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1.
Tamara Elzein Virginie Kreim Achraf Ghorbal Sophie Bistac 《Journal of Polymer Science.Polymer Physics》2006,44(22):3272-3281
Friction‐deposited layers of atactic polystyrene (PS) on inert and OH‐grafted gold substrates were the subject of this study to establish a relationship between the friction process and the resulting anisotropy of the transferred polymer chains. We show, by using polarization‐modulation infrared reflection‐absorption spectroscopy that the deposited PS chains involve an anisotropy in which PS main backbone is rather perpendicular to the friction support, fact that is surprising when compared with the majority of polymers where the anisotropy is along the sliding direction. Moreover, our calculation of the orientation angles revealed that PS chains are more perpendicular in the transferred layers than in spin‐coated films. This particular anisotropy is probably due to a parallel reorientation of the phenyl ring on the friction support whatever the surface chemistry is. On the other hand, this study was useful to rectify the assignment of infrared bands unclearly reported in the literature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3272–3281, 2006 相似文献
2.
John R. Peterson Tamara J. Winter Hoang D. Do Robin D. Rogers 《Journal of chemical crystallography》1989,19(1):135-145
Structural and conformational information obtained from the crystal structure and solution1H nmr investigations of the title compound are compared. The 4-aryltetralone, C24H24O10, crystallizes as a chloroform solvate in the monoclinic space group, P21/n, witha=12.519(4),b=17.938(6),c=12.534(9)Å,=111.90(5)°, and Dcalc=1.51 g cm–3 forZ=4. The data for this compound were collected at –150°C. Least-squares refinement of 2796 observed [F
o5(F
o)] reflections led to the final agreement index ofR=0.062. A threefold static disorder was observed for one of the carboxyl groups. The second carboxyl group participates in an intramolecular hydrogen bond and is thus ordered. The1H nmr spectrum revealed the title compound to exist as a keto-enol tautomeric mixture in solution. Vicinal hydrogen coupling constant analysis proved reliable in ascertaining B-ring stereochemistry of 2,3-disubstituted-4-aryltetralones. 相似文献
3.
4.
Microwave assisted free radical copolymerization of diisopropyl fumarate (DIPF) and benzyl acrylate (BzA) with different copolymer compositions was performed using benzoyl peroxide as initiator. The effect of the reaction conditions on the macromolecular characteristics, monomer reactivity ratio and copolymer properties were studied. The monomer conversion and average molecular weights increase with the content of BzA units in the copolymer. The copolymers were characterized by IR, 1H and 13C-NMR spectroscopies and the molecular weights were analyzed with size exclusion chromatography (SEC). The reactivity ratios obtained from an extended Kelen-Tüdös method under microwave irradiations are a factor which is double than those obtained by thermal copolymerization. The product r1r2 = 0.152 suggests a preference of both propagating macroradicals toward consecutive homopolymerization. The hydrodynamic and polydispersity size were measured in ethylacetate, tetrahydrofuran and methylethylketone with a quasi-elastic light scattering (QELS) technique showing that the quality of the solvents increases in the order: EA < THF < MEK. 相似文献
5.
Tamara Borisova Sergey Fridrikh Yuli Gotlib Grigoriy Medvedev Natalja Nikonorova Sergey Skorokhodov Vjacheslav Zuev 《Macromolecular Symposia》1993,72(1):67-80
A series of thermotropic main chain polymers with extended dimethylsiloxane segments was investigated. The study of dielectric properties of polymers revealed the relationship between their ability to form a mesophase and their molecular mobility. The peculiar behaviour of dielectric α-relaxation parameters during the transition from mesomorphic to isotropic members of this polymeric series was shown. The theoretical approaches were developed for understanding macrochain dynamics of liquid crystalline polymers. The theoretical and experimental results are in good agreement. 相似文献
6.
Svetlana I. Dorovskikh Denis E. Tryakhov Darya D. Klyamer Alexander S. Sukhikh Irina V. Mirzaeva Natalia B. Morozova Tamara V. Basova 《Molecules (Basel, Switzerland)》2022,27(7)
To search for new suitable Pd precursors for MOCVD/ALD processes, the extended series of fluorinated palladium complexes [Pd(CH3CXCHCO(R))2] with β-diketone [tfa−1,1,1-trifluoro-2,4-pentanedionato (1); pfpa−5,5,6,6,6-pentafluoro-2,4-hexanedionato (3); hfba−5,5,6,6,7,7,7-heptafluoro-2,4-heptanedionato (5)] and β-iminoketone [i-tfa−1,1,1-trifluoro-2-imino-4-pentanonato (2); i-pfpa−5,5,6,6,6-pentafluoro-2-imino-4-hexanonato (4); i-hfba-5,5,6,6,7,7,7-heptafluoro-2-imino-4-heptanonato (6)] ligands were synthesized with 70–80% yields and characterized by a set of experimental (SXRD, XRD, IR, NMR spectroscopy, TG) and theoretical (DFT, Hirshfeld surface analysis) methods. Solutions of Pd β-diketonates contained both cis and trans isomers, while only trans isomers were detected in the solutions of Pd β-iminoketonates. The molecules 2–6 and new polymorphs of complexes 3 and 5 were arranged preferentially in stacks, and the distance between molecules in the stack generally increased with elongation of the fluorine chain in ligands. The H…F contacts were the main ones involved in the formation of packages of molecules 1–2, and C…F, F…F, NH…F contacts appeared in the structures of complexes 4–6. The stability of complexes and their polymorphs in the crystal phases were estimated from DFT calculations. The TG data showed that the volatility differences between Pd β-iminoketonates and Pd β-diketonates were minimized with the elongation of the fluorine chain in the ligands. 相似文献
7.
Tamara Bezrodna Georgyi Klishevich Volodymyr Melnyk Vira Nesprava Olexandr Roshchin 《Molecular Crystals and Liquid Crystals》2020,697(1):60-67
AbstractFluorescence and absorption spectra of the 2-fluoronaphthalene admixtures in naphthalene were studied at low temperature (T?=?4.2 К). Two types of pairwise impurity centers were formed at admixture concentrations of more than 1?wt%. Polarization of absorption bands was detected; these spectra were determined by resonance interactions between molecules of the impurity center. Resonant splitting of electronic levels for the translationally nonequivalent molecules in the unit cell of the naphthalene crystal was analyzed for the case, when one molecule was in the similar phase with the incident light wave and the other one was in antiphase. 相似文献
8.
Frontispiece: Synthesis of Calcium(II) Amidinate Precursors for Atomic Layer Deposition through a Redox Reaction between Calcium and Amidines 下载免费PDF全文
9.
Tamara Brider Gary Gellerman 《Tetrahedron letters》2012,53(42):5611-5615
A new approach for a short synthesis of novel medicinally-important mono-, bis- and tris-1,8-naphthalimide peptidyl derivatives is described. The method generates efficiently 1,8-naphthalimides with variable spacer lengths and charged, polar or hydrophobic residues at desired positions, which can increase binding affinity, conformational stability, intracellular transport and/or biological activity. The synthetic routes reported in this work are both general and applicable, and significantly expand the scope of potential 1,8-naphthalimide anticancer candidates. 相似文献
10.
Tuniyazi Abuduaini Vincent Roy Julien Marlet Catherine Gaudy-Graffin Denys Brand Ccile Baronti Franck Touret Bruno Coutard Tamara R. McBrayer Raymond F. Schinazi Luigi A. Agrofoglio 《Molecules (Basel, Switzerland)》2021,26(5)
A series of hitherto unknown (1,4-disubstituted-1,2,3-triazol)-(E)-2-methyl-but-2-enyl nucleosides phosphonate prodrugs bearing 4-substituted-1,2,3-triazoles were prepared in a straight approach through an olefin acyclic cross metathesis as the key synthetic step. All novel compounds were evaluated for their antiviral activities against HBV, HIV and SARS-CoV-2. Among these molecules, only compound 15j, a hexadecyloxypropyl (HDP)/(isopropyloxycarbonyl-oxymethyl)-ester (POC) prodrug, showed activity against HBV in Huh7 cell cultures with 62% inhibition at 10 μM, without significant cytotoxicity (IC50 = 66.4 μM in HepG2 cells, IC50 = 43.1 μM in HepG2 cells) at 10 μM. 相似文献