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971.
Sahoo AK Nakamura Y Aratani N Kim KS Noh SB Shinokubo H Kim D Osuka A 《Organic letters》2006,8(18):4141-4144
Highly efficient synthesis of meso,meso-dibromo doubly and triply fused diporphyrins has been achieved through a powerful oxidative coupling mediated by AuCl3-AgOTf combination. In addition, palladium-catalyzed debromination of meso-bromoporphyrins has been developed. This debromination protocol enables employment of bromine as a protecting group for the reactive meso-position of porphyrins. 相似文献
972.
A facile approach for synthesis of bipolar oligofluorenes, TAZ-OF(n)-NPh, n = 2 or 3 end-capped with hole-transporting diphenylamino and electron-transporting triazole moieties by Suzuki cross-coupling as the key reaction has been developed. This novel bipolar oligofluorenes exhibited blue-emission, high thermal and morphological stabilities. The single-layer OLED based on TAZ-OF(2)-NPh exhibited superior device performance with a maximum luminance of 1128 cd m(-2) and luminance efficiency of up to 0.83 cd A(-1). 相似文献
973.
Stereoisomeric bicyclic tert-alcohols afforded identical ring-expansion products via cationic anti-Markovnikov rearrangement from perpendicular tert-cations into identical six-membered ring secondary cations by the treatment with TiCl4. These results provide evidence that the reaction takes place by the cationic stepwise mechanism. [reaction: see text] 相似文献
974.
Mochizuki T Kondo Y Abe H Taylor CW Potter BV Matsuda A Shuto S 《Organic letters》2006,8(7):1455-1458
[structure: see text] 5'-Deoxy-5'-phenyladenophostin A (5), designed as a useful IP(3) receptor ligand based on the previous structure-activity relationship studies, was successfully synthesized via two key stereoselective glycosidation steps. This compound proved to be a highly potent IP(3) receptor agonist. 相似文献
975.
A magnetic vortex core in a ferromagnetic circular nanodot has a resonance frequency originating from the confinement of the vortex core. By the micromagnetic simulation including the spin-transfer torque, we show that the vortex core can be resonantly excited by an ac (spin-polarized) current through the dot and that the resonance frequency can be tuned by the dot shape. The resistance measurement under the ac current successfully detects the resonance at the frequency consistent with the simulation. 相似文献
976.
977.
Hiroshi Nozaki 《Journal of Combinatorial Theory, Series A》2010,117(7):810-826
A subset X in the d-dimensional Euclidean space is called a k-distance set if there are exactly k distinct distances between two distinct points in X and a subset X is called a locally k-distance set if for any point x in X, there are at most k distinct distances between x and other points in X.Delsarte, Goethals, and Seidel gave the Fisher type upper bound for the cardinalities of k-distance sets on a sphere in 1977. In the same way, we are able to give the same bound for locally k-distance sets on a sphere. In the first part of this paper, we prove that if X is a locally k-distance set attaining the Fisher type upper bound, then determining a weight function w, (X,w) is a tight weighted spherical 2k-design. This result implies that locally k-distance sets attaining the Fisher type upper bound are k-distance sets. In the second part, we give a new absolute bound for the cardinalities of k-distance sets on a sphere. This upper bound is useful for k-distance sets for which the linear programming bound is not applicable. In the third part, we discuss about locally two-distance sets in Euclidean spaces. We give an upper bound for the cardinalities of locally two-distance sets in Euclidean spaces. Moreover, we prove that the existence of a spherical two-distance set in (d−1)-space which attains the Fisher type upper bound is equivalent to the existence of a locally two-distance set but not a two-distance set in d-space with more than d(d+1)/2 points. We also classify optimal (largest possible) locally two-distance sets for dimensions less than eight. In addition, we determine the maximum cardinalities of locally two-distance sets on a sphere for dimensions less than forty. 相似文献
978.
Hiroshi Hirai 《Combinatorica》2010,30(3):295-326
In this paper, we consider the metric packing problem for the commodity graph of disjoint two triangles K
3+K
3, which is dual to the multiflow feasibility problem for the commodity graph K
3+K
3. We prove a strengthening of Karzanov’s conjecture concerning quarterintegral packings by certain bipartite metrics. 相似文献
979.
Yumiko Sano Keishi Kato Masaaki Yokoyama Yasuhiko Shirota Hiroshi Mikawa 《Molecular Crystals and Liquid Crystals》2013,570(1-2):137-141
Glass-forming properties of 2-pyrazoline derivatives were examined and discussed in terms of the molecular structure. The results show that the molecular shape of 1,3,5-triaryl-2-pyrazolines is responsible for the glass-forming properties of these compounds. Glass transition points of several 1,3,5-triaryl-2-pyrazoline derivatives were measured. 相似文献
980.
Kenichi Imaeda Hiroo Inokuchi Kenji Ichimura Shinichi Inoue Satoshi Nakakita Hiroshi Okamoto 《Molecular Crystals and Liquid Crystals》2013,570(1):667-670
Abstract Solid state 1H NMR of (KH)3C60 was measured in the temperature range between ?80 and 60 °C. A doublet spectrum composed of main peak at ?7.0 ppm and shoulder peak at ~0 ppm was observed at room temperature. The negative chemical shift of the main peak indicates that hydrogen in (KH)3C60 exists as a hydride-like ion. The 60 °C spectrum became singlet at ?5.8 ppm due to motional narrowing. 相似文献