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171.
Oxidative Annulation of Arenecarboxylic and Acrylic Acids with Alkynes under Ambient Conditions Catalyzed by an Electron‐Deficient Rhodium(III) Complex 下载免费PDF全文
Eiji Kudo Dr. Yu Shibata Mutsumi Yamazaki Koji Masutomi Dr. Yuta Miyauchi Miho Fukui Haruki Sugiyama Prof. Dr. Hidehiro Uekusa Prof. Dr. Tetsuya Satoh Prof. Dr. Masahiro Miura Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14190-14194
It has been established that an electron‐deficient CpE rhodium(III) complex catalyzes the oxidative [4+2] annulation of substituted arenecarboxylic and acrylic acids with alkynes under ambient conditions (at RT–40 °C, under air) without using excess amounts of substrates to produce the corresponding substituted isocoumarins and α‐pyrones in high yields. Minor modification of reaction conditions depending on the coordination ability of alkynes realized the high efficiency. 相似文献
172.
173.
Akihiko Nakatsuka Kazumasa Sugiyama Makio Ohkawa Osamu Ohtaka Keiko Fujiwara Akira Yoshiasa 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(10):716-719
The Sr–Ge–O system has an earth‐scientific importance as a potentially good low‐pressure analog of the Ca–Si–O system, one of the major components in the constituent minerals of the Earth's crust and mantle. However, it is one of the germanate systems that has not yet been fully examined in the phase relations and structural properties. The recent findings that the SrGeO3 high‐pressure perovskite phase is the first Ge‐based transparent electronic conductor make the Sr–Ge–O system interesting in the field of materials science. In the present study, we have revealed the existence of a new high‐pressure strontium germanate, SrGe2O5. Single crystals of this compound crystallized as a co‐existent phase with SrGeO3 perovskite single crystals in the sample recovered in the compression experiment of SrGeO3 pseudowollastonite conducted at 6 GPa and 1223 K. The crystal structure consists of germanium–oxygen framework layers stacked along [001], with Sr atoms located at the 12‐coordinated cuboctahedral site; the layers are formed by the corner linkages between GeO6 octahedra and between GeO6 octahedra and GeO4 tetrahedra. The present SrGe2O5 is thus isostructural with the high‐pressure phases of SrSi2O5 and BaGe2O5. Comparison of these three compounds leads to the conclusion that the structural responses of the GeO6 and GeO4 polyhedra to cation substitution at the Sr site are much less than that of the SrO12 cuboctahedron to cation substitution at the Ge sites. Such a difference in the structural response is closely related to the bonding nature. 相似文献
174.
Fluorescent polymeric thermometers consisting of only N-alkylacrylamide and fluorescent components show rather low temperature resolution in their functional ranges (ca. 15-50 degrees C) because of the occurrence of intermolecular aggregation, which causes hysteresis in their fluorescence response to changes in temperature. By adding an ionic component to prevent such intermolecular aggregation, we obtained four fluorescent polymeric thermometers that offer high temperature resolution (<0.2 degrees C). Each new fluorescent polymeric thermometer covered the temperature range, 9-33 degrees C, 30-51 degrees C, 49-66 degrees C or 4-38 degrees C. 相似文献
175.
Kobayashi M Takashima A Ishii T Naka H Uchiyama M Yamaguchi K 《Inorganic chemistry》2007,46(4):1039-1041
We have obtained a novel heterobimetallic iron-magnesium complex, (THF)4Mg(mu-Br)2FeBr2 (THF = tetrahydrofuran), which showed reverse photochromism in THF. The response exhibited in this system is associated with d-orbital splitting of the Fe atom and a change in the molecular aggregation state (dimerization). 相似文献
176.
Suematsu NJ Ogawa Y Yamamoto Y Yamaguchi T 《Journal of colloid and interface science》2007,310(2):648-652
Nanoparticles self-assembled into ring-shaped aggregates that were arranged in a two-dimensional (2D) hexagonal pattern. This hierarchic pattern was prepared by casting a toluene solution composed of polystyrene (PS) and Ag nanoparticles (NP). Dewetting of the thin composite layer induced the mesoscopic hexagonal array of PS-NP droplets. Within each dried droplet (dot), Ag nanoparticles self-assembled into a spot- or a ring-shaped 2D superlattice alternatively depending on the size of the dot, which was controlled by the molecular weight of PS. 相似文献
177.
178.
Akira Hirao Masahiro Kitamura Mayumi Hayashi Surapich Loykulnant Kenji Sugiyama 《Macromolecular Symposia》2005,226(1):35-50
Anionic polymerizations of four new dual-functionalized styrene and α-methylstyrene derivatives, 3-(4-(4-isopropenylphenoxy)butyl)styrene ( 4 ), 3-(4-(2-isopropenylphenoxy)butyl)-α-methylstyrene ( 5 ), 4-(4-(4-isopropenylphenoxy)butyl)-α-methylstyrene ( 6 ), and 4-(4-(2-vinylphenoxy)butyl)styrene ( 7 ), were carried out in THF at -78 °C with sec-BuLi as an initiator. Both 4 and 5 underwent anionic polymerization in a living manner to quantitatively afford functionalized polystyrenes and poly(α-methylstyrene)s having α-methylstyrene moiety in each monomer unit and precisely controlled chain lengths. On the other hand, insoluble polymers were obtained by the anionic polymerization of 6 and 7 under the same conditions. The positional effect of substituent on anionic polymerization was discussed. 相似文献
179.
M. Noda Y. Adachi H. Sugiyama T. Nakaiso M. Okuyama 《Applied Physics A: Materials Science & Processing》2000,71(1):113-116
Preferentially (105)-oriented SrxBi2+yTa2O9 (SBT) thin films on SiN/SiO2/p-Si(100) prepared by the pulsed laser deposition (PLD) method at a temperature as low as 400 °C, which is the lowest process temperature for growing SBT ferroelectric thin films on a silicon nitride film. Excess Bi promotes crystallization of the SBT film. A metal-ferroelectric-nitride-oxide-semiconductor (MFNOS) structure, which is very important in ferroelectric gate memory FET, has been fabricated by depositing the SBT film on silicon nitride-oxide-silicon. The MFNOS structures show capacitance-voltage (C-V) hysteresis corresponding to ferroelectric hysteresis. A memory window of the C-V hysteresis is improved, to be as high as 3.5 V in the SBT(400 nm)/SiNx(7 nm)/SiO2(18 nm)/Si compared with the window of 2.7 V in the SBT(400 nm)/SiO2(27 nm)/Si (MFOS), where the thicknesses of their insulator layers are nearly the same. Little degradation is induced in the C-V characteristics of the SiNx/SiO2/p-Si structure when depositing the SBT film by PLD at low temperature. It is also found that the SiNx layer acts as a diffusion barrier against component atoms in the SBT film during its deposition. Finally, the MFNOS structure prepared at the low temperature is very promising for a next-generation ferroelectric gate memory FET. 相似文献
180.
Ritsuko Nagahata Jun‐Ichi Sugiyama Meenakshi Goyal Michihiko Asai Mitsuru Ueda Kazuhiko Takeuchi 《Journal of polymer science. Part A, Polymer chemistry》2000,38(18):3360-3368
Thermal ring‐opening polymerization of a uniform macrocyclic ethylene terephthalate dimer with and without catalyst was investigated for the first time. Although polymerization progressed without a catalyst, the reaction was extremely slow and all the products were colored. Various transesterification catalysts were tested for their activity toward this ring‐opening polymerization. Among the various catalysts, 1,3‐dichloro‐1,1,3,3‐tetrabutyldistannoxane exhibited the highest catalytic activity, and a colorless polymer with a weight‐average molecular weight of 36,100 was obtained in 100% yield by heating for 3 min at 200 °C. It is noteworthy that our method does not need a vacuum because no side products are formed during the process. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3360–3368, 2000 相似文献