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91.
Maxime Robin Stphane Mialhe Valrie Pique Robert Faure Jean‐Pierre Galy 《Journal of heterocyclic chemistry》2002,39(2):295-298
Novel 7,8,9,10‐tetrahydrothiazolo[5,4‐a]acridine and 1,2,3,4‐tetrahydro‐12H‐benzothiazolo[2,3‐b]‐quinazolin‐12‐one derivatives were synthesized in one step from the corresponding benzothiazoles. These two new tetracyclic skeletons were unambiguously characterized and are presently in pharmacological tests. 相似文献
92.
Valrie Sciannamea Maxime Bernard Jean‐Marie Catala Robert Jrme Christophe Detrembleur 《Journal of polymer science. Part A, Polymer chemistry》2006,44(21):6299-6311
The C‐phenyl‐N‐tert‐butylnitrone/azobisisobutyronitrile pair is able to impart control to the radical polymerization of n‐butyl acrylate as long as a two‐step process is implemented, that is, the prereaction of the nitrone and the initiator in toluene at 85 °C for 4 h followed by the addition and polymerization of n‐butyl acrylate at 110 °C. The structure of the in situ formed nitroxide has been established from kinetic and electron spin resonance data. The key parameters (the dissociation rate constant, combination rate constant, and equilibrium constant) that govern the process have been evaluated. The equilibrium constant between the dormant and active species is close to 1.6 × 10?12 mol L?1 at 110 °C. The dissociation rate constant and the activation energy for the C? ON bond homolysis are 1.9 × 10?3 s?1 and 122 ± 15 kJ mol?1, respectively. The rate constant of recombination between the propagating radical and the nitroxide is as high as 1.2 × 109 L mol?1 s?1. Finally, well‐defined poly(n‐butyl acrylate)‐b‐polystyrene block copolymers have been successfully prepared. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6299–6311, 2006 相似文献
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Blowing of silica microforms on silicon carbide 总被引:1,自引:0,他引:1
Silicon carbide ceramics have great potential for use in harsh environment applications, however many technical challenges still need to be addressed, including high temperature stability. The oxidation of SiC in air up to temperatures of 2053 K was conducted and resulted in the formation of a thermally grown silica scale that does not prove to be protective for very high temperature applications because of its rapid degradation. Examination of the oxide scale using scanning electron microscopy revealed the presence of striking features formed in a manner analogous to conventional glass blowing techniques. These features occurred for oxidation temperatures of at least 1773 K. The interfacial reaction between SiC and the oxide scale is responsible for the production of gases that must somehow escape. If the viscosity of the silica scale is low enough then it can be deformed freely by this pressure buildup. 相似文献
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Dinuclear Palladium Complexes with Two Ligand‐Centered Radicals and a Single Bridging Ligand: Subtle Tuning of Magnetic Properties 下载免费PDF全文
M. Sc. Daniël L. J. Broere Dr. Serhiy Demeshko Prof. Dr. Bas de Bruin Dr. Evgeny A. Pidko Prof. Dr. Joost N. H. Reek Dr. Maxime A. Siegler Dr. Martin Lutz Dr. Jarl Ivar van der Vlugt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5879-5886
The facile and tunable preparation of unique dinuclear [(L?)Pd?X?Pd(L?)] complexes (X=Cl or N3), bearing a ligand radical on each Pd, is disclosed, as well as their magnetochemistry in solution and solid state is reported. Chloride abstraction from [PdCl( NNOISQ )] ( NNOISQ =iminosemiquinonato) with TlPF6 results in an unusual monochlorido‐bridged dinuclear open‐shell diradical species, [{Pd( NNO ISQ)}2(μ‐Cl)]+, with an unusually small Pd‐Cl‐Pd angle (ca. 93°, determined by X‐ray). This suggests an intramolecular d8–d8 interaction, which is supported by DFT calculations. SQUID measurements indicate moderate antiferromagnetic spin exchange between the two ligand radicals and an overall singlet ground state in the solid state. VT EPR spectroscopy shows a transient signal corresponding to a triplet state between 20 and 60 K. Complex 2 reacts with PPh3 to generate [Pd(NNOISQ)(PPh3)]+ and one equivalent of [PdCl( NNOISQ )]. Reacting an 1:1 mixture of [PdCl( NNOISQ )] and [Pd(N3)( NNOI SQ)] furnishes the 1,1‐azido‐bridged dinuclear diradical [{Pd( NNO ISQ)}2(κ1‐N;μ‐N3]+, with a Pd‐N‐Pd angle close to 127° (X‐ray). Magnetic and EPR measurements indicate two independent S=1/2 spin carriers and no magnetic interaction in the solid state. The two diradical species both show no spin exchange in solution, likely because of unhindered rotation around the Pd?X?Pd core. This work demonstrates that a single bridging atom can induce subtle and tunable changes in structural and magnetic properties of novel dinuclear Pd complexes featuring two ligand‐based radicals. 相似文献
98.
Maxime Charman Frédéric Léonardi Sébastien Dominguez Cédric Bissuel Christophe Derail 《Journal of Polymer Science.Polymer Physics》2011,49(22):1597-1604
The dispersion of multiwalled carbon nanotubes (CNTs) in an ethylene propylene rubber matrix was investigated using an internal mixer. Poly(ethylene‐co‐polyvinyl acetate) (EVA) statistic copolymer was used as a dispersing agent. The effects of the concentration of the dispersing agent and the matrix viscosity on the quality of the dispersion of 1 wt % of CNTs were studied by using microscopy and rheology in the melt state. It was demonstrated that the dispersion is governed principally by the viscosity of the matrix. As expected, better dispersion was observed when the matrix exhibited a lower viscosity. The influence of the filler content on the rheological and electrical properties is presented. A Cross model with a yield stress is proposed to describe the rheological behavior of these materials, which exhibit a viscoelastic solid behavior from 1 wt % CNT content. Electrical measurement data indicate that the electrical percolation threshold was 2.9 wt %. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1597–1604, 2011 相似文献
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Maxime Bergeron Thomas Johnson Jean‐Franois Paquin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2011,123(47):11308-11312