排序方式: 共有124条查询结果,搜索用时 15 毫秒
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Masaki Shimizu Prof. Dr. Youhei Takeda Masahiro Higashi Tamejiro Hiyama Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(20):3653-3656
Minimum requirements : Crystals and thin films of 1,4‐bis(alkenyl)‐2,5‐dipiperidinobenzenes, which contain only one benzene ring as the aromatic component, emit visible light with excellent solid‐state quantum yields upon irradiation with UV light. Polystyrene thin films doped with the benzenes also exhibit brilliant fluorescence. By modifying the alkenyl groups, the emission color can be tuned in the range from blue to red.
63.
Aiko Fukazawa Dr. Yasunori Ichihashi Youhei Kosaka Shigehiro Yamaguchi Prof. Dr. 《化学:亚洲杂志》2009,4(11):1729-1740
The intramolecular trans‐halophosphanylation of 2‐(aminophosphanyl)phenylacetylenes mediated by PBr3 followed by the oxidation with H2O2, produces 3‐bromobenzo[b]phosphole oxide derivatives. This cyclization is also used for the synthesis of a 3‐iodo derivative by conducting the reaction in the presence of LiI. Based on this synthetic method, various benzophosphole‐containing π‐conjugated compounds, including a phosphoryl and methylene‐bridged stilbene 10 , 2,3,6,7‐tetraphenylbenzo[1,2‐b:4,5‐b′]diphosphole‐P,P′‐dioxides 11 , and their phosphine sulfide derivatives 12 , are synthesized. The study of the structure–property relationships in a series of the bridged stilbenes, including a bis(methylene)‐bridged stilbene 10 , and a bis(phosphoryl)‐bridged stilbene, reveals that as the contribution of the phosphoryl groups increased, the absorption and emission maxima substantially shift to longer wavelengths. The intrinsic substituent effects of the phosphoryl group in this skeleton are to decrease the oscillator strength of the electronic transition and thus decrease the radiative decay rate constants from the singlet excited state. Nevertheless, these compounds maintain high fluorescence quantum yields (ΦF>0.8) owing to the significantly retarded nonradiative decay process. In the study of the benzodiphosphole derivatives 11 and 12 , their cyclic voltammetry revealed that both of the phosphoryl and phosphine sulfide derivatives have low reduction potentials (?1.7 to ?1.8 V vs ferrocene/ferrocenium couple) with the high reversibility of the redox waves. These compounds also showed high thermal stabilities with the high glass transition temperatures of 147–159 °C, indicative of their potential utilities as amorphous materials. 相似文献
64.
T Nagamachi Y Takeda K Nakayama S Minakata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):12035-12045
Highly selective and versatile methods for the synthesis of aza[60]fulleroids and aziridino[60]fullerenes from C(60) have been developed. The reactions utilized N,N-dihalosulfonamides as an N(1) source. The photophysical, electrochemical, and thermal properties of the iminofullerenes were investigated by means of UV/Vis spectroscopy, cyclic voltammetry, and thermogravimetry, respectively. Furthermore, photovoltaic cells based on the synthesized iminofullerenes were fabricated. The power conversion efficiencies (PCEs) of the devices showed moderate values ranging from 1.33 to 2.35?%. 相似文献
65.
Y Takeda TL Andrew JM Lobez AJ Mork TM Swager 《Angewandte Chemie (International ed. in English)》2012,51(36):9042-9046
A thin-film transistor: An n-type polymer semiconductor, poly(2,3-bis(perfluorohexyl)thieno[3,4-b]pyrazine), was synthesized through a Pd-catalyzed polycondensation employing a perfluorinated multiphase solvent system. This is the first example of an n-type polymer semiconductor with exclusive solubility in fluorinated solvents. The fabrication of organic field effect transistors containing this new n-type polymer semiconductor is shown. 相似文献
66.
[reaction: see text] A novel binaphthyl-based diamine (R)-2 was designed and synthesized. A protonic acid-(R)-2 salt catalyst has the advantage of exhibiting unprecedented high exo selectivity in the asymmetric Diels-Alder reaction of alpha,beta-unsaturated aldehydes. For instance, the reaction between cinnamaldehyde and cyclopentadiene in the presence of 12 mol % of binaphthyl-based diamine (R)-2 and 10 mol % of p-TsOH.H(2)O in alpha,alpha,alpha-trifluorotoluene at -20 degrees C gave the corresponding exo cycloadduct with 92% ee as a major diastereomer (exo/endo = 13/1). 相似文献
67.
Paola Zimmermann Crocomo Dr. Masato Okazaki Takumi Hosono Prof. Dr. Satoshi Minakata Prof. Dr. Youhei Takeda Prof. Dr. Przemyslaw Data 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202200826
Previous work has reported the synthesis of donor–acceptor–donor molecules based on dibenzophenazine acceptor group, presenting thermally activated delayed fluorescent (TADF) properties and their application in the assembly of highly efficient electroluminescent devices. Herein, we focus on the characterisation of charge carrier species through UV-Vis-NIR spectroelectrochemical and potentiostatic EPR techniques, in addition to the investigation of electropolymerisation properties of some compounds depicted in this study. The promising electrochromic features of both small molecules and conjugated polymers led to the assembly and investigation of electrochromic devices, evidencing the materials’ versatility, applied in such different approaches as electrochromic windows and electroluminescent devices. Furthermore, the assembled OLEDs provided high efficiencies, with small roll-off, EQEs up to 20.5 % and luminance values up to 85 000 cd/m2. 相似文献
68.
Micha? E. Paw?owski Youhei Sakano Yoko Miyamoto Mitsuo Takeda 《Optics Communications》2006,260(1):68-72
The phase-crossing algorithm is proposed for white-light interferometry, which uses the multi-color phase information of spectrally decomposed interferograms recorded simultaneously with color-sensitive image sensors. The location of zero optical path difference is identified as the singular point at which the phase becomes color invariant, and is determined accurately with a sub-sampling-interval resolution from the crossing point of the multi-color phase distributions obtained by the Fourier transform method. An experimental result is presented that demonstrates the performance of the phase-crossing algorithm. 相似文献
69.
We consider the estimation of error variance in the analysis of experiments using two level orthogonal arrays. We address
the estimator which is the minimum of all the estimators which we obtain by pooling some sums of squares for factorial effects.
Under squared error loss, we discuss whether or not this estimator uniformly improves upon the best positive multiple of error
sum of squares. We show that when we have two factorial effects, we obtain uniform improvement. However, we show that when
we have more than two factorial effects, we cannot necessarily obtain uniform improvement. Further, the above results are
applied to the problem of estimating the smallest scale parameter of chi-square distributions. 相似文献
70.
Daisuke Kinoshita Youhei Kimura Masaru Tada Kin-ya Akiba 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1339-1343
Abstract 1,8-dimethoxy-10-methyl-9-methylene-9H-thioxanthenium salt (4) was prepared and the structure was determined by X-ray analysis to show the bond length between O─C is 2.80 A. This is too long to effect a hypervalent bonding. Bis[(1,8-dimethoxy) thioxanthylidene]allene (5) was prepared to be a symmetric compound in solution. Methylation of 5 with Meerwein reagent afforded S-monomethylated product (6) in solution and 6 gradually decomposed to C (or S)-monoprotonated allene (7), which was separately prepared as stable compound. 相似文献