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Frontispiece: Auger Ionization Beats Photo‐Oxidation of Semiconductor Quantum Dots: Extended Stability of Single‐Molecule Photoluminescence
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Misawa T Aoyama H Furuyama T Dodo K Sagawa M Miyachi H Kizaki M Hashimoto Y 《Chemical & pharmaceutical bulletin》2008,56(10):1490-1495
Benzhydrol-type analogs of 1'-acetoxychavicol acetate (ACA) were developed as inhibitors of human leukemia HL-60 cell growth based on quantitative structure-activity relationship (QSAR) analysis. An analog containing an anthracenyl moiety (8) was a potent inhibitor with the IC(50) value of 0.12 microM. 相似文献
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Sakano T Higashiguchi K Matsuda K 《Chemical communications (Cambridge, England)》2011,47(29):8427-8429
Tetraphenylporphyrin (TPP) rhodium chlorides coordinated by planar and twisted 4-phenylpyridine derivatives were synthesized. An STM image was taken by a 2-D phase separation technique and the conductance was evaluated. Difference in apparent height between these phenylpyridines reflects the conductance ratio of ligands. 相似文献
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Masaki Horie Tatsuaki Sakano Kohtaro Osakada 《Journal of organometallic chemistry》2006,691(26):5935-5945
Thiols functionalized with N-aryl[3]azaferrocenophane formulated as HS-(CH2)n-N(CH2Cp)2Fe (1: n = 6, 2: n = 8, 3: n = 10, 4: n = 12) and disulfide obtained by oxidation of 4 (5) were synthesized via three or four steps reactions starting from 1,1′-ferrocenedimethanol, 4-aminophenol, and α,ω-aklanedithiol. Self-assembled monolayers (SAMs) of these thiols and disulfide on gold electrode were prepared by immersing the electrode in MeCN solutions of the compounds. Cyclic voltammograms of the SAM of 1 (n = 6) exhibited reversible redox of the Fe center at E1/2 = 0.26 V (vs. Ag+/Ag) in the presence of Et4NBF4 in MeCN and at E1/2 = 0.40 V (vs. AgCl/Ag) in the presence of NaClO4 in H2O. Addition of HClO4 to the solutions shifted the redox peaks to higher potentials, E1/2 = 0.51 V (vs. Ag+/Ag) in MeCN and E1/2 = 0.48 V (vs. AgCl/Ag) in H2O, respectively, which was ascribed to positive charge of tertiary ammonium group formed by protonation of the amino group of the azaferrocenophane. E1/2 of SAM of 1 in H2O solution varies depending on the anion contained in the electrolyte, NaClO4 (0.40 V), NaBF4 (0.46 V), Na2SO4 (0.53 V), and NaCl (0.55 V). Kinetic data of electron transfer between the Fe center and the gold surface of the SAM of 2-4 were obtained with variable scanning rate. Laviron’s analysis provided tunneling constant β, 0.05 Å−1, suggesting that the structural changes in the SAMs on oxidation/reduction undergoes the insignificant change of the kinetic constants of the electron transfer depending on the range of the spacer length. In the acidic aqueous media, the kinetic parameters indicated that the imbalanced electron transfer between oxidized and reduced states of the Fe center was caused by the protonation of bridged amine group of azaferrocenophane. 相似文献
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A highly sensitive method for measuring endogenous vitamin K1, menaquinone-4 (which is one of the K2 vitamins) and vitamin K1 2,3-epoxide in human plasma was developed, based on high-performance liquid chromatography with coulometric reduction and fluorimetric detection, following extraction from plasma and purification on a Sep-Pak silica cartridge. The detection limits of vitamin K1, menaquinone-4 and vitamin K1 2,3-epoxide were 5, 5 and 8 pg per injection for the standard substances and 30, 30 and 50 pg/ml in human plasma, respectively. 相似文献
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Abe I Sakano Y Sodeyama M Tanaka H Noguchi H Shibuya M Ebizuka Y 《Journal of the American Chemical Society》2004,126(22):6880-6881
Recombinant beta-amyrin synthase from Pisum sativum converted 24,30-bisnor-2,3-oxidosqualene into a 3:1:0.2 mixture of 29,30-bisnor-beta-amyrin, 29,30-bisnorgermanicol, and 29,30-bisnor-delta-amyrin. Further, enzyme reactions with [23-13C]- and [23,23-2H]-labeled isotopomers demonstrated that the cyclization did not proceed through formation of a lupanyl primary cation with a five-membered E-ring, but an electrophilic addition of the tetracyclic C-18 cation on to the terminal double bond directly generated a thermodynamically favored pentacyclic secondary cation with a less-strained six-membered E-ring. Interestingly, the formation of the three regioisomers suggested that the absence of the terminal methyl groups resulted in a structural perturbation in the folding conformation of the E-ring of the oleanyl cation at the active site of the enzyme. 相似文献
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