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141.
Mamiko Ninomiya Yoshio Ando Fumitaka Kudo Ken Ohmori Keisuke Suzuki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4308-4314
The enantioselective total synthesis of actinorhodin ( 1 ) is described. The synthesis features 1) dual benzyne reactions en route to the monomer, 2) the trans‐selective installation of the side chain, and 3) a regioselective oxidative dimerization. 相似文献
142.
Yasunori Muranishi Yue Wang Mamiko Odoko Nobuo Okabe 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):m307-m310
In the three title complexes, namely (2,2′‐biquinoline‐κ2N,N′)dichloropalladium(II), [PdCl2(C18H12N2)], (I), and the corresponding copper(II), [CuCl2(C18H12N2)], (II), and zinc(II) complexes, [ZnCl2(C18H12N2)], (III), each metal atom is four‐coordinate and bonded by two N atoms of a 2,2′‐biquinoline molecule and two Cl atoms. The PdII atom has a distorted cis‐square‐planar coordination geometry, whereas the CuII and ZnII atoms both have a distorted tetrahedral geometry. The dihedral angles between the N—M—N and Cl—M—Cl planes are 14.53 (13), 65.42 (15) and 85.19 (9)° for (I), (II) and (III), respectively. The structure of (II) has twofold imposed symmetry. 相似文献
143.
144.
207Pb magic angle spinning (MAS)-NMR spectra have been obtained for various Pb-containing crystalline compounds and high lead glasses. The isotropic chemical shifts were determined for the crystalline samples. The more ionic lead atoms with a coordination number larger than six had relatively small chemical shifts between 0 and 2382 ppm with respect to crystalline Pb(NO3)2. On the other hand, the covalent lead atoms with PbO3 trigonal and PbO4 square pyramidal configurations gave a multiplet line profile with shifts ranging from about 3000 to 6000 ppm. The lead atoms with different local environments in PbSiO3 (alamosite) and H-Pb2SiO4, for instance, could be clearly distinguished from each other on the basis of the isotropic chemical shift. The NMR spectra for the high lead glasses of composition 67PbO·33SiO2, 80PbO·20B2O3 and 70PbO· 30GaO1.5 were found to exhibit an extremely broad peak with a shift ranging from about 3000 to 6000 ppm. This shift indicates that, in these glasses, neither such highly ionic lead atoms as found in symmetrical PbO6 octahedra nor such highly covalent ones as found in PbO4 square pyramids in the PbO crystal are predominant, but instead PbO3 trigonal or PbO4 square pyramids, with two or three other neighboring oxygens at larger distances as found in H-Pb2SiO4 or PbSiO3, are the major lead-oxygen configuration. 相似文献
145.
Claudia E. Murar Mamiko Ninomiya Satomi Shimura Ufuk Karakus Onur Boyman Jeffrey W. Bode 《Angewandte Chemie (International ed. in English)》2020,59(22):8425-8429
Chemical protein synthesis allows the construction of well‐defined structural variations and facilitates the development of deeper understanding of protein structure–function relationships and new protein engineering strategies. Herein, we report the chemical synthesis of interleukin‐2 (IL‐2) variants on a multimilligram scale and the formation of non‐natural disulfide mimetics that improve stability against reduction. The synthesis was accomplished by convergent KAHA ligations; the acidic conditions of KAHA ligation proved to be valuable for the solubilization of the hydrophobic segments of IL‐2. The bioactivity of the synthetic IL‐2 and its analogues were shown to be equipotent to recombinant IL‐2 and exhibit improved stability against reducing agents. 相似文献
146.
We present a novel method to retrieve angular distributions of high-order harmonic generation from a single molecule. This technique uses an iterative procedure based only on experimental results of time and angle-dependent harmonic signals, and no actual shape of molecular orbital is assumed. The molecular axis distribution in a target gas can simultaneously be deduced in this procedure. The angle-dependent signal retrieved for a single N2 and O2 molecule is demonstrated to reflect the highest occupied molecular orbital, excluding the ambiguity due to the imperfect alignment. 相似文献
147.
Dr. Ken Motokura Daiki Kashiwame Naoki Takahashi Dr. Akimitsu Miyaji Prof. Dr. Toshihide Baba 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(30):10030-10037
Copper diphosphine complexes have been found to be highly active and selective homogeneous catalysts for the hydrosilylation of CO2. The structure of the phosphine ligands strongly affects their catalytic activity. Turnover number (TON) reaches 70 000 after 24 hours with 1,2‐bis(diisopropylphosphino)benzene as a ligand under 1 atmosphere of CO2. 1H and 13C NMR spectra, carried out under the reaction conditions, showed the reaction mechanism through insertion of CO2 into Cu? H to afford Cu/formate species. 相似文献
148.
149.
Lihua Lin Pongpen Kaewdee Vikas Nandal Ryota Shoji Hiroyuki Matsuzaki Kazuhiko Seki Mamiko Nakabayashi Naoya Shibata Xiaoping Tao Xizhuang Liang Yiwen Ma Takashi Hisatomi Tsuyoshi Takata Prof. Kazunari Domen 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310607
Photocatalytic water splitting is an ideal means of producing hydrogen in a sustainable manner, and developing highly efficient photocatalysts is a vital aspect of realizing this process. The photocatalyst Y2Ti2O5S2 (YTOS) is capable of absorbing at wavelengths up to 650 nm and exhibits outstanding thermal and chemical durability compared with other oxysulfides. However, the photocatalytic performance of YTOS synthesized using the conventional solid-state reaction (SSR) process is limited owing to the large particle sizes and structural defects associated with this synthetic method. Herein, we report the synthesis of YTOS particles by a flux-assisted technique. The enhanced mass transfer efficiency in the flux significantly reduced the preparation time compared with the SSR method. In addition, the resulting YTOS showed improved photocatalytic H2 and O2 evolution activity when loaded with Rh and Co3O4 co-catalysts, respectively. These improvements are attributed to the reduced particle size and enhanced crystallinity of the material as well as the slower decay of photogenerated carriers on a nanosecond to sub-microsecond time range. Further optimization of this flux-assisted method together with suitable surface modification is expected to produce high-quality YTOS crystals with superior photocatalytic activity. 相似文献