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121.
Electrogenerated Chemiluminescence of Cationic Triangulene Dyes: Crucial Influence of the Core Heteroatoms
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Dr. Catherine Adam Antoine Wallabregue Haidong Li Jérôme Gouin Dr. Rémi Vanel Stéphane Grass Dr. Johann Bosson Dr. Laurent Bouffier Prof. Jérôme Lacour Prof. Neso Sojic 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):19243-19249
Trianguleniums are fascinating conjugated hexacyclic cations that exhibit interesting electronic and optical properties. Herein, the electrogenerated chemiluminescence (ECL) emission of this family of fluorescent dyes is reported for the first time. Redox behavior and fluorescence properties of eight cationic triangulene luminophores with different heteroatom patterns in the core structure and various pending substituents were examined to rationalize the ECL. Clearly, the more electron‐rich the carbocation, the more efficient the corresponding ECL; two very distinct classes of triangulenes can be drawn from these studies by using an ECL wall sufficiency formalism. 相似文献
122.
Dr. Vivien Rauch Dr. Yoshihiro Kikkawa Dr. Matthieu Koepf Dr. Ismail Hijazi Dr. Jennifer A. Wytko Dr. Stéphane Campidelli Antoine Goujon Dr. Masatoshi Kanesato Dr. Jean Weiss 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13437-13444
The assembly of imidazole‐functionalized phenanthroline‐strapped zinc porphyrins (ZnPorphen) with alkyl or polyethylene glycol (PEG) side chains was studied in solution and by AFM after casting on highly oriented pyrolytic graphite (HOPG) or mica. The nature of the solvent and its evaporation time influenced the morphology of the objects observed. On HOPG, short rods of about 100 nm were observed after fast evaporation of solutions of the alkyl derivatives in CHCl3, THF, or pyridine, whereas islands of aligned rows of longer wires were obtained from methylcyclohexane (MCH). Slow evaporation of MCH led to a three‐dimensional assembly. The PEG porphyrin assembled into short wires on HOPG or fibers on mica after slow evaporation of solutions in THF. This study shows the role of surface–molecule interactions in the interfacial assembly of ZnPorphen derivatives and contributes to understanding the parameters that control their noncovalent assembly into molecular wires on a surface. 相似文献
123.
Dr. Georgian Melinte Dr. Veselina Georgieva Dr. Marie‐Anne Springuel‐Huet Dr. Andreï Nossov Prof. Ovidiu Ersen Dr. Flavien Guenneau Prof. Antoine Gedeon Dr. Ana Palčić Dr. Krassimir N. Bozhilov Dr. Cuong Pham‐Huu Prof. Shilun Qiu Dr. Svetlana Mintova Dr. Valentin Valtchev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18316-18327
The principle aspects and constraints of the dynamics and kinetics of zeolite nucleation in hydrogel systems are analyzed on the basis of a model Na‐rich aluminosilicate system. A detailed time‐series EMT‐type zeolite crystallization study in the model hydrogel system was performed to elucidate the topological and temporal aspects of zeolite nucleation. A comprehensive set of analytical tools and methods was employed to analyze the gel evolution and complement the primary methods of transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR) spectroscopy. TEM tomography reveals that the initial gel particles exhibit a core–shell structure. Zeolite nucleation is topologically limited to this shell structure and the kinetics of nucleation is controlled by the shell integrity. The induction period extends to the moment when the shell is consumed and the bulk solution can react with the core of the gel particles. These new findings, in particular the importance of the gel particle shell in zeolite nucleation, can be used to control the growth process and properties of zeolites formed in hydrogels. 相似文献
124.
Dr. Konrad Viehrig Dr. Frank Surup Dr. Carsten Volz Dr. Jennifer Herrmann Dr. Antoine Abou Fayad Sebastian Adam Dr. Jesko Köhnke Prof. Dr. Dirk Trauner Prof. Dr. Rolf Müller 《Angewandte Chemie (International ed. in English)》2017,56(26):7407-7410
Secondary metabolome mining efforts in the myxobacterial multiproducer of natural products, Chondromyces crocatus Cm c5, resulted in the isolation and structure elucidation of crocagins, which are novel polycyclic peptides containing a tetrahydropyrrolo[2,3-b]indole core. The gene cluster was identified through an approach combining genome analysis, targeted gene inactivation in the producer, and in vitro experiments. Based on our findings, we developed a biosynthetic scheme for crocagin biosynthesis. These natural products are formed from the three C-terminal amino acids of a precursor peptide and thus belong to a novel class of ribosomally synthesized and post-translationally modified peptides (RiPPs). We demonstrate that crocagin A binds to the carbon storage regulator protein CsrA, thereby inhibiting the ability of CsrA to bind to its cognate RNA target. 相似文献
125.
Any positive matrix M partitioned in four n-by-n blocks satisfies the unitarily invariant norm inequality , where ω is the width of the numerical range of . Some related inequalities and a reverse Lidskii majorization are given. 相似文献
126.
Doussineau T Kerleroux M Dagany X Clavier C Barbaire M Maurelli J Antoine R Dugourd P 《Rapid communications in mass spectrometry : RCM》2011,25(5):617-623
Ions from compounds of megadalton (MDa) molecular weight were produced in an electrospray ionization source from solutions of poly(ethylene oxide) (PEO) samples with average molecular weights ranging from 1,000,000 to 7,000,000 Da. Charge detection mass spectrometry (CDMS) has been used to determine the mass of the MDa PEOs. Simultaneous measurement of the charge and velocity of individual ions allows the mass determination of the ion, after calibration of the instrument with independent samples. In addition to the mass spectra, CDMS generates charge-versus-mass plots, which allow investigation of the charging of electrosprayed ions over a broad range of masses. The experimental charging capacity of MDa PEOs is compared with a simple model based on the affinity of alkali cations for oxygen sites and on the electrostatic potential energy of the charged polymer. The charging capacity of PEOs was also investigated as a function of the concentration of and the type of alkali ions. 相似文献
127.
De Winter J Lemaur V Ballivian R Chirot F Coulembier O Antoine R Lemoine J Cornil J Dubois P Dugourd P Gerbaux P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(35):9738-9745
Ion mobility spectrometry coupled with mass spectrometry was used to experimentally determine the three-dimensional structure of multiply charged sodium cationized polylactides (PLA). In particular, the experiments were conducted to evaluate the influence of the charge state and the size on the gas-phase conformation of cationized PLA. The measured collision cross sections were then compared to calculated values obtained by computational chemistry methods. The most striking feature was the experimental and theoretical observation of a breaking point in the quasilinear relationship between the average collision cross sections and the number of monomer units for the triply charged cations. This breaking point was theoretically demonstrated, for the doubly and triply charged cations, to be associated with a significant folding of the polymer chains around the cationizing agents. The occurrence of such breaking points could be exploited to correlate the charge state of the most intense ion series observed upon electrospray ionization with the number-average molecular mass of a polymer. 相似文献
128.
129.
Antoine Gloria Stefan Neukamm 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2011,28(6):941
We prove under some general assumptions on elastic energy densities (namely, frame indifference, minimality at identity, non-degeneracy and existence of a quadratic expansion at identity) that homogenization and linearization commute at identity. This generalizes a recent result by S. Müller and the second author by dropping their assumption of periodicity. As a first application, we extend their Γ-convergence commutation diagram for linearization and homogenization to the stochastic setting under standard growth conditions. As a second application, we prove that the Γ-closure is local at identity for this class of energy densities. 相似文献
130.
Berthe J Garcia JM Ocando E Kato T Saffon-Merceron N De Cózar A Cossío FP Baceiredo A 《Journal of the American Chemical Society》2011,133(40):15930-15933
The synthesis of the first isolable C-phosphino-Ge-aminogermyne, stabilized by a phosphine ligand, has been achieved. X-ray diffraction analysis indicates a quite long Ge-C bond whose length is between that of a single and a double bond but consistent with the theoretically predicted values for a germyne bearing π-donating substituents. The isomerization of this germyne derivative affords a new stable N-heterocyclic germylene through migration of the original phosphine ligand from germanium to the carbon center. 相似文献