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51.
Keisuke Wada Misaki Suzuki Dr. Takahiro Kakuta Prof. Dr. Tada-aki Yamagishi Dr. Shunsuke Ohtani Dr. Shixin Fa Dr. Kenichi Kato Prof. Dr. Shigehisa Akine Prof. Dr. Tomoki Ogoshi 《Angewandte Chemie (International ed. in English)》2023,62(19):e202217971
Controlling dynamic chirality and memorizing the controlled chirality are important. Chirality memory has mainly been achieved using noncovalent interactions. However, in many cases, the memorized chirality arising from noncovalent interactions is erased by changing the conditions such as the solvent and temperature. In this study, the dynamic planar chirality of pillar[5]arenes was successfully converted into static planar chirality by introducing bulky groups through covalent bonds. Before introducing the bulky groups, pillar[5]arene with stereogenic carbon atoms at both rims existed as a pair of diastereomers, and thus showed planar chiral inversion that was dependent on the chain length of the guest solvent. The pS and pR forms, regulated by guest solvents, were both diastereomerically memorized by introducing bulky groups. Furthermore, the diastereomeric excess was amplified by crystallization of the pillar[5]arene. The subsequent introduction of bulky groups yielded pillar[5]arene with an excellent diastereomeric excess (95 % de). 相似文献
52.
Tetsuro Murahashi Naohiro Kato Sensuke Ogoshi Hideo Kurosawa 《Journal of organometallic chemistry》2008,693(5):894-898
The reaction of a substitutionally labile dipalladium(I) complex [Pd2(CH3CN)6][BF4]2 (1) with 1,3,5,7-cyclooctatetraene (COT) in acetonitrile afforded [Pd2(μ-η3:η3-C8H8)(CH3CN)4][BF4]2 (2). The reaction of 2 with COT in acetonitrile yielded [Pd2(μ-η3:η3-C16H16)(CH3CN)4][BF4]2 (4), where COT is dimerized via C-C bond formation. Complexes 2 and 4 were structurally characterized by X-ray diffraction analyses. In dichloromethane, COT isomerized to styrene at room temperature in the presence of catalytic amount of 1, 2, or 4. 相似文献
53.
We report on hybrids of water-soluble calix[8]arenes and single-walled carbon nanotubes (SWCNTs); the hybrids formed supramolecular SWCNTs network polymer by adding guest dimer. 相似文献
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56.
Porous Carbon Fibers Containing Pores with Sizes Controlled at the Ångstrom Level by the Cavity Size of Pillar[6]arene 下载免费PDF全文
Dr. Tomoki Ogoshi Kumiko Yoshikoshi Ryuta Sueto Dr. Hirotomo Nishihara Prof. Tada‐aki Yamagishi 《Angewandte Chemie (International ed. in English)》2015,54(22):6466-6469
We report a new synthesis method of fibrous carbon material with pores sizes that are precisely controlled at the Ångstrom level, by carbonization of two dimensional (2D) porous sheets of pillar[6]arenes. The 2D porous sheets were prepared by 2D supramolecular polymerization induced by oxidation of hydroquinone units of pillar[6]arenes. Owing to the hexagonal structure of pillar[6]arene, the assembly induced by 2D supramolecular polymerization gave hexagonal 2D porous sheets, and the highly ordered structure of the 2D porous sheets formed regular fibrous structures. Then, carbonization of the 2D porous sheets afforded fibrous carbon materials with micropores. The micropore size of the fibrous porous carbon prepared from pillar[6]arene was the same size as that of the starting material pillar[6]arene assembly. 相似文献
57.
Inside Back Cover: Porous Carbon Fibers Containing Pores with Sizes Controlled at the Ångstrom Level by the Cavity Size of Pillar[6]arene (Angew. Chem. Int. Ed. 22/2015) 下载免费PDF全文
58.
Enantiomers of bulky percyclohexylmethyl-substituted pillar[5]arene (Cy-C1-Pillar) were able to be separated by chiral column chromatography, and the separated enantiomers did not racemize. Even though modified with the bulky cyclohexylmethyl-substituents at both rims, Cy-C1-Pillar was able to capture a guest molecule. 相似文献
59.
We synthesized chiral-substituents modified pillar[5]arene for the first time. The chiral-substituents modified pillar[5]arene showed planar chirality and interconversion between (pS) and (pR) forms took place quickly. The planar chirality was switched by temperature, solvents, and addition of achiral guest. As the measurement temperature increased, the diastereomeric excess was decreased. The diastereomeric excesses were high in low-permittivity solvents, while a low diastereomeric excess was observed in high-permittivity solvents. Addition of achiral guest induced an increase of negative CD intensities. 相似文献
60.
Murahashi T Okuno T Usui K Takase K Otani T Ogoshi S Kurosawa H 《Dalton transactions (Cambridge, England : 2003)》2011,40(10):2383-2387
The transmetallation of the palladacyclopentadiene complex Pd{C(COOMe)C(COOMe)C(COOMe)C(COOMe)}(bipy) with the dicationic Pd(II) complex [Pd(bipy)(CH(3)CN)(2)][BF(4)](2) afforded a terminally σ-palladated diene complex [Pd(2){μ-η(1):η(1)-C(COOMe)C(COOMe)C(COOMe)C(COOMe)}(bipy)(2)(CH(3)CN)(2)][BF(4)](2). It was revealed by X-ray crystallographic analysis that replacement of the acetonitrile ligands in a terminally σ-palladated diene complex with PPh(3) ligands resulted in the conformation change of the σ-palladated diene moiety from skewed s-cis to planar s-trans. Treatment of a bis-triphenylphosphine dipalladium complex [Pd(2)(PPh(3))(2)(CH(3)CN)(4)][PF(6)](2) with dimethoxyacetylene dicarboxylate (DMAD) (1 equiv.) in acetonitrile resulted in the insertion of DMAD to the Pd-Pd bond to afford [Pd(2){μ-η(1):η(1)-C(COOMe)C(COOMe)}(PPh(3))(2)(CH(3)CN)(4)][PF(6)](2). Addition of the second DMAD gave the ylide-type complex [Pd(2){μ-η(2):η(3)-C(COOMe)C(COOMe)C(COOMe)C(COOMe)(PPh(3))}(PPh(3))(2)(CH(3)CN)(3)][PF(6)](2) of which the structure was determined by X-ray crystallographic analysis. 相似文献