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21.
Tachi Y Aita K Teramae S Tani F Naruta Y Fukuzumi S Itoh S 《Inorganic chemistry》2004,43(15):4558-4560
A dicopper(I) complex supported by a novel asymmetric pentapyridine dinucleating ligand, consisting of tetradentate and tridentate metal-binding sites, has been synthesized and characterized. The dicopper(I) complex reacted with molecular oxygen at a low temperature to give an unprecedented mu-peroxo dicopper(II) complex presumably having a mu-eta1:eta2 binding mode, the spectroscopic features and the reactivity of which have been explored in detail. 相似文献
22.
Fukuzumi S Okamoto K Yoshida Y Imahori H Araki Y Ito O 《Journal of the American Chemical Society》2003,125(4):1007-1013
A ferrocene-quinone dyad (Fc-Q) with a rigid amide spacer and Fc-(Me)Q dyad, in which the amide proton acting as a hydrogen-bonding acceptor is replaced by the methyl group, are employed to examine the effects of hydrogen bonding on both the thermal and the photoinduced electron-transfer reactions. The hydrogen bonding of the semiquinone radical anion with the amide proton in Fc-Q(.-) produced by the electron-transfer reduction of Fc-Q is indicated by the significant positive shift of the one-electron reduction potential of Fc-Q. The hyperfine coupling constants of Fc-Q(.-) also indicate the existence of hydrogen bonding, agreeing with those predicted by the density functional calculation. The hydrogen-bonding dynamics in the photoinduced electron transfer from the ferrocene (Fc) to the quinone moiety (Q) in Fc-Q have been successfully detected in the femtosecond laser flash photolysis experiments. Thermal intramolecular electron transfer from Fc to Q in Fc-Q and Fc-(Me)Q also occurs efficiently in the presence of metal ions in acetonitrile at 298 K. The hydrogen bond formed between the semiquinone radical anion and the amide proton in Fc-Q results in remarkable acceleration of the rate of metal ion-promoted electron transfer as compared to the rate of Fc-(Me)Q in which hydrogen bonding is prohibited. The metal ion-promoted electron-transfer rates are well correlated with the binding energies of superoxide ion-metal ion complexes, which are derived from the g(zz) values of the ESR spectra. 相似文献
23.
24.
Shunichi Sakamoto Toshiyuki Sasaki Ayana Sato‐Tomita Satoshi Takamizawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(39):13860-13864
As altering permanent shapes without loss of material function is of practical importance for material molding, especially for elastic materials, shape‐rememorization ability would enhance the utility of elastic crystalline materials. Since diffusionless plastic deformability can preserve the crystallinity of materials, the interconversion of diffusionless mechanical deformability between superelasticity and ferroelasticity could enable shape rememorization of superelastic single crystals. This study demonstrates the shape rememorization of an organosuperelastic single crystal of 1,4‐dicyanobenzene through time‐reversible interconversion of superelasticity–ferroelasticity relaxation by holding the mechanically twinned crystal without heating. The shape‐rememorization ability of the organosuperelastic crystal indicates the compatibility of superelasticity (antiferroelasticity) and ferroelasticity as well as the intrinsic workability of organic crystalline materials capable of recovering their crystal functions under mild conditions. 相似文献
25.
Takeshi Eitoku Kazuya Taniguchi Yuta Nakazato Shunichi Ono Kenji Katayama 《Optical Review》2010,17(1):5-9
Formation process of gold nanoparticles was investigated by near-field heterodyne transient grating method. In the absence
of the protective agents, although the diffusion of H[AuICl2] could be observed after the photo-reduction of H[AuIIICl4], the diffusion of nanoparticle-seeds was not observed. On the other hand, in the presence of the protective agents, the
diffusion of a complex molecule (Au and protective agent) and nanoparticle-seeds could be observed. From these results, it
was found that enough amount of the complex is essential for the nanoparticle formation. We also investigated the formation
process with four different chemicals as a protective agent. The hydrodynamic radius of nanoparticle-seeds generated in the
poly(vinyl pyrrolidone) and TritonX-100 solutions were larger than those generated in the Tween 20 and Brij 58 solutions.
The former two have hydrophilic chain in the molecular structure; on the other hand, the latter two have hydrophobic alkyl
chain. Based on those facts, we concluded that the interaction between the chains of the complex molecule plays an important
role in the nanoparticle formation process. 相似文献
26.
Katsuya Maeyama Kenji Yamashita Shugo Maeda Noriyuki Yonezawa Shunichi Aikawa Yasuhiko Yoshida 《合成通讯》2013,43(23):4158-4170
Optically active aromatic ether ketone macrocycles containing 2,2′-dimethoxy-1,1′-binaphthyl-6,6′-diyl moieties were synthesized through electrophilic aromatic substitution reaction and stepwise nucleophilic aromatic substitution reactions. Structures of the resulting macrocycles were confirmed by NMR and matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass measurements. 相似文献
27.
Kei Ohkubo Kentaro Mizushima Shunichi Fukuzumi 《Research on Chemical Intermediates》2013,39(1):205-220
Efficient photocatalytic oxygenation of toluene occurs under visible light irradiation of 9-mesityl-10-methylacridinium (Acr+–Mes) in oxygen-saturated acetonitrile containing toluene and aqueous hydrochloric acid with a xenon lamp for 15 h. The oxygenated products, benzoic acid (70 %) and benzaldehyde (30 %), were formed after the photoirradiation. The photocatalytic reaction is initiated by intramolecular photoinduced electron transfer from the mesitylene moiety to the singlet excited state of the Acr+ moiety of Acr+–Mes, which affords the electron-transfer state, Acr?–Mes?+. The Mes?+ moiety can oxidize chloride ion (Cl?) by electron transfer to produce chlorine radical (Cl?), whereas the Acr? moiety can reduce O2 to O 2 ?? . The Cl? radical produced abstracts a hydrogen from toluene to afford benzyl radical in competition with the bimolecular radical coupling of Cl?. The benzyl radical reacts with O2 rapidly to afford the peroxyl radical, leading to the oxygenated product, benzaldehyde. Benzaldehyde is readily further photooxygenated to yield benzoic acid with Acr?–Mes?+. In the case of an aromatic compound with electron-donating substituents, 1,3,5-trimethoxybenzene, photocatalytic chlorination occurred efficiently under the same photoirradiation conditions to yield a monochloro-substituted compound, 2,4,6-trimethoxychlorobenzene. 相似文献
28.
Wen‐Jing Shi Dr. Mohamed E. El‐Khouly Dr. Kei Ohkubo Prof. Shunichi Fukuzumi Prof. Dennis K. P. Ng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(34):11332-11341
An efficient functional mimic of the photosynthetic antenna‐reaction center has been designed and synthesized. The model contains a near‐infrared‐absorbing aza‐boron‐dipyrromethene (ADP) that is connected to a monostyryl boron‐dipyrromethene (BDP) by a click reaction and to a fullerene (C60) using the Prato reaction. The intramolecular photoinduced energy and electron‐transfer processes of this triad as well as the corresponding dyads BDP‐ADP and ADP‐C60 have been studied with steady‐state and time‐resolved absorption and fluorescence spectroscopic methods in benzonitrile. Upon excitation, the BDP moiety of the triad is significantly quenched due to energy transfer to the ADP core, which subsequently transfers an electron to the fullerene unit. Cyclic and differential pulse voltammetric studies have revealed the redox states of the components, which allow estimation of the energies of the charge‐separated states. Such calculations show that electron transfer from the singlet excited ADP (1ADP*) to C60 yielding ADP.+‐C60.? is energetically favorable. By using femtosecond laser flash photolysis, concrete evidence has been obtained for the occurrence of energy transfer from 1BDP* to ADP in the dyad BDP‐ADP and electron transfer from 1ADP* to C60 in the dyad ADP‐C60. Sequential energy and electron transfer have also been clearly observed in the triad BDP‐ADP‐C60. By monitoring the rise of ADP emission, it has been found that the rate of energy transfer is fast (≈1011 s?1). The dynamics of electron transfer through 1ADP* has also been studied by monitoring the formation of C60 radical anion at 1000 nm. A fast charge‐separation process from 1ADP* to C60 has been detected, which gives the relatively long‐lived BDP‐ADP.+C60.? with a lifetime of 1.47 ns. As shown by nanosecond transient absorption measurements, the charge‐separated state decays slowly to populate mainly the triplet state of ADP before returning to the ground state. These findings show that the dyads BDP‐ADP and ADP‐C60, and the triad BDP‐ADP‐C60 are interesting artificial analogues that can mimic the antenna and reaction center of the natural photosynthetic systems. 相似文献
29.
Akter Sharmin Tanabe Tomoki Maejima Satoshi Kawauchi Satoko Sato Shunichi Hinoki Akinari Aosasa Suefumi Yamamoto Junji Nishidate Izumi 《Optical Review》2016,23(2):354-359
Optical Review - To quantify the changes in optical properties of in vivo rat liver tissue, we applied diffuse reflectance spectroscopy (DRS) system using single-reflectance fiber probe during... 相似文献
30.
过氧化氢既可用作环境友好的绿色氧化剂,也可用作燃料电池中的太阳能燃料,因而受到越来越多的关注.本文综述了太阳能驱动分子氧氧化水制备过氧化氢及其作为绿色氧化剂和燃料的研究进展.利用太阳能将水的e-和4e-氧化与分子氧的e-还原相结合,使光催化生产过氧化氢成为可能;本文讨论了与e-和4e-水氧化选择性及e-和4e-氧还原选择性相关的催化反应控制.由于光催化e-氧化水和e-还原分子氧的过程都产生过氧化氢,因此该组合的催化效率较高.太阳能光驱动水氧化及分子氧还原生产过氧化氢与过氧化氢催化氧化底物相结合,在该过程中分子氧用作最环保的氧化剂. 相似文献