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561.
Anouti M Caillon-Caravanier M Le Floch C Lemordant D 《The journal of physical chemistry. B》2008,112(31):9406-9411
Novel alkylammonium-cation-based protic acid ionic liquids (PILs) were prepared through a simple and atom-economic neutralization reaction between an amine, such as diisopropylmethylamine, and diisopropylethylamine, and a Br?nsted acid, HX, where X is HCOO-, CH 3COO-, or HF2-. The density, viscosity, acidic scale, electrochemical window, temperature dependency of ionic conductivity, and thermal properties of these PILs were measured and investigated in detail. Results show that protonated alkylammonium such as N-ethyldiisopropyl formate and N-methyldiisopropyl formate are liquid at room temperature and possess very low viscosities, that is, 18 and 24 cP, respectively, at 25 degrees C. An investigation of their thermal properties shows that they present a wide liquid range up to -100 degrees C and a heat thermal stability up to 350 degrees C. Alkylammonium-based PILs have a relatively low cost and low toxicity and show a high ionic conductivity (up a 8 mS cm(-1)) at room temperature. They have wide applicable perspectives for fuel cell devices, thermal transfer fluids, and acid-catalyzed reaction media and catalysts as replacements of conventional inorganic acids. 相似文献
562.
In ionic liquids, the diffusion coefficients of a redox couple vary considerably between the neutral and radical ion forms of the molecule. For a reduction, the inequality of the diffusion coefficients is characterized by the ratio gamma = D(red)/D(ox), where D(red) and D(ox) are the diffusion coefficients of the electrogenerated radical anion and of the corresponding neutral molecule, respectively. In this work, measurements of gamma have been performed by scanning electrochemical microscopy (SECM) in transient feedback mode, in three different room temperature ionic liquids (RTILs) sharing the same anion and with a series of nitro-derivative compounds taken as a test family. The smallest gamma ratios were determined in an imidazolium-based RTIL and with the charge of the radical anion localized on the nitro group. Conversely, gamma tends to unity when the radical anion is fully delocalized or when the nitro group is sterically protected by bulky substituents. The gamma ratios, standard potentials of the redox couple measured in RTILs, and those observed in a classical organic solvent were compared for the investigated family of compounds. The stabilization energies approximately follow the gamma ratios in a given RTIL but change considerably between ionic liquids with the nature of the cation. 相似文献
563.
Cottenye N Teixeira F Ponche A Reiter G Anselme K Meier W Ploux L Vebert-Nardin C 《Macromolecular bioscience》2008,8(12):1161-1172
Oligonucleotide model surfaces allowing independent variation of topography and chemical composition were designed to study the adhesion and biofilm growth of E.coli. Surfaces were produced by covalent binding of oligonucleotides and immobilization of nucleotide-based vesicles. Their properties were confirmed through a combination of fluorescence microscopy, XPS, ellipsometry, AFM and wettability studies at each step of the process. These surfaces were then used to study the response of three different strains of E.coli quantified in a static biofilm growth mode. This study led to convincing evidence that oligonucleotide-modified surfaces, independent of the topographical feature used in this study, enhanced curli expression without an increase in the number of adherent bacteria. 相似文献
564.
Raphaël M. Jungers Vladimir Protasov Vincent D. Blondel 《Linear algebra and its applications》2008,428(10):2296-2311
For a given finite set Σ of matrices with nonnegative integer entries we study the growth with t of
max{‖A1?At‖:Ai∈Σ}. 相似文献
565.
Gandon V Aubert C Malacria M Vollhardt KP 《Chemical communications (Cambridge, England)》2008,(13):1599-1601
In the presence of CpCo(C(2)H(4))(2), alpha,omega-diynes undergo hydroaminative coupling with amides to furnish new dienamides with control of regio- and stereochemistry. 相似文献
566.
567.
Cottenye N Syga MI Nosov S Müller AH Ploux L Vebert-Nardin C 《Chemical communications (Cambridge, England)》2012,48(20):2615-2617
The polymer modification of short nucleotide sequences has been achieved for future use as self-assembled biologically active structures with sizes in the nanometre range. Co-assembly of the resulting DNA-based amphiphilic block copolymers with native proteins demonstrates the self-assembly of biological-like vesicular structures. 相似文献
568.
Gour N Kedracki D Safir I Ngo KX Vebert-Nardin C 《Chemical communications (Cambridge, England)》2012,48(44):5440-5442
For the very first time, highly efficient synthesis of DNA-peptide hybrids to scaffold self-assembled nanostructures is described. Oligonucleotide conjugation to the diphenylalanine dipeptide triggers a morphological transition from fibrillar to vesicular structures which may potentially be used as delivery vehicles, since they exhibit pH triggered release. 相似文献
569.
Bakri R Booth A Harle G Middleton PS Wills C Clegg W Harrington RW Errington RJ 《Chemical communications (Cambridge, England)》2012,48(22):2779-2781
Controlled reductive assembly of capped Keggin anions [PMo(12)O(40)(ML(m))(n)](3-) has been achieved by reduction of [PMo(12)O(40)](3-) with sodium-mercury amalgam in the presence of metal halides, as exemplified by the rational syntheses of mono-capped [PMo(12)O(40){Co(MeCN)(2)}](3-) and bi-capped [PMo(12)O(40)(VO)(2)](3-) and [PMo(12)O(40)Sb(2)](3-). 相似文献
570.
Marvin KA Thadani NN Atkinson CA Keller EL Stevenson KJ 《Chemical communications (Cambridge, England)》2012,48(50):6289-6291
Ru and Ru(x)Ni(30) dendrimer encapsulated nanoparticles (DENs) were synthesized using a redox-displacement method. DEN catalytic activity for the reduction of p-nitrophenol was evaluated and found to be dependent on the ratio of metals present. 相似文献