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排序方式: 共有927条查询结果,搜索用时 281 毫秒
921.
922.
Eishun Tsuchida Teruyuki Komatsu Yasuko Mastukawa Tomoyuki Okada 《Macromolecular Symposia》2002,186(1):1-6
Incorporation of different structured synthetic hemes, 5,10,15,20-tetraphenylporphyrinatoiron(II) derivetives with a covalently linked proximal base [FeP( 1 ) to FeP( 7 )], into human serum albumin (HSA), provides seven types of albumin-heme hybrids (HSA-FeP) with different O2-binding abilities. An HSA host absorbs a maximum of eight FeP molecules in each case. The obtained all HSA-FePs can reversibly bind and release O2 under physiological conditions (in aqueous media, pH 7.3, 37°C) as similar as hemoglobin and myoglobin. The difference in the fence structures did not affect the O2-binding parameters, however the axial histidine coordination significantly increased the O2-binding affinity, which is ascribed to the low O2-dissociation rate constants. The most remarkable effect of the heme structure appeared in the half-lifetime (τ1/2) of the O2-adduct complex. The dioxygenated rHSA-FeP( 4 ) showed an unusually long lifetime (τ1/2: 25 hr at 37°C) which is ca. 13-fold longer than that of rHSA-FeP( 1 ). 相似文献
923.
5-(4-Trimethylsilyethynylphenyl)-10,15,20-triphenylplatinumporphyrin was synthesized and copolymerized with trimethylsilylpropyne to give a new high-molecular-weight porphyrin polymer. The polymer formed a smooth and tough coating on many types of surfaces. The coating showed a strong blue luminescence from the platinumporphyrin residue which was quenched in the presence of oxygen. The relationship of the luminescence intensity vs oxygen pressure displayed a remarkably high pressure sensitivity in the low oxygen pressure area, which was ascribed to the high oxygen permeability of the polymer. 相似文献
924.
Jun Manabe Nagisa Sako Mizuki Ito Dr. Masaru Fujibayashi Dr. Chisato Kato Dr. Goulven Cosquer Prof. Katsuya Inoue Dr. Kiyonori Takahashi Prof. Takayoshi Nakamura Prof. Tomoyuki Akutagawa Dr. Seiya Shimono Dr. Hiroki Ishibashi Prof. Yoshiki Kubota Prof. Sadafumi Nishihara 《欧洲无机化学杂志》2023,26(34):e202300449
Materials exhibiting irreversible phase transitions, leading to changes in their properties, have a potential for novel application in electronic components such as a non-rewritable high-security memory. Here, we focused on the two salts, [(9-triptycylammonium)([18]crown-6)][Ni(dmit)2] ( 1 ) and [(9-triptycylammonium)([15]crown-5)][Ni(dmit)2] ( 2 ), which featured 2D sheet structures with alternately stacked cation and anion layers. Both salts exhibit similar cation arrangements, however, their anion arrangements differ significantly. The temperature-dependent magnetic susceptibilities of 1 and 2 were well reproduced by the alternating chain model (JAC1/kB=−306(8), JAC2/kB=−239(3) K) and the Curie-Weiss model (θ=−3.9(1) K), respectively. 1 experience a reversible phase transition around 40–60 K, causing anomalies in magnetic behavior. Moreover, an irreversible single-crystal-to-single-crystal phase transition to 1′ undergo at ~381 K, inducing a rearrangement of [Ni(dmit)2]− anions and a resistivity decrease from 6.5×106 to 6.5×102 Ω cm. The susceptibility curve of 1′ was reproduced by a combination of the Curie-Weiss and dimer models (Jdimer/kB=−407(5), θ=−26.7(5) K). The irreversible transition of 1 is the first example for such supramolecule and [Ni(dmit)2]− system to our knowledge, in opening potential new-type materials. 相似文献
925.
Dr. Wei Zheng Dr. Kosuke Oki Dr. Ranajit Saha Dr. Yuh Hijikata Prof. Eiji Yashima Dr. Tomoyuki Ikai 《Angewandte Chemie (International ed. in English)》2023,62(11):e202218297
Defect-free one-handed contracted helical tubular ladder polymers with a π-electron-rich cylindrical helical cavity were synthesized by alkyne benzannulations of the random-coil precursor polymers containing 6,6′-linked-1,1′-spirobiindane-7,7′-diol-based chiral monomer units. The resulting tightly-twisted helical tubular ladder polymers showed remarkably high enantioseparation abilities toward a variety of chiral hydrophobic aromatics with point, axial, and planar chiralities. The random-coil precursor polymer and analogous rigid-rod extended helical ribbon-like ladder polymer with no internal helical cavity exhibited no resolution abilities. The molecular dynamics simulations suggested that the π-electron-rich cylindrical helical cavity formed in the tightly-twisted tubular helical ladder structures is of key importance for producing the highly-enantioseparation ability, by which chiral aromatics can be enantioselectively encapsulated by specific π-π and/or hydrophobic interactions. 相似文献
926.
Prof. Ming-Shui Yao Prof. Ken-ichi Otake Jiajia Zheng Masahiko Tsujimoto Dr. Yi-Fan Gu Lu Zheng Dr. Ping Wang Dr. Shivanna Mohana Dr. Mickaele Bonneau Tomoyuki Koganezawa Tetsuo Honma Hirotaka Ashitani Shogo Kawaguchi Prof. Yoshiki Kubota Prof. Susumu Kitagawa 《Angewandte Chemie (International ed. in English)》2023,62(35):e202308990
A one-stone, two-bird method to integrate the soft porosity and electrical properties of distinct metal–organic frameworks (MOFs) into a single material involves the design of conductive-on-insulating MOF (cMOF-on-iMOF) heterostructures that allow for direct electrical control. Herein, we report the synthesis of cMOF-on-iMOF heterostructures using a seeded layer-by-layer method, in which the sorptive iMOF core is combined with chemiresistive cMOF shells. The resulting cMOF-on-iMOF heterostructures exhibit enhanced selective sorption of CO2 compared to the pristine iMOF (298 K, 1 bar, S from 15.4 of ZIF-7 to 43.2–152.8). This enhancement is attributed to the porous interface formed by the hybridization of both frameworks at the molecular level. Furthermore, owing to the flexible structure of the iMOF core, the cMOF-on-iMOF heterostructures with semiconductive soft porous interfaces demonstrated high flexibility in sensing and electrical “shape memory” toward acetone and CO2. This behavior was observed through the guest-induced structural changes of the iMOF core, as revealed by the operando synchrotron grazing incidence wide-angle X-ray scattering measurements. 相似文献
927.