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排序方式: 共有121条查询结果,搜索用时 31 毫秒
1.
In situ scanning tunneling microscopy (STM) was used to examine the structure of thiocyanate adlayers specifically adsorbed
on Rh(111) in solutions of potassium hydroxide and perchloric acid, both containing potassium thiocyanate (KSCN). An atomically
flat terrace-step structure was consistently observed on Rh(111) surfaces prepared by the flame-annealing-quenching method.
The Rh(111)-(1 × 1) atomic structure was discerned on the atomically flat terrace even in the alkaline solution. High-resolution
STM images disclosed two different structures of the SCN− adlayers, () and (2 × 2), in the alkaline and the acidic media, respectively. In each structure, an individual adsorbed SCN− ion appeared as a single spot with a constant corrugation height in STM images, suggesting that SCN− ions adsorbed predominantly with their
S-ends at particular bonding sites on Rh(111). The difference in the adlayer structure in the two solutions can be attributed
to the interaction between adsorbed SCN− and coadsorbed K+ in the alkaline solution, and is different from that between adsorbed SCN− and H+ in the acidic solution.
Received: 26 February 1997 / Accepted: 3 March 1997 相似文献
2.
By immersing Au substrate into a benzene solution containing both cobalt(II) phthalocyanine (CoPc) and copper(II) tetraphenyl-21H,23H-porphine (CuTPP), a two-dimensional alternate bimolecular structure was formed on the reconstructed Au(100)-(hex) surface. 相似文献
3.
Yoshimoto S Honda Y Murata Y Murata M Komatsu K Ito O Itaya K 《The journal of physical chemistry. B》2005,109(18):8547-8550
Adlayers of ZnOEP were prepared on reconstructed Au(100)-(hex) and unreconstructed Au(100)-(1 x 1) surfaces by immersing into a benzene solution containing ZnOEP molecules, and the adlayer structures were characterized by scanning tunneling microscopy (STM). A hexagonally arranged ZnOEP array was formed on an Au(100)-(hex) surface, whereas a rectangularly arranged ZnOEP array was found on an Au(100)-(1 x 1) surface. The adlayer structure of ZnOEP was dependent upon the underlying Au atomic arrangements. Furthermore, an investigation of the spuramolecular assembly for these modified surfaces was carried out by using an open-cage C(60) derivative (opened C(60)). A supramolecular assembled adlayer with a 1:1 composition of opened C(60)/ZnOEP was formed on Au(100)-(hex), whereas aggregates of opened C(60) were found on the ZnOEP-modified Au(100)-(1 x 1) surface. Electrochemical responses of opened C(60) were significantly influenced by underlying ZnOEP arrays. This finding suggests that precise control of underlying ZnOEP adlayers with the Au atomic structure is important to recognize the opened C(60) on them. 相似文献
4.
Uchida K Saito M Murakami A Kobayashi T Nakamura S Irie M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(2):534-542
A photochromic polymer film containing three different diarylethene derivatives, that is, 1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene (1), 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene (2), and 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene (3) was prepared. Upon UV irradiation, the three derivatives changed to their closed-ring isomers having different colors, yellow, red, and blue. They showed different spectra not only in UV/Vis region but also in the IR spectral region. Upon irradiation with visible light of appropriate wavelengths, each closed-ring isomer was selectively bleached, and three bits eight states recording was performed. The eight states could be read out nondestructively by using IR light of appropriate wavenumbers. 相似文献
5.
Mizuno A Inomata N Miya M Kamei T Shibata M Tatsuoka T Yoshida M Takiguchi C Miyazaki T 《Chemical & pharmaceutical bulletin》1999,47(2):246-256
A series of 1-aminoalkyl-pyrrolo[2,3-c]azepin-8-one derivatives was synthesized and evaluated as alpha 1 adrenergic and serotonin 2 (5-HT2) receptor antagonists, with the aim of finding a novel antihypertensive agent potently exhibiting both activities. Some compounds with a 4-[4-(4-fluorobenzoyl)piperidino]butyl group at the 1-position exhibited both activities, and varied significantly in terms of the substituents at the 4-position of the pyrroloazepine ring. Among the compounds obtained in this study, (E)-1-[4-[4-(4-fluorobenzoyl)piperidino]-butyl]-4-hydroxyimino-7- methyl-1,4,5,6,7,8-hexahydropyrrolo[2,3-c]azepin-8-one (15a, SUN9221) displayed potent alpha 1-adrenergic antagonistic activity (pA2 = 8.89 +/- 0.21) and 5-HT2 antagonistic activity (pA2 = 8.74 +/- 0.22) in isolated guinea pig arteries. This compound exhibited antihypertensive activity and a duration of action equivalent to orally administered prazosin or doxazosin, 3 mg/kg, in conscious spontaneously hypertensive rats, as well as potent antiplatelet aggregation activity. 相似文献
6.
Homoleptic cyclometalated iridium complexes with highly efficient red phosphorescence and application to organic light-emitting diode 总被引:7,自引:0,他引:7
Tsuboyama A Iwawaki H Furugori M Mukaide T Kamatani J Igawa S Moriyama T Miura S Takiguchi T Okada S Hoshino M Ueno K 《Journal of the American Chemical Society》2003,125(42):12971-12979
Phosphorescence studies of a series of facial homoleptic cyclometalated iridium(III) complexes have been carried out. The complexes studied have the general structure Ir(III)(C-N)(3), where (C-N) is a monoanionic cyclometalating ligand: 2-(5-methylthiophen-2-yl)pyridinato, 2-(thiophen-2-yl)-5-trifluoromethylpyridinato, 2,5-di(thiophen-2-yl)pyridinato, 2,5-di(5-methylthiophen-2-yl)pyridinato, 2-(benzo[b]thiophen-2-yl)pyridinato, 2-(9,9-dimethyl-9H-fluoren-2-yl)pyridinato, 1-phenylisoquinolinato, 1-(thiophen-2-yl)isoquinolinato, or 1-(9,9-dimethyl-9H-fluoren-2-yl)isoquinolinato. Luminescence properties of all the complexes at 298 K in toluene are as follows: quantum yields of phosphorescence Phi(p) = 0.08-0.29, emission peaks lambda(max) = 558-652 nm, and emission lifetimes tau = 0.74-4.7 micros. Bathochromic shifts of the Ir(thpy)(3) family [the complexes with 2-(thiophen-2-yl)pyridine derivatives] are observed by introducing appropriate substituents, e.g., methyl, trifluoromethyl, or thiophen-2-yl. However, Phi(p) of the red emissive complexes (lambda(max) > 600 nm) becomes small, caused by a significant decrease of the radiative rate constant, k(r). In contrast, the complexes with the 1-arylisoquinoline ligands are found to have marked red shifts of lambda(max) and very high Phi(p) (0.19-0.26). These complexes are found to possess dominantly (3)MLCT (metal-to-ligand charge transfer) excited states and have k(r) values approximately 1 order of magnitude larger than those of the Ir(thpy)(3) family. An organic light-emitting diode (OLED) device that uses Ir(1-phenylisoquinolinato)(3) as a phosphorescent dopant produces very high efficiency (external quantum efficiency eta(ex) = 10.3% and power efficiency 8.0 lm/W at 100 cd/m(2)) and pure-red emission with 1931 CIE (Commission Internationale de L'Eclairage) chromaticity coordinates (x = 0.68, y = 0.32). 相似文献
7.
8.
Dr. Yohei Hattori Tatsuya Maejima Yumi Sawae Jun-ichiro Kitai Prof. Masakazu Morimoto Dr. Ryojun Toyoda Prof. Hiroshi Nishihara Prof. Satoshi Yokojima Dr. Shinichiro Nakamura Prof. Kingo Uchida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(50):11441-11450
The cyclization reaction of diarylethenes having an azulene ring occurs only via higher excited states. Novel diarylethenes having an azulene ring with a strong donor or acceptor were synthesized and examined in these reactions. A derivative having an electron-donating 1,3-benzodithiol-2-ylidenemethyl group at the 1-position of the azulene ring showed photochromism, whereas neither a derivative having a π-conjugated electron-donating group at the 3-position of the azulene ring nor derivatives having a π-conjugated electron-withdrawing group at the 1- or 3-position of the azulene ring showed any photochromism. The photoreactivities of these compounds were explained by calculating forces and bond orders on the excited states using density functional theory (DFT) and time-dependent (TD)-DFT. 相似文献
9.
Hiroshi Takikawa Arata Nishii Hiromu Takiguchi Hirotoshi Yagishita Masato Tanaka Keiichi Hirano Masanobu Uchiyama Ken Ohmori Keisuke Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(30):12440-12444
An intramolecular benzyne–phenolate [4+2] cycloaddition is reported. Benzyne precursors, having vicinal halogen‐sulfonate functionalities, linked with a phenol(ate) by various tether groups undergo efficient intramolecular [4+2] cycloaddition by treatment with either Ph3MgLi or nBuLi for halogen–metal exchange to form various benzobarrelenes. 相似文献
10.
Okada S Okinaka K Iwawaki H Furugori M Hashimoto M Mukaide T Kamatani J Igawa S Tsuboyama A Takiguchi T Ueno K 《Dalton transactions (Cambridge, England : 2003)》2005,(9):1583-1590
This study reports substituent effects of iridium complexes with 1-phenylisoquinoline ligands. The emission spectra and phosphorescence quantum yields of the complexes differ from that of tris(1-phenylisoquinolinato-C2,N)iridium(iii)(Irpiq) depending on the substituents. The maximum emission peak, quantum yield and lifetime of those complexes ranged from 598-635 nm, 0.17-0.32 and 1.07-2.34 micros, respectively. This indicates the nature of the substituents has a significant influence on the kinetics of the excited-state decay. The substituents attached to phenyl ring have an influence on a stability of the HOMO. Furthermore, those substituents have effect on the contribution to a mixing between 3pi-pi* and (3)MLCT for the lowest excited states. Some of the complexes display the larger quantum yield than Irpiq, which has the quantum yield of 0.22. The organic light emitting diode (OLED) device based on tris [1-(4-fluoro-5-methylphenyl)isoquinolinato-C2,N]iridium(iii)(Ir4F5Mpiq) yielded high external quantum efficiency of 15.5% and a power efficiency of 12.4 lm W(-1) at a luminance of 218 cd m(-2). An emission color of the device was close to an NTSC specification with CIE chromaticity characteristics of (0.66, 0.34). 相似文献