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151.
Takanori Iwasaki Shin Murakami Youhei Takeda Norimitsu Tohnai Nobuaki Kambe 《化学:亚洲杂志》2020,15(8):1349-1354
Changes in the photophysical properties of pyrene ( Py )‐octafluoronaphthalene ( OFN ) co‐crystals ( Py ? OFN ) upon mechanical stimuli are described herein. The Py ? OFN co‐crystal showed a mechano‐induced bathochromic shift in emission, and a similar tendency was observed for the 1,3,6,8‐tetramethylpyrene‐ OFN co‐crystal. These shifts are due to disruption of the microscopic molecular orientation in the co‐crystal, which allows for excimer formation. In sharp contrast to the parent Py ? OFN and methyl‐substituted Py ‐ OFN co‐crystals, no mechano‐induced bathochromic shift was observed when longer alkyl chains were introduced to the 1‐, 3‐, 6‐, and 8‐positions of the Py chromophore. This photophysical opposability against mechanical stimuli could be explained by the orthogonally oriented alkyl groups on the Py ring, which existed between two Py cores like pillars. This fixed OFN to maintain the face‐to‐face alternatively stacked structure of the co‐crystal and thus prevented the formation of the Py excimer. The pillar effect demonstrated herein provides a rational design for co‐crystalline systems that are photophysically stable against mechanical stresses. 相似文献
152.
Shigeru Murata Tadashi Sugawara Nobuaki Nakashima Keitaro Yoshihara Hiizu Iwamura 《Tetrahedron letters》1984,25(18):1933-1936
Laser-flash photolysis studies have been carried out on a solution of ap- and sp-9-(2-azido-4,6-dimethylphenyl)fluorenes (3) in methanol-ether at 25°C. The rates of formation of azanorcaradiene (5) from ap-nitrene (4) ap, and of 9-methoxyfluorene (7) from o-quinoid intermediate (6) were determined. The deuterium isotope effect on the migration of the hydrogen is discussed. 相似文献
153.
As a non-commutative extension of the Lévy Laplacian for entire functions on a nuclear space, we define the quantum Lévy Laplacian acting on white noise operators. We solve a heat type equation associated with the quantum Lévy Laplacian and study its relation to the classical Lévy heat equation. The solution to the quantum Lévy heat equation is obtained also from a normal-ordered white noise differential equation involving the quadratic quantum white noise. 相似文献
154.
Nobuaki Soh Koji Makihara Tomoyuki Ariyoshi Daisuke Seto Tomoharu Maki Hizuru Nakajima Koji Nakano Toshihiko Imato 《Analytical sciences》2008,24(2):293-296
A fluorescent probe, DPPEC (1,2-dipalmitoylglycerophosphorylethanolamine labeled with coumarin) was developed for detecting hydroxyl radical (*OH) in lipid membranes. The coumarin moiety contributes to the fluorescent detection of *OH and the phospholipids moiety gives a driving force to localize the probe in lipid membranes. DPPEC in liposomal membranes rapidly reacted with *OH and increased the fluorescence intensity, depending on the concentration of *OH. The increase in the fluorescence intensity induced by *OH was effectively suppressed by the addition of DMSO. The probe exhibited a higher fluorescence response to *OH over other reactive oxygen species, such as hydrogen peroxide, nitric oxide, peroxynitrite, alkylperoxyl radical, and hypochlorite. DPPEC would be useful as a new type of fluorescent probe that can localize in lipid membranes and detect *OH efficiently. 相似文献
155.
Nobukazu Ohnishi Yunosuke Makita Akimasa Yamada Hisao Asakura Tokue Matsumori 《Applied Surface Science》1991,50(1-4):233-236
The dependence of photoluminescence (PL) spectra at 2 K on the substrate orientation is reported for GaAs grown by molecular beam epitaxy (MBE). Samples investigated are GaAs grown on (n11)A- and (n11)B-oriented substrates where n is 2, 3, 5 and 9, and those on (321)A- (110)B- and (100)A-oriented ones. It was demonstrated that emissions denoted by defect-induced bound excitons (DIBE) present strong crystal orientation dependence. In the (n11) series, DIBE was enhanced peculiarly in (211)A and (311)A substrates and two sharp emissions denoted by t* and v3 were specifically observed there, but they were completely quenched for the (211)B substrate. When n exceeds 3, DIBE was observed ubiquitously in (n11)A and (n11)B substrates. The (321)A substrate indicated a most idiosyncratic DIBE with a strong enhancement of t* and v3. These results show that the spectral features pertinent to DIBE fully reflect the whole stacking process of impinging molecular beams on the growth front which is governed by the surface structure inherent to the surface dangling bonds of the substrate. 相似文献
156.
We have calculated the electronic states of AgX and CuX (X = Cl, Br, I) by using the DV-Xα method. The density of states (DOS) and the bond overlap populations (BOP) of AgX and CuX are calculated by assuming the several model clusters with the nearest, second, and third-neighbor atoms. The cluster-size variations of DOS and BOP are discussed from the viewpoint of the chemical bond between the neighboring ions. We found that the BOP of AgI and CuX are larger than those of AgCl and AgBr. This result is consistent with the Phillips ionicity for A
N
B8-N
compounds. Furthermore, we have investigated the variation of the BOP between Ag and I ions along the diffusion path of the mobile Ag ions in the model cluster for α-AgI. 相似文献
157.
Double silylation of 1,3-butadienes with chlorosilanes was found to proceed by using titanocene dichloride as the catalyst in the presence of nBuMgCl, giving rise to 1,4-disilylated 2-butenes in good yields. Aryl substituted alkenes also afforded 1,2-disilylated products under similar conditions. 相似文献
158.
159.
Uranium (IV) in polynary uranium oxides is determined after the solid has been dissolved in a warm mixed solution of sulphuric and phosphoric acids containing excess Ce(IV). The latter is titrated with a Fe(II) standard solution using ferroin as indicator. This method is especially effective for (mixed) uranium oxides which are difficult to dissolve in hot Ce(IV) sulphuric acid. The standard deviation of the determined x value in polynary oxides is estimated to be below ± 0.004 for samples of 10–30 mg. 相似文献
160.