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排序方式: 共有65条查询结果,搜索用时 15 毫秒
1.
2.
Synthesis and properties of monodisperse oligofluorene-functionalized truxenes: highly fluorescent star-shaped architectures 总被引:2,自引:0,他引:2
Kanibolotsky AL Berridge R Skabara PJ Perepichka IF Bradley DD Koeberg M 《Journal of the American Chemical Society》2004,126(42):13695-13702
This paper describes the strategy toward novel monodisperse, well-defined, star-shaped oligofluorenes with a central truxene core and from monofluorene to quaterfluorene arms. Introduction of solubilizing n-hexyl groups at both fluorene and truxene moieties results in highly soluble, intrinsically two-dimensional nanosized macromolecules T1-T4. The radius for the largest oligomer of ca. 3.9 nm represents one of the largest known star-shaped conjugated systems. Cyclic voltammetry experiments reveal reversible or quasi-reversible oxidation and reduction processes (Eox = +0.74 to 0.80 V, Ered = -2.66 to 2.80 eV vs Fc/Fc+), demonstrating excellent electrochemical stability toward both p- and n-doping, while the band gaps of the oligomers are quite high (EgCV = 3.20-3.40 eV). Close band gaps of 3.05-3.29 eV have been estimated from the electron absorption spectra. These star-shaped macromolecules demonstrate good thermal stability (up to 400-420 degrees C) and improved glass transition temperatures with an increase in length of the oligofluorene arms (from Tg = 63 degrees C for T1 to 116 degrees C for T4) and show very efficient blue photoluminescence (lambdaPL = 398-422 nm) in both solution (PhiPL = 70-86%) and solid state (PhiPL = 43-60%). Spectroelectrochemical experiments reveal that compounds T1-T4 are stable electrochromic systems which change their color reversibly from colorless in the neutral state (approximately 340-400 nm) to colored (from red to purple color; approximately 500-600 nm) in the oxidized state. 相似文献
3.
Kanibolotsky D. S. Bieloborodova O. A. Kotova N. V. Lisnyak V. V. 《Journal of Thermal Analysis and Calorimetry》2003,71(2):583-591
The enthalpies of mixing of liquid binary Fe-Ge (1765±5 K) and Fe-Si (1750±5 K) alloys were determined using a high-temperature
isoperibolic calorimeter. The thermodynamic properties of Fe-Ge melts were also studied by electromotive force method in the
temperature range of 1250-1580 K. The comparison of our measurement results with literature data has been performed. The extreme
negative values of integral enthalpy of mixing and alternating-sign deviations from Raoult's low for germanium can be explained
by the influence of binary clusters formation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Kanibolotsky A Roquet S Cariou M Leriche P Turrin CO de Bettignies R Caminade AM Majoral JP Khodorkovsky V Gorgues A 《Organic letters》2004,6(13):2109-2112
[structure: see text] In four new dendrimers terminated by 12 electroactive tetrathiafulvalenyl substituents, the tridimensional character of the inter- and intradendrimeric charge and electron transfer, and hence of the electroconductivity, is evidenced by examination of the electronic spectra of their corresponding neutral state and cation radical, dication, and mixed-valence salts, including a closed-shell anion. 相似文献
5.
Kanibolotsky D. S. Golovataya N. V. Lisnyak V. V. 《Journal of Thermal Analysis and Calorimetry》2004,76(1):323-327
The enthalpies of mixing of liquid Gd-Si (1770±5 K) and Al-Gd (1760±5 K) alloys have been measured by high-temperature isoperibolic
calorimetry. The calorimetric study of the gadolinium-based liquid alloys demonstrates the great negative enthalpies of mixing,
which is associated with the contribution of GdSi and GdAl2 intermetallides into the liquid-state thermodynamics. The comparison of obtained results with literature data has been performed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
In this paper,we study the surface instability of a cylindrical pore in the absence of stress. This instability is called the Rayleigh-Plateau instabilty. We consider the model developed by Spencer et ... 相似文献
7.
Iryna Chepurna Valentyn Kanibolotsky Volodymyr Strelko 《Journal of Sol-Gel Science and Technology》2013,68(3):500-508
Hydrated zirconium dioxide samples were synthesized via original sol–gel route by two-step neutralization of zirconium oxychloride. Spherical granules of zirconia materials were prepared using a well-known “oil-drop” method. By the use of low temperature nitrogen adsorption, it is shown that surface fractal dimension of synthesized xerogels strongly depends on synthesis conditions, chemical and hydrothermal treatments. It is established that the change of synthesis conditions allows to obtain zirconium containing materials with developed porous structure: BET surface area—250–450 m2/g, pore diameter—2.0–4.2 nm, surface fractal dimension—2.28–2.63. It is shown that surface fractal dimension is an important parameter allowing to control the final properties of synthesized material and to determine the reasons of non-reproducibility of adsorptive, catalytic and other physical and chemical properties of zirconium containing oxides from synthesis to synthesis. 相似文献
8.
Ebraheem Abdu Musad Saleh Abdullah Mohammed AL Dawsari Kakul Husain Ismail Hassan Kutty K.M.Lokanatha Rai 《Molecules (Basel, Switzerland)》2021,26(2)
A novel synthesis of thiazolo[2,3-b]quinazolines 4(a–e), pyrido[2′,3′:4,5]thiazolo[2,3-b]quinazolines {5(a–e), 6(a–e), and 7(a–e)}, pyrano[2′,3′:4,5]thiazolo[2,3-b]quinazolines 8(a–e), and benzo[4,5]thiazolo[2,3-b]quinazoloine9(a–e) derivatives starting from 2-(Bis-methylsulfanyl-methylene)-5,5-dimethyl-cyclohexane-1,3-dione 2 as efficient α,α dioxoketen dithioacetal is reported and the synthetic approaches of these types of compounds will provide an innovative molecular framework to the designing of new active heterocyclic compounds. In our study, we also present optimization of the synthetic method along with a biological evaluation of these newly synthesized compounds as antioxidants and antibacterial agents against the bacterial strains, like S. aureus, E. coli, and P. aeruginosa. Among all the evaluated compounds, it was found that some showed significant antioxidant activity at 10 μg/mL while the others exhibited better antibacterial activity at 100 μg/mL. The results of this study showed that compound 6(c) possessed remarkable antibacterial activity, whereas compound 9(c) exhibited the highest efficacy as an antioxidant. The structures of the new synthetic compounds were elucidated by elemental analysis, IR, 1H-NMR, and 13C-NMR. 相似文献
9.
Gomez L Slutzky C Ferron J de La Figuera J Camarero J Vazquez De Parga AL de Miguel JJ Miranda R 《Physical review letters》2000,84(19):4397-4400
Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands. 相似文献
10.