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31.
32.
Synthesis,Characterization, and Electronic Structures of Porphyrins Fused with Polycyclic Aromatic Ring Systems 下载免费PDF全文
Prof. Dr. Tetsuo Okujima Dr. John Mack Dr. Jun Nakamura Gugu Kubheka Prof. Dr. Tebello Nyokong Dr. Hua Zhu Naoki Komobuchi Prof. Dr. Noboru Ono Prof. Dr. Hiroko Yamada Prof. Dr. Hidemitsu Uno Prof. Dr. Nagao Kobayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14730-14738
A series of porphyrins fused with acenaphthylene, phenanthroline, and benzofluoranthene polycyclic aromatic rings were prepared by means of a 3+1 porphyrin synthesis approach and subsequent retro‐Diels–Alder reaction of bicyclo[2.2.2]octadiene‐fused precursors. Analysis of the magnetic circular dichroism spectra and the results of time‐dependent DFT calculations are used to identify the reasons for the trends observed in the wavelengths and relative intensities of the Q bands of the products. Michl's perimeter model is used as a conceptual framework to explain the changes in the relative energies of the frontier π‐molecular orbitals. 相似文献
33.
Self‐Assembled Fibers Containing Stable Organic Radical Moieties: Alignment and Magnetic Properties in Liquid Crystals 下载免费PDF全文
Hiroki Eimura Yoshikazu Umeta Prof. Dr. Hiroko Tokoro Prof. Dr. Masafumi Yoshio Prof. Dr. Shin‐ichi Ohkoshi Prof. Dr. Takashi Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8872-8878
Macroscopically oriented stable organic radicals have been obtained by using a liquid–crystalline (LC) gel composed of an l ‐isoleucine‐based low molecular weight gelator containing a 2,2,6,6‐tetramethylpiperidine 1‐oxyl moiety. The LC gel has allowed magnetic measurements of the oriented organic radical. The gelator has formed fibrous aggregates in liquid crystals via intermolecular hydrogen bonds. The fibrous aggregates of the radical gelator are formed and oriented on cooling by applying a magnetic field to the mixture of liquid crystals and the gelator. Superconducting quantum interference device (SQUID) measurements have revealed that both oriented and nonoriented fibrous aggregates exhibited antiferromagnetic interactions, in which super‐exchange interaction constant J is estimated as ?0.89 cm?1. 相似文献
34.
Nobutaka Yamaoka Kohei Sumida Itsuki Itani Hiroko Kubo Yusuke Ohnishi Sho Sekiguchi Dr. Toshifumi Dohi Prof. Dr. Yasuyuki Kita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(44):15004-15011
Metal‐free oxidative C? C coupling by using polyalkoxybenzene‐derived diaryliodonium(III) salts as both the oxidant and aryl source has been developed. These salts can induce single‐electron‐transfer (SET) oxidation to yield electron‐rich arenes and subsequently transfer the polyalkoxyphenyl group into in situ generated aromatic radical cations to produce biaryl products. The reaction is promoted by a Lewis acid that activates the iodonium salts. It has been revealed that the reactivity of the salts under acidic conditions is quite different to their known behavior under basic conditions. The reactivity preference of a series of iodonium salts in the SET oxidation and their ligand transfer abilities have been systematically investigated and the results are summarized in this report. 相似文献
35.
Suzuki T Arai K Goto H Hanano M Watanabe J Tomono K 《Chemical & pharmaceutical bulletin》2002,50(6):741-743
Nifedipine-containing calcium phosphate cement (CPC) was prepared, and nifedipine (NF) release from this preparation was evaluated by the shaking method (SK), Japanese Pharmacopoeia XIV (JPXIV) paddle method (PD), and JPXIV flow-through cell method (FT). The release of NF from the CPC preparation continued for 7 d or longer by all these methods. This suggests that the release of NF can be controlled by preparing NF-containing CPC. The release pattern of NF from CPC in these tests was found to follow the Higuchi equation. However, the Higuchi constant differed among the three dissolution tests, probably because the apparent tortuosity of capillary system (tau) varied. 相似文献
36.
37.
Ikeda S Sanuki R Miyachi H Miyashita H Taniguchi M Odashima K 《Journal of the American Chemical Society》2004,126(33):10331-10338
A Ni(0)/ZnCl(2) system effectively promotes the coupling of enones and alkene-tethered alkynes. In the reaction with 1,6-enynes, the oxidative cyclization of Ni(0) species on enones across the alkyne part followed by ZnCl(2)-promoted cleavage generates alkenylnickel intermediates. Subsequent migratory insertion of the tethered alkene occurs with 5-exo-cyclization. When the resulting sigma-alkylnickel intermediates have beta-hydrogen atoms, the reaction terminates by beta-hydrogen elimination to provide cyclopentane derivatives. On the other hand, a sigma-alkylnickel intermediate that does not have beta-hydrogen atoms undergoes the insertion of a second alkene unit to cause a domino effect via a three-fold C-C bond formation process with and without the cleavage of one C-C bond. 相似文献
38.
Machida K Takehara E Kobayashi H Kikuchi M 《Chemical & pharmaceutical bulletin》2003,51(12):1417-1419
Two new iridoid glycosides, 7 beta,8 beta-epoxy-8 alpha-dihydrogeniposide (1) and 8-epiapodantheroside (2), were isolated, together with six known (3-8) and three artifact (9-11) iridoids, from the leaves of Gardenia jasminoides cv. fortuneana Hara. Their structures were established based on chemical and spectral data. 相似文献
39.
Nishizawa M Yadav VK Skwarczynski M Takao H Imagawa H Sugihara T 《Organic letters》2003,5(10):1609-1611
[reaction: see text] Hg(OTf)(2) exhibits remarkable catalytic activity for the hydroxylative cyclization of 1,6-enynes. The present procedure should involve a sequence of mercuration of a terminal alkyne, carbocyclization, hydration, and protodemercuration that regenerates the catalyst. 相似文献