

    International Nuclear Information System (INIS)

    Polymer electrolyte complexes of poly (N-vinyl pyrrolidone) (PVP)-sulfamic acid (NH2SO3H) were prepared by a familiar solution casting method with different molar concentrations of PVP and sulfamic acid. The interaction between PVP and NH2SO3H was confirmed by Fourier transform infrared spectroscopy analysis. Laser microscopy analysis was used to study the surface morphology of the polymer complexes. The glass transition temperature (Tg) and the melting temperature (Tm) of polymer complexes were computed from Differential scanning calorimetric studies. AC impedance spectroscopic measurements revealed that the polymer complex, 97 mol% PVP-3 mol% NH2SO3H shows higher ionic conductivity with two different activation energies above and below the glass transition temperature (Tg). Dielectric studies confirmed that the dc conduction mechanism has dominated in the polymer complexes. The value of power law exponent (n) confirmed the translational motion of ions from one site to another vacant site in these complexes

  13. On complex compounds of molybdenum(5) with nicotinic amide, isonicotinic acid hydrazide and some of its derivatives

    International Nuclear Information System (INIS)

    Oxychloride complexes of molybdenum (5) with polyfunctional ligands (L), namely with nicotinamide (NA), isonicotinic acid hydrazide (INH) and its derivatives (ftivazide, saluzide and larusan) have been synthesized and investigated. In ethanol all the ligands independently of their molar ratio form with MoCl5 a non-electrolite compound MoOCl3xL2. Infrared spectra of the complexes suggest that in Mo(5) complexeS with NA and INH the central atom is bound through the pyridine nitrogen, whereas in the complexes with INH derivatives it is bound throught the carbonyl group oxygen

  14. Protonation of D-gluconate and its complexation with Np(V) in acidic to nearly neutral solutions

    International Nuclear Information System (INIS)

    Thermodynamic properties of the protonation of D-gluconic acid (HGH4(aq)) and its complexation with Np(V) have been studied in acidic to nearly neutral solutions at t = 25 C and I = 1 M NaClO4 by potentiometry, spectrophotometry and calorimetry. The protonation constant (log KH) and enthalpy (ΔHH) of the carboxylate group are determined to be (3.30 ± 0.10) and -(4.03 ± 0.07) kJ mol-1, respectively. Gluconate forms two Np(V) complexes in nearly neutral solutions. The formation constants and enthalpies of complexation are: log β1 = (1.48 ± 0.03) and ΔH1 = -(7.42 ± 0.13) kJ mol-1 for NpO2(GH4)(aq), log β = (2.14 ± 0.09) and ΔH2 = -(12.08 ± 0.45) kJ mol-1 for NpO2(GH4)2-. The thermodynamic parameters indicate that gluconic acid, like isosaccharinic acid and other α-hydroxycarboxylic acids, is a slightly stronger acid and forms stronger complexes with Np(V) than simple monocarboxylic acids. (orig.)

  15. Complexing properties of the main organic acids used in decontamination solutions and reactions involved in their degradation or elimination

    International Nuclear Information System (INIS)

    In a PWR primary cooling system, the oxides produced are chromium enriched and then difficult to dissolve. So the chemical decontamination processes often uses the alternation of oxidizing and reducing steps. The reducing step generally uses a mixture of organic acids, most often oxalic and citric acids. In the EMMA decontamination process, developed by EDF, ascorbic acid is used in addition as a stronger reducing agent. It is important for a good control of the process to know accurately which complexes are formed and which products result from reactions of organic acids with oxides or from final destruction during waste treatment. This is necessary to assess the risks of radioactive elements leaching by complex formation during the storage of the concrete embedded polymers. So, it has been necessary to study accurately: - the acid-base and redox properties of these organic acids; - the nature and the stability constants of the complexes formed with the metal cations originating from the stainless steel constituents: Fe, Ni, Cr, Co. This corresponds to the first part of the present study. The second one deals with the dissolution of hydroxides and the destruction of the complexes formed through reaction with a cation exchanger in H+ form, leading, by ion-exchange, to the fixation of the metal cations and the regeneration of the acids. (authors). 3 figs., 4 tabs., 8 refs

  16. Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows.

    Directory of Open Access Journals (Sweden)

    Enrica ePessione

    2012-06-01

    Full Text Available Lactic Acid Bacteria (LAB are ancient organisms that cannot biosynthesize functional cytochromes, and cannot get ATP from respiration. Besides sugar fermentation, they evolved electrogenic decarboxylations and ATP-forming deiminations. The right balance between sugar fermentation and decarboxylation/deimination ensures buffered environments thus enabling LAB to survive in human gastric trait and colonize gut. A complex molecular cross-talk between LAB and host exists. LAB moonlight proteins are made in response to gut stimuli and promote bacterial adhesion to mucosa and stimulate immune cells. Similarly, when LAB are present, human enterocytes activate expression of specific genes only. Furthermore, LAB antagonistic relationships with other microorganisms constitutes the basis for their antiinfective role. Histamine and tyramine are LAB bioactive catabolites that act on the CNS, causing hypertension and allergies. Nevertheless, some LAB biosynthesize both GABA, that has relaxing effect on gut smooth muscles, and beta-phenylethylamine, that controls satiety and mood. Since LAB have reduced amino acid biosynthetic abilities, they developed a sophisticated proteolytic system, that is also involved in antihypertensive and opiod peptide generation from milk proteins.Short-chain fatty acids are glycolytic and phosphoketolase end-products, regulating epithelial cellproliferation and differentiation. Nevertheless, they constitute a supplementary energy source for the host, causing weight gain. Human metabolism can also be affected by anabolic LAB products such as conjugated linoleic acids (CLA. Some CLA isomers reduce cancer cell viability and ameliorate insulin resistance, while others lower the HDL/LDL ratio and modify eicosanoid production, with detrimental health effects.A further appreciated LAB feature is the ability to fix selenium into seleno-cysteine Thus opening interesting perspectives for their utilization as antioxidant nutraceutical

  17. Synthesis, Characterization, and Antibacterial Studies of Mixed Ligand Dioxouranium Complexes with 8-Hydroxyquinoline and Some Amino Acids

    OpenAIRE

    Patil, Sunil S.; Thakur, Ganesh A.; Shaikh, Manzoor M.

    2011-01-01

    Mixed ligand complexes of dioxouranium (VI) of the type [UO2(Q)(L)·2H2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and amino acids (HL) such as L-threonine, L-tryptophan, and L-isoleucine as secondary ligands. The metal complexes have been characterized by elemental analysis, electrical conductance, magnetic susceptibility measurements, and spectral and thermal studies. The electrical conductance studies of the complexes indicate their nonelectrolytic nature. Mag...

  18. Synthesis, structural characterization and biological studies of some nalidixic acid-metal complexes: Metalloantibiotic complexes of some divalent and trivalent metal ions

    Science.gov (United States)

    Al-Khodir, Fatima A. I.; Refat, Moamen S.

    2015-08-01

    This article describes the synthesis, characterization, computational and biological assessments of some divalent and trivalent metal (Ca(II), Fe(III), Pd(II) and Au(III)) complexes of nalidixic acid (nixH). The structures of these complexes were assigned using elemental analyses and spectral measurements e.g., IR, Raman, 1H NMR, 13C NMR and electronic techniques. These results indicated that, nalidixic acid reacts as a bidentate ligand bound to the metal ion through the oxygen atoms of carbonyl and carboxylate groups. The molar conductance measurements of the complexes in DMSO correspond to be non-electrolyte nature. Thus, these complexes may be formulated as [Ca(nix)(Cl)(H2O)3]. H2O, [Fe(nix)(Cl)2(H2O)2]·3H2O, [Pd(nix)(Cl)(H2O)] and [Au(nix)(Cl)2]. Base on the Coats-Redfern and Horowitz-Metzeger methods, the kinetic thermodynamic parameters (E∗, ΔS∗, ΔH∗ and ΔG∗) of the thermal decomposition reactions have been calculated from thermogravimetric curves of TG and DTG. The nano-scale range of the nalidixic acid complexes have been discussed using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) analyzer. The computational studies for the synthesized complexes have been estimated.

  19. Bis(allyl)-ruthenium(iv) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions.

    Science.gov (United States)

    Tomás-Mendivil, Eder; Francos, Javier; González-Fernández, Rebeca; González-Liste, Pedro J; Borge, Javier; Cadierno, Victorio

    2016-09-14

    Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P([double bond, length as m-dash]O)H. The compounds [RuCl2(η(3):η(3)-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η(3):η(3)-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η(3):η(3)-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η(3):η(3)-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance. PMID:27510460

  20. New copper(II) complexes with dopamine hydrochloride and vanillymandelic acid: Spectroscopic and thermal characterization

    Science.gov (United States)

    Mohamed, Gehad G.; Nour El-Dien, F. A.; El-Nahas, R. G.

    2011-10-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. The Cu(II) chelates with coupled products of dopamine hydrochloride (DO.HCl) and vanillymandelic acid (VMA) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical techniques namely IR, magnetic and UV-vis spectra are used to investigate the structure of these chelates. Cu(II) forms 1:1 (Cu:DO) and 1:2 (Cu:VMA) chelates. DO behave as a uninegative tridentate ligand in binding to the Cu(II) ion while VMA behaves as a uninegative bidentate ligand. IR spectra show that the DO is coordinated to the Cu(II) ion in a tridentate manner with ONO donor sites of the phenolic- OH, -NH and carbonyl- O, while VMA is coordinated with OO donor sites of the phenolic- OH and -NH. Magnetic moment measurements reveal the presence of Cu(II) chelates in octahedral and square planar geometries with DO and VMA, respectively. The thermal decomposition of Cu(II) complexes is studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  1. Pickering Emulsion Gels Prepared by Hydrogen-Bonded Zein/Tannic Acid Complex Colloidal Particles.

    Science.gov (United States)

    Zou, Yuan; Guo, Jian; Yin, Shou-Wei; Wang, Jin-Mei; Yang, Xiao-Quan

    2015-08-26

    Food-grade colloidal particles and complexes, which are formed via modulation of the noncovalent interactions between macromolecules and natural small molecules, can be developed as novel functional ingredients in a safe and sustainable way. For this study was prepared a novel zein/tannic acid (TA) complex colloidal particle (ZTP) based on the hydrogen-bonding interaction between zein and TA in aqueous ethanol solution by using a simple antisolvent approach. Pickering emulsion gels with high oil volume fraction (φ(oil) > 50%) were successfully fabricated via one-step homogenization. Circular dichroism (CD) and small-angle X-ray scattering (SAXS) measurements, which were used to characterize the structure of zein/TA complexes in ethanol solution, clearly showed that TA binding generated a conformational change of zein without altering their supramolecular structure at pH 5.0 and intermediate TA concentrations. Consequently, the resultant ZTP had tuned near neutral wettability (θ(ow) ∼ 86°) and enhanced interfacial reactivity, but without significantly decreased surface charge. These allowed the ZTP to stabilize the oil droplets and further triggered cross-linking to form a continuous network among and around the oil droplets and protein particles, leading to the formation of stable Pickering emulsion gels. Layer-by-layer (LbL) interfacial architecture on the oil-water surface of the droplets was observed, which implied a possibility to fabricate hierarchical interface microstructure via modulation of the noncovalent interaction between hydrophobic protein and natural polyphenol. PMID:26226053

  2. Enantioselective Hydrolysis of Amino Acid Esters Promoted by Bis(β-cyclodextrin) Copper Complexes

    Science.gov (United States)

    Xue, Shan-Shan; Zhao, Meng; Ke, Zhuo-Feng; Cheng, Bei-Chen; Su, Hua; Cao, Qian; Cao, Zhen-Kun; Wang, Jun; Ji, Liang-Nian; Mao, Zong-Wan

    2016-02-01

    It is challenging to create artificial catalysts that approach enzymes with regard to catalytic efficiency and selectivity. The enantioselective catalysis ranks the privileged characteristic of enzymatic transformations. Here, we report two pyridine-linked bis(β-cyclodextrin) (bisCD) copper(II) complexes that enantioselectively hydrolyse chiral esters. Hydrolytic kinetic resolution of three pairs of amino acid ester enantiomers (S1-S3) at neutral pH indicated that the “back-to-back” bisCD complex CuL1 favoured higher catalytic efficiency and more pronounced enantioselectivity than the “face-to-face” complex CuL2. The best enantioselectivity was observed for N-Boc-phenylalanine 4-nitrophenyl ester (S2) enantiomers promoted by CuL1, which exhibited an enantiomer selectivity of 15.7. We observed preferential hydrolysis of L-S2 by CuL1, even in racemic S2, through chiral high-performance liquid chromatography (HPLC). We demonstrated that the enantioselective hydrolysis was related to the cooperative roles of the intramolecular flanking chiral CD cavities with the coordinated copper ion, according to the results of electrospray ionization mass spectrometry (ESI-MS), inhibition experiments, rotating-frame nuclear Overhauser effect spectroscopy (ROESY), and theoretical calculations. Although the catalytic parameters lag behind the level of enzymatic transformation, this study confirms the cooperative effect of the first and second coordination spheres of artificial catalysts in enantioselectivity and provides hints that may guide future explorations of enzyme mimics.

  3. Improvement of the photo stabilization of PVC films in the presence of thioacetic acid benzothiazole complexes

    International Nuclear Information System (INIS)

    The photo stabilization of poly(vinyl chloride) (PVC) films by 2-thioacetic acid benzothiazole with Sn (II), Cd (II), Ni (II), Zn (II) and Cu (II) complexes was investigated. The PVC films containing concentration of complexes 0.5 % by weight were produced by the same casting method from tetrahydrofuran (THF) solvent. The photo stabilization activities of these compounds were determined by monitoring the carbonyl, polyene and hydroxyl indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (φcs) of these complexes in PVC films was evaluated and found to range between 4.71 x 10-8 and 8.98 x 10-8. Results obtained showed that the rate of photo stabilization of PVC in the presence of the additive follows the trend: Sn(L)2 > Cd(L)2 > Ni(L)2 > Zn(L)2 > Cu(L)2. According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among them HCl scavenging, UV absorption, peroxide decomposer and radical scavenger for photo stabilizer additives mechanisms were suggested. (author)

  4. Mixed ligand oxovanadium(IV) complexes with salicylic acid and N,N-bidentate ligands

    International Nuclear Information System (INIS)

    Two mixed-ligand oxovanadium(IV) complexes VO(A)(B) [where H2A=salicylic acid and B=2,2'-bipyridine or 1,10-phenanthroline (hereafter, bipy and phen respectively)] have been synthesized and characterized by magnetic moment and spectral (IR, UV/VIS and EPR) data. The A2- ion acts as a bidentate dinegative ligand while B ligands acts as a neutral bidentate. The magnetic susceptibility values indicate the existence of a small amount of antiferromagnetic interaction. The vanadium atoms in the complexes are hexacoordinated and the coordination sphere is of the type [VO(OO)(NN)], where O atoms are of oxo, carboxylic and phenolic type and N atoms are of pyridine type. The sixth coordination site is occupied by phenolic oxygen of the neighbouring molecule forming a bridge. The vv=o confirms the hexacoordination. All the complexes have dxy1 type axial EPR spectra and they exhibit two ligand field transitions at 740 and 440 nm. (author)

  5. Complexes between ovalbumin nanoparticles and linoleic acid: Stoichiometric, kinetic and thermodynamic aspects.

    Science.gov (United States)

    Sponton, Osvaldo E; Perez, Adrián A; Carrara, Carlos R; Santiago, Liliana G

    2016-11-15

    Stoichiometric, kinetic and thermodynamic aspects of complex formation between heat-induced aggregates of ovalbumin (ovalbumin nanoparticles, OVAn) and linoleic acid (LA) were evaluated. Extrinsic fluorescence data were fitted to modified Scatchard model yielding the following results: n: 49±2 LA molecules bound per OVA monomer unit and Ka: 9.80±2.53×10(5)M. Kinetic and thermodynamic properties were analyzed by turbidity measurements at different LA/OVA monomer molar ratios (21.5-172) and temperatures (20-40°C). An adsorption approach was used and a pseudo-second-order kinetics was found for LA-OVAn complex formation. This adsorption process took place within 1h. Thermodynamic parameters indicated that LA adsorption on OVAn was a spontaneous, endothermic and entropically-driven process, highlighting the hydrophobic nature of the LA and OVAn interaction. Finally, Atomic Force Microscopy imaging revealed that both OVAn and LA-OVAn complexes have a roughly rounded form with size lower than 100nm. PMID:27283701

  6. Synthesis and structural studies of complexes of Cu, Co, Ni and Zn with isonicotinic acid hydrazide and isonicotinic acid (1-naphthylmethylene)hydrazide

    OpenAIRE

    ANGELA KRIZA; LUCICA VIORICA ABABEI; NICOLETA CIOATERA; ILEANA RĂU; NICOLAE STĂNICĂ

    2010-01-01

    Eight new complexes of Cu(II), Co(II), Ni(II) and Zn(II) with isonicotinic acid hydrazide (isoniazid, (INH)) and isonicotinic acid (1-naphthylmethylene)hydrazide (INNMH), having the formula of the type [M(INH)(ac)2] or [M(INNMH)(ac)2] (M = Co(II), Ni(II) and Zn(II)) and [Cu(INH)(ac)2]2, [Cu(INNMH)(ac)2]2, were synthesized and characterized. All complexes were characterized based on elemental analyses, and IR, UV–VIS–NIR and EPR spectroscopy, as well as by thermal analysis and determination of...

  7. Study on complex formation of cadmium (II) ions, 6. Formation constants of cadmium (II) complexes with 2-mercaptoacetic, 2-mercaptopropionic, and 3-mercaptopropionic acids

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Haruo (Government Industrial Research Inst., Nagoya (Japan)); Ohtaki, Hitoshi

    1983-10-01

    The formations of cadmium (II) complexes with 2-mercaptoacetic acid (H/sub 2/L). 2-mercaptopropionic acid (H/sub 2/L'), and 3-mercaptopropionic acid were investigated in 3 mol dm/sup -3/ LiCIO/sub 4/ solutions of pH 5.0 to 10.0 at 25/sup 0/C by potentiometric titration. The 1:1 and 1:2 complexes, as well as a protonated complex of the CdHL/sup +/ (or CdHL'/sup +/)-type were found in each solution containing H/sub 2/L or H/sub 2/L' as a ligand. A mixed ligand complex, CdLL'/sup 2 -/, was also formed in a solution containing both ligands. The 1:1 complex was also found in a solution containing 3-mercaptopropionic acid. The formation constants of the complexes were as follows: CdL, log ..beta../sub 1010/ = 4.34; CdL/sub 2//sup 2 -/, log ..beta../sub 1020/ = 6.49; CdHL/sup +/, log ..beta../sub 1110/ = 11.08; CdL', log ..beta../sub 1001/ = 5.66; CdL'/sub 2//sup 2 -/, log ..beta../sub 1002/ = 8.51; CdHL'/sup +/, log ..beta../sub 1101/ = 11.22; CdLL'/sup 2 -/, log ..beta../sub 1011/ = 7.93, and Cd (3-mercaptopropionic acid), log ..beta../sub 1010/ or log ..beta../sub 1001/ = 4.55.

  8. Novel lanthanide complexes constructed from 3, 4-dimethoxybenzoic acid: crystal structures, spectrum and thermochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiao-Xia; Wu, Jun-Chen [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry & Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Ren, Ning, E-mail: ningren9@163.com [College of Chemical engineering & Material, Handan College, Handan 056005 (China); Zhao, Chun-Li [Raoyang High School of Hebei, Raoyang 053900 (China); Zhang, Jian-Jun, E-mail: jjzhang6@126.com [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry & Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Zong, Guang-Cai; Gao, Jie [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry & Material Science, Hebei Normal University, Shijiazhuang 050024 (China)

    2015-09-10

    Graphical abstract: Four novel lanthanide coordination polymers [Ln(3,4-DMOBA){sub 3}(H{sub 2}O){sub 2}]·H{sub 2}O·C{sub 2}H{sub 5}OH (Ln = Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA = 3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Single crystal structures indicates 1 D stucture of the title complexes are linked by hydrogen bonds to form a three-dimensional (3-D) structure. Complex 2 exhibits the characteristic emission of Tb{sup 3+} ion({sup 5}D{sub 4} → {sup 7}F{sub 6-3}). The investigation of TG-FTIR and IR spectra of the evolved gases shows uncoordinated water and ethanol molecules tend to lose firstly, and then 3,4-DMOBA ligands begin to decompose. - Highlights: • Four lanthanide coordination polymers were synthesized and characterized. • 1-D chain structures of the title complexes are are linked by hydrogen bonds to form a 3-D structures. • Thermal decomposition processes of the title complexes were studied using TG-FTIR techniques. • IR spectra of evolved gases in thermal decomposition process were obtained and analyzed. - Abstract: Four novel lanthanide complexes [Ln(3,4-DMOBA){sub 3}(H{sub 2}O){sub 2}]·H{sub 2}O·C{sub 2}H{sub 5}OH (Ln = Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA = 3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Structural analyses reveal that adjacent lanthanide ions are connected by 3,4-DMOBA ligands adopting bridging bidentate mode to generate one-dimensional (1-D) structure with the uncoordinated water and ethanol molecules. 1-D structures are linked by hydrogen bonds to form a three-dimensional (3-D) structure, which is rarely observed in lanthanide carboxylic acids complexes. Under the radiation of UV light, complex 2 exhibits the characteristic emission of Tb{sup 3+} ion ({sup 5}D{sub 4} → {sup 7}F{sub 6-3}). The thermal decomposition mechanism is investigated by TG-FTIR technology. IR spectra of the evolved gases show that the uncoordinated water and ethanol

  9. Novel lanthanide complexes constructed from 3, 4-dimethoxybenzoic acid: crystal structures, spectrum and thermochemical properties

    International Nuclear Information System (INIS)

    Graphical abstract: Four novel lanthanide coordination polymers [Ln(3,4-DMOBA)3(H2O)2]·H2O·C2H5OH (Ln = Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA = 3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Single crystal structures indicates 1 D stucture of the title complexes are linked by hydrogen bonds to form a three-dimensional (3-D) structure. Complex 2 exhibits the characteristic emission of Tb3+ ion(5D4 → 7F6-3). The investigation of TG-FTIR and IR spectra of the evolved gases shows uncoordinated water and ethanol molecules tend to lose firstly, and then 3,4-DMOBA ligands begin to decompose. - Highlights: • Four lanthanide coordination polymers were synthesized and characterized. • 1-D chain structures of the title complexes are are linked by hydrogen bonds to form a 3-D structures. • Thermal decomposition processes of the title complexes were studied using TG-FTIR techniques. • IR spectra of evolved gases in thermal decomposition process were obtained and analyzed. - Abstract: Four novel lanthanide complexes [Ln(3,4-DMOBA)3(H2O)2]·H2O·C2H5OH (Ln = Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA = 3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Structural analyses reveal that adjacent lanthanide ions are connected by 3,4-DMOBA ligands adopting bridging bidentate mode to generate one-dimensional (1-D) structure with the uncoordinated water and ethanol molecules. 1-D structures are linked by hydrogen bonds to form a three-dimensional (3-D) structure, which is rarely observed in lanthanide carboxylic acids complexes. Under the radiation of UV light, complex 2 exhibits the characteristic emission of Tb3+ ion (5D4 → 7F6-3). The thermal decomposition mechanism is investigated by TG-FTIR technology. IR spectra of the evolved gases show that the uncoordinated water and ethanol molecules lose in the first step. And then 3,4-DMOBA ligand is decomposed into H2O, CO2 and other gaseous molecules as well as the gaseous

  10. Synthesis and structural studies of complexes of Cu, Co, Ni and Zn with isonicotinic acid hydrazide and isonicotinic acid (1-naphthylmethylenehydrazide

    Directory of Open Access Journals (Sweden)

    ANGELA KRIZA

    2010-02-01

    Full Text Available Eight new complexes of Cu(II, Co(II, Ni(II and Zn(II with isonicotinic acid hydrazide (isoniazid, (INH and isonicotinic acid (1-naphthylmethylenehydrazide (INNMH, having the formula of the type [M(INH(ac2] or [M(INNMH(ac2] (M = Co(II, Ni(II and Zn(II and [Cu(INH(ac2]2, [Cu(INNMH(ac2]2, were synthesized and characterized. All complexes were characterized based on elemental analyses, and IR, UV–VIS–NIR and EPR spectroscopy, as well as by thermal analysis and determination of their molar conductivity and magnetic moments. The structure of INNMH was established by single crystal X-ray analysis. In all complexes, both ligands were coordi¬nated to the metal via N and O. The complexes of Cu (II were dimeric, with four bridges between acetate ions and Cu(II.

  11. Stereoselective analysis of D and L dansyl amino acids as the mixed chelate copper(II) complexes by HPLC.

    Science.gov (United States)

    Lam, S

    1984-09-01

    This paper reviews the mixed chelation approach to resolution of the optical isomers of D and L dansyl amino acids by high performance liquid chromatography. The use of eluants containing Cu(II) complexes of L-proline, L-arginine, L-histidine, and L-histidine methyl ester effected the separation of many D and L amino acids, including those with aliphatic, polar, and aromatic substituents. The mechanism of separation, which is based on the preferential ternary complex formation of the analyte amino acid and the chiral chelate with Cu(II) in the mobile phase, is discussed. The stereoselectivity depends mainly on the different steric interactions between the alkyl side chains of the amino acid analytes and the chiral ligands coordinating around Cu(II), although such parameters as pH, temperature, organic modifier, and concentration of the chiral additive also affect the chromatographic separation. Among the chiral ligands studied, L-histidine methyl ester is unique in that it possesses both achiral selectivity for the dansyl amino acids and chiral selectivity for the respective D and L enantiomers. With a mobile phase gradient of acetonitrile in a buffer containing Cu(II) L-histidine methyl ester complex, a stereoselective procedure was devised for the analysis of D and L amino acid enantiomers, achieving the separation that the current amino acid analyzer could not perform. Finally, the use of the mixed chelation approach in two biomedical studies is described. In the first application, the histidine methyl ester gradient was adapted for analyzing amino acids in cerebrospinal fluid; in the second, an L-aspartame Cu(II) complex eluant was developed for measuring the urine concentration of D and L pipecolic acid (piperidine-2-carboxylic acid), a metabolite of lysine. PMID:6490790

  12. Solvent extraction of tricomponent complexes of zirconium and scandium with salicylic acid and collidine

    International Nuclear Information System (INIS)

    Extraction of tricomponent compounds of zirconium and scandium with salicylic acid (Sal) and collidine (Col) has been studied. Addition of Col widens considerably the pH range of maximum extraction of zirconium salicylate and makes it possible to extract quantitatively both zirconium and scandium in the following pH range: scandium at pH 3.8-5.2; zirconium at pH 2-4. Optimum concentrations of salicylic acid and collidine are 0.05 mol/l and 0.375 mol/l, respectively. The composition of the complexes being extracted has been studied by the shift equilibrium method. Chloroform extracts complexes having the ratio Zr:Sal:Col=1:2:1(pH=3); Sc:Sal:Col=1:3:1(pH=4), and 1:2:1(pH=5). The composition of the complexes being formed is assumed to be [Zr(OH)3(HSal)2]-[ColH+] (pH=3); Sc(HSal)3xCol (pH=4.0); Sc(OH)(HSal)2xCol (pH=5.0). Extraction of collidine-salicylate complexes of Hf, Th, La, and Y under the conditions of optimum extraction of zirconium and scandium has been investigated when concentration of Zr and Sc in the solution is 3.0.10μ-5-1.37.10-4 mol/l, respectively. It has been shown that hafnium is extracted quantitatively (95-100%) at pH 2.3-4.6; thorium at pH 3.0-6.4; 60% of yttrium is extracted at pH 4.0-4.8; 25% of lanthanum is extracted at pH 3.3-4.9. At pH 2.0 it is possible to separate Zr from Sc,Y, and La; at pH 1.4-1.5 from small amounts of Hf and Tn. Separation of zirconium, from small amounts of hafnium, 10-fold amounts of thorium, 100-fold amounts of scandium and lanthanum is also possible

  13. Synthesis, X-Ray Crystal Structures, Biological Evaluation, and Molecular Docking Studies of a Series of Barbiturate Derivatives

    Directory of Open Access Journals (Sweden)

    Assem Barakat

    2016-01-01

    Full Text Available A series of barbiturates derivatives synthesized and screened for different set of bioassays are described. The molecular structures of compounds 5a, 5d, and 5f were solved by single-crystal X-ray diffraction techniques. The results of bioassay show that compounds 4a, 4b, 4c, 4d, 4e, 4f, and 4g are potent antioxidants in comparison to the tested standards, butylated hydroxytoluene (BHT, and N-acetylcysteine. Compounds 4a–4e (IC50=101.8±0.8–124.4±4.4 μM and 4g (IC50=104.1±1.9 μM were more potent antioxidants than the standard (BHT, IC50=128.8±2.1 μM. The enzyme inhibition potential of these compounds was also evaluated, in vitro, against thymidine phosphorylase, α-glucosidase, and β-glucuronidase enzymes. Compounds 4c, 4h, 4o, 4p, 4q, 5f, and 5m were found to be potent α-glucosidase inhibitors and showed more activity than the standard drug acarbose, whereas compounds 4v, and 5h were found to be potent thymidine phosphorylase inhibitors, more active than the standard drug, 7-deazaxanthine. All barbiturates derivatives (4a–4x, 4z, and 5a–5m were found to be noncytotoxic against human prostate (PC-3, Henrietta Lacks cervical (HeLa and Michigan Cancer Foundation-7 breast (MCF-7 cancer cell lines, and 3T3 normal fibroblast cell line, except 4y which was cytotoxic against all the cell lines.

  14. Regulation of fatty acid oxidation in mouse cumulus-oocyte complexes during maturation and modulation by PPAR agonists.

    Directory of Open Access Journals (Sweden)

    Kylie R Dunning

    Full Text Available Fatty acid oxidation is an important energy source for the oocyte; however, little is known about how this metabolic pathway is regulated in cumulus-oocyte complexes. Analysis of genes involved in fatty acid oxidation showed that many are regulated by the luteinizing hormone surge during in vivo maturation, including acyl-CoA synthetases, carnitine transporters, acyl-CoA dehydrogenases and acetyl-CoA transferase, but that many are dysregulated when cumulus-oocyte complexes are matured under in vitro maturation conditions using follicle stimulating hormone and epidermal growth factor. Fatty acid oxidation, measured as production of ³H₂O from [³H]palmitic acid, occurs in mouse cumulus-oocyte complexes in response to the luteinizing hormone surge but is significantly reduced in cumulus-oocyte complexes matured in vitro. Thus we sought to determine whether fatty acid oxidation in cumulus-oocyte complexes could be modulated during in vitro maturation by lipid metabolism regulators, namely peroxisome proliferator activated receptor (PPAR agonists bezafibrate and rosiglitazone. Bezafibrate showed no effect with increasing dose, while rosiglitazone dose dependently inhibited fatty acid oxidation in cumulus-oocyte complexes during in vitro maturation. To determine the impact of rosiglitazone on oocyte developmental competence, cumulus-oocyte complexes were treated with rosiglitazone during in vitro maturation and gene expression, oocyte mitochondrial activity and embryo development following in vitro fertilization were assessed. Rosiglitazone restored Acsl1, Cpt1b and Acaa2 levels in cumulus-oocyte complexes and increased oocyte mitochondrial membrane potential yet resulted in significantly fewer embryos reaching the morula and hatching blastocyst stages. Thus fatty acid oxidation is increased in cumulus-oocyte complexes matured in vivo and deficient during in vitro maturation, a known model of poor oocyte quality. That rosiglitazone further

  15. Hydrogen bonded complexes of cyanuric acid with pyridine and guanidinium carbonate

    Indian Academy of Sciences (India)

    K Sivashankar

    2000-12-01

    Hydrogen bonded complexes of cyanuric acid (CA) with pyridine, [C3N3H3O3:C5H5N], 1, and guanidinium carbonate [C3H2N3][C(NH2)3], 2, have been prepared at room temperature and characterized by single-crystal X-ray diffraction. Structure of 1 shows pyridine molecules substituting the inter-tape hydrogen bond in CA by N-H…N and C-H…O hydrogen bonds. The structure reveals CA-pyridine hydrogen-bonded single helices held together by dimeric N-H…O hydrogen bonding between CA molecules. In 2, the CA tapes, resembling a sine wave interact with the guanidinium cations through N-H…O and N-H…N hydrogen bonds forming guanidinium cyanurate sheets.

  16. A novel therapeutic strategy for experimental stroke using docosahexaenoic acid complexed to human albumin

    Directory of Open Access Journals (Sweden)

    Belayev Ludmila

    2016-01-01

    Full Text Available Despite tremendous efforts in ischemic stroke research and significant improvements in patient care within the last decade, therapy is still insufficient. There is a compelling, urgent need for safe and effective neuroprotective strategies to limit brain injury, facilitate brain repair, and improve functional outcome. Recently, we reported that docosahexaenoic acid (DHA; 22:6, n-3 complexed to human albumin (DHA-Alb is highly neuroprotective after temporary middle cerebral artery occlusion (MCAo in young rats. This review highlights the potency of DHA-Alb therapy in permanent MCAo and aged rats and whether protection persists with chronic survival. We discovered that a novel therapy with DHA-Alb improved behavioral outcomes accompanied by attenuation of lesion volumes even when animals were allowed to survive three weeks after experimental stroke. This treatment might provide the basis for future therapeutics for patients suffering from ischemic stroke.

  17. Inelastic neutron scattering study of tetramethylpyrazine in the complex with chloranilic acid

    International Nuclear Information System (INIS)

    The tunnel splitting of the methyl librational ground states in the hydrogen bonded tetramethylpyrazine-chloranilic acid (TMP-CLA) complex are determined for temperatures T≤28 K by high resolution neutron spectroscopy. Three tunnel modes are resolved at T = 2.4 K. Their relative intensities show that the crystal structure must be different from the proposed space group. Tunnelling and methyl librational modes from the measured density of states are combined into rotational potentials. There are discrepancies of activation energies calculated for these potentials and those obtained from quasielastic scattering of neutrons at T≥50 K due to structural differences in the two respective temperature regimes. Rotational potentials in TMP-CLA are significantly weaker as in pure TMP

  18. A pharmacokinetic and clinical evaluation of iron poly (sorbitol-gluconic acid) complex.

    Science.gov (United States)

    Campbell, B C; Lawrence, J R; Sumner, D J; Kelman, A; Smith, A; Elliott, H L; Goldberg, A

    1980-01-01

    The pharmacokinetics of iron poly (sorbitol-gluconic acid) complex (IPSG) were studied following a single intramuscular injection of 59Fe-labelled IPSG to 4 iron deficient-patients. The results showed a more rapid uptake of iron from the site of injection than that reported with iron dextran while there was a lower urinary excretion than found with iron sorbitol citrate. A clinical study was carried out in 11 patients with iron deficiency anaemia. Patients were allocated at random to receive IPSG as either 250 mg or 500 mg elemental iron per week for 8 weeks. A satisfactory response to therapy was obtained with each regimen whether measured by an increase in haemoglobin concentration or in serum ferritin concentration. Few side-effects were encountered but discomfort and staining at the injection site was found on the higher dose schedule. PMID:7208542

  19. Effect of iron poly (sorbitolgluconic acid) complex on urinary cellular excretion.

    Science.gov (United States)

    Elliott, H L; Lawrence, J R; Campbell, B C; Goldberg, A; Smart, L E

    1981-01-01

    The intramuscular injection of 250 mg iron poly (sorbitol-gluconic acid) complex caused no increase in urinary cellular or bacterial excretion in 8 patients with chronic pyelonephritis, 4 patients with non-infective renal disease, and 4 controls. However, in 4 patients with chronic infective disease of the renal tract given 500 g there was a significant increase in cellular excretion. This response was not seen in 2 control patients, nor in 2 patients with non-infective renal disease. Using a differential staining technique, this increase in urinary cellular excretion was found to be due, not to leucocytes, but to renal tubular cells. The precise significance of this is unclear, but there would be concern that the high concentration of excreted iron was providing a 'toxic' insult to susceptible, infection-damaged cells. PMID:7226874

  20. Pharmacological Study on Antitumor Activity of 5-Fluorouracil-1-Acetic Acid and Its Rare Earth Complexes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The antitumor activity of 5-fluorouracil-1-acetic acid(HFAA) and its lanthanide complexes(La(FAA)3, Eu(FAA)3) were studied. The results show that HFAA, La(FAA)3 and Eu(FAA)3 with the concentrations of 1.0×10-5~1.0×10-2 μg·ml-1 inhibit the colony formation of leukemia cells(L1210) and the growth of transplanted tumor sarcoma 180(S180), hepatic carcinoma(HEPA) and ehrlich ascites tumor(EC) as well. The maximum inhibitory rate of Eu(FAA)3 for S180 is 38.4%, that HFAA and La(FAA)3 for EC are 22.4% and 43.4%, respectively. The life prolongation rate of Eu(FAA)3 for HEPA bearing mice is as long as 284%.

  1. Filler modification for papermaking with starch/oleic acid complexes with the aid of calcium ions.

    Science.gov (United States)

    Huang, Xiujie; Shen, Jing; Qian, Xueren

    2013-10-15

    To mitigate the negative effect of filler addition on paper strength and improve filler retention, filler modification with hydrogen bonding polymers (e.g., starch) or their composites is an interesting research topic. Differing from previous reports, the concept related to the deposition of starch/oleic acid complexes on precipitated calcium carbonate (PCC) with the aid of calcium ions was demonstrated. The introduction of calcium ions resulted in effective starch deposition. As a result of filler modification, filler retention and the tensile strength of the filled paper were simultaneously improved essentially due to the aggregation of PCC particles in filler modification process as well as improved filler bondability. The concept demonstrated in this brief study may provide an alternative approach to filler bondability enhancement for improved papermaking performances. PMID:23987430

  2. Study on the concentration of unsaturated fatty acid methyl esters by urea complexation

    International Nuclear Information System (INIS)

    This study was done to obtain concentrated unsaturated fatty acid methyl esters (FAME) by urea complexation from soybean derived FAME. Effects of urea-to-FAME ratio, 95% ethanol-to-FAME ratio, crystallization temperature and time on the purification of unsaturated FAME were investigated through single factor experiments. Optimum conditions to obtain maximum FAME yield of NUCF with the purity of unsaturated FAME greater than 98% were established using Box-Behnken design (BBD) method and response surface methodology (RSM). Under optimal conditions, the FAME yield was 58.08%, and the purity of unsaturated FAME was 98% at a urea-to-FAME ratio of 1.23, 95% ethanol-to-FAME ratio of 7 and crystallization temperature of 0 degree C. Verification results revealed that the predicted values were reasonably close to experimentally observed values of 56.93% and 98.01%. (author)

  3. Synthesis, structure and complex formation properties of alkyl derivatives of ethylxantogenic acids

    International Nuclear Information System (INIS)

    efficiency of metal extraction influences the structure of reactant, the concentration and the nature an acid. The derivatives of xanthogenic acid have shown to be weak extractants of noble metals from acid mediums. The most effective extractants were: S-heptyl - (3,0 M, Au, 64 %) and S-amyl-(1,0 M, Ag, 81,8 %; 3,0 M, Os, 66,7 %) from sulfuric acid medium; and S-amylxanthogenate (6,0 M, Ag, 65,5 %) from hydrochloric medium. Branching of alkyl chain (i-C4H9) results in some increase of efficiency of extraction of Au and Ag from acid mediums. Thus, alkyl derivatives of xanthogenic acid are synthesized and the structure of the obtained substances are confirmed by IR, H1 NMR, and mass spectrometry data have been studied their complex formation properties in relation to noble metals

  4. Crystal structure of Cr (III) complex containing nitrilotriacetic acid and 4, 4'-bipyridine

    International Nuclear Information System (INIS)

    The title compound (C10H9N2)[Cr(C6H7NO6)2](C10H8N2).2H2O or (4,4'-bipy H)[Cr(nta H)2](4,4'-bipy). 2H2O (ntaH3 is nitrilotriacetic acid) was synthesized by reaction of Cr(NO3)3.9H2O with 4,4'-bipyridine, and nitrilotriacetic acid with 4:2:1 molar ratio in aqueous solution. The crystal structure of this complex was identified using X-ray crystallography. The unit cell parameters are as follows: a= 9.8501(3) Angstrom, b = 13.157(2) Angstrom, c = 26.842(4) Angstrom, β = 104.807(7)degree. The final R value is 0.041 for 7747 independent reflections. The title compound crystallized in monoclinic system and belongs to P21/c space group. The central CrIII atom is coordinated by two tridentaid (ntaH2) ligands and the resulted CrO4N2 set can be described as distorted octahedral geometry. The asymmetric unit contains two half of anionic complex, one 4, 4'-bipyridinium ion, (4, 4'-bipy H)+, one neutral 4, 4'-bipyridine molecule and two non-coordinated water molecules. Intramolecular hydrogen bonds, π-π [centroid -centroid distances of 3.674 A], C-H...π, O-H...π and N-H...π stacking interactions [with distance of 3.714, 3.736 and 3.270 A respectively], connect the various components into a supramolecular structures.

  5. Structural and thermodynamic study of rare earth(III) complexation by poly-hydroxylated carboxylic acids: synthesis of new extractants and outlook for the extraction of these cations

    International Nuclear Information System (INIS)

    The aim of this work is: to improve the knowledge on the binding sites of the poly-hydroxylated carboxylic acids with the trivalent lanthanide(III) ions by comparing them to gluconic acid (previously studied) and to molecules with different configuration and with a variable number of OH functions (threonic acid, glyceric acid, 2-hydroxy-butanoic acid, 3-hydroxy-butanoic acid). To find the best complexing agent among different acids (aldonic acids, aldaric acids, di-hydroxybenzoic acids) (determination of the set of complexes and their stability constants by potentiometry, NMR and UV-Visible spectroscopy). To synthesize hydrophobic monoamides from one lactone form of saccharic acid, to study their complexing power and their capacity to extract the trivalent lanthanide(III) ions. (author)

  6. nC60 deposition kinetics: the complex contribution of humic acid, ion concentration, and valence.

    Science.gov (United States)

    McNew, Coy P; LeBoeuf, Eugene J

    2016-07-01

    The demonstrated toxicity coupled with inevitable environmental release of nC60 raise serious concerns about its environmental fate and transport, therefore it is crucial to understand how nC60 will interact with subsurface materials including attached phase soil and sediment organic matter (AP-SOM). This study investigated the attachment of nC60 onto a Harpeth humic acid (HHA) coated silica surface under various solution conditions using a quartz crystal microbalance with dissipation monitoring. The HHA coating greatly enhanced nC60 attachment at low ion concentrations while hindering attachment at high ion concentrations in the presence of both mono and divalent cations. At low ion concentrations, the HHA greatly reduced the surface potential of the silica, enhancing nC60 deposition through reduction in the electrostatic repulsion. At high ion concentrations however, the reduced surface potential became less important due to the near zero energy barrier to deposition and therefore non-DLVO forces dominated, induced by compaction of the HHA layer, and leading to hindered attachment. In this manner, observed contributions from the HHA layer were more complex than previously reported and by monitoring surface charge and calculated DLVO interaction energy alongside attachment experiments, this study advances the mechanistic understanding of the variable attachment contributions from the humic acid layer. PMID:27061365

  7. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II

    Directory of Open Access Journals (Sweden)

    Jeffrey R. Koenitzer

    2016-08-01

    Full Text Available Nitro-fatty acids (NO2-FA are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2 reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H+ and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval.

  8. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II.

    Science.gov (United States)

    Koenitzer, Jeffrey R; Bonacci, Gustavo; Woodcock, Steven R; Chen, Chen-Shan; Cantu-Medellin, Nadiezhda; Kelley, Eric E; Schopfer, Francisco J

    2016-08-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H(+) and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. PMID:26722838

  9. Neodymium(III) Complexes of Dialkylphosphoric and Dialkylphosphonic Acids Relevant to Liquid-Liquid Extraction Systems.

    Science.gov (United States)

    Lumetta, Gregg J; Sinkov, Sergey I; Krause, Jeanette A; Sweet, Lucas E

    2016-02-15

    The complexes formed during the extraction of neodymium(III) into hydrophobic solvents containing acidic organophosphorus extractants were probed by single-crystal X-ray diffractometry, visible spectrophotometry, and Fourier-transform infrared spectroscopy. The crystal structure of the compound Nd(DMP)3 (1, DMP = dimethyl phosphate) revealed a polymeric arrangement in which each Nd(III) center is surrounded by six DMP oxygen atoms in a pseudo-octahedral environment. Adjacent Nd(III) ions are bridged by (MeO)2POO(-) anions, forming the polymeric network. The diffuse reflectance visible spectrum of 1 is nearly identical to that of the solid that is formed when an n-dodecane solution of di(2-ethylhexyl)phosphoric acid (HA) is saturated with Nd(III), indicating a similar coordination environment around the Nd center in the NdA3 solid. The visible spectrum of the HA solution fully loaded with Nd(III) is very similar to that of the NdA3 material, both displaying hypersensitive bands characteristic of an pseudo-octahedral coordination environment around Nd. These spectral characteristics persisted across a wide range of organic Nd concentrations, suggesting that the pseudo-octahedral coordination environment is maintained from dilute to saturated conditions. PMID:26815878

  10. Neodymium(III) Complexes of Dialkylphosphoric and Dialkylphosphonic Acids Relevant to Liquid-Liquid Extraction Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lumetta, Gregg J.; Sinkov, Sergey I.; Krause, Jeanette A.; Sweet, Lucas E.

    2016-01-27

    The complexes formed during the extraction of neodymium(III) into hydrophobic solvents containing acidic organophosphorus extractants were probed by single-crystal X-ray diffractometry, visible spectrophotometry, and Fourier-transform infrared spectroscopy. The crystal structure of the compound Nd(DMP)3 (1, DMP = dimethyl phosphate) revealed a polymeric arrangement in which each Nd(III) center is surrounded by six DMP oxygen atoms in a pseudo-octahedral environment. Adjacent Nd(III) ions are bridged by (MeO)2POO– anions, forming the polymeric network. The diffuse reflectance visible spectrum of 1 is nearly identical to that of the solid that is formed when an n-dodecane solution of di-(2-ethylhexyl)phosphoric acid (HA) is saturated with Nd(III), indicating a similar coordination environment around the Nd center in the NdA3 solid. The visible spectrum of the HA solution fully loaded with Nd(III) is very similar to that of the NdA3 material, both displaying hypersensitive bands characteristic of an pseudo-octahedral coordination environment around Nd. These spectral characteristics persisted across a wide range of organic Nd concentrations, suggesting that the pseudo-octahedral coordination environment is maintained from dilute to saturated conditions.

  11. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings.

    Science.gov (United States)

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-05-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/- 2°C following the ramp up. The system is demonstrated to provide linear results between 10(4) and 10(8) CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  12. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings

    Science.gov (United States)

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-01-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/− 2°C following the ramp up. The system is demonstrated to provide linear results between 104 and 108 CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  13. Effects of pH and fulvic acids concentration on the stability of fulvic acids--cerium (IV) oxide nanoparticle complexes.

    Science.gov (United States)

    Oriekhova, Olena; Stoll, Serge

    2016-02-01

    The behavior of cerium (IV) oxide nanoparticles has been first investigated at different pH conditions. The point of zero charge was determined as well as the stability domains using dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. A baseline hydrodynamic diameter of 180 nm was obtained indicating that individual CeO2 nanoparticles are forming small aggregates. Then we analyzed the particle behavior at variable concentrations of fulvic acids for three different pH-electrostatic scenarios corresponding to positive, neutral and negative CeO2 surface charges. The presence of fulvic acids was found to play a key role on the CeO2 stability via the formation of electrostatic complexes. It was shown that a small amount of fulvic acids (2 mg L(-1)), representative of environmental fresh water concentrations, is sufficient to stabilize CeO2 nanoparticles (50 mg L(-1)). When electrostatic complexes are formed between negatively charged FAs and positively charged CeO2 NPs the stability of such complexes is obtained with time (up to 7 weeks) as well as in pH changing conditions. Based on zeta potential variations we also found that the fulvic acids are changing the CeO2 acid-base surface properties. Obtained results presented here constitute an important outcome in the domain of risk assessment, transformation and removal of engineered nanomaterials released into the environment. PMID:26347935

  14. Investigation of interaction preferences in protein-nucleic acid complexes by the evaluation of interaction energy matrix of amino acid-base pairs

    Czech Academy of Sciences Publication Activity Database

    Jakubec, Dávid; Vondrášek, Jiří

    Praha: Ústav organické chemie a biochemie AV ČR, 2016. s. 68. ISBN 978-80-86241-55-5. [Prague Protein Spring Meeting 2016: Proteins and their Design /4./. 05.05.2016-08.05.2016, Praha] Institutional support: RVO:61388963 Keywords : protein-nucleic acid complexes * interaction energy Subject RIV: CF - Physical ; Theoretical Chemistry

  15. Synthesis,characterization and properties of some rare earth complexes with pyrazolone and 2,6-pyridinecarboxylic acid

    Directory of Open Access Journals (Sweden)

    CHEN Jing

    2014-06-01

    Full Text Available A new solid ternary complex of copper with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 and 2,6-pyridinecarboxylic acid Na[Cu(PMBP (PDA]has been synthesized and characterized by elemental analysis,FT-IR,UV-Vis,XRD,TG-DTA,and XPS.The antibacterial test indicated that the complex exhibited moderate antibacterial ability against Escherichia coli and Staphylococcus aureus.The interactions of the complex with calf thymus DNA (CT DNAwas investigated by employing florescence spectroscopic studies and ultraviolet spectrum spectrom etries.The results indicated that the complex can intercalate between DNA base pairs.

  16. Hybrid polymeric hydrogels via peptide nucleic acid (PNA)/DNA complexation.

    Science.gov (United States)

    Chu, Te-Wei; Feng, Jiayue; Yang, Jiyuan; Kopeček, Jindřich

    2015-12-28

    This work presents a new concept in hybrid hydrogel design. Synthetic water-soluble N-(2-hydroxypropyl)methacrylamide (HPMA) polymers grafted with multiple peptide nucleic acids (PNAs) are crosslinked upon addition of the linker DNA. The self-assembly is mediated by the PNA-DNA complexation, which results in the formation of hydrophilic polymer networks. We show that the hydrogels can be produced through two different types of complexations. Type I hydrogel is formed via the PNA/DNA double-helix hybridization. Type II hydrogel utilizes a unique "P-form" oligonucleotide triple-helix that comprises two PNA sequences and one DNA. Microrheology studies confirm the respective gelation processes and disclose a higher critical gelation concentration for the type I gel when compared to the type II design. Scanning electron microscopy reveals the interconnected microporous structure of both types of hydrogels. Type I double-helix hydrogel exhibits larger pore sizes than type II triple-helix gel. The latter apparently contains denser structure and displays greater elasticity as well. The designed hybrid hydrogels have potential as novel biomaterials for pharmaceutical and biomedical applications. PMID:26394062

  17. Syntheses and Crystal Structures of Two Complexes with 3-(3-Pyridyl)acrylic Acid

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The reaction of 3-(3-pyridyl)acrylic acid (H(3-PYA)) with Co(NO3)2·6H2O or Complex 1 crystallizes in monoclinic, space group C2/c with a = 9.9473(12), b = 13.7227(16), c =14.7376(18) (A), β = 99.043(2)°, V = 1986.7(4) (A)3, Z = 4, Dc = 1.549 g/cm3, μ = 0.921 mm 1, F(000)= 964, R = 0.0786 and wR = 0.1443. Six types of hydrogen bonds and π-π packing interactions molecular architecture. Complex 2 crystallizes in monoclinic, space group P21/n with a =11.3630(16), b = 7.0346(10), c = 12.1365(18) (A), β = 112.545(3)°, V = 896.0(2) (A)3, Z = 2, Dc =1.997 g/cm3,μ = 0.785 mm-1, F(000) = 438, R = 0.0787 and wR = 0.1550. The discrete entity Mn(Ⅱ)(3-PYD)2(H2O)4 is extended into a 3-D supramolecular architecture by four kinds of hydrogen bonds.

  18. SYNTESIS OF THE COMPLEXES OF MACROPOROUS SULFONATED RESINS WITH FERRIC CHLORIDE AND THEIR CATALYTIC BEHAVIOR FOR SETERIFICATION OF ACETIC ACID WITH BUTANOL

    Institute of Scientific and Technical Information of China (English)

    HuangWenqiang; HouXin; 等

    1997-01-01

    The complex resins prepared from macroporous sulfonated resin D72(H+ form) with ferric chloride or ferric chloride hexahydrate have both sites of Bronsted acid and Lewis acid.In the catalysis of exterification of acetic acid with butanol the complex resins show to have much higher catalytic activity than that of its matrix.a conventional sulfonated cation exchange resin D72.

  19. Bovine lactoferrin binds oleic acid to form an anti-tumor complex similar to HAMLET.

    Science.gov (United States)

    Fang, Bing; Zhang, Ming; Tian, Mai; Jiang, Lu; Guo, Hui Yuan; Ren, Fa Zheng

    2014-04-01

    α-Lactalbumin (α-LA) can bind oleic acid (OA) to form HAMLET-like complexes, which exhibited highly selective anti-tumor activity in vitro and in vivo. Considering the structural similarity to α-LA, we conjectured that lactoferrin (LF) could also bind OA to obtain a complex with anti-tumor activity. In this study, LF-OA was prepared and its activity and structural changes were compared with α-LA-OA. The anti-tumor activity was evaluated by methylene blue assay, while the apoptosis mechanism was analyzed using flow cytometry and Western blot. Structural changes of LF-OA were measured by fluorescence spectroscopy and circular dichroism. The interactions of OA with LF and α-LA were evaluated by isothermal titration calorimetry (ITC). LF-OA was obtained by heat-treatment at pH8.0 with LD50 of 4.88, 4.95 and 4.62μM for HepG2, HT29, and MCF-7 cells, respectively, all of which were 10 times higher than those of α-LA-OA. Similar to HAMLET, LF-OA induced apoptosis in tumor cells through both death receptor- and mitochondrial-mediated pathways. Exposure of tryptophan residues and the hydrophobic regions as well as the loss of tertiary structure were observed in LF-OA. Besides these similarities, LF showed different secondary structure changes when compared with α-LA, with a decrease of α-helix and β-turn and an increase of β-sheet and random coil. ITC results showed that there was a higher binding number of OA to LF than to α-LA, while both of the proteins interacted with OA through van der Waals forces and hydrogen bonds. This study provides a theoretical basis for further exploration of protein-OA complexes. PMID:24368211

  20. Synthesis of 3,5-diisopropyl[carboxy-14C]salicylic acid and its 67Cu complex

    International Nuclear Information System (INIS)

    The synthesis of 3,5-diisopropyl[carboxy-14C]salicylic acid was achieved via Kolbe-Schmitt carboxylation of potassium 2,4-di-isopropylphenolate. The yield of this acid was 81% based upon the weight of the product and 93% based upon radioactivity incorporated into the labeled acid which contains 98% 14C in the carboxyl group (specific activity = 5.1 μCi/mg). The labeled acid was characterized by ultraviolet spectrophotometry and purity established by thin-layer chromatography, autoradiography, and liquid scintillation counting. A 90% yield of the double labeled 14C, 67Cu-complex (specific activity = 4.6 μCi 67Cu/mg) was obtained using conditions developed with non-radioactive reactants. The presence of 67Cu in this complex was established using γ-ray emission spectrophometry. (author)

  1. The molecular cloning and characterization of BM1P1 and BM1P2 proteins, putative positive transcription factors involved in barbiturate-mediated induction of the genes encoding cytochrome P450BM-1 of Bacillus megaterium.

    Science.gov (United States)

    He, J S; Liang, Q; Fulco, A J

    1995-08-01

    Analysis of a 1.3-kilobase segment of 5'-flanking DNA from the barbiturate-inducible P450BM-1 gene (CYP106) of Bacillus megaterium revealed two open reading frames. One, BM1P1, encodes 98 amino acids and is located 267 base pairs upstream from the sequence encoding cytochrome P450BM-1 but in the opposite orientation. The second, BM1P2 (88 amino acids), is 892 base pairs upstream from the P450BM-1 coding sequence and in the same coding strand. The expression of BM1P1 and BM1P2 was strongly stimulated in cells grown in the presence of pentobarbital, and the BM1P1 gene product exerted positive control on expression of P450BM-1. When a 177-base pair fragment encompassing the overlapping promoter regions of the P450BM-1 and BM1P1 genes was used as a probe in DNA binding assays, the BM1P1 and BM1P2 gene products and Bm3R1 (the repressor protein regulating the barbiturate-mediated expression of P450BM-3) could bind individually, but the addition of BM1P1 or BM1P2 to a binding mixture containing Bm3R1 completely prevented the appearance of a Bm3R1 binding band. When a 208-base pair fragment containing a Barbie box sequence and located upstream of the 177-base pair fragment was used as a probe, only a Bm3R1 binding band was detected. Although neither BM1P1 and BM1P2 appeared to bind to this 208-base pair fragment, their presence strongly inhibited the binding of Bm3R1 to the same probe. The evidence suggests that BM1P1 and BM1P2 may, in part, act as positive regulatory proteins involved in the expression of the P450BM-1 gene by interfering with the binding of the repressor protein, Bm3R1, to the regulatory regions of P450BM-1. PMID:7629192

  2. Purification and properties of the fatty acids synthetase complex from Neurospora crassa, and the nature of the fas-mutation.

    Science.gov (United States)

    Elovson, J

    1975-01-01

    A procedure is described for the purification of the fatty acid synthetase complex (FAS) from Neurospora crassa. The enzyme complex has a molecular weight of 2.3 times 10(6), contains 6 mol of 4'-phosphopantetheine per mol, and on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate gives a single band, or a closely spaced doublet, which comigrates with standard myosin (molecular weight, 2 times 10(5)). Since the slightly retarded component in the doublet accounts for all protein-bound 4'-phosphopantetheine, the complex appears to be made up of 11 to 12 equally sized subunits, 6 of which carry the acyl carrier protein function. In this unusual arrangement, notably the lack of the low-molecular-weight acyl carrier protein component seen in other FAS systems, as well as in its enzymatic properties, the Neurospora FAS complex is quite similar to the yeast enzyme. The FAS complex of a saturated fatty acid-requiring mutant, previously disignated cel-, contains less than 2% of the 4'-phosphopantetheine prosthetic groups found in the wild-type complex. The leaky phenotype of this mutant, here designated fas-, is accounted for by a residual fatty acid synthesizing activity in its FAS complex, which is several-fold higher than expected from its residual content of 4'-phosphopanthetheine. Images PMID:126228

  3. Investigation of non-covalent complexes of glutathione with common amino acids by electrospray ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Zhao-yun DAI; Yan-qiu CHU; Bo WU; Liang WU; Chuan-fan DING

    2008-01-01

    Aim: To study the non-covalent interaction between glutathione and common amino acids. Methods: A stoichiometry of glutathione and common amino acids were mixed to reach the equilibrium, and then the mixed solution was investigated by electrospray ionization mass spectrometry (ESI-MS). The binding of the com-plexes was further examined by collision-induced dissociation (CID) in a tandem mass spectrometer as well as UV spectroscopy. To avoid distinct ionization effi-ciency discrepancy and signal suppression in the ESI-MS measurements, the interaction between glutathione (GSH) and glutamate (Glu) was quantitatively evaluated. The total concentrations and series of m/z of peak intensities for glu-tathione and amino acids could be achieved, respectively. Due to the existence of some oligomeric species arising from glutathione or amino acids, an improved calculation formula was proposed to calculate the dissociation constants of glu-tathione binding to amino acids. Results: The ESI mass spectra revealed that glutathione could interact easily with Met, Phe, Tyr, Ser, or lie to form non-cova-lent complexes. The binding of the complexes was further confirmed by CID experiments in a tandem mass spectrometer as well as UV spectroscopy. Moreover, an improved calculation formula was successfully applied to determine the disso-ciation constants of glutathione binding to Glu, His, or Gln. Finally, a possible formation mechanism for the complexes of glutathione with amino acids was proposed. Conclusion: The reduced polypeptide y-glutathione can interact with each of 8 common amino acids, including Glu, His, and Gin to form non-covalent complexes with different affinity.

  4. Effects of RAMEA-complexed polyunsaturated fatty acids on the response of human dendritic cells to inflammatory signals

    Directory of Open Access Journals (Sweden)

    Éva Rajnavölgyi

    2014-12-01

    Full Text Available The n−3 fatty acids are not produced by mammals, although they are essential for hormone synthesis and maintenance of cell membrane structure and integrity. They have recently been shown to inhibit inflammatory reactions and also emerged as potential treatment options for inflammatory diseases, such as rheumatoid arthritis, asthma and inflammatory bowel diseases. Dendritic cells (DC play a central role in the regulation of both innate and adaptive immunity and upon inflammatory signals they produce various soluble factors among them cytokines and chemokines that act as inflammatory or regulatory mediators. In this study we monitored the effects of α-linoleic acid, eicosapentaenoic acid and docosahexaenoic acid solubilized in a dimethyl sulfoxide (DMSO/ethanol 1:1 mixture or as complexed by randomly methylated α-cyclodextrin (RAMEA on the inflammatory response of human monocyte-derived dendritic cells (moDC. The use of RAMEA for enhancing aqueous solubility of n−3 fatty acids has the unambiguous advantage over applying RAMEB (the β-cyclodextrin analog, since there is no interaction with cell membrane cholesterol. In vitro differentiated moDC were left untreated or were stimulated by bacterial lipopolysaccharide and polyinosinic:polycytidylic acid, mimicking bacterial and viral infections, respectively. The response of unstimulated and activated moDC to n−3 fatty acid treatment was tested by measuring the cell surface expression of CD1a used as a phenotypic and CD83 as an activation marker of inflammatory moDC differentiation and activation by using flow cytometry. Monocyte-derived DC activation was also monitored by the secretion level of the pro- and anti-inflammatory cytokines IL-1β, TNF-α, IL-6, IL-10 and IL-12, respectively. We found that RAMEA-complexed n−3 fatty acids reduced the expression of CD1a protein in both LPS and Poly(I:C stimulated moDC significantly, but most efficiently by eicosapentaenic acid, while no significant

  5. Preparation of polymer-rare earth complex using salicylic acid-containing polystyrene and its fluorescence emission property

    Energy Technology Data Exchange (ETDEWEB)

    Gao Baojiao, E-mail: gaobaojiao@126.com [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China); Zhang Wei; Zhang Zhengguo; Lei Qingjuan [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China)

    2012-08-15

    Salicylic acid (SA) was first bonded onto the side chains of polystyrene (PS), obtaining functional macromolecule SAPS. Using the salicylic acid-containing polystyrene as a macromolecular ligand, a polymer-rare earth complex, SAPS-Eu(III), was prepared. The structure of SAPS-Eu(III) was characterized, and the fluorescence properties of SAPS-Eu(III) were mainly investigated. The experimental results show that the complex SAPS-Eu(III) has fine chemical stability because of the bidentate chelating effect of salicylic acid ligand. More important, the ligand SA on the side chains of PS can strongly sensitize the fluorescence emission of the center ion, Eu{sup 3+} ion, and it enables the complex SAPS-Eu(III) to produce the apparent 'Antenna Effect'. In the diluted solution of the functional macromolecule SAPS, the formed complex SAPS-Eu(III) belongs to an intramolecular complex, or an intrachain complex. For the binary intramolecular complex SAPS-Eu(III), the apparent saturated coordination number of SA of SAPS towards Eu{sup 3+} ion is equal to 10, and here the binary intrachain complex SAPS-Eu(III) has the strongest fluorescence emission. On this basis, small-molecule 1,10-phenanthroline (Phen) acting as a co-ligand is added and the ternary complex SAPS-Eu(III)-Phen will be formed. As long as a small amount of Phen is added (in the molar ratio 1:1 (n(Phen):n(Eu))), the coordination of the two kinds of ligands, SA of SAPS and Phen, to Eu{sup 3+} ion will reach complete saturation, and here the fluorescence emission of the ternary complex will be further enhanced via the complementary coordination effect in comparison with that of the binary complex SAPS-Eu(III). - Highlights: Black-Right-Pointing-Pointer We prepared the functional polystyrene, SAPS, on whose side chain salicylic acid ligand was bonded. Black-Right-Pointing-Pointer The polymer-rare earth complex, SAPS-Eu(III), was prepared and a stronger 'antenna effect' was produced. Black

  6. Preparation of polymer–rare earth complex using salicylic acid-containing polystyrene and its fluorescence emission property

    International Nuclear Information System (INIS)

    Salicylic acid (SA) was first bonded onto the side chains of polystyrene (PS), obtaining functional macromolecule SAPS. Using the salicylic acid-containing polystyrene as a macromolecular ligand, a polymer–rare earth complex, SAPS–Eu(III), was prepared. The structure of SAPS–Eu(III) was characterized, and the fluorescence properties of SAPS–Eu(III) were mainly investigated. The experimental results show that the complex SAPS–Eu(III) has fine chemical stability because of the bidentate chelating effect of salicylic acid ligand. More important, the ligand SA on the side chains of PS can strongly sensitize the fluorescence emission of the center ion, Eu3+ ion, and it enables the complex SAPS–Eu(III) to produce the apparent “Antenna Effect”. In the diluted solution of the functional macromolecule SAPS, the formed complex SAPS–Eu(III) belongs to an intramolecular complex, or an intrachain complex. For the binary intramolecular complex SAPS–Eu(III), the apparent saturated coordination number of SA of SAPS towards Eu3+ ion is equal to 10, and here the binary intrachain complex SAPS–Eu(III) has the strongest fluorescence emission. On this basis, small-molecule 1,10-phenanthroline (Phen) acting as a co-ligand is added and the ternary complex SAPS–Eu(III)–Phen will be formed. As long as a small amount of Phen is added (in the molar ratio 1:1 (n(Phen):n(Eu))), the coordination of the two kinds of ligands, SA of SAPS and Phen, to Eu3+ ion will reach complete saturation, and here the fluorescence emission of the ternary complex will be further enhanced via the complementary coordination effect in comparison with that of the binary complex SAPS–Eu(III). - Highlights: ► We prepared the functional polystyrene, SAPS, on whose side chain salicylic acid ligand was bonded. ► The polymer-rare earth complex, SAPS–Eu(III), was prepared and a stronger “antenna effect” was produced. ► For the intramolecular complex SAPS–Eu(III), the apparent

  7. Benzene-Poly-Carboxylic Acid Complex, a Novel Anti-Cancer Agent Induces Apoptosis in Human Breast Cancer Cells

    OpenAIRE

    Fares, Fuad; Azzam, Naiel; Fares, Basem; Larsen, Stig; Lindkaer-Jensen, Steen

    2014-01-01

    Some cases of breast cancer are composed of clones of hormonal-independent growing cells, which do not respond to therapy. In the present study, the effect of Benzene-Poly-Carboxylic Acid Complex (BP-C1) on growth of human breast-cancer cells was tested. BP-C1 is a novel anti-cancer complex of benzene-poly-carboxylic acids with a very low concentration of cis-diammineplatinum (II) dichloride. Human breast cancer cells, MCF-7 and T47D, were used. Cell viability was detected by XTT assay and ap...

  8. KINETIC STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A NOVEL COPOLYMER- BOUND CIS- DICARBONYLRHODIUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuying; YUAN Guoqing; CHEN Rongyao

    1989-01-01

    The kinetic study of carbonylation of methanol-acetic acid mixture to acetic acid and acetic anhydride over a cis-dicarbonylrhodium complex (MVM' Rh)coordinated with the ethylene diacrylate (M')crosslinked copolymer of methyl acrylate (M) and 2 - vinylpyridine (V) shows that the rate of reaction is zero order with respect to both reactants methanol and carbon monoxide, but first order in the concentrations of promoter methyl iodide and rhodium in the complex . Polar solvents can accelerate the reaction .Activation parameters were calculated from the experimental results, being comparable to that of the homogeneous system . A mechanism similar to that of soluble rhodium catalyst was proposed .

  9. Humic Acid Complexation of Th, Hf and Zr in Ligand Competition Experiments: Metal Loading and Ph Effects

    Science.gov (United States)

    Stern, Jennifer C.; Foustoukos, Dionysis I.; Sonke, Jeroen E.; Salters, Vincent J. M.

    2014-01-01

    The mobility of metals in soils and subsurface aquifers is strongly affected by sorption and complexation with dissolved organic matter, oxyhydroxides, clay minerals, and inorganic ligands. Humic substances (HS) are organic macromolecules with functional groups that have a strong affinity for binding metals, such as actinides. Thorium, often studied as an analog for tetravalent actinides, has also been shown to strongly associate with dissolved and colloidal HS in natural waters. The effects of HS on the mobilization dynamics of actinides are of particular interest in risk assessment of nuclear waste repositories. Here, we present conditional equilibrium binding constants (Kc, MHA) of thorium, hafnium, and zirconium-humic acid complexes from ligand competition experiments using capillary electrophoresis coupled with ICP-MS (CE- ICP-MS). Equilibrium dialysis ligand exchange (EDLE) experiments using size exclusion via a 1000 Damembrane were also performed to validate the CE-ICP-MS analysis. Experiments were performed at pH 3.5-7 with solutions containing one tetravalent metal (Th, Hf, or Zr), Elliot soil humic acid (EHA) or Pahokee peat humic acid (PHA), and EDTA. CE-ICP-MS and EDLE experiments yielded nearly identical binding constants for the metal- humic acid complexes, indicating that both methods are appropriate for examining metal speciation at conditions lower than neutral pH. We find that tetravalent metals form strong complexes with humic acids, with Kc, MHA several orders of magnitude above REE-humic complexes. Experiments were conducted at a range of dissolved HA concentrations to examine the effect of [HA]/[Th] molar ratio on Kc, MHA. At low metal loading conditions (i.e. elevated [HA]/[Th] ratios) the ThHA binding constant reached values that were not affected by the relative abundance of humic acid and thorium. The importance of [HA]/[Th] molar ratios on constraining the equilibrium of MHA complexation is apparent when our estimated Kc, MHA values

  10. Synthesis and characterization of mixed ligand complexes of bio-metals with pyrimidine nucleoside (uridine) and amino acids

    Indian Academy of Sciences (India)

    P Rabindra Reddy; A Mohan Reddy

    2000-12-01

    The mixed ligand complexes of Cu(II), Ni(II) and Co(II) with uridine and amino acids, L-alanine, L-phenylalanine and L-tryptophan were synthesized and characterized by elemental analysis, conductivity data, infrared spectra, electronic spectra and magnetic susceptibility data. In these complexes, the nucleoside (uridine) acts as a monodentate ligand coordinating through O(4) under the conditions of investigation, whereas the amino acids coordinate through the carboxylate oxygen and the amino nitrogen. Distorted octahedral geometry for Cu(II) and octahedral geometries for both Ni(II) and Co(II) are proposed.

  11. The Cell Wall Teichuronic Acid Synthetase (TUAS) Is an Enzyme Complex Located in the Cytoplasmic Membrane of Micrococcus luteus

    OpenAIRE

    Anderson, John S.; Alexander, Alice A.; Lingyi Lynn Deng; Sijin Lei

    2010-01-01

    The cell wall teichuronic acid (TUA) of Micrococcus luteus is a long-chain polysaccharide composed of disaccharide repeating units [-4-β-D-ManNAcAp-(1→6)α-D-Glcp−1-]n, which is covalently anchored to the peptidoglycan on the inner cell wall and extended to the outer surface of the cell envelope. An enzyme complex responsible for the TUA chain biosynthesis was purified and characterized. The 440 kDa enzyme complex, named teichuronic acid synthetase (TUAS), is...

  12. Complexation of Eu3+ and Am3+ with soil humic acid extracted from Okchon Basin of Korean Peninsula

    International Nuclear Information System (INIS)

    The complexation of Eu3+ and Am3+ ions with the humic acids has been investigated at various pH (4.0, 4.5, 5.0, 5.4) in 0.1M NaClO4 solution using solvent extraction technique. Two humic acids are used in this study: humic acid extracted from the soil of Taejon on the Okchon Basin of Korea (TJHA) and commercially available one from Aldrich Chemical Co. (AHA). The total carboxylate group concentration were determined to be 3.58 meq/g and 4.59 meq/g for Taejon and Aldrich humic acids, respectively. The conditional stability constants (log β1 and log β2), dependent on the pH of the solution, of the complexes of Eu3+ and Am3+ ions with the humic acids have been determined at the ionic medium of 0.1M NaClO4. The values of stability constant with the degree of ionization α of TJHA for Eu and Am complexes are quite well agreed with those of Lake Bradford humic acid (LBHA), indicating that structural characteristics of TJHA and LBHA may be quite similar to one another. (author)

  13. Syntheses and fluorescent properties of complexes of Eu(Ⅲ) with HTTA,TPPO and benzoic acid

    Institute of Scientific and Technical Information of China (English)

    ZHAN Xuehui; XIAO Zhongliang; ZHAN Hanhui; ZHAO Xuehui; ZHOU Suian; LI Fei

    2009-01-01

    A series of Eu(Ⅲ) complexes of α-thenoyltrifluoroacetone(HTTA) with trioctylphosphine oxide(TPPO) and benzoic acid(BA) or its two derivatives, p-toluic acid(PTA) and p-methoxybenzoic acid(POA) were synthesized and were characterized with elemental analysis, IR spectroscopy, scanning electronic microscopy and fluorescent spectra. The complexes were revealed to be Eu(BA)(TTA)2TPPO2, Eu(PTA)(TTA)2TPPO2 and Eu(POA)(TTA)2TPPO2. The excitation and absorption spectra of the complex Eu(POA)(TTA)2TPPO2 in MeOH solution were investigated in detail. The experimental result showed that relatively cheap materials with sharp red luminescence could be pre-pared, when benzoic acid or its two derivatives were added in Eu(Ⅲ) complexes of α-thenoyltdfluoroacetone with trioctylphosphine oxide. The relative fluorescence intensity of the Eu(Ⅲ) complexes decreased in the following order: Eu(POA)(TTA)2TPPO2> Eu(PTA)(TTA)2TPPO2>Eu(BA)(TTA)2TPPO2.

  14. Ruthenium sulfate complexes forming during electrochemical dissolution of Ni-Fe-Ru alloys in sulfuric acid solutions

    International Nuclear Information System (INIS)

    Ruthenium sulfate complexes, prepared by anodic dissolution of Ni-Fe-Ru alloys in sulfuric acid solutions, have been studied. Ruthenium oxidation states in the complexes, their charge, dimensions, are determined, and Fe effect on the formation of different forms of complexes is clarified. Using the method of gel-chromatography, it is established, that at the anode potential >= 1w0 V ruthenium transfers into solution in the form of several neutral and anion complex forms of Ru(4): grey-violet polymeric ones (dimensions 1.6-2.3 nm), presumably containing the groupings (Rusub(n)(OH)sub(2(n-1))) or [Rusub(n)Osub(2(n-1))], where n>=3, red dimeric ones, containing (RuO)2, mixture of monomeric browngrey sulfate complexes with the grouping RuO. Fe hinders the formation of Ru complex polymeric forms

  15. Complex formation of cadmium with sugar residues, nucleobases, phosphates, nucleotides, and nucleic acids.

    Science.gov (United States)

    Sigel, Roland K O; Skilandat, Miriam; Sigel, Astrid; Operschall, Bert P; Sigel, Helmut

    2013-01-01

    Cadmium(II), commonly classified as a relatively soft metal ion, prefers indeed aromatic-nitrogen sites (e.g., N7 of purines) over oxygen sites (like sugar-hydroxyl groups). However, matters are not that simple, though it is true that the affinity of Cd(2+) towards ribose-hydroxyl groups is very small; yet, a correct orientation brought about by a suitable primary binding site and a reduced solvent polarity, as it is expected to occur in a folded nucleic acid, may facilitate metal ion-hydroxyl group binding very effectively. Cd(2+) prefers the guanine(N7) over the adenine(N7), mainly because of the steric hindrance of the (C6)NH(2) group in the adenine residue. This Cd(2+)-(N7) interaction in a guanine moiety leads to a significant acidification of the (N1)H meaning that the deprotonation reaction occurs now in the physiological pH range. N3 of the cytosine residue, together with the neighboring (C2)O, is also a remarkable Cd(2+) binding site, though replacement of (C2)O by (C2)S enhances the affinity towards Cd(2+) dramatically, giving in addition rise to the deprotonation of the (C4)NH(2) group. The phosphodiester bridge is only a weak binding site but the affinity increases further from the mono- to the di- and the triphosphate. The same also holds for the corresponding nucleotides. Complex stability of the pyrimidine-nucleotides is solely determined by the coordination tendency of the phosphate group(s), whereas in the case of purine-nucleotides macrochelate formation takes place by the interaction of the phosphate-coordinated Cd(2+) with N7. The extents of the formation degrees of these chelates are summarized and the effect of a non-bridging sulfur atom in a thiophosphate group (versus a normal phosphate group) is considered. Mixed ligand complexes containing a nucleotide and a further mono- or bidentate ligand are covered and it is concluded that in these species N7 is released from the coordination sphere of Cd(2+). In the case that the other ligand

  16. Stabilization of polyion complex nanoparticles composed of poly(amino acid) using hydrophobic interactions.

    Science.gov (United States)

    Akagi, Takami; Watanabe, Kazuki; Kim, Hyungjin; Akashi, Mitsuru

    2010-02-16

    We report the design and preparation of polyion complex (PIC) nanoparticles composed of anionic hydrophobically modified and cationic poly(amino acid) and the effect of hydrophobic interactions on the stability of these PIC nanoparticles under physiological conditions. We selected poly(gamma-glutamic acid) (gamma-PGA) as the biodegradable anionic polymer and poly(epsilon-lysine) (epsilon-PL) as the cationic polymer. Amphiphilic graft copolymers consisting of gamma-PGA and L-phenylalanine (L-Phe) as the hydrophobic side chain were synthesized by grafting L-Phe to gamma-PGA. The PIC nanoparticles were prepared by mixing gamma-PGA-graft-L-Phe (gamma-PGA-Phe) with epsilon-PL in phosphate buffered saline (PBS). The formation and stability of the PIC nanoparticles were investigated by dynamic light scattering (DLS) measurements. Monomodal anionic PIC nanoparticles were obtained using nonstoichiometric mixing ratios. When unmodified gamma-PGA was mixed with epsilon-PL in PBS, the formation of PIC nanoparticles was observed. However, within a few hours after the preparation, the PIC nanoparticles dissolved in the PBS. In contrast, gamma-PGA-Phe/epsilon-PL nanoparticles showed high stability for a prolonged period of time in PBS and over a wide range of pH values. The stability and size of the PIC nanoparticles depended on the gamma-PGA-Phe/epsilon-PL mixing ratio and the hydrophobicity of the gamma-PGA. The improved stability of the PIC nanoparticles was attributed to the formation of hydrophobic domains in the core of the nanoparticles. The fabrication of PIC nanoparticles using hydrophobic interactions was very useful for the stabilization of the nanoparticles. These results will provide a novel concept in the design of carrier systems composed of PIC. It is expected that the gamma-PGA-Phe/epsilon-PL nanoparticles will have great potential as multifunctional carriers for pharmaceutical and biomedical applications, such as drug and vaccine delivery systems. PMID:20017513

  17. Needlelike and spherical polyelectrolyte complex nanoparticles of poly(l-lysine) and copolymers of maleic acid.

    Science.gov (United States)

    Müller, M; Reihs, T; Ouyang, W

    2005-01-01

    We report on the bulk and surface properties of dispersions consisting of nonstoichiometric polyelectrolyte complex (PEC) nanoparticles. PEC nanoparticles were prepared by mixing poly(l-lysine) (PLL) or poly(diallyldimethylammonium chloride) (PDADMAC) with poly(maleic acid-co-alpha-methylstyrene) (PMA-MS) or poly(maleic acid-co-propylene) (PMA-P). The monomolar mixing ratio was n-/n+ = 0.6, and the concentration ranged from 1 to 6 mmol/L. Subsequent centrifugation enabled the separation of the excess polycation, resulting in a stable coacervate phase further used in the experiments. The bulk phase parameters turbidity and hydrodynamic radius (R(h)) of the PEC nanoparticles showed a linear dependence on the total polymer content independently of the mixed polyelectrolytes. This can be interpreted by the increased collision probability of the polyelectrolyte chains when the overlap concentration is approached or exceeded. Different morphologies of the cationic PEC nanoparticles, which were solution-cast onto Si supports, were obtained by atomic force microscopy (AFM). The combinations of PLL/PMA-MS and PDADMAC/PMA-MS revealed more or less hemispherical particle shapes, whereas that of PLL/PMA-P revealed an elongated needlelike particle shape. Circular dichroism and attenuated total reflection Fourier transform infrared (ATR-FTIR) measurements proved the alpha-helical conformation for the PEC PLL/PMA-P and the random coil conformation for the PEC PLL/PMA-MS. We conclude that stiff alpha-helical PLL induces anisotropic elongated PEC nanoparticles, whereas randomly coiled PLL forms isotropic spherical PEC nanoparticles. PMID:15620340

  18. X-Ray Absorption Fine Structure Investigation of Copper(II) Mixed Ligand Complexes with Pyridinedicarboxylic Acid as Primary Ligand

    Science.gov (United States)

    Dar, D. Ah.; Gaur, A.; Soni, B.; Shrivastava, B. D.; Prasad, J.; Srivastava, K.; Jha, S. N.; Bhattacharyya, D.

    2015-05-01

    The X-ray absorption fine structure (XAFS) spectra at the K-edge of the copper complexes Cu(PDC)(Mim)3 H2O ( 1) and Cu(PDC)2(EA)2H2O ( 2) (where PDC - Pyridine-2,3-dicarboxylic acid, Mim - 2-methylimidazole, and EA - ethyl acetate) have been investigated. The experimental extended X-ray absorption fine structure data of complex 1 have been analyzed by fitting the theoretical model generated from its own crystallographic data. The crystallographic data for complex 2 are not available. It has been found by comparing the intensity of the pre-edge peaks and X-ray absorption near edge structure features of complexes 1 and 2 that both complexes possess square pyramidal geometry around the copper centers and thus complex 2 is analogous to complex 1. Hence, the theoretical model generated for complex 1 has been fitted to the experimental EXAFS data of complex 2 to determine the structural parameters of complex 2. The coordination geometry of both complexes has been depicted. Further, the chemical shifts have been used to determine the oxidation state as well as to estimate the effective nuclear charge on the copper atom.

  19. Thermodynamics of mixed-ligand complex formation of zinc nitrilotriacetate with amino acids and dipeptides in solution

    International Nuclear Information System (INIS)

    Highlights: • Stable mixed ligand complexes of ZnNta with amino acids and dipeptides. • Histamine-like coordination mode of His in the complex ZnNtaHis. • Glycine-like coordination of Lys and Orn in the complexes ZnNtaL and ZnNtaHL • NH2, CO-coordination mode of GlyGly in the complex ZnNtaGG. • NH2, N− or NH2, N−, COO-coordination modes of GlyGly in the complex ZnNtaGGH−1. - Abstract: The isothermal calorimetry, pH-potentiometric titration and 1H and 13C NMR methods has been used to study the mixed-ligand complex formation in the systems Zn2+–Nta3––L− (L = His, Orn, Lys, GlyGly, AlaAla) in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO3). The thermodynamic parameters of formation of the mixed complexes have been determined. The relationship between the probable coordination modes of the complexone and amino acid or dipeptide molecules in the mixed-ligand complex and the thermodynamic parameters has been discussed

  20. Thermodynamics of mixed-ligand complex formation of zinc nitrilotriacetate with amino acids and dipeptides in solution

    Energy Technology Data Exchange (ETDEWEB)

    Pyreu, Dmitrii, E-mail: pyreu@mail.ru [Department of Inorganic and Analytic Chemistry, Ivanovo State UniversityErmak 39, Ivanovo 153025 (Russian Federation); Gruzdev, Matvey; Kumeev, Roman [G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Ivanovo (Russian Federation); Gridchin, Sergei [Ivanovo State University of Chemistry and Technology, Ivanovo (Russian Federation)

    2014-10-20

    Highlights: • Stable mixed ligand complexes of ZnNta with amino acids and dipeptides. • Histamine-like coordination mode of His in the complex ZnNtaHis. • Glycine-like coordination of Lys and Orn in the complexes ZnNtaL and ZnNtaHL • NH{sub 2}, CO-coordination mode of GlyGly in the complex ZnNtaGG. • NH{sub 2}, N{sup −} or NH2, N{sup −}, COO-coordination modes of GlyGly in the complex ZnNtaGGH{sub −1}. - Abstract: The isothermal calorimetry, pH-potentiometric titration and {sup 1}H and {sup 13}C NMR methods has been used to study the mixed-ligand complex formation in the systems Zn{sup 2+}–Nta{sup 3–}–L{sup −} (L = His, Orn, Lys, GlyGly, AlaAla) in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO{sub 3}). The thermodynamic parameters of formation of the mixed complexes have been determined. The relationship between the probable coordination modes of the complexone and amino acid or dipeptide molecules in the mixed-ligand complex and the thermodynamic parameters has been discussed.