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71.
Teruo Beppu Kosuke Tomiguchi Akito Masuhara Yong‐Jin Pu Hiroshi Katagiri 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(25):7440-7443
Benzene is the simplest aromatic hydrocarbon with a six‐membered ring. It is one of the most basic structural units for the construction of π conjugated systems, which are widely used as fluorescent dyes and other luminescent materials for imaging applications and displays because of their enhanced spectroscopic signal. Presented herein is 2,5‐bis(methylsulfonyl)‐1,4‐diaminobenzene as a novel architecture for green fluorophores, established based on an effective push–pull system supported by intramolecular hydrogen bonding. This compound demonstrates high fluorescence emission and photostability and is solid‐state emissive, water‐soluble, and solvent‐ and pH‐independent with quantum yields of Φ=0.67 and Stokes shift of 140 nm (in water). This architecture is a significant departure from conventional extended π‐conjugated systems based on a flat and rigid molecular design and provides a minimum requirement for green fluorophores comprising a single benzene ring. 相似文献
72.
Gold clusters protected by 3-mercaptophenylboronic acid (3-MPB) with a mean core diameter of 1.1 nm are successfully isolated, and their absorption, magnetic circular dichroism (MCD), and chiroptical responses in metal-based electronic transition regions, which can be induced by surface D-/L-fructose complexation, are examined. It is well-known that MCD basically corresponds to electronic transitions in the absorption spectrum, so simultaneous deconvolution analysis of electronic absorption and MCD spectra of the gold cluster compound is conducted under the constrained requirement that a single set of Gaussian components be used for their fitting. We then find that fructose-induced chiroptical response is explained in terms of the deconvoluted spectra experimentally obtained. We believe this spectral analysis is expected to benefit better understanding of the electronic states and the origin of the optical activity in chiral metal clusters. 相似文献
73.
Edwin W. Y. Wong Akito Miura Mathew D. Wright Qi He Prof. Charles J. Walsby Dr. Soji Shimizu Prof. Nagao Kobayashi Prof. Daniel B. Leznoff 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(39):12404-12410
In 1965, gold(II) phthalocyanine (AuPc, 1 ) was described to be synthesized from unsubstituted 1,3‐diiminoisoindoline and gold powder or AuBr. Compound 1 has been regarded as a rare example of a paramagnetic gold(II) complex. However, its chemistry, especially the oxidation state of the central gold ion, has not been previously explored due to the inherent insolubility of 1 caused by its unsubstituted structure. In our attempt to synthesize soluble AuPcs by using 5,6‐di‐substituted 1,3‐diiminoisoindolines, gold(III) phthalocyanine chloride ( 3 ) and a gold(III) complex of an unprecedented ring‐contracted phthalocyanine analogue ([18]tribenzo‐pentaaza‐triphyrin(4,1,1), 4 ) were isolated. With this discrepant result from the original literature in hand, a reinvestigation of the original AuPc synthesis by using unsubstituted 1,3‐diiminoisoindoline and various gold salts (including gold powder and AuBr) was performed, finding that only unsubstituted analogues of 3 and 4 or free‐base phthalocyanine were obtained. No gold(II)‐containing species could be isolated. 相似文献
74.
In this paper, we examine covering graphs that are obtained from the d -dimensional integer lattice by adding pendant edges. In the case of d=1, we show that the Laplacian on the graph has a spectral gap and establish a necessary and sufficient condition under which the Laplacian has no eigenvalues. In the case of d=2, we show that there exists an arrangement of the pendant edges such that the Laplacian has no spectral gap. 相似文献
75.
Hirozumi Azuma Akito Sagisaka Isao Ito Nobuo Kamiya Akihiko Nishimura Michiaki Mori Koichi Ogura 《Applied Surface Science》2009,255(24):9783-9786
Commercial single crystal silicon wafers and amorphous silicon films piled on single crystal silicon wafers were irradiated with a femtosecond pulsed laser and a nanosecond pulsed laser at irradiation intensities between 1017 W/cm2 and 109 W/cm2. In the single crystal silicon substrate, the irradiated area was changed to polycrystalline silicon and the piled silicon around the irradiated area has spindly column structures constructed of polycrystalline and amorphous silicon. In particular, in the case of the higher irradiation intensity of 1016 W/cm2, the irradiated area was oriented to the same crystal direction as the substrate. In the case of the lower irradiation intensity of 108 W/cm2, only amorphous silicon was observed around the irradiated area, even when the target was single crystal silicon. In contrast, only amorphous silicon particles were found to be piled on the amorphous silicon film, irrespective of the intensity and pulse duration.Three-dimensional thermal diffusion equation for the piled particles on the substrate was solved by using the finite difference methods. The results of our heat-flow simulation of the piled particles almost agree with the experimental results. 相似文献
76.
Science China Mathematics - Motivated by the study of coupled Kähler-Einstein metrics by Hultgren and Witt Nyström (2018) and coupled Kähler-Ricci solitons by Hultgren (2017), we... 相似文献
77.
Yusuke Hotta Tsukasa Kaneko Ryuji Hayashi Akito Yamamoto Shota Morimoto Junya Chiba Takenori Tomohiro 《化学:亚洲杂志》2019,14(3):398-402
We developed a novel diazirine‐based photolabeling agent having a (coumarin‐4‐yl)methyl ester scaffold, which exhibited multiple photochemical properties of crosslinking, fluorogenicity and cleavage. These properties can be kinetically regulated via photoinduced electron transfer between diazirine and coumarin moieties. The C?O bond of (coumarin‐4‐yl)methyl ester can be cleaved via photochemical excitation of coumarin moiety, that function has been initially quenched by the diazirine moiety. Upon diazirine photolysis with 365‐nm light, interacting protein was stably captured with photoactivatable ligand probe. Then, the unlocked cleavage function was activated with 313 nm light, and the reaction was accelerated in a weakly‐basic solution. The crosslinked protein could be selectively isolated with attachment of a small coumarin tag on the surface. This multi‐functional labeling agent has a great potential to facilitate LC‐MS/MS‐based protein identification. 相似文献
78.
Keigo Matsuyama Akito Fukui Kohei Miura Hisashi Ichimiya Yuki Aoki Yuki Yamada Prof. Atsushi Ashida Prof. Takeshi Yoshimura Prof. Norifumi Fujimura Prof. Daisuke Kiriya 《ChemistryOpen》2019,8(7):908-914
Transition metal dichalcogenides (TMDCs) have received attention as atomically thin post-silicon semiconducting materials. Tuning the carrier concentrations of the TMDCs is important, but their thin structure requires a non-destructive modulation method. Recently, a surface-charge transfer doping method was developed based on contacting molecules on TMDCs, and the method succeeded in achieving a large modulation of the electronic structures. The successful dopant is a neutral benzyl viologen (BV0); however, the problem remains of how to effectively prepare the BV0 molecules. A reduction process with NaBH4 in water has been proposed as a preparation method, but the NaBH4 simultaneously reacts vigorously with the water. Here, a simple method is developed, in which the reaction vial is placed on a hotplate and a fragment of air-stable metal is used instead of NaBH4 to prepare the BV0 dopant molecules. The prepared BV0 molecules show a strong doping ability in terms of achieving a degenerate situation of a TMDC, MoS2. A key finding in this preparation method is that a convection flow in the vial effectively transports the produced BV0 to a collection solvent. This method is simple and safe and facilitates the tuning of the optoelectronic properties of nanomaterials by the easily-handled dopant molecules. 相似文献
79.
80.
Photomobile Polymer Materials: Photoresponsive Behavior of Cross‐Linked Liquid‐Crystalline Polymers with Mesomorphic Diarylethenes 下载免费PDF全文
Dr. Jun‐ichi Mamiya Akito Kuriyama Naoki Yokota Dr. Munenori Yamada Prof. Dr. Tomiki Ikeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3174-3177
Cross‐linked liquid‐crystalline (LC) polymers with a mesomorphic diarylethene were prepared to demonstrate a versatile strategy for cross‐linked photochromic LC polymers as photomobile materials. Upon exposure to UV light to cause photocyclization of the diarylethene chromophore, the cross‐linked polymer films bend toward an actinic light source. By irradiation with visible light to cause a closed‐ring to open‐ring isomerization, the bent films revert to the initial flat state. Without visible‐light irradiation, the bent films remain bent even at 120 °C, indicating high thermal stability of the cross‐linked diarylethene LC polymers. 相似文献