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371.
Toganoh M Gokulnath S Kawabe Y Furuta H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(14):4380-4391
A series of 5,10,15-tris(pentafluorophenyl) doubly N-confused bilanes were synthesized in a stepwise manner with the aid of sterically demanding N-protecting groups, in which the difference in reactivity between regular pyrrole and N-confused pyrrole plays a crucial role in the synthetic strategy. Some doubly N-confused bilanes were converted into porphyrinoids or a unique 2:2 copper(II) complex with a helical structure. In addition, the conformations and electronic states of the doubly N-confused bilanes were investigated theoretically, giving fruitful information about the effect of confusion on the bilane skeleton. 相似文献
372.
M Tamaki T Harada K Fujinuma K Takanashi M Shindo M Kimura Y Uchida 《Chemical & pharmaceutical bulletin》2012,60(9):1134-1138
The substitution of each constituent amino acid residue of gramicidin S (GS), cyclo(-Val(1,1')-Orn(2,2')-Leu(3,3')-D-Phe(4,4')-Pro(5,5')-)(2) with Lys residue indicated that each side chain structure of the constituent amino acid residues affect largely the antibiotic activity and hemolytic activity of GS. Further, the substitution of D-Phe(4,4') and Pro(5,5') residues with basic amino acid residues as a Lys residue results the high antibiotic activity and the very low hemolytic activity. Thus, we have found novel positions on the scaffold of GS at D-Phe(4,4') and Pro(5,5') residues whose modification will significantly increase the therapeutic index. 相似文献
373.
The CCSD(T) level interaction energies of eight orientations of nitrobenzene-benzene complexes and nine orientations of nitrobenzene dimers at the basis set limit have been estimated. The calculated interaction energy of the most stable slipped-parallel (C(s)) nitrobenzene-benzene complex was -4.51 kcal/mol. That of the most stable slipped-parallel (antiparallel) (C(2h)) nitrobenzene dimer was -6.81 kcal/mol. The interaction energies of these complexes are significantly larger than that of the benzene dimer. The T-shaped complexes are substantially less stable. Although nitrobenzene has a polar nitro group, electrostatic interaction is always considerably weaker than the dispersion interaction. The dispersion interaction in these complexes is larger than that in the benzene dimer, which is the cause of the preference of the slipped-parallel orientation in these complexes. 相似文献
374.
Masaki Matsui Yoshinori Asamura Kazumasa Funabiki Tsukasa Yoshida 《Tetrahedron》2010,66(37):7405-1642
Substituited triple rhodanine indoline dyes showed higher performance than known triple rhodanine derivative (D150). A few triple rhodanine indoline derivatives showed comparable conversion efficiency to D149. 相似文献
375.
A new universality class of quantum criticality emerging in itinerant electron systems with strong local electron correlations is discussed. The quantum criticality of a Ce- or Yb-valence transition gives us a unified explanation for unconventional criticality commonly observed in heavy fermion metals such as YbRh(2)Si(2), β-YbAlB(4), YbCu(5-x)Al(x), and CeIrIn(5). The key origin is due to the locality of the critical valence fluctuation mode emerging near the quantum critical end point of the first-order valence transition, which is caused by strong electron correlations for f electrons. The wider relevance of this new criticality and important future measurements to uncover its origin are also discussed. 相似文献
376.
Miyabe H Yoshida K Reddy VK Matsumura A Takemoto Y 《The Journal of organic chemistry》2005,70(14):5630-5635
[reaction: see text] The viability of oximes as nucleophiles in transition-metal-catalyzed allylic substitution was examined. The oxygen atom of oxime acted as a reactive nucleophile in the reaction of a pi-allyl palladium complex. In the presence of Pd(PPh3)4, the allylic substitution of oximes with allylic carbonate afforded the linear O-allylated oxime ethers selectively without a base. In contrast, the palladium-catalyzed reaction with allylic acetate proceeded smoothly in the presence of K2CO3 or Et2Zn as a base. Selective formation of nitrones was achieved by using palladium(II) catalyst. In the presence of Pd(cod)Cl2, the allylic substitution of oximes with allylic acetate afforded the N-allylated nitrones under solvent-free conditions, as a result of the reaction with the nitrogen atom of oximes. 相似文献
377.
Dipyrrolyldiketone boron complexes, as π-conjugated acyclic anion receptors, act as building subunits of various assemblies through noncovalent interactions in the form of receptor-anion complexes. Instead of, or in addition to, the modification of receptor structures, the introduction of anion modules as building blocks for the assemblies was found to be useful in forming various soft materials. Gallic carboxylate derivatives 3-n (n = 16, 18, 20), as tetrabutylammonium (TBA) salts, form receptor-anion-module complexes that can be used to fabricate supramolecular assemblies. Combinations of aliphatic anion modules 3-n and receptors 1a,b along with a TBA cation afforded products with mesophases, which were indicated by differential scanning calorimetry and polarized optical microscopy. X-ray diffraction measurements of the solid states and mesophases of 1a·3-n·TBA and 1b·3-n·TBA revealed highly ordered structures including lamellar structures, which could be modulated by the lengths of the alkyl chains of the modules. Functional materials exhibiting electrical conductivity were fabricated by using combinations of anionic building blocks that form assemblies by themselves and π-conjugated acyclic receptors. 相似文献
378.
We study spin models as introduced in [20]. Such a spin model can be defined as a square matrix satisfying certain equations, and can be used to compute an associated link invariant. The link invariant associated with a symmetric spin model depends only trivially on link orientation. This property also holds for quasi-symmetric spin models, which are obtained from symmetric spin models by certain gauge transformations preserving the associated link invariant. Using a recent result of [16] which asserts that every spin model belongs to some Bose-Mesner algebra with duality, we show that the transposition of a spin model can be realized by a permutation of rows. We call the order of this permutation the index of the spin model. We show that spin models of odd index are quasi-symmetric. Next, we give a general form for spin models of index 2 which implies that they are associated with a certain class of symmetric spin models. The symmetric Hadamard spin models of [21] belong to this class and this leads to the introduction of non-symmetric Hadamard spin models. These spin models give the first known example where the associated link invariant depends non-trivially on link orientation. We show that a non-symmetric Hadamard spin model belongs to a certain triply regular Bose-Mesner algebra of dimension 5 with duality, and we use this to give an explicit formula for the associated link invariant involving the Jones polynomial. 相似文献
379.
We experimentally investigate the critical behavior of a phase transition between two topologically different turbulent states of electrohydrodynamic convection in nematic liquid crystals. The statistical properties of the observed spatiotemporal intermittency regimes are carefully determined, yielding a complete set of static critical exponents in full agreement with those defining the directed percolation class in 2+1 dimensions. This constitutes the first clear and comprehensive experimental evidence of an absorbing phase transition in this prominent nonequilibrium universality class. 相似文献
380.
Tetsuya Okunaka Harubumi Kato Katsuo Aizawa Takuzo Ohtani Hirofumi Kawabe Takayuki Asahara Hitoshi Nakajima Ikuhiro Yamasawa Chiharu Ibukiyama Susumu O'Hata Yoshihiro Hayata 《Photochemistry and photobiology》1987,46(5):769-775
Abstract A new diagnostic and therapeutic endoscopic system consisting of an excimer pulse dye laser is presented. This report demonstrates the accumulation of hematoporphyrin derivative (HpD) in atheroma as shown by the fluorescence of HpD using this equipment. Atheroma was induced in the aorta of WHHL (Watanabe heritable hyperlipidemic) rabbits, 5 mg kg−1 HpD was injected intravenously and the rabbits were sacrificed 24 h later. The aorta was dissected and the localization of HpD was examined. Characteristic peaks of the fluorescence of HpD at 630, 665 and 690 nm wavelength were detected in the atheromatous lesion. However, in the fatty plaque, the emission peak at 630 nm was lower and the 665 nm peak faded away. No fluorescence with peaks was detected in the normal area. The ratio of fluorescence intensity in atheroma, border zones and normal areas was 10.4 : 5.0 : 1.0. On normal rabbits made atherosclerotic by diet and balloon damage, an ultra thin endoscopic catheter was inserted from the descending aorta of atherosclerotic rabbits under anesthesia. Essentially the same data was obtained by these studies in vivo as was obtained in the in vitro studies. The above data suggests the possibility of future applications of this equipment for diagnosis of atheroma. 相似文献