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121.
Dr. Xiaomin Liu Shih-Ya Chen Qiang Chen Xuelin Yao Dr. Márton Gelléri Dr. Sandra Ritz Dr. Sachin Kumar Prof. Dr. Christoph Cremer Prof. Dr. Katharina Landfester Prof. Dr. Klaus Müllen Prof. Dr. Sapun H. Parekh Prof. Dr. Akimitsu Narita Prof. Dr. Mischa Bonn 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(1):504-510
122.
Qiang Chen Di Wang Martin Baumgarten Dieter Schollmeyer Klaus Müllen Akimitsu Narita 《化学:亚洲杂志》2019,14(10):1703-1707
Dibenzo[hi,st]ovalene (DBOV) is a nanographene with a combination of zigzag and armchair edges, consisting of 38 sp2 carbons. Excellent optical properties with strong red emission have been demonstrated. Here we report the regioselective bromination of DBOV bearing two mesityl groups ( DBOV‐Mes ) by treatment with N‐bromosuccinimide (NBS) under mild conditions. The dibrominated DBOV was further subjected to transition‐metal‐catalyzed cross‐coupling reactions, that is, Suzuki and Sonogashira coupling, demonstrating the edge‐decoration of DBOV with different functional groups. Notably, DBOVs arylated at the bay regions showed intense red emission and enhanced fluorescence quantum yields of up to 0.97. Amphoteric reduction and oxidation behavior were observed by cyclic voltammetry (CV) measurements. Chemical oxidation to stable radical cation species was also demonstrated, followed by reduction back to their neutral species. 相似文献
123.
124.
Takafumi Shiraogawa Gaelle Candel Ryoichi Fukuda Ilaria Ciofini Carlo Adamo Akimitsu Okamoto Masahiro Ehara 《Journal of computational chemistry》2019,40(1):127-134
Recently, exciton-controlled hybridization-sensitive fluorescent oligonucleotide (ECHO) probe, which shows strong emission in the near-infrared region via hybridization to the target DNA and/or RNA strand, has been developed. In this work, photophysical properties of the chromophores of these probes and the fluorescent mechanism have been investigated by the SAC-CI and TD-DFT calculations. Three fluorescent cyanine chromophores whose excitation is challenging for TD-DFT methods, have been examined regarding the photo-absorption and emission spectra. The SAC-CI method well reproduces the experimental values with respect to transition energies, while the quantitative prediction by TD-DFT calculations is difficult for these chromophores. Some stable structures of H-aggregate system were computationally located and two of the configurations were examined for the photo-absorption. The present results support for the assumption based on experimental measurement in which strong fluorescence is due to the monomer unit in nearly planar structure and its suppression of probes is to the H-aggregates of two exciton units. Stokes shifts of these three chromophores were qualitatively reproduced by the theoretical calculations, while the energy splitting due to H-aggregate in the hybridized probe was slightly overestimated. © 2018 Wiley Periodicals, Inc. 相似文献
125.
Juan Hong Xuxian Xiao Haoliang Liu Evgenia Dmitrieva Alexey A. Popov Zidong Yu Prof. Ming-De Li Dr. Tatsuhiko Ohto Jun Liu Prof. Akimitsu Narita Pengcai Liu Prof. Hirokazu Tada Prof. Xiao-Yu Cao Prof. Xiao-Ye Wang Yingping Zou Prof. Klaus Müllen Prof. Yunbin Hu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(58):e202202243
We present here the synthesis and in-depth physicochemical characterization of a double hetero[7]helicene fused with four triazole rings at both helical ends. The comparison of this triazole-fused double helicene with the previously reported all-carbon and thiadiazole-fused analogs revealed the huge impact of the embedded aromatic rings on the photophysical features. The small structural variation of the terminal rings from thiadiazole to triazole caused a dramatic change of the photoluminescence quantum yields (PLQYs) from <1 % to 96 %, while the replacement of the terminal benzene rings with triazole rings induced a tenfold enhancement of the circularly polarized luminescence dissymmetry factor. These observations were well corroborated with transient absorption analysis and/or theoretic calculations. In addition, the triazole-fused double helicene exhibited ambipolar redox behavior, enabling the generation of radical cation and anion species by electrochemical and chemical methods and showing its potential for spin-related applications. 相似文献
126.
Mixed-ligand Cu(I) complexes containing phosphinesulfide ligands were synthesized, and the structure and emission properties were studied for the Cu(I) complexes. X-ray crystallographic study showed that a chelating phosphinesulfide and diimine are coordinated to Cu(I) center. Coordination geometry around Cu(I) center of each complex is described as a distorted tetrahedron. Some of the complexes show photoluminescence in the solid state. 相似文献
127.
We report on the development of a nucleoside labeled with a nitronyl nitroxide group, NNU, and the synthesis of oligodeoxynucleotides containing NNU. The spin signals of NNU-containing oligodeoxynucleotides varied with the degree of hybridization of the complementary strand and the distance between nitronyl nitroxide spins. 相似文献
128.
129.
A. Sugimoto T. Ekino R. Ukita K. Shohara H. Okabe J. Akimitsu A.M. Gabovich 《Physica C: Superconductivity and its Applications》2010,470(20):1070-1072
Iron-oxypnictide superconductor NdFeAs(O0.9F0.1) was studied using both low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) and tunnel break junction (BJ) methods. STM topography showed granular and spot structures with a typical size of several nanometers, most probably governed by fluorine atom distribution. The majority of STS conductance, G, versus voltage, V, curves revealed V-shaped structures, whereas some of G(V) dependences possessed coherent gap peaks or kinks at gap energies. At the same time, G(V) dependences obtained by the BJ technique showed clear-cut coherence peaks with peak-to-peak distances Vpp = 4Δ/e ∼ 25 mV at 4.2 K, where Δ is the superconducting energy gap, e > 0 is the elementary charge. This yields Δ(0) = 6–7 meV, so that the ratio 2Δ(0)/kBTc is about 3–4, kB being the Boltzmann constant. This value is consistent with the conventional weak-coupling s-wave Bardeen–Cooper–Schrieffer theory. 相似文献
130.
Strontium ferrite SrFe12O19 (SrM) thick films have been synthesized using a spinning coating sol–gel process. The coating sol was formed from SrFe12O19 powders dispersed in the strontium ferrite raw sol. XRD, TEM, SEM, vibrating sample magnetometer (VSM) and ac susceptometer were employed to evaluate the structure, composition and magnetic properties of SrFe12O19 thick films. The results indicated that a uniform and crack-free coating of Strontium ferrite with ∼15 μm thickness can be produced with a good deal of consistency. The magnetization hysteresis loops were almost the same for magnetic fields both applied in parallel and perpendicular. 相似文献