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111.
Bourdolle A Allali M Mulatier JC Le Guennic B Zwier JM Baldeck PL Bünzli JC Andraud C Lamarque L Maury O 《Inorganic chemistry》2011,50(11):4987-4999
Two europium complexes with bis(bipyridine) azamacrocyclic ligands featuring pendant arms with or without π-conjugated donor groups are synthesized and fully characterized by theoretical calculations and NMR spectroscopy. Their photophysical properties, including two-photon absorption, are investigated in water and in various organic solvents. The nonfunctionalized ligand gives highly water-stable europium complexes featuring bright luminescence properties but poor two-photon absorption cross sections. On the other hand, the europium complex with an extended conjugated antenna ligand presents a two-photon absorption cross section of 45 GM at 720 nm but is poorly luminescent in water. A detailed solvent-dependent photophysical study indicates that this luminescence quenching is not due to the direct coordination of O-H vibrators to the metal center but to the increase of nonradiative processes in a protic solvent induced by an internal isomerization equilibrium. 相似文献
112.
Møllendal H Samdal S Matrane A Guillemin JC 《The journal of physical chemistry. A》2011,115(27):7978-7983
An improved synthesis of a compound of potential astrochemical interest, allenylisocyanide (H(2)C═C═CHNC), is reported together with its microwave spectrum, which has been investigated in the 8-120 GHz spectral range to facilitate a potential identification in interstellar space. The spectra of the ground vibrational state and of five vibrationally excited states belonging to three different vibrational modes have been assigned for the parent species. A total of 658 transitions with a maximum value of J = 71 were assigned for the ground state and accurate values obtained for the rotational and quartic centrifugal distortion constants. The spectra of five heavy-atom ((13)C and (15)N) isotopologues were also assigned. The dipole moment was determined to be μ(a) = 11.93(16) × 10(-30) C m, μ(b) = 4.393(44) × 10(-30) C m, and μ(tot) = 12.71(16) × 10(-30) C m. The spectroscopic work has been augmented by theoretical calculations at the CCSD/cc-pVTZ and B3LYP/cc-pVTZ levels of theory. The theoretical calculations are generally in good agreement with the experimental results. 相似文献
113.
Stéphanie Delbaere Gaston Vermeersch Jean-Claude MicheauAuthor vitae 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2011,12(2):74-105
The good understanding of a photochromic reaction mechanism requires the establishment of the list of all the transient species and the definition of their connecting processes. The purpose of kinetic studies is the determination of the main photochromic parameters, such as the quantum yields of photoisomerization, rate constants of thermal relaxation and spectra of transient species. These data allow the establishment of structure properties relationships in order to select the best substituents to improve photochromic performances within a given series. In this review, we describe the dynamic behaviour of various photochromic systems during thermal relaxation after irradiation, from the simplest mono-exponential decay to the more complicated multi-exponential dynamics. Then, we analyse the evolution of the long-lived isomers under continuous irradiation. Several pedagogical examples and tricks to perform easy kinetic analysis are given in the appendices. 相似文献
114.
Local shrinkage and stress induced by thermo-oxidation in composite materials at high temperatures 总被引:1,自引:0,他引:1
Marco Gigliotti Loic Olivier Dinh Quy Vu Jean-Claude Grandidier Marie Christine Lafarie-Frenot 《Journal of the mechanics and physics of solids》2011,59(3):696-712
The paper is concerned with the modelling, simulation and experimental characterisation of local shrinkage strains and stresses induced by thermo-oxidation phenomena in the IM7/977-2 carbon/epoxy composite material at elevated temperatures. The oxygen concentration and mechanical fields were established through a coupled model constructed from a unified multiphysical approach and the thermodynamics of irreversible processes. The model was implemented in the ABAQUS® finite element commercial code. Simulations of thermo-oxidation-induced matrix shrinkage were run at a local scale, i.e., the scale of the elementary constituents of the composite, the fibre and the matrix. The experimental assessment was done at the same scale, and the local matrix shrinkage profiles were measured by confocal interferometric microscopy.A good agreement was found between the simulated and measured profiles, validating the unified model. The thermo-oxidation induced stress field was analysed to understand the influence of the environment on the onset of damage in composite materials at elevated temperature. 相似文献
115.
Maynadié J Delavaux-Nicot B Lavabre D Donnadieu B Daran JC Sournia-Saquet A 《Inorganic chemistry》2004,43(6):2064-2077
[(C(5)H(5))Fe(C(5)H(4)COCH=CHC(6)H(4)NEt(2))] (1) has been electrochemically evaluated toward different cations in solution. Calcium sensing by this compound and its two new derivatives [(C(5)H(5))Fe(C(5)H(4)CO(CH=CH)(2)C(6)H(4)NMe(2))] (2) and [(C(5)H(5))Fe(C(5)H(4)CH=CHCOCH=CHC(6)H(4)NEt(2))] (3) that exhibit a conjugated link between the ferrocene unit and the nitrogen atom has been thoroughly examined. Compounds 2 and 3 have been structurally characterized by single-crystal X-ray diffraction studies. The three related protonated species [1H][BF(4)] (4), [2H][BF(4)] (5), and [3H][BF(4)] (6) have been isolated in a good yield. NMR experiments clearly established that calcium interaction occurs in the vicinity of the carbonyl group, and mass spectrometry studies confirmed that this interaction, which involves several ligand-Ca(2+) adducts, is complex. A combination of electrochemical and NMR experiments highlighted an original salt influence on the electrochemical calcium sensing result. 相似文献
116.
Jean-Claude Muller Henri Rarouz John Daly Peter Schönholzer 《Helvetica chimica acta》1982,65(5):1454-1466
The structure of new 2-oxo-2,8-dihydro-[l,2,4]oxadiazolo-[2,3-a]pyrimidine-carbamates 1 was established by correlating the IR. and NMR. data with these of analogous compounds. A X-ray crystallographic analysis of 1c gave an unequivocal proof of structural assignment. 相似文献
117.
We propose, in this paper, a unified method of generating a regularized integral equation in the double layer potential approach for 3D anisotropic elastodynamics. Our regularization preserves the causality in the time-domain. The method is based on a special decomposition of the hypersingular kernel which appears in the integral representation of the stress tensor. 相似文献
118.
The first successful preparation of 14,36-didehydro pristinamycins IIA and IIB is reported via different strategies. 相似文献
119.
The transposition of the molecular ions (ring contraction) of 2-decalones is demonstrated by a study of the [M–28]+˙ peak and its homologue in labelled products using ionization and appearance energy measurements, and mass analysed ion kinetic energy and collision induced dissociation spectra. 相似文献
120.