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61.
Recent Progress in the Development of Solid‐State Luminescent o‐Carboranes with Stimuli Responsivity
Junki Ochi Kazuo Tanaka Yoshiki Chujo 《Angewandte Chemie (International ed. in English)》2020,59(25):9841-9855
o‐Carborane, a cluster compound containing boron and adjacent carbon atoms, displays intriguing luminescent properties. Recently, compounds containing o‐carborane units were found to show suppressed aggregation‐induced quenching and intense solid‐state emission; they also show potential for the development of stimuli‐responsive luminochromic materials. In this Minireview, we introduce three kinds of fundamental photochemical properties: aggregation‐induced emission, twisted intramolecular charge transfer in crystals, and environment‐sensitive excimer formation in solids. Based on these properties, several types of luminochromism, such as thermos‐, vapo‐, and mechanochromism, have been discovered. Based mainly on results from recent studies, we illustrate these mechanisms as well as unique luminescent behaviors of o‐carborane derivatives. 相似文献
62.
K. Moritani M. Okada T. Fukuyama Y. Teraoka A. Yoshigoe T. Kasai 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(1):111-115
We report a study on the oxidation process induced by a hyperthermal oxygen
molecular beam (HOMB) on Cu(110) using X-ray photoemission spectroscopy in
conjunction with a synchrotron radiation source. The oxidation process
induced by energetic O2 beams on Cu(110), depending on the azimuthal
angle of incidence, suggests that the –Cu–O– added row structure has a role
in inhibiting adsorption as a steric obstacle for incident O2
molecules. 相似文献
63.
Motohiro Tanaka Kousuke Moritani Tomokazu Hirota Noriaki Toyoda Isao Yamada Norio Inui Kozo Mochiji 《Rapid communications in mass spectrometry : RCM》2010,24(10):1405-1410
A size‐selected argon (Ar) gas‐cluster ion beam (GCIB) was applied to the secondary ion mass spectrometry (SIMS) of a 1,4‐didodecylbenzene (DDB) thin film. The samples were also analyzed by SIMS using an atomic Ar+ ion projectile and X‐ray photoelectron spectroscopy (XPS). Compared with those in the atomic‐Ar+ SIMS spectrum, the fragment species, including siloxane contaminants present on the sample surface, were enhanced several hundred times in the Ar gas‐cluster SIMS spectrum. XPS spectra during beam irradiation indicate that the Ar GCIB sputters contaminants on the surface more effectively than the atomic Ar+ ion beam. These results indicate that a large gas‐cluster projectile can sputter a much shallower volume of organic material than small projectiles, resulting in an extremely surface‐sensitive analysis of organic thin films. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
64.
65.
James P. Kutney Ursula Bunzli-Trepp Toshio Honda Junki Katsube Brian R. Worth 《Helvetica chimica acta》1978,61(5):1554-1564
The general reactivity of various sites in the vindoline series has been investigated. The facility of electrophilic substitution at C(15) and the effect of steric crowding on reactions at C(4) are discussed. At the basic nitrogen sites, oxidations with mercuric acetate and potassium permanganate are also discussed. 相似文献
66.
Sugahara M Moritani Y Kuroda T Kondo K Shimadzu H Ukita T 《Chemical & pharmaceutical bulletin》2000,48(4):589-591
6,7-Diethoxy-1-[1-(2-methoxyethyl)-2-oxo-1,2-dihydropyridin- 4-yl]naphthalene-2,3-dimethanol [T-440, (1)] is a potential anti-asthmatic agent based on selective phosphodiesterase 4 inhibition. It was necessary for the further evaluation of 1 to develop an efficient synthetic route for 1, especially the construction of the 1-(2-methoxyethyl)-2-pyridone moiety. We examined an N-selective alkylation of pyridone derivative (2) in basic media. 2-Methoxyethylation of 2 with 2-methoxyethyl iodide utilizing LiH as the base gave predominantly an N-alkyl pyridone derivative (3a) in 82% yield (N/O-alkylation=92/8), which is compatible with an ab initio calculation of transition-state structures for the methylation of 2-pyridone. Single crystallization of a crude mixture of 3a and 4a furnished pure 3a, which is a key synthetic intermediate of 1. 相似文献
67.
Hiroyoshi Takamura Junki Ando Takeshi Murata Daisuke Uemura 《Tetrahedron letters》2008,49(31):4626-4629
The stereoselective synthesis of the C79-C96 fragment of symbiodinolide is described in which the spiroacetalization and Kotsuki coupling are the key steps. 相似文献
68.
Tomoya Miura Junki Nakahashi Takanori Sasatsu Masahiro Murakami 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1150-1154
The stereoselective synthesis of anti isomers of γ‐boryl‐substituted homoallylic alcohols is disclosed. (E)‐1,2‐Di(boryl)alk‐1‐enes undergo Ru‐catalyzed double‐bond transposition with control of the geometry. The in situ generated (E)‐1,2‐di(boryl)alk‐2‐enes add to aldehydes in a stereospecific manner. The alkenylboron group within the product is amenable to a variety of synthetic derivatizations. 相似文献
69.
70.
Nagakubo J Ashizawa M Kawamoto T Tanioka A Mori T 《Physical chemistry chemical physics : PCCP》2011,13(32):14370-14377
For a material for organic thin-film transistors, not only high mobility but also low threshold voltage and long-term stability are important requirements. In order to realize these properties, materials with relatively large oxidation potentials, namely weak donors, have been designed as p-channel organic semiconductors. Here we propose a different strategy; transistor properties of dibenzotetrathiafulvalene (DBTTF) are significantly improved by the introduction of tert-butyl groups. Although this chemical modification does not much change the ionization potential, small threshold voltage and stability over several months are attained together with the improved mobility, probably due to some kind of passivation effect of the bulky tert-butyl groups. In contrast, the systematic fluorine substitution rapidly diminishes the transistor performance. There are two kinds of herringbone structures with much different dihedral angles of about 50° and 130°, and the tert-butyl compound falls into the former category. 相似文献