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Borovkov VV Lintuluoto JM Sugiura M Inoue Y Kuroda R 《Journal of the American Chemical Society》2002,124(38):11282-11283
Interaction of the achiral syn (face-to-face) conformer of the ethane-bridged bis(zinc octaethylporphyrin) with the enantiopure 1,2-diaminocyclohexane results in the exclusive formation of a supramolecular chiral tweezer. This 1:1 host-guest complex exhibits remarkable stability in both solution (even upon photoexcitation) and solid-state phases, with a high degree of optical activity arising from the two-point interaction mode and optimal spatial geometry. 相似文献
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A hexapeptide motif, RKLPDA, that recognizes the surface of titanium was identified from a peptide phage selection. Mutational analyses showed electrostatic interaction was a major factor in the binding, paving a new way to modify the surface of Ti with active biomolecules. 相似文献
417.
Matsuzaki H Matsuoka T Kishida H Takizawa K Miyasaka H Sugiura K Yamashita M Okamoto H 《Physical review letters》2003,90(4):046401
In iodine-bridged binuclear Pt compounds, R(4)[Pt(2)(pop)(4)I]nH(2)O and R(')(2)[Pt(2)(pop)(4)I]nH(2)O (pop=P(2)O5H2-2), electronic structures on the PtPtI chains have been controlled between a diamagnetic charge-density-wave (CDW) state and a paramagnetic charge-polarization (CP) state by modification of the counterions (R, R') located between chains. In the R=(C2H5)2NH+2 compound, a pressure-induced CP to CDW transition with a drastic color change is identified. This transition is accompanied by a large hysteresis loop within which photoinduced transition between CDW and CP can be driven by selecting the excitation photon energy. 相似文献
418.
Three new trimeric stilbenes from Gnetum gnemon 总被引:1,自引:0,他引:1
Iliya I Ali Z Tanaka T Iinuma M Furasawa M Nakaya K Shirataki Y Murata J Darnaedi D Matsuura N Ubukata M 《Chemical & pharmaceutical bulletin》2003,51(1):85-88
Three stilbene trimers (gnemonols D, E, F) were isolated from the root of Gnetum gnemon. The structures were determined by spectroscopic analysis. In addition, the antioxidant activity of the compounds on lipid peroxide inhibition and super oxide scavenging activity were also investigated. 相似文献
419.
Kanehama R Umemiya M Iwahori F Miyasaka H Sugiura K Yamashita M Yokochi Y Ito H Kuroda S Kishida H Okamoto H 《Inorganic chemistry》2003,42(22):7173-7181
New molecular charge-transfer complexes of bis(ethylenedithio)tetrathiafulvalene (ET), (ET)Cu(2)Br(4) (1), (ET)(2)Cu(6)Br(10) (2), (ET)(2)[Cu(4)Br(6)ET] (3), (ET)(2)Cu(2)Br(4) (4), (ET)(2)Cu(3)Br(7)(H(2)O) (5), and (ET)(2)Cu(6)Br(10)(H(2)O)(2) (6), have been synthesized by diffusing reaction of ET and Cu(II)Br(2). Their crystal structures and physical properties have been investigated. X-ray analyses revealed that ET molecules coordinated to the copper ions with the sulfur atoms of the ethylenedithio groups in all compounds. The Cu-S distances are found in the range 2.268(5)-2.417(8) A, being close to the typical Cu(I)-S coordination bond distances. Strong d-pi interactions between d-electrons of the copper ions and pi-electrons of the ET molecules can be expected through the Cu-S coordination bonds. ET molecules behave as trans-bidentate ligands bonding to two different copper ions in 1 and 3, as cis-bidentate ligands in 2, 5, and 6, and as monodentate ligands in 4. In the crystal structure of 3, there are two types of ET molecules in the crystal structure, where the first type is a trans-bidentate ligand and the second forms a stacking structure by itself. Compounds 1, 2, 4, and 6 show semiconducting behavior down to low temperature (sigma(RT) = 1.6 x 10(-2) S cm(-1) and E(a) = 122 meV for 1, sigma(RT) = 2.1 S cm(-1) and E(a) = 21 meV for 2, sigma(RT) = 5.4 x 10(-4) S cm(-1) and E(a) = 239 meV for 4, and sigma(RT) = 5.1 x 10(-2) S cm(-1) and E(a) = 207 meV for 6). On the other hand, in 3, a metal-like region is observed along the b-axis and c-axis, due to the contribution of stacked ET molecules, and a metal-semiconductor transition occurs at 280 and 270 K, respectively. Also, 5 exhibits metallic conductivity in the temperature ranges 240-300 and 200-300 K along the b-axis and c-axis, respectively, despite the oxidation state of ET with 2+. 相似文献
420.