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31.
Toshihide Taniguchi Mitsutaka Imoto Motonori Takeda Takeo Nakai Masatoshi Mihara Toshiyuki Iwai Takatoshi Ito Takumi Mizuno Akihiro Nomoto Akiya Ogawa 《Heteroatom Chemistry》2015,26(6):411-416
A new method for the hydrolysis of diazonium salts, without the formation of tar, was developed. A two‐phase system consisting of cyclopentyl methyl ether (CPME) and water is very effective for the hydrolysis of diazonium salts. Using this solvent system, the diazonium salt prepared from 3‐(4‐nitrophenoxy)aniline gave 3‐(4‐nitrophenoxy)phenol in high yield (96%) within 20 min. The synthesized phenol is an industrially important raw material in polymer syntheses. Furthermore, the use of the present two‐phase system of CPME and water successfully brought about the efficient conversions of several m‐substituted anilines into the corresponding m‐substituted phenols. This is the first example of hydrolysis of diazonium salts using the two‐phase system (CPME and water). 相似文献
32.
Fujitsuka M Tojo S Shibahara M Watanabe M Shinmyozu T Majima T 《The journal of physical chemistry. A》2011,115(5):741-746
In the present study, delocalization of a positive charge in π-stacked multi-benzene rings in multilayered para- and meta-cyclophanes, in which benzene rings are connected by propyl chains to form a chromophore array with the face-to-face structure, was investigated by means of transient absorption spectroscopy during the pulse radiolysis using dichloroethane as a solvent. The local excitation and charge resonance (CR) bands were successfully observed. It was revealed that the CR band shifted to the longer wavelength side with the number of the benzene rings. The stabilization energy estimated from the peak position of the CR band showed the efficient charge delocalization over the cyclophanes. Furthermore, the CR bands showed the slight spectral change attributable to the change in distribution of the conformers. The substantially long lifetime of the CR band can be explained on the basis of the smaller charge distribution on the outer layers of the multilayered cyclophanes. 相似文献
33.
Prof. Dr. Motonori Watanabe Yuka Ono Prof. Dr. Tatsumi Ishihara Prof. Dr. Yuan Jay Chang Prof. Dr. Masahiko Shibahara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202200790
Novel donor–acceptor dyads containing [2.2]- and [3.3]paracyclophane (PCP) as the bridging moiety were synthesized and used to effectively fabricate dye-sensitized hydrogen production systems. All the prepared compounds had a phenothiazine and a cyanoacrylic acid/pyridinyl acrylonitrile moiety acting as an electron donor and acceptor, respectively. Although cyclic voltammetry measurements showed similar electron-donating properties among all the synthesized dyads, the lowest absorption energy of the [2.2]PCP moiety was lower than that of the [3.3]PCP one; this was due to its shorter distance between benzene rings, which could effectively drive the charge transfer between the donor and acceptor chromophores. Under visible light (>395 nm), a dyad-loaded photocatalyst in a 0.5 M aqueous glycerol solution generated detectable hydrogen gases. The optimal turnover number and photocurrent order exhibited the same trend as the hydrogen production rate since the suggested number of excited photons played a critical role in hydrogen production. 相似文献
34.
Dr. Takaaki Miyazaki Prof. Dr. Motonori Watanabe Prof. Dr. Toshinori Matsushima Dr. Ching-Ting Chien Prof. Dr. Chihaya Adachi Prof. Dr. Shih-Sheng Sun Prof. Dr. Hiroyuki Furuta Prof. Dr. Tahsin J. Chow 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(41):10677-10684
Heptacene ( 1 ) has been produced via a monoketone precursor, 2 , which was prepared from 1,2,4,5-tetrabromobenzene in nine steps in a total yield of 10 %. Compound 2 was converted to 1 quantitatively by heating at 202 °C. Heptacene exhibited high thermal stability in the solid state without any observable change over two months. To investigate the potential value of 1 as a material for p-type organic field-effect transistors (OFETs), top-contact OFET devices were fabricated by vacuum deposition of 1 onto a hexamethyldisilazane (HMDS)/SiO2/Si substrate. The best hole mobility performance was 2.2 cm2 V−1 s−1. This is the first report of stable heptacene being used in an effective device and examined for its charge carrier properties. 相似文献
35.
Toshiaki Shimasaki Shunsuke Okajima Rino Ishikawa Shinji Kawaguchi Takeshi Akimoto Naoto Asano Tetsuo Iwanaga Motonori Watanabe Naozumi Teramoto Mitsuhiro Shibata 《Tetrahedron》2018,74(20):2454-2465
Fully conjugated macrocycles 1a?1c composed of m-diethynylene-phenylene-bridged two dibenzofuran, dibenzothiophene and carbazole units were synthesized via Sonogashira cross coupling reactions under high-diluted condition. These conjugated macrocycles were fully characterized by 1H NMR, 13C NMR, FT-IR, Mass spectroscopies and elemental analysis. Photophysical and redox properties of 1a?1c were investigated by means of UV–vis/fluorescence spectroscopies and cyclic voltammetry, respectively, and those features were compared with those of the corresponding linear phenylethynyldibenzoheterols 11a?11c. Furthermore, their structural and electronic insights were studied by theoretical calculations at the B3LYP/cc-pVDZ//B3LYP/6-31G(d) level of theory. 相似文献
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37.
Uwe Witt Motonori Yamamoto Ursula Seeliger Rolf-Joachim Müller Volker Warzelhan 《Angewandte Chemie (International ed. in English)》1999,38(10):1438-1442
It is completely plausible that unmodified materials of natural origin, such as the native macromolecules cellulose or starch, are biodegradable. If these materials are modified then degradation may, depending on the degree of modification, be more difficult or even impossible. In the same manner synthesized macromolecules, whether from renewable or petrochemical sources, could be inert or completey biodegradable, depending on their chemical structure. 相似文献
38.
Dr. Yuan Jay Chang Po‐Ting Chou Szu‐Yu Lin Dr. Motonori Watanabe Zhi‐Qian Liu Ju‐Ling Lin Prof. Dr. Kew‐Yu Chen Prof. Dr. Shih‐Sheng Sun Prof. Dr. Ching‐Yang Liu Prof. Dr. Tahsin J. Chow 《化学:亚洲杂志》2012,7(3):572-581
A series of organic dyes were prepared that displayed remarkable solar‐to‐energy conversion efficiencies in dye‐sensitized solar cells (DSSCs). These dyes are composed of a 4‐tert‐butylphenylamine donor group (D), a cyanoacrylic‐acid acceptor group (A), and a phenylene‐thiophene‐phenylene (PSP) spacer group, forming a D‐π‐A system. A dye containing a bulky tert‐butylphenylene‐substituted carbazole (CB) donor group showed the highest performance, with an overall conversion efficiency of 6.70 %. The performance of the device was correlated to the structural features of the donor groups; that is, the presence of a tert‐butyl group can not only enhance the electron‐donating ability of the donor, but can also suppress intermolecular aggregation. A typical device made with the CB‐PSP dye afforded a maximum photon‐to‐current conversion efficiency (IPCE) of 80 % in the region 400–480 nm, a short‐circuit photocurrent density Jsc=14.63 mA cm?2, an open‐circuit photovoltage Voc=0.685 V, and a fill factor FF=0.67. When chenodeoxycholic acid (CDCA) was used as a co‐absorbent, the open‐circuit voltage of CB‐PSP was elevated significantly, yet the overall performance decreased by 16–18 %. This result indicated that the presence of 4‐tert‐butylphenyl substituents can effectively inhibit self‐aggregation, even without CDCA. 相似文献
39.
Motonori Watanabe Ting-Han Chao Ching-Ting Chien Shun-Wei Liu Yuan Jay Chang Kew-Yu Chen Tahsin J. Chow 《Tetrahedron letters》2012,53(18):2284-2287
2-Chlorotetracene and 2-bromotetracene were generated in high purity from their monoketone precursors either by heating or upon irradiation of light. Crystals of two compounds were prepared by physical vapor transport method. Organic field effect transistors made with the single crystals of these two compounds were fabricated effectively. Their p-type transistor characteristics are described. 相似文献