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291.
Satoshi Matsunaga Yusuke Inoue Takuya Otaki Hironori Osada Kenji Nomiya 《无机化学与普通化学杂志》2016,642(7):539-545
Al‐ and Ga‐containing open‐Dawson polyoxometalates (POMs), K10[{Al4(μ‐OH)6}{α,α‐Si2W18O66}] · 28.5H2O ( Al4 ‐ open ) and K10[{Ga4(μ‐OH)6}(α,α‐Si2W18O66)] · 25H2O ( Ga4 ‐ open ) were synthesized by the reaction of trilacunary Keggin POM, [A‐α‐SiW9O34]10–, with Al(NO3)3 · 9H2O or Ga(NO3)3 · nH2O, and unequivocally characterized by single‐crystal X‐ray analysis, 29Si and 183W NMR, and FT‐IR spectroscopy as well as elemental analysis and TG/DTA. Single‐crystal X‐ray analysis revealed that the {M4(μ‐OH)6}6+ (M = Al, Ga) clusters were included in an open pocket of the open‐Dawson polyanion, [α,α‐Si2W18O66]16–, which was constituted by the fusion of two trilacunary Keggin POMs via two W–O–W bonds. These two open‐Dawson structural POMs showed clear difference of the bite angles depending on the size of ionic radii. In cases of both compounds, the solution 29Si and 183W NMR spectra in D2O showed only one signal and five signals, respectively. These spectra were consistent with the molecular structures of Al4 ‐ and Ga4 ‐ open , suggesting that these polyoxoanions were obtained as single species and maintained their molecular structures in solution. 相似文献
292.
293.
There is a need to boost the rate constant of reverse intersystem crossing (kRISC) in thermally activated delayed fluorescence (TADF) materials for applications to organic light-emitting diodes. Recently, energy level matching of the locally excited state (LE) and charge transfer state (CT) has been reported to enhance kRISC. In this study, we conceptually demonstrate that kRISC can be improved even between CT states without LE states, through the use of different types of CT states. On the basis of this concept, we design a new compound, named DMAC-bPmT, where two phenyl groups of a well-known TADF material DMAC-TRZ are substituted by pyrimidine groups. Theoretical calculations indicated that the energy levels of the different CT states of DMAC-bPmT are very close and enhanced spin orbit coupling may be expected between them. As predicted, DMAC-bPmT experimentally exhibited a kRISC three times as high as that of DMAC-TRZ. 相似文献
294.
Triarylboron‐Based Fluorescent Organic Light‐Emitting Diodes with External Quantum Efficiencies Exceeding 20 % 下载免费PDF全文
Dr. Katsuaki Suzuki Shosei Kubo Dr. Katsuyuki Shizu Dr. Tatsuya Fukushima Prof. Dr. Atsushi Wakamiya Prof. Dr. Yasujiro Murata Prof. Dr. Chihaya Adachi Prof. Dr. Hironori Kaji 《Angewandte Chemie (International ed. in English)》2015,54(50):15231-15235
Triarylboron compounds have attracted much attention, and found wide use as functional materials because of their electron‐accepting properties arising from the vacant p orbitals on the boron atoms. In this study, we design and synthesize new donor–acceptor triarylboron emitters that show thermally activated delayed fluorescence. These emitters display sky‐blue to green emission and high photoluminescence quantum yields of 87–100 % in host matrices. Organic light‐emitting diodes using these emitting molecules as dopants exhibit high external quantum efficiencies of 14.0–22.8 %, which originate from efficient up‐conversion from triplet to singlet states and subsequent efficient radiative decay from singlet to ground states. 相似文献
295.
296.
Recent progress in photocatalytic decomposition of water to H2 and O2 using simple oxide semiconductor catalysts has been reviewed. Addition of Na2CO3 to Pt/TiO2 suspension in water enhanced the stoichiometric decomposition significantly. This Na2CO3 addition method has been proved to be very useful to accelerate water splitting over various kinds of oxide semiconductor photocatalysts. The role of CO3
2– anion on the acceleration of water splitting was clarified. Finally, it was firstly demonstrated in the world that water was decomposed efficiently and stoichiometrically to H2 and O2 using a 3 wt% NiOx/TiO2 photocatalyst under real solar light irradiation in Tsukuba, Japan by this Na2CO3 addition method. 相似文献
297.
Hiroshi Hiratsuka Takahiro Okamoto Satoshi Kuroda Tetsuo Okutsu Hironori Maeoka Mitsumasa Taguchi Tetsutaro Yoshinaga 《Research on Chemical Intermediates》2001,27(1-2):137-153
Reaction intermediates produced upon the photolysis of benzyl chloride have been studied in glassy matrix and in solution. In the steady-state photolysis both benzyl radicals and structural isomers of benzyl chloride were formed in ethanol, while in 3-methylpentane the structural isomers were predominantly formed. The nanosecond laser photolyses of benzyl chloride in ethanol and in cyclohexane also generated benzyl radicals and structural isomers at room temperature. In acetonitrile, in addition to these species, benzyl cations were observed in the early stage after the photolysis. 相似文献
298.
Tetsuo Ohta Hironori Fujisawa Mitsuru Kawazome Yasuto Nakai Isao Furukawa 《Journal of heterocyclic chemistry》2001,38(1):159-164
Novel method for the synthesis of 3‐acyl‐1,6‐dialkyl‐7‐methyl‐1,6‐naphthyridine‐2,5(1H,6H)‐diones (2) was developed. The reaction of 2‐acyl‐1‐alkylamino‐1‐ethoxyethylenes (1) with acetyl chloride or β‐keto amide 3 with acetyl chloride in the presence of p‐toluenesulfonic acid gave 2 in moderate yield (14‐59% yield). 相似文献
299.
Akihiko Nishimura Hironori Ohba Koichi Ogura Takemasa Shibata 《Optics Communications》1994,110(5-6):561-564
The absolute values of the oscillator strength ƒ were measured for the six spectral lines of Gd by means of laser absorption spectroscopy with the atomic vapor produced by electron beam heating. The ƒ values obtained for the transition are 0–17381 cm−1, 215–17750 cm−1, 533–17795 cm−1, 999–18070 cm−1, 999–17931 cm−1, 1719–18070 cm−1 were obtained to be 0.0036, 0.012, 0.014, 0.019, 0.0075 and 0.039, respectively. The error of ƒ values was 24% due to uncertainty of metastable states' density. 相似文献
300.
Hironori Izawa Yoshiro Kaneko Jun-ichi Kadokawa 《Journal of carbohydrate chemistry》2013,32(4):179-190
In this paper, we describe the apparent production of enzymatically synthesized amylose in DMSO by means of the calcium alginate hydrogel beads/DMSO system as the reaction field of the phosphorylase-catalyzed enzymatic polymerization. When the calcium alginate hydrogel beads including glucose-1-phosphate, maltoheptaose, and phosphorylase were suspended in DMSO and the system was slowly stirred at 40°C for 12 h, the reaction proceeded to produce amylose, which eluted to the DMSO solution. The obtained amylose was purified by the treatment with ion-exchange resins, and its structure was confirmed by the 1H NMR spectrum. The time-course experiment in the present system revealed that the phosphorylase-catalyzed enzymatic polymerization was carried out for 15 min on the inside of the calcium alginate hydrogel beads and the produced amylose was gradually eluted to the surrounding DMSO solution. The comparison of the present system with the general enzymatic polymerization in aqueous buffer solution suggested that the yield and the degree of polymerization of amylose in the present system were comparable to those in aqueous buffer solution. 相似文献