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排序方式: 共有181条查询结果,搜索用时 15 毫秒
71.
Poly(thiaheterohelicene): a stiff conjugated helical polymer comprised of fused benzothiophene rings
A novel helical aromatic polymer comprised of fused benzothiophene rings, poly(thiaheterohelicene), was synthesized via an intramolecular ring-closing reaction with a controlled helicity to one-sided bias. The synthetic helicity control involved the induction of the helical conformation and its fixation. The ladder polymer showed both an extended pi-conjugation and planarity and a very stiff helical structure. [structure: see text] 相似文献
72.
Hiroyasu Nishiguchi Shuji Kimura Tatsumi Ishihara Yusaku Takita 《Research on Chemical Intermediates》1998,24(4):391-399
Cu ion-exchanged SAPO-34 which is a highly active catalyst for selective reduction of NO with C3H6, was synthesized and the Cu ion was characterized in the SAPO-34 by ESR, XPS, IR, and XAFS. ESR study indicated that two
kinds of Cu(II) with different environments exist in SAPO-34. The Cu(II) species disappeared immediately by C3H6 treatment and recovered by oxygen treatment. XAFS study indicated that most of the Cu(II) was reduced to Cu(I) under the
presence of C3H6.
These studies revealed that a selective NO reduction by C3H6 over SAPO-34 should proceed by the redox reaction of a copper ion between Cu(I) and Cu(II). 相似文献
73.
Tomohisa Takita Yoji Umezawa Sei-ichi Saito Hajime Morishima Hamao Umezawa Yasuhiko Muraoka Masanobu Suzuki Masami Otsuka Susumu Kobayashi Masaji Ohno 《Tetrahedron letters》1981,22(7):671-674
Deglyco-bleomycin A2, the aglycon of bleomycin A2, has been synthesized for the first time. 相似文献
74.
Experimental study of color degree of freedom of gluons in e+e- annihilation at sqrt s around 60 GeV
Abe K Amako K Arai Y Asano Y Chiba M Chiba Y Daigo M Emura T Fukawa M Fukui T Fukushima Y Haba J Hemmi Y Higuchi M Hirose T Hojyo Y Homma Y Hoshi Y Ikegami Y Ishihara N Kamitani T Kanematsu N Kanzaki J Kikuchi R Kondo T Korhonen TT Koseki T Kurashige H Matsui T Minami M Miyake K Mori S Nagashima Y Nakamura T Nakano I Narita Y Odaka S Ogawa K Ohama T Ohsugi T Okamoto A Ono A Oyama T Sakamoto H Sakuda M Sasao N Sato M Shioden M Shirai J Shirakata M Sugimoto S Sumiyoshi T Suzuki A Suzuki Y 《Physical review letters》1991,66(3):280-284
75.
76.
Munakata M Liu SQ Konaka H Kuroda-Sowa T Suenaga Y Maekawa M Nakagawa H Yamazaki Y 《Inorganic chemistry》2004,43(2):633-641
Reaction of [2.2]paracyclophane (pcp) with silver(I) trifluoroacetate (AgCF(3)CO(2)) and silver(I) pentafluoroproprionate (AgC(2)F(5)CO(2)) has led to isolation of three novel intercalation polymers: [Ag(4)(pcp)(CF(3)CO(2))(4)](C(6)H(6)) (1), [Ag(4)(pcp)(CF(3)CO(2))(4)](C(6)H(3)Me(3)) (2), and [Ag(4)(pcp)(C(2)F(5)CO(2))(4)](pcp) (3). Structure studies using single crystal X-ray diffraction have shown that all compounds contain two-dimensional layered frameworks based on cation-pi interactions, in which pcp exhibits an unprecedented micro-tetra-eta(2) coordination mode. Guest molecules which weakly interact with the host pcp via C-H.pi interactions are intercalated between layers. The guest-eliminated complexes (1a and 2a) and guest-reincorporated ones (1b or 1c and 2b or 2c), accompanied by small structural changes, were confirmed by (1)H NMR, thermogravimetric analysis, mass spectra, and X-ray powder diffraction patterns. The structural changes from 1 --> 1a --> 1c (=1) can take place reversibly in the process of exposure of 1a to benzene vapor. The original framework of complex 2 is also completely recovered by immersing 2a in mesitylene as well as exposing it to mesitylene vapor. 相似文献
77.
78.
Dr. Yuma Morimoto Yusaku Takagi Dr. Toru Saito Dr. Takehiro Ohta Prof. Dr. Norimitsu Tohnai Prof. Dr. Motohiro Nakano Prof. Dr. Shinobu Itoh 《Angewandte Chemie (International ed. in English)》2018,57(26):7640-7643
A bis(μ‐oxido)dinickel(III) complex was synthesized and characterized by single crystal X‐ray diffraction, resonance Raman, and ESI‐mass measurements. Magnetic susceptibility measurements by SQUID and EPR spectroscopy reveal that the complex has a triplet ground state, which is unprecedented for high‐valent metal (M) complexes with [M2(μ‐O)2] diamond core. DFT studies indicate ferromagnetic coupling of the nickel(III) centers. The complex exhibits hydrogen abstraction reactivity and oxygenation reactivity toward external substrates. 相似文献
79.
Hirata KS Inoue K Ishida T Kajita T Kihara K Nakahata M Nakamura K Ohara S Sato N Totsuka Y Yaginuma Y Mori M Oyama Y Suzuki A Takahashi K Yamada M Suda T Tajima T Miyano K Miyata H Takei H Fukuda Y Kodera E Nagashima Y Takita M Kaneyuki K Tanimori T Beier EW Frank ED Frati W Kim SB Mann AK Newcomer FM Van Berg R Zhang W 《Physical review D: Particles and fields》1992,45(10):3355-3360
80.
Hirata KS Inoue K Ishida T Kajita T Kihara K Nakahata M Nakamura K Ohara S Sato N Suzuki Y Totsuka Y Yaginuma Y Mori M Oyama Y Suzuki A Takahashi K Yamada M Koshiba M Nishijima K Suda T Tajima T Miyano K Miyata H Takei H Fukuda Y Kodera E Nagashima Y Takita M Yokoyama H Kaneyuki K Takeuchi Y Tanimori T Beier EW Feldscher LR Frank ED Frati W Kim SB Mann AK Newcomer FM Van Berg R Zhang W 《Physical review D: Particles and fields》1992,45(6):2170