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81.
Takehiko Nishio Tatsuhiro Tokunaga Yoshimori Omote 《Journal of heterocyclic chemistry》1985,22(2):405-407
β-Sulfenyl α, β-unsaturated ketones 1a-c reacted with guanidine or amidines to give pyrimidine derivatives 3 in 14-76% yields. Treatment of ketones 1 with diamines such as ethylenediamine and o -phenylenediamine afforded the seven-membered heterocycles, 2,3-dihydro-1,4-diazepine 5 and 2,3-benzo-1,4-diazepines 8a-c . 相似文献
82.
Supattra Somsri Naoto Kuwamura Tatsuhiro Kojima Nobuto Yoshinari Takumi Konno 《Chemical science》2020,11(34):9246
Cyclodextrins are widely used cyclic oligosaccharides of d-glucose whose hydrophilic exterior is covered by hydroxyl groups and whose hydrophobic interior is surrounded by lipophilic moieties. Because of this structural feature, cyclodextrin molecules commonly aggregate into dimensional structures via intermolecular hydrogen bonds, and their aggregation into closed oligomeric architectures has been achieved only via the attachment of functional substituent groups to the cyclodextrin rings. Here, we report the first structurally characterized self-assembly of non-substituted γ-cyclodextrin molecules into cyclic hexamers, which was realized in a chiral coordination framework composed of complex-anions with d-penicillamine rather than l- or dl-penicillamine. The self-assembly is accompanied by the 3D-to-2D structural transformation of porous coordination frameworks to form helical hexagonal cavities that accommodate helical γ-cyclodextrin hexamers. This finding provides new insight into the development of cyclodextrin chemistry and host–guest chemistry based on chiral recognition and crystal engineering processes.The complex anions with d-penicillamine are organized into a 3D porous framework that allows the inclusion of γ-CD. The inclusion is accompanied by the 3D-to-2D transformation of porous frameworks so as to accept cyclic hexamers of γ-CD. 相似文献
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Supramolecular Interaction of Fullerenes with a Curved π‐Surface of a Monomeric Quadruply Ring‐Fused Porphyrin 下载免费PDF全文
Yuta Saegusa Dr. Tomoya Ishizuka Dr. Tatsuhiro Kojima Dr. Shigeki Mori Prof. Dr. Masaki Kawano Prof. Dr. Takahiko Kojima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5302-5306
Molecular binding of fullerenes, C60 and C70, with the ZnII complex of a monomeric ring‐fused porphyrin derivative ( 2 ‐py) as a host molecule, which has a concave π‐conjugated surface, has been confirmed spectroscopically. The structures of associated complexes composed of fullerenes and 2 ‐py were explicitly established by X‐ray diffraction analysis. The fullerenes in the 2:1 complexes, which consist of two 2 ‐py molecules and one fullerene molecule, are fully covered by the concave surfaces of the two 2 ‐py molecules in the crystal structure. In contrast, in the crystal structure of the 1:1 complex consisting of one 2 ‐py molecule and one C60 molecule, the C60 molecule formed a π–π stacked pair with a C60 molecule in the neighboring complex using a partial surface, which was uncovered by the 2 ‐py molecule. Additionally, the molecular size of fullerene adopted significantly affects the 1H NMR spectral changes and the redox properties of 2 ‐py upon the molecular binding. 相似文献
86.
Frontispiece: Supramolecular Interaction of Fullerenes with a Curved π‐Surface of a Monomeric Quadruply Ring‐Fused Porphyrin 下载免费PDF全文
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Sato T Awano H Haba O Katagiri H Pu YJ Takahashi T Yonetake K 《Dalton transactions (Cambridge, England : 2003)》2012,41(27):8379-8389
We have synthesized a series of platinum (Pt) complexes having a rod-like ligand: 'Pt(F(2)PPy)acac', 'Pt(12F(2)PPy)acac', and 'Pt(12F(2)PPyO4)acac'. The crystal form of Pt(12F(2)PPy)acac was successfully determined to be triclinic by single-crystal X-ray structural analysis. The molecules were parallelly aligned in the unit cell. Monomer and excimer emissions of Pt(12F(2)PPy)acac were observed in hexane solution, poly(methyl methacrylate) film, and various nematic LCs. Homogeneous LC cells with the Pt complex/LC mixtures exhibited polarized optical emission resulting from monomer and excimer states. The PL intensity perpendicular to the orientation direction was higher than the parallel one in the whole wavelength region of the Pt complex and the polarization ratio of the excimer was higher than that of the monomer. The polarization ratios of the excimers were estimated to be 1.4-2.5 in nematic LC at room temperature, and decreased gradually with increasing temperature. The polarization ratios of Pt(12F(2)PPyO4)acac were higher than those of Pt(F(2)PPy)acac and Pt(12F(2)PPy)acac in all the LCs. 相似文献
90.
Oya K Nakazawa T Kittaka S Tsunetomo K Kintaka K Nishii J Hirao K 《Optics letters》2005,30(2):192-194
Silica-based one-dimensional photonic crystal (1D-PC) is fabricated by use of a high-spatial-frequency grating with input and output surfaces tilted with respect to its periodic direction. An incident beam is coupled with the first photonic band in the second Brillouin zone of the 1D-PC. The output beam angle changes 3 degrees with a wavelength change of 1%. A prototype of an ultrasmall demultiplexer is demonstrated by use of a silica slab waveguide with 1D-PC. 相似文献