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721.
Shin-ichi Kawaguchi 《Tetrahedron letters》2006,47(23):3919-3922
Under an atmosphere of nitrogen, the photoinduced reaction of tetraphenyldiphosphine (1) with alkynes (2) generates vicinal bisphosphinated alkenes (3) as air-sensitive compounds, which can be isolated by treatment with elemental sulfur. A novel E to Z isomerization of 3 is revealed to take place upon continuous photoirradiation. 相似文献
722.
Naumov P Sakurai K Asaka T Belik AA Adachi S Takahashi J Koshihara SY 《Inorganic chemistry》2006,45(13):5027-5033
The structural grounds of the decrease of point and lattice symmetries coupled with switching of the exchange interaction in single crystals of a highly strained, coordinationally unsaturated bisdiaminecopper(II) cation are described. The combined magnetic susceptibility and X-ray diffraction results indicate that the interplay between the inherent vibronic instability and ligand-field strain imposed by moderately flexible, coordinationally shielding ligands enables effective switching of the pseudo-Jahn-Teller d9 centers between states with different exchange interaction in the low-temperature regime and valence orbital orientation and coordination geometry in the high-temperature regime. Within the low-temperature hysteresis region, the phase transition can also be induced by excitation of the ligand-to-metal charge-transfer bands, resulting in overall shrinkage of the lattice. The compound is a prototype of weakly electronically coupled one-dimensional Jahn-Teller systems, which can undergo phase transitions induced by light, in addition to heating, cooling, and change of pressure, and it represents a prospective basis for the design of switching materials capable of multimode external control. 相似文献
723.
Tabayashi K Yamamoto K Takahashi O Tamenori Y Harries JR Gejo T Iseda M Tamura T Honma K Suzuki IH Nagaoka S Ibuki T 《The Journal of chemical physics》2006,125(19):194307
Inner-shell excitation spectra and fragmentation of small clusters of formic acid have been studied in the oxygen K-edge region by time-of-flight fragment mass spectroscopy. In addition to several fragment cations smaller than the parent molecule, we have identified the production of HCOOH.H+ and H3O+ cations characteristic of proton transfer reactions within the clusters. Cluster-specific excitation spectra have been generated by monitoring the partial ion yields of the product cations. Resonance transitions of O1s(C[double bond]O/OH) electrons into pi(CO)* orbital in the preedge region were found to shift in energy upon clusterization. A blueshift of the O1s(C[double bond]O)-->pi(CO)* transition by approximately 0.2 eV and a redshift of the O1s(OH)-->pi(CO)* by approximately 0.6 eV were observed, indicative of strong hydrogen-bond formation within the clusters. The results have been compared with a recent theoretical calculation, which supports the conclusion that the formic-acid clusters consist of the most stable cyclic dimer andor trimer units. Specifically labeled formic acid-d, HCOOD, was also used to examine the core-excited fragmentation mechanisms. These deuterium-labeled experiments showed that HDO+ was formed via site-specific migration of a formyl hydrogen within an individual molecule, and that HD2O+ was produced via the subsequent transfer of a deuterium atom from the hydroxyl group of a nearest-neighbor molecule within a cationic cluster. Deuteron (proton) transfer from the hydroxyl site of a hydrogen-bond partner was also found to take place, producing deuteronated HCOOD.D+ (protonated HCOOH.H+) cations within the clusters. 相似文献
724.
725.
Anion recognition properties of d-ribose-based receptors α- and β-1 were measured by 1H NMR in CDCl3 and MeCN-d3. Receptor β-1 showed effective binding with anions by cooperative hydrogen bonds of cis-diol. The anomeric isomer α-1 is a less effective anion receptor which has similar cis-diol as a recognition site, indicating that the stereo configuration of the anomeric position is of significant influence on the anion recognition ability. 相似文献
726.
727.
Koji Kakutani Yoshinori Matsuda Kayo Haneda Dai Sekoguchi Teruo Nonomura Junji Kimbara Kazumi Osamura Shin-ichi Kusakari Hideyoshi Toyoda 《Journal of Electrostatics》2012,70(2):207-211
An insulated conductor wire (ICW) paralleled with an earthed net was used to observe movements by vinegar flies in relation to their electricity release. ICW was negatively charged to create a positive charge on the net. At particular voltages, flies were attracted to ICW. This attraction was triggered by the deprivation of the insect negative charge with the net. Eventually the insects became net positive and were drawn to the ICW negative charge. The attracted insects generated bioelectricity through skeletal muscular movements. However, the electricity produced was depleted by the net without neutralizing their positive charge in the insect body. 相似文献
728.
Sebastian Lalik Olaf Stefaczyk Dorota Dardas Aleksandra Deptuch Tetiana Yevchenko Shin-ichi Ohkoshi Monika Marzec 《Molecules (Basel, Switzerland)》2022,27(12)
Modification of the physical properties of the (S)-MHPOBC antiferroelectric liquid crystal (AFLC) by doping with low concentrations of gold nanoparticles is presented for the first time. We used several complementary experimental methods to determine the effect of Au nanoparticles on AFLC in the metal–organic composites. It was found that the dopant inhibits the matrix crystallization process and modifies the phase transitions temperatures and switching time, as well as increases the helical pitch and spontaneous polarization, while the tilt angle slightly changes. We also showed that both the LC matrix and Au nanoparticles show strong fluorescence in the green light range, and the contact angle depends on the temperature and dopant concentration. 相似文献
729.
Shin-ichi Naya Atsunobu Akita Yoko Morita Musashi Fujishima Hiroaki Tada 《Chemical science》2022,13(42):12340
A big question in the field of plasmonic photocatalysis is why a typical photocatalyst consisting of gold nanoparticles and rutile titanium(iv) oxide (Au/R-TiO2) usually exhibits activity much higher than that of Au/anatase TiO2 (Au/A-TiO2) under visible-light irradiation. Shedding light on the origin should present important guidelines for the material design of plasmonic photocatalysts. Au nanoparticles (NPs) were loaded on ordinary irregular-shaped TiO2 particles by the conventional deposition precipitation method. Transmission electron microscopy analyses for the Au/TiO2 particles ascertain that faceting of Au NPs is induced on R-TiO2 by using a domain-matching epitaxial junction with the orientation of (111)Au//(110)R-TiO2, whereas non-faceted hemispherical Au NPs are exclusively formed on A-TiO2. The faceting probability of Au NPs (Pf) on R-TiO2 increases with decreasing Au particle size (dAu) to reach 14% at dAu = 3.6 nm. A clear positive correlation between the photocatalytic activity and Pf in several test reactions indicates that the heteroepitaxial junction-induced faceting of Au NPs is the principal factor for governing the plasmonic photocatalytic activity of Au/TiO2. In light of this finding, R-TiO2 nanorods with a high percentage (95%) of {110} facets were hydrothermally synthesized and used for the support of Au NPs. Consequently, the Pf value increases to as much as 94% to enhance the photocatalytic activity with respect to that of Au/R-TiO2 with Pf = 14% by factors of 2.2–4.4 depending on the type of reaction.In the represented plasmonic photocatalyst consisting of Au nanoparticles (NPs) and TiO2, the combination of crystal facet engineering of TiO2 and atom-level-interface control between Au NP and TiO2 gives rise to a drastic activity enhancement. 相似文献
730.