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101.
The growth kinetics of self-assembled monolayers (SAMs) of thiophene compounds on Au(111) surfaces was revealed by Fourier-transform
infrared reflection absorption spectroscopy (FT-IR-RAS). Thiophene and terthiophene form well-ordered SAMs on Au(111) surfaces
by immersing gold substrates into their ethanol solutions for ca. 15 h. Gibbs free energies for the adsorption processes of thiophene and terthiophene were found to be identical. However,
the growth and molecular orientation of SAMs are different between two thiophene compounds. Terthiophene in SAMs orients parallel
to the surface. The SAM growth of terthiophene obeys a time-dependent Langmuir scheme. On the other hand, the thiophene SAM undergoes a two-step growth process with unique molecular orientations.
In the primary phase, thiophene assumes a parallel orientation on the Au(111) surface. In the second phase, thiophene is oriented
close to the normal of the surface. The different growth process between thiophene and terthiophene is attributable to the
topology of sulfur positions in the molecules.
Received 23 May 2001 and Received in final form 11 February 2002 相似文献
102.
103.
Jukiya Sakamoto Yuhei Umeda Kenta Rakumitsu Michinori Sumimoto Hayato Ishikawa 《Angewandte Chemie (International ed. in English)》2020,59(32):13414-13422
A collective synthesis of glycosylated monoterpenoid indole alkaloids is reported. A highly diastereoselective Pictet–Spengler reaction with α‐cyanotryptamine and secologanin tetraacetate as substrates, followed by a reductive decyanation reaction, was developed for the synthesis of (?)‐strictosidine, which is an important intermediate in biosynthesis. This two‐step chemical method was established as an alternative to the biosynthetically employed strictosidine synthase. Furthermore, after carrying out chemical and computational studies, a transition state for induction of diastereoselectivity in our newly discovered Pictet–Spengler reaction is proposed. Having achieved the first enantioselective total synthesis of (?)‐strictosidine in just 10 steps, subsequent bioinspired transformations resulted in the concise total syntheses of (?)‐strictosamide, (?)‐neonaucleoside A, (?)‐cymoside, and (?)‐3α‐dihydrocadambine. 相似文献
104.
105.
106.
Rapid Synthesis of D‐A′‐π‐A Dyes through a One‐Pot Three‐Component Suzuki–Miyaura Coupling and an Evaluation of their Photovoltaic Properties for Use in Dye‐Sensitized Solar Cells
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Shunsuke Irie Dr. Shinichiro Fuse Dr. Masato M. Maitani Prof. Yuji Wada Dr. Yuhei Ogomi Prof. Shuzi Hayase Dr. Tatsuo Kaiho Dr. Hisashi Masui Dr. Hiroshi Tanaka Prof. Takashi Takahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(7):2507-2514
Twenty‐four D‐A′–π‐A dyes were rapidly synthesized through a one‐pot three‐component Suzuki–Miyaura coupling reaction, which was assisted by microwave irradiation. We measured the absorption spectra, electrochemical properties, and solar‐cell performance of all the synthesized dyes. The D5 πA4 dye contained our originally designed rigid and nonplanar donor and exerted the highest efficiency at 5.4 %. The short‐circuit current (Jsc) was the most important parameter for the conversion efficiency (η) in the case of the organic D‐A′‐π‐A dyes. Optimal ranges for the D‐A′‐π‐A dyes were observed for high values of Jsc/λmax at λ=560–620 nm, an optical‐absorption edge of λ=690–790 nm, and EHOMO and ELUMO values of <1.14 and ?0.56 to ?0.76 V, respectively. 相似文献
107.
Rapid Synthesis of Thiophene‐Based,Organic Dyes for Dye‐Sensitized Solar Cells (DSSCs) by a One‐Pot,Four‐Component Coupling Approach 下载免费PDF全文
Keisuke Matsumura Soichi Yoshizaki Dr. Masato. M. Maitani Prof. Yuji Wada Dr. Yuhei Ogomi Prof. Shuzi Hayase Dr. Tatsuo Kaiho Dr. Shinichiro Fuse Dr. Hiroshi Tanaka Prof. Takashi Takahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9742-9747
This one‐pot, four‐component coupling approach (Suzuki–Miyaura coupling/C?H direct arylation/Knoevenagel condensation) was developed for the rapid synthesis of thiophene‐based organic dyes for dye‐sensitized solar cells (DSSCs). Seven thiophene‐based, organic dyes of various donor structures with/without the use of a 3,4‐ethylenedioxythiophene (EDOT) moiety were successfully synthesized in good yields based on a readily available thiophene boronic acid pinacol ester scaffold (one‐pot, 3‐step, 35–61 %). Evaluation of the photovoltaic properties of the solar cells that were prepared using the synthesized dyes revealed that the introduction of an EDOT structure beside a cyanoacrylic acid moiety improved the short‐circuit current (Jsc) while decreasing the fill factor (FF). The donor structure significantly influenced the open‐circuit voltage (Voc), the FF, and the power conversion efficiency (PCE). The use of a n‐hexyloxyphenyl amine donor, and our originally developed, rigid, and nonplanar donor, both promoted good cell performance (η=5.2–5.6 %). 相似文献
108.
Rainwater,soil water,and soil nitrate effects on oxygen isotope ratios of nitrous oxide produced in a green tea (Camellia sinensis) field in Japan 下载免费PDF全文
109.
The PdII-catalyzed tandem cyclization of chiral allylic alcohols possessing an internal epoxide and a terminal alcohol provided a contiguous THF–THP and THF–THP ring units stereospecifically. The cyclizations take place via a 5-exo-tet-5-exo-trig mode, however, the cyclization of methyl substituted epoxy diols proceeded via 6-endo-tet-6-exo-trig fashion in a part to construct the oxygen-fused THP–THP ring. The different reaction rates of precursors, which are different stereochemistry at allylic alcohol have been elucidated. 相似文献
110.
Ema T Ura N Eguchi K Ise Y Sakai T 《Chemical communications (Cambridge, England)》2011,47(21):6090-6092
Chiral diporphyrin receptor 1, which has a macrocyclic cavity to sandwich aromatic guest molecules via double π-π stacking interactions, enabled the naked-eye detection of an aromatic explosive as well as chiral discrimination in NMR. 相似文献