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91.
Self-assembled monolayers (SAMs) of optically active Co(III) complexes ((S)-2/(R)-2) that contain (S)- or (R)-phenylalanine derivatives as a molecular recognition site were constructed on Au electrodes ((S)-2-Au/(R)-2-Au). Molecular recognition characteristics induced by the S and R configurations were investigated by measurements of electron-transfer reactions with horse heart cytochrome c (cyt c). The electrochemical studies indicate that the maximum current of cyt c reduction is obtained when the Au electrode is modified by 2 with a moderate coverage of approximately 4.0 x 10(-11) mol cm(-2). Since the Au electrode is not densely packed with the Co(III) units at this concentration, we conclude that the penetrative association process between cyt c and the Co(III) unit plays an important role in this electron-transfer system. The differences in the electron-transfer rates of (S)-2-Au and (R)-2-Au increase with increasing scan rates, a result indicating that the chiral ligand has an influence on the rate of association of the complexes with cyt c. 3-Au has a mixed monolayer composed of 2 and hexanethiol and exhibits electron-transfer behavior comparable to 2-Au. The difference in the association rates of (S)-3-Au and (R)-3-Au is larger than that between (S)-2-Au and (R)-2-Au, which indicates that the molecular recognition ability of 3-Au has been enhanced by filling the gap between molecules of 2 with hexanethiols. The differences in the oxidation rates of cyt c(II) between (S)-2-Au and (R)-2-Au and between (S)-3-Au and (R)-3-Au were larger than the differences in the rates of the reduction of cyt c(III); this suggests that the size of the heme crevice varies according to the oxidation state of cyt c.  相似文献   
92.
A novel container complex in which a 1.4 nm gold cluster is confined within a hexaporphyrin cage was synthesized; the cage showed notable confinement capability for the cluster core, but allowed the interpenetration of small molecules into the interstitial space.  相似文献   
93.
Tomohiko Fujii 《Tetrahedron》2005,61(33):7874-7893
Circadian rhythmic plant leaf-movement, called nyctinasty, is controlled by a time-course change in the internal concentration of the leaf-movement factor in the plant body. We revealed that specific binding proteins (210 and 180 kDa) for the leaf-movement factor, potassium lespedezate (1), are contained in the plasma membrane of the plant motor cell by using novel synthetic photoaffinity probes. These proteins are localized on the motor cell in the plant body, and would be potential receptors for the leaf-movement factor to control the leaf-movement. Our study is a rare successful result of the detection of membrane receptors by using a synthetic photoaffinity probe designed on a biologically active natural product. And these results also advance a guideline for probe design towards successful photoaffinity labeling.  相似文献   
94.
Anions PF 6 and CF 3 SO 3 are trapped by the new radical host [(Cu-dppe)3{hat-(CN)6}]2+, which was synthesized in a one-pot reaction from a copper(I ) source, hat-(CN)6, and dppe in acetone. The trapped salts have been characterized both in solution and in the solid state (see picture: A: PF6, CF3SO3). hat-(CN)6=hexaazatriphenylene hexacarbonitrile; dppe=1,2-bis(diphenylphosphanyl)ethane.  相似文献   
95.
Novel gel systems demonstrating rhythmically pulsatile mechanical motion similar to that of a heartbeat were developed. Self-oscillations of swelling and deswelling for the polymer hydrogels were realized by coupling pH and temperature sensitive hydrogels with a non-linear chemical reaction in the external solution media. The novel gel dynamics exhibiting cyclic and rhythmical oscillations may establish a new concept for functional materials that work under dynamic oscillating states.  相似文献   
96.
A series of hydrazone and N-acylhydrazone derivatives of dehydroabietic acid were synthesized and evaluated for BK channel-opening activities in an assay system of CHO-K1 cells expressing hBKa channels.The assay results indicated that the activities of the investigated compounds were influenced by the physicochemical properties of the substituent at hydrazone moiety.  相似文献   
97.
98.
The application of layered solids for molecular recognition is summarized. By using layered solids (silicates, aluminosilicates, titanates, hydroxides, and so on), ions and molecules can be concentrated from aqueous and vapor phases. The large surface area and tunable surface properties derived from the layered structures contribute to molecular recognition. The choice of materials and modification of the nanostructure were carefully investigated to optimize the performance based on molecular recognition (selective adsorption, substrate selective reaction, detection, etc.). The progress made in materials syntheses (variation of layered materials, sophisticated modification, controlled morphology, and processing) has made the design of materials more attractive and realistic.  相似文献   
99.
Novel polyamide with chiral environment was obtained from aromatic diamine, 4,4′‐diaminodiphenylmethane (DADPM), and N‐α‐protected L ‐glutamic acid, N‐α‐benzoyl‐L ‐glutamic acid (Benzoyl‐L ‐Glu‐OH). The optical rotation ([α]D ) of the polyamide was determined to be 3.6° (c = 1.00 g/dL in DMF), implying that the optically active polyamide was obtained. The present polyamide gave a durable self‐standing membrane. The membrane selectively incorporated the D ‐isomer of Ac‐Trp from racemic mixture of Ac‐Trp. The adsorption selectivity toward Ac‐D ‐Trp was determined to be 1.95. It showed chiral separation ability by adopting potential difference as a driving force for membrane transport. The permselectivity was dependent on the potential difference, and at the applied potential difference of 3.0 V, the membrane selectively transported Ac‐D ‐Trp and the permselectivity toward Ac‐D ‐Trp was determined to be 1.84, which was close to the adsorption selectivity of 1.95. Contrary to this, the membrane showed opposite permselectivity at the applied potential difference of 2.0 V and the permselectivity toward the L ‐isomer reached 2.48. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2530–2538, 2009  相似文献   
100.
Benzylzirconocene intermediate, which was readily prepared by the reaction of o-alkoxymethylstyrene with `Cp2Zr' under mild conditions, reacted with allylic halides or phosphates in the presence of catalytic amount of CuCl to give allylated products in good yields.  相似文献   
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