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31.
Photolysis of acyclic monothioimides gave β-lactams and thioamides via Type II reaction involving γ-hydrogen abstraction by thiocarbonyl group. 相似文献
32.
The CNDO/2 and INDO calculations were performed on s-triazine and s-tetrazine. The s-triazine has three lone-pairs in a molecule, and these can be combined into three combinations, A, ns and nA. Among the three, ns and nA are degenerated when the whole interaction conserves its molecular point symmetry, D3h. The s-tetrazine has four lone-pairs, which can be transformed into four combinations, SS,SA, AS and AA. The energies of these orbitals show interesting behavior. The results were subjected to an analysis from the standpoint of the through-space and through-bond interactions using the localized molecular orbitals. As a result of these analyses, the interactions were expressed by several interaction terms. 相似文献
33.
Shin-ya K Sugeta H Shin S Hamada Y Katsumoto Y Ohno K 《The journal of physical chemistry. A》2007,111(35):8598-8605
The absolute configuration and conformation of 1-phenylethanol (1-PhEtOH) have been determined by matrix-isolation infrared (IR) and vibrational circular dichroism (VCD) spectroscopy combined with quantum chemical calculations. Quantum chemical calculations have identified that there are three conformers, namely, I, II, and III, in which characteristic intramolecular interactions are found. The IR spectrum-conformation correlation for 1-PhEtOH has been developed by the Ar matrix-isolation IR measurement and used for the assignments of the observed IR bands. In a dilute CCl(4) solution, 1-PhEtOH exists predominantly as conformer I along with a trace amount of conformer II. By considering conformations and intermolecular hydrogen-bonding in the spectral simulation for (S)-1-PhEtOH, we have successfully reproduced the VCD spectrum of (-)-1-PhEtOH observed in a dilute CS(2) solution. Thus, (-)-1-PhEtOH is of S-configuration and conformer I in the dilute solution. The same method has been applied to analyze the VCD spectra measured in the liquid state of (-)-1-PhEtOH. The absolute configuration of 1-PhEtOH in the condensed phase is enabled by identifying VCD bands that are insensitive to conformational changes and intermolecular interactions. The present work provides a combinatorial procedure for determination of both the absolute configuration and the conformation of chiral molecules in a dilute solution and condensed phase. 相似文献
34.
Shigeru Arimoto Kenichi Fukui Hiromu Ohno Keith F. Taylor Paul G. Mezey 《International journal of quantum chemistry》1997,63(1):149-163
By extending the methodology given in Parts I and II of this series of articles, certain dynamical systems of chemical kinetic equations are analyzed in the setting of the Banach algebra B(ℬ︁) of all bounded operators acting on a Banach space ℬ︁. In this article, we proceed from the general setting of B(ℬ︁), which played a central role in Part II, toward its specific application to the dynamical systems. In our analysis, crucial initial steps are taken by (i) equipping the abstract space ℬ︁ with the “positive quadrant,” which we denote by Γ(ℝ+n), and by (ii) investigating the asymptotic behavior of the solution χϵ(t) of the initial-value problem is suitably specified for our application purposes. The main theorem and its two specialized versions, together with the notions of Γ-semipositive operators and semipositive matrices presented here, serve as fundamental tools for the analysis of a class of dynamical systems of chemical kinetic equations whose examples were illustratively treated in the previous parts of this series of articles. The techniques developed here for an asymptotic analysis of chemical kinetic dynamical systems will be linked and unified with those for the asymptotic analysis of quantum mechanical systems in a forthcoming part of this series of articles. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 149–163, 1997 相似文献
35.
36.
Hiroyuki Asanuma Taiga Fujii Tomohiro Kato Hiromu Kashida 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2012,13(2):124-135
The optical behavior of an organized dye assembly is different from that of the isolated dye; this difference is explained using molecular exciton theory. The theory predicts that mutual orientation, the number of dyes in the cluster, and combinations of different dyes should display given characteristic spectroscopic behaviors due to coherent interactions. Comparison of theoretical predictions with experimental results has been limited so far. One of the reasons is the absence of a rigid and well-organized system that can control the orientation and size of the dye assembly. Recently, the DNA duplex has been used to assemble chromophores in a programmed manner. Use of DNA allows organized dye assembly with a given size and particular orientation. In this review, we evaluate the spectroscopic behavior of the H-type aggregate based on molecular exciton theory and compare it with actual dye assembly with DNA duplex. Furthermore, we demonstrate the importance of coherent interactions on the observed optical properties of dyes assembled in a DNA duplex. 相似文献
37.
38.
Gensei Teramoto Takafumi Oda Hiromu Saito Hironari Sano Yuji Fujita 《Journal of Polymer Science.Polymer Physics》2004,42(14):2738-2746
We investigated the crystalline morphology of isotactic polypropylene obtained by melt crystallization under carbon dioxide (CO2) at various pressures. Spherulites consisting of regularly arranged fibrils without subsidiary lamellae were obtained by crystallization under CO2 below 2 MPa, whereas large spherulites consisting of irregularly arranged fibrils with subsidiary lamellae were obtained under ambient pressure. Distorted domain crystals with uniform optical anisotropy consisting of α‐form were found to be obtained under CO2 above 2 MPa, and needle crystals consisting of γ‐form were obtained above 12 MPa. Transmission electron micrographs showed that straight and thick lamellae are regularly arranged in both the distorted domain crystals and the needle crystals. The uniformly thick lamellae were confirmed by differential scanning calorimetry thermograms; that is, the melting temperature is higher and the melting peak is sharper than those obtained under ambient pressure. Such characteristic crystalline morphologies obtained under CO2 may be attributed to local ordering in the melt state. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2738–2746, 2004 相似文献
39.
Hiromu Saito Motoshi Matsuura Takashi Inoue 《Journal of Polymer Science.Polymer Physics》1991,29(12):1541-1546
Depolarized light scattering measurements on single-phase mixtures of dissimilar polymers, poly(methyl methacrylate) (PMMA)/poly (acrylonitrile-co-styrene) (SAN, AN content = 15 wt %) and PMMA/poly (vinylidene fluoride) (PVDF) were carried out. The effective mean-square optical anisotropy γ2 of the mixtures was found to be much higher than that estimated by the simple additivity of γ2 of component polymers. From the deviation, the order parameter (1 + J12) was estimated to be in a range of 2–13, depending on the blend composition. This suggests local ordering in the single-phase mixtures, i.e., nematic alignment of the locally stretched dissimilar chains. In contrast, the deviation was slight in the polymer/solvent systems, SAN/MMA (monomer) and PVDF/butanone. The degree of ordering decreased with increasing temperature. T. The Specific interaction evidenced by FTIR spectroscopy exhibited a similar temperature dependence. Thus, local ordering seems to be induced by specific interactions and chain connectivity. The temperature dependence of J12 was successfully described by the Landau-de Gennes theory; J ∞ (T + T0)/ T, T0 being the isotropic-nematic transition temperature, as in the case of liquid crystals. 相似文献
40.
Total Synthesis and Biological Evaluation of the Glycosylated Macrocyclic Antibiotic Mangrolide A 下载免费PDF全文
Hiromu Hattori Joel Roesslein Dr. Patrick Caspers Dr. Katja Zerbe Dr. Hideki Miyatake‐Ondozabal Dr. Daniel Ritz Dr. Georg Rueedi Prof. Dr. Karl Gademann 《Angewandte Chemie (International ed. in English)》2018,57(34):11020-11024
The macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram‐negative pathogens. Reported is the first enantioselective total synthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two β‐selective glycosylations. The synthesis of mangrolide A and its analogues enabled the re‐examination of its activity against bacterial pathogens, and only minimal activity was observed. 相似文献