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31.
Suetsuna T Dragoe N Harneit W Weidinger A Shimotani H Ito S Takagi H Kitazawa K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(22):5079-5083
We describe the HPLC separation and identification of N@C60 and N2@C60. These species were observed after eleven sequential HPLC separations. Their retention times are in the same range as those of the other noninteractive endohedral species of C60, such as noble gas endohedral C60. The separation factors of these endohedrals were evaluated by using a mixture of hexane/toluene as eluent. We note that this is the first evidence for the N2@C60 molecule existing in the form of endohedral C60 complex. 相似文献
32.
Remarkable effect of pore size on the catalytic activity of mesoporous silica for the acetalization of cyclohexanone with methanol 总被引:2,自引:0,他引:2
Iwamoto M Tanaka Y Sawamura N Namba S 《Journal of the American Chemical Society》2003,125(43):13032-13033
The catalytic activity of mesoporous silica (MCM-41) for the acetalization of cyclohexanone shows a volcano-shaped dependence on the pore diameter. The diameter of the cyclohexanone molecule is ca. 0.75 nm, while its acetalization with methanol was well accelerated on MCM-41 with a pore diameter of approximately 1.9 nm, and smaller or larger pores were not suitable for the catalysis. The catalytic activity was independent of the Al concentration. 相似文献
33.
Hiroko Tani Shunya Takahashi Keiko Hasumi Tomoki Tatefuji Yayoi Hongo Hiroyuki Koshino 《Tetrahedron: Asymmetry》2009,20(4):457-460
(E)-9,10-Dihydroxy-2-decenoic acid 1 was isolated as a new compound from royal jelly. The planar structure was deduced by spectroscopic analyses, whereas the absolute configuration was established by chemical synthesis of both enantiomers of 1. The natural product was revealed to be ca. 3.5:1 mixture of (R)- and (S)-acids by comparison of 1 with authentic samples. 相似文献
34.
Quenching of exciton luminescence caused by coloration with u.v.-irradiation in KI and KI:Tl has been studied. Reduction in the luminescence intensity by coloration is found to depend on the coloration temperature as well as on the concentration of Tl+ ions. Evidences are shown that the defects with which excitons interact are vacancies and V-centers. 相似文献
35.
Shojiro Kimura Hitoshi Ohta Mitsuhiro Motokawa Seitaro Mitsudo Wen-Jye Jang Masahi Hasegawa Humihiko Takei 《International Journal of Infrared and Millimeter Waves》1996,17(5):833-841
Submillimeter wave ESR system in Kobe University is presented. It covers the frequency region from 60 to 383GHz and can apply the pulsed magnetic field up to 30T. The measurement of Y2Cu2O5 single crystals using our system is presented. 相似文献
36.
37.
Koshino K 《Physical review letters》2007,98(22):223902
In order to investigate the nonlinear dynamics of photons, one must in principle solve a quantum many-particle problem, which usually requires intensive computation. In this study, we show that the spatial wave function of photons after nonlinear interaction can be obtained with less computation by assuming a classical input pulse and calculating a correlation function in the output field. This method is particularly useful when nonlinear optical media have many mechanical degrees of freedom, where quantum many-particle problems become extremely difficult. 相似文献
38.
Yuko Izuchi Nobuhiro KanomataHiroyuki Koshino Yayoi HongoTadashi Nakata Shunya Takahashi 《Tetrahedron: Asymmetry》2011,22(2):246-251
The formal total synthesis of aspergillide A 1 is described. The cross-metathesis of enone 6 with 6-hepten-2-ol derivative 5 provided E-olefin 15 corresponding to the C4-C14 backbone of 1. The CBS asymmetric reduction of 15 gave allyl alcohol 16, which was transformed into β-alkoxyacrylate 4 which had a formyl group. SmI2-induced reductive cyclization of 4 gave a 2,6-syn-2,3-trans THP derivative 3 in good yield. After methoxymethylation of 3, the resulting compound 19 was submitted to desilylation and hydrolysis, to afford Fuwa’s key intermediate 2 for the total synthesis of 1. 相似文献
39.
Structural revision of the cell-adhesion inhibitory eremophilane sesquiterpenoid peribysins C and D is reported. A CAST/CNMR system is utilized in the reinvestigation of 13C NMR chemical shift values and structures, and geometric analyses with molecular and quantum mechanics calculations, and revalidation of NMR data support the revised structures. 相似文献
40.
The first total syntheses of acetogenin 3 and its 4 S,8 R-isomer are described. The key step involves intermolecular metathesis of an alpha,beta-unsaturated ketone carrying a tetrahydropyranyl lactone with a tetrahydrofuran derivative. Compound 3 has spectroscopic and physical data consistent with those of natural montanacin D, suggesting that the absolute configuration of the natural product is as shown in 3. 相似文献