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981.
Shuhei Furukawa Dr. Kenji Hirai Keiji Nakagawa Yohei Takashima Ryotaro Matsuda Dr. Takaaki Tsuruoka Dr. Mio Kondo Dr. Rie Haruki Dr. Daisuke Tanaka Dr. Hirotoshi Sakamoto Satoru Shimomura Osami Sakata Dr. Susumu Kitagawa Prof. 《Angewandte Chemie (International ed. in English)》2009,48(10):1766-1770
MOF on MOF: Core–shell porous coordination polymer (PCP) crystals are fabricated at the single‐crystal level by epitaxial growth in solution. Synchrotron X‐ray diffraction measurements unveiled the structural relationship between the shell crystal and the core crystal, where in‐plane rotational epitaxial growth compensates the difference in lattice constant.
982.
Rongjun He Dr. Changhua Ding Dr. Keiji Maruoka Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(25):4559-4561
It′s a PTC : A highly efficient reaction of 3‐aryloxindoles in an asymmetric Michael addition was achieved by using a quaternary tetraalkylphosphonium salt as a chiral phase‐transfer catalyst (PTC). The products were obtained in quantitative yields high ee values. The reaction of 3‐aryloxindoles in an asymmetric Mannich reaction using the same catalyst also proved to be feasible.
983.
984.
Nadtanet Nunthaboot Fumio Tanaka Sirirat Kokpol Haik Chosrowjan Seiji Taniguchi Noboru Mataga 《Journal of photochemistry and photobiology. A, Chemistry》2009,201(2-3):191-196
The ultrafast non-exponential fluorescence decay of FMN binding protein (FBP) was analyzed with three electron transfer (ET) theories, Marcus theory, Bixon and Jortner theory and Kakitani and Mataga theory. Center to center distances between electron acceptor, the excited isoalloxazine, and donors, Trp-32, Tyr-35 and Trp-106, in FBP were determined by molecular dynamic simulation. Electron transfer parameters containing in these theories were determined so as to fit the calculated decay with the observed decay, according to a non-linear least squares method. Introduction of electrostatic energies between isoalloxazine anion and other ionic groups and between the donor cations and other ionic groups in the protein into any ET theories improved the fitting. The non-exponential behavior in the fluorescence decay is considered to be ascribed to a fluctuation of the protein structure with long period. 相似文献
985.
986.
Keiji Hirose 《Journal of inclusion phenomena and macrocyclic chemistry》2010,68(1-2):1-24
Machines at a molecular level are in perpetual Brownian motion even at an ambient temperature. One of the representative issues of researches on molecular machines is a development of technology, which can control Brownian motion. This review presents our efforts to achieve the first rationally designed molecular brake systems of threading/dethreading motions, a shuttling motion, and a rocking motion that work reversibly and quantitatively in response to external stimuli without producing any chemical wastes. These molecular brake systems were constructed from a dumbbell shaped secondary ammonium axle and a ring component having photo and thermally reactive moiety. 相似文献
987.
Bera NC Maeda S Morokuma K Viggiano AA 《The journal of physical chemistry. A》2010,114(50):13189-13197
Proton affinity and fluoride affinity of nerve agent VX at all of its possible sites were calculated at the RI-MP2/cc-pVTZ//B3LYP/6-31G* and RI-MP2/aug-cc-pVTZ//B3LYP/6-31+G* levels, respectively. The protonation leads to various unique structures, with H(+) attached to oxygen, nitrogen, and sulfur atoms; among which the nitrogen site possesses the highest proton affinity of -ΔE ~ 251 kcal/mol, suggesting that this is likely to be the major product. In addition some H(2), CH(4) dissociation as well as destruction channels have been found, among which the CH(4) + [Et-O-P(═O)(Me)-S-(CH(2))(2)-N(+)(iPr)═CHMe] product and the destruction product forming Et-O-P(═O)(Me)-SMe + CH(2)═N(+)(iPr)(2) are only 9 kcal/mol less stable than the most stable N-protonated product. For fluoridization, the S-P destruction channel to give Et-O-P(═O)(Me)(F) + [S-(CH(2))(2)-N-(iPr)(2)](-) is energetically the most favorable, with a fluoride affinity of -ΔE ~ 44 kcal. Various F(-) ion-molecule complexes are also found, with the one having F(-) interacting with two hydrogen atoms in different alkyl groups to be only 9 kcal/mol higher than the above destruction product. These results suggest VX behaves quite differently from surrogate systems. 相似文献
988.
989.
Keiji Tagami 《Topology and its Applications》2012,159(3):833-849
Turaev and Turner introduced a bijection between unoriented topological quantum field theories and extended Frobenius algebras. In this paper, we will show that there exists a bijective correspondence between unoriented (1+1)-dimensional homotopy quantum field theories and extended crossed group algebras. 相似文献
990.
We developed a new method for stereoselective construction of an all-carbon quaternary stereogenic center on a carbocyclic ring based on regio- and stereoselective S(N)2' alkylation reactions of γ,δ-epoxy-α,β-unsaturated cyclic ketones. Treatment of the ketones, which were readily prepared in enantiomerically pure form by means of aldol condensations between 3-ethoxy-2-cycloalkenones and α,β-epoxy aldehydes, with a R(2)Zn-CuCN reagent afforded anti-S(N)2' products stereoselectively. Conversely, the corresponding syn-S(N)2' products were stereoselectively obtained through two-step transformations of the same γ,δ-epoxy-α,β-unsaturated cyclic ketones: (1) conversion of the epoxide moiety to a chlorohydrin by treatment with MgCl(2) and (2) subsequent S(N)2' substitution of the chlorohydrin with a R(2)Zn-CuCN reagent. These substitution products with their chiral trans-allylic alcohol moieties are promising precursors for complex molecules. For example, Eschenmoser-Claisen rearrangement of one of the substitution products resulted in stereoselective formation of a keto amide having contiguous quaternary and tertiary stereogenic centers. 相似文献