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41.
Spectroscopic and thermodynamic investigations on complexation of naphthalene-appended amino-beta-cyclodextrins 1 and 2 with cyclic alcohols (cyclohexanol and cycloheptanol) and acyclic alcohols (1-pentanol, 2-pentanol, 1-hexanol, and 1-heptanol) have been carried out. Host 1 exhibits a drastic fluorescent enhanced-signal change in the presence of alcohol guests in aqueous solution. [structure: see text] 相似文献
42.
Y. Goto K. Nakashima K. Mitsuishi M. Takafuji S. Sakaki H. Ihara 《Chromatographia》2002,56(1-2):19-23
Summary Poly(octadecyl acrylate) exists in a crystalline state at room temperature. This crystalline state was formed even after being
grafted onto silica through the terminal group of the polymer. When this polymer-grafted silica (Sil-ODAn) was used as a reversed phase liquid chromatography packing material, better selectivity for diastereomerized phenylethylamines
derivatized by (S)-(−)-(2,3-naphthalenedicarboximidyl)propionyl fluoride was observed at room temperature than was observed
for simple octadecylated silica (ODS). On the other hand, increasing temperature reduced the selectivity to be close to that
of ODS. Additional experiments showed the better selectivity derived from Sil-ODAn was due to both the highly-oriented structure of the polymer and the carbonyl-π interaction with the diastereomer. A theoretical
investigation of this carbonyl-π interaction is also described briefly. 相似文献
43.
Dr. Bishnu Prasad Bastakoti Prof. Kevin C.‐W. Wu Dr. Masamichi Inoue Prof. Shin‐ichi Yusa Prof. Kenichi Nakashima Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(15):4812-4817
We have developed core‐shell‐corona‐type polymeric micelles that can integrate multiple functions in one system, including the capability of accommodating hydrophobic dyes into core and hydrophilic drug into the shell, as well as pH‐triggered drug‐release. The neutral and hydrophilic corona sterically stabilizes the multifunctional polymeric micelles in aqueous solution. The mineralization of calcium phosphate (CaP) on the PAA domain not only enhances the diagnostic efficacy of organic dyes, but also works as a diffusion barrier for the controlled release. 相似文献
44.
Liquid deposition patterning of conducting polymer ink onto hard and soft flexible substrates via dip-pen nanolithography 总被引:1,自引:0,他引:1
Nakashima H Higgins MJ O'Connell C Torimitsu K Wallace GG 《Langmuir : the ACS journal of surfaces and colloids》2012,28(1):804-811
Ink formulations and protocols that enable the deposition and patterning of a conducting polymer (PEDOT:PSS) in the nanodomain have been developed. Significantly, we demonstrated the ability to pattern onto soft substrates such as silicone gum and polyethylene terephthalate (PET), which are materials of interest for low cost, flexible electronics. The deposition process and dimensions of the polymer patterns are found to be critically dependent on a number of parameters, including the pen design, ink properties, time after inking the pen, dwell time of the pen on the surface, and the nature of material substrate. By assessing these different parameters, an improved understanding of the ability to control the dimensions of individual PEDOT:PSS structures down to 600 nm in width and 10-80 nm in height within patterned arrays was obtained. This applicability of DPN for simple and nonreactive liquid deposition patterning of conducting polymers can lead to the fabrication of organic nanoelectronics or biosensors and complement the efforts of existing printing techniques such as inkjet and extrusion printing by scaling down conductive components to submicrometer and nanoscale dimensions. 相似文献
45.
Methane derivatives of CH(3)-X (X: H, F, Cl, Br, I, and CN) were ionized and fragmented by an intense femtosecond laser with a 40 fs pulse at 0.8 microm in intensities of 10(13)-10(15) W cm(-2). The curves of the ionization yields of CH(3)-X versus laser intensities have been found to be fitted with an atomic ionization theory (the theory of Perelomov, Popov, and Terent'ev) that has been established to reproduce experimental results well for rare gas atoms. The saturation intensities have been reproduced within a factor of 1.6 of the calculated ones. For molecules with low ionization potentials such as amines, another atomic ionization theory (the theory of Ammosov, Delone, and Krainov) reproduced the saturation intensities. The atomiclike ionization behavior of molecules indicates that the fragmentation occurs after the ionization. The fragmentation mechanisms after the ionization of some molecular ions are discussed. 相似文献
46.
Takao K Yasui H Yamamoto S Sasaki D Kawasaki S Watanabe G Tadano K 《The Journal of organic chemistry》2004,69(25):8789-8795
The total syntheses of (+)-mycoepoxydiene and (-)-1893A have been completed. The present synthetic strategy features the use of one-pot ring-opening/cross metathesis (ROM/CM) followed by a ring-closing metathesis (RCM) reaction, allowing for the concise construction of the 9-oxabicyclo[4.2.1]nona-2,4-diene framework from a 7-oxabicyclo[2.2.1]hept-2-ene derivative and 1,3-butadiene. The sequential metathesis product was converted into (+)-mycoepoxydiene through the oxidative rearrangement of a furfuryl alcohol to a pyranone, thereby establishing its absolute stereochemistry. From the common intermediate, a structurally related natural product (-)-1893A was also synthesized via the vinylogous aldol reaction. 相似文献
47.
Naoya Kishikawa Nobuhiro Ohkubo Kaname Ohyama Kenichiro Nakashima Naotaka Kuroda 《Analytical and bioanalytical chemistry》2009,393(4):1337-1343
A sensitive and selective chemiluminescence assay for the determination of quinones was developed. The method was based on
generation of reactive oxygen species through the redox reaction between quinone and dithiothreitol as reductant, and then
the generated reactive oxygen was detected by luminol chemiluminescence. The chemiluminescence was intense, long-lived, and
proportional to quinone concentration. It is concluded that superoxide anion was involved in the proposed chemiluminescence
reaction because the chemiluminescence intensity was decreased only in the presence of superoxide dismutase. Among the tested
quinones, the chemiluminescence was observed from 9,10-phenanthrenequinone, 1,2-naphthoquinone, and 1,4-naphthoquinone, whereas
it was not observed from 9,10-anthraquinone and 1,4-benzoquinone. The chemiluminescence property was greatly different according
to the structure of quinones. The chemiluminescence was also observed for biologically important quinones such as ubiquinone.
Therefore, a simple and rapid assay for ubiquinone in pharmaceutical preparation was developed based on the proposed chemiluminescence
reaction. The detection limit (blank + 3SD) of ubiquinone was 0.05 μM (9 ng/assay) with an analysis time of 30 s per sample.
The developed assay allowed the direct determination of ubiquinone in pharmaceutical preparation without any purification
procedure.
Figure Chemiluminescence generated through the redox cycle of quinone 相似文献
48.
Miyasaka H Nezu T Sugimoto K Sugiura K Yamashita M Clérac R 《Inorganic chemistry》2004,43(18):5486-5488
Heterometallic linear tetramers [Mn(5-R-saltmen)Ni(pao)(bpy)(2)](2)(ClO(4))(4) (5-R-saltmen(2-) = N,N'-1,1,2,2-tetramethylethylene bis(5-R-salicylideneiminate); pao(-) = pyridine-2-aldoximate; bpy = 2,2'-bipyridine, R = H, 1; Cl, 2; Br, 3; MeO, 4) have been synthesized and structurally characterized. These compounds exhibit a [Ni(II)-NO-Mn(III)-(O)(2)-Mn(III)-ON-Ni(II)] skeleton where -ON- is an oximate bridge between Mn(III) and Ni(II) ions and -(O)(2)- is a bi-phenolate bridge between Mn(III) ions. These tetramers can be seen as oligomeric units of the heterometallic Mn(III)(2)-Ni(II) chain observed in a family of single-chain magnets (Clérac, R.; Miyasaka, H.; Yamashita, M.; Coulon, C. J. Am. Chem. Soc. 2002, 124, 12837. Miyasaka, H.; Clérac, R.; Mizushima, K.; Sugiura, K.; Yamashita, M.; Wernsdorfer, W.; Coulon, C. Inorg. Chem. 2003, 42, 8203.). Magnetic measurements on these tetramers confirm the nature of the magnetic interactions reported for the Mn(III)(2)-Ni(II) chains: a strong antiferromagnetic Mn(III)/Ni(II) coupling via the oximate bridge (J(Ni-Mn) ranges from -23.7 to -26.1 K) and a weak ferromagnetic Mn(III)/Mn(III) coupling through the bi-phenolate bridge (J(Mn-Mn) ranges from +0.4 to +0.9 K). These magnetic interactions lead to tetramers with an S = 2 ground state. 相似文献
49.
Shigendo?Enomoto Ken-ichi?Kumagai Taro?Tamura Miki?Hasegawa Kyoko?Nakada Toshihiko?Hoshi Michio?KobayashiEmail author 《Monatshefte für Chemie / Chemical Monthly》2004,135(5):471-481
Summary. Fluoranthene (FA) forms a 1:1 van der Waals complex with benzene in cyclohexane. The 1H NMR spectrum of this complex shows that the FA moiety in the complex state has five kinds of hydrogen atoms and that the 1H NMR peaks assigned to the protons attached to the naphthalene skeleton are largely shifted to higher magnetic field on complex formation with benzene. These observations indicate that the complex takes the structure of CS symmetry, in which the benzene molecule mainly interacts with the electronic system localized on the naphthalene moiety of FA. The present ab initio calculations reproduce well the 1H NMR spectral shifts mentioned above and the experimentally predicted CS structure of the complex. According to the PPP calculations for the electronic absorption spectral changes on the complex formation, the FA-benzene complex is considered to take a sandwich type structure. 相似文献
50.
Biju V Muraleedharan D Nakayama K Shinohara Y Itoh T Baba Y Ishikawa M 《Langmuir : the ACS journal of surfaces and colloids》2007,23(20):10254-10261
We identified an insect neuropeptide, namely, allatostatin 1 from Drosophila melanogaster, that transfects living NIH 3T3 and A431 human epidermoid carcinoma cells and transports quantum dots (QDs) inside the cytoplasm and even the nucleus of the cells. QD-conjugated biomolecules are valuable resources for visualizing the structures and functions of biological systems both in vivo and in vitro. Here, we selected allatostatin 1, Ala-Pro-Ser-Gly-Ala-Gln-Arg-Leu-Tyr-Gly-Phe-Gly-Leu-NH2, conjugated to streptavidin-coated CdSe-ZnS QDs. This was followed by investigating the transfection of live mammalian cells with QD-allatostatin conjugates, the transport of QDs by allatostatin inside the nucleus, and the proliferation of cells in the presence of allatostatin. Also, on the basis of dose-dependent proliferation of cells in the presence of allatostatin we identified that allatostatin is not cytotoxic when applied at nanomolar levels. Considering the sequence similarity between the receptors of allatostatin in D. melanogaster and somatostatin/galanin in mammalian cells, we expected interactions and localization of allatostatin to somatostatin/galanin receptors on the membranes of 3T3 and A431 cells. However, with QD conjugation we identified that the peptide was delivered inside the cells and localized mainly to the cytoplasm, microtubules, and nucleus. These results indicate that allatostatin is a promising candidate for high-efficiency cell transfection and nucleus-specific cell labeling. Also, the transport property of allatostatin is promising with respect to label/drug/gene delivery and high contrast imaging of live cells and cell organelles. Another promising application of allatostatin is that the transport of QDs inside the nucleus would lift the limit of general photodynamic therapy to nucleus-specific photodynamic therapy, which is expected to be more efficient than photosensitization at the cell membrane or in the cytoplasm as a result of the short lifetime of singlet oxygen. 相似文献