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排序方式: 共有139条查询结果,搜索用时 15 毫秒
1.
2.
Masami Sakamoto Kazuya Yoshiwara Fumitoshi Yagishita Wataru Yoshida Takashi Mino Tsutomu Fujita 《Research on Chemical Intermediates》2013,39(1):385-395
The irradiation of methyl 2- and 3-chromonecarboxylate in the presence of various alkenes afforded cyclobutane type adducts, whose structures were established by X-ray structural analysis. Methyl 2-chromonecarboxylate showed higher photochemical reactivity than methyl 3-chromonecarboxylate, in which endo adducts were yielded as major products. 相似文献
3.
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
4.
Sonoko Kikuchi Kazuteru Kawauchi Sadatsugu Ooki Masaru Kurosawa Hisashi Honjho Teruo Yagishita 《Analytical sciences》2004,20(8):1111-1112
Using Raman spectroscopy without any preparation, we analyzed the brominated flame retardant, polybromodiphenyl ethers (PBDEs), which has been prohibited by the European Union. The typical Raman bands of PBDEs, which are clearly different from those of other brominated flame retardants, are from 100 to 300 cm(-1). In our analysis, the detection limit was about 100 ppm, and the analysis took about 1 min, whereas the usual method of solvent extraction using gas chromatography/mass spectroscopy takes 50 h. 相似文献
5.
We investigated the electronic structure of low-lying electronic states of Mn2 using a newly developed relativistic model core potential (spdsMCP). Calculations were performed at complete active space self-consistent field (CASSCF) and second-order multiconfiguration quasidegenerate perturbation theory (MCQDPT2) levels. The MCQDPT2 calculations reveal that the 1Σg+ state is the ground state. Calculated spectroscopic constants are very similar to the results of recent all-electron calculations and experimental values, indicating that the spdsMCP works well for Mn2, which requires a highly correlated calculation. The wave functions of low-lying states are also analyzed at the CASSCF level. 相似文献
6.
Electronic energy levels of naphthalene were calculated by semi-empirical ASMO-CI method including a part of doubly excited configurations as well as all singly excited configurations. The result obtained seems to indicate that with respect to the amount of the mixing of CI to be invoked it is sufficient to take into account all singly excited configurations only.The interpretation of spectra was also discussed.
One of us (H. I.) wishes to express his thanks to Professor K. Suzuki for encouragement throughout this work. 相似文献
Zusammenfassung Die Energieniveaus der Elektronen im Naphthalin-Molekül wurden mittels einer halbempirischen ASMO-CI-Methode unter Einschluß einer Reihe von einfach und doppelt angeregten Zuständen berechnet. Dabei zeigt sich, daß es wahrscheinlich genügt, nur einfach angeregte Zustände in die Rechnung einzubeziehen.
Résumé Les états énergétiques du naphthaléne ont été calculés par une méthode ASMO-CI semiempirique où une partie des configurations diexcitées et toutes les configurations monoexcitées ont été inclues. Le résultat indique qu'il suffit de ne tenir compte que des configurations monoexcitées. Les spectres sont discutés.
One of us (H. I.) wishes to express his thanks to Professor K. Suzuki for encouragement throughout this work. 相似文献
7.
Satoru Nakashima Yuichi Masuda Izumi Motoyama Hirotoshi Sano 《Hyperfine Interactions》1988,40(1-4):319-322
It was found that the packing of cations and anions influences the electronic structures of mixed-valence binuclear ferrocene derivatives. Temperature-dependence of the mixed-valence state of 11, 1111-diisobutylbiferrocenium triiodide was observed in a crystalline state, whereas only a trapped-valence state was found in a dispersed state. The packing effect was also observed for a series of 11, 1111-dialkyl- and 11, 1111-bis(methylbenzyl)biferrocenium triiodides by means of ESR spectroscopy. 相似文献
8.
In 1′, 1‴-dibutylbiferrocenium triiodide crystals A show temperature-independent trapped-valence state, while crystals B show
a valence-delocalization of the mixed-valence state. The mixed-valence states of both crystals are discussed in relation to
their crystal structures.
Address after October 1991: Department of Chemistry, Faculty of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima
724, Japan 相似文献
9.
利用软X射线共振非弹性散射谱(resonant inelastic soft X-ray scattering, RIXS)对3d过渡金属硫化物中的硫化锰(MnS)电子结构进行了研究.通过分析Mn2+的2p63d5→2p53d6→2p63d5二次光子过程,得到了共振非弹性散射谱中的两类非弹性峰,d-d电子跃迁和电荷转移(charge-transfer)跃迁.这两部分跃迁分别共振增强于L边附近及伴随峰附近.基于Hartree-Fock方法的多重态计算分别模拟了原子近似下和立方体Oh对称群下共振非弹性散射谱及吸收谱.计算得MnS实际晶体场10Dq值介于0.80eV—0.85eV之间.对MnS和MnO CT跃迁差异的讨论表明MnS较强的CT跃迁来源于其较窄的能隙宽度.
关键词:
软X射线共振非弹性散射
软X射线吸收谱
d-d跃迁
电荷转移 相似文献
10.
The electronic structure of the proflavine cation is studied by the SCF –ASMO –CI method using the Pariser–Parr–Pople approximations. It is shown that the band at 445 mμ may be assigned to the 1A1 → 1B1, transition polarized along the long axis of the molecule. The bands in the neighbourhood of 260 mμ, which are composed of three absorption bands, are tentatively assigned to the 1A1 → 1B1, 1A1 → 1B1, and 1A1 → 1A1 transitions, respectively, in order of decreasing wavelength. The spectrum of the acridine orange cation may be understood to have the same assignment as that of the proflavine cation. The acridine dye cations are well known for their dimerization with concentration. The intermolecular distances in these dimers are estimated from the band shifts due to the formation of dimers, using the exciton theory. The main contribution to the molecular interaction is shown to be the electrostatic dipole–dipole interaction. Since the first excitation band of the dye molecule which exhibits a remarkable change due to the formation of the DNA–acridine dye complex, is suggested to be polarized along the long axis, preference of the outside stacking or the intercalation model is qualitatively discussed from the spectral shift of the acridine dye bound to the DNA, assuming simple models. 相似文献