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101.
Till J. B. Zähringer Julian A. Moghtader Maria-Sophie Bertrams Dr. Bibhisan Roy Masanori Uji Prof. Dr. Nobuhiro Yanai Prof. Dr. Christoph Kerzig 《Angewandte Chemie (International ed. in English)》2023,62(8):e202215340
Several energy-demanding photoreactions require harsh UV light from inefficient light sources. The conversion of low-energy visible light to high-energy singlet states via triplet-triplet annihilation upconversion (TTA-UC) could offer a solution for driving such reactions under mild conditions. We present the first annihilator with an emission maximum in the UVB region that, combined with an organic sensitizer, is suitable for blue-to-UVB upconversion. The annihilator singlet was successfully employed as an energy donor in subsequent FRET activations of aliphatic carbonyls. This hitherto unreported UC-FRET reaction sequence was directly monitored using laser spectroscopy and applied to mechanistic irradiation experiments demonstrating the feasibility of Norrish chemistry. Our results provide clear evidence for a novel blue light-driven substrate or solvent activation strategy, which is important in the context of developing more sustainable light-to-chemical energy conversion systems. 相似文献
102.
Takeda T Yamamoto M Yoshida S Tsubouchi A 《Angewandte Chemie (International ed. in English)》2012,51(29):7263-7266
Unsymmetrical ketones and allyltitanocenes generated by the desulfurizative titanation of γ,γ-disubstituted allyl phenyl sulfides react under highly diastereoselective construction of adjacent quaternary stereocenters (see scheme; R(L) = large group, R(S) = small group). The title reaction is stereospecific: the anti- and syn-homoallylic alcohols are obtained by the reaction of E- and Z-allylic sulfides, respectively. 相似文献
103.
Yamamoto Y Yamamoto A Furuta SY Horie M Kodama M Sato W Akiba KY Tsuzuki S Uchimaru T Hashizume D Iwasaki F 《Journal of the American Chemical Society》2005,127(42):14540-14541
The oxidized octaethyltetraphenylporphyrin (1, OETPP) and the corresponding newly prepared octaisobutyltetraphenylporphyrin (3, OisoBuTPP) could be isolated from the reaction of OETPPLi2 (or OisoBuTPPLi2) with SOCl2. The X-ray analysis and the characteristic UV-vis spectra of 1 and 3 revealed that these are the first examples of 16 pi nonaromatic porphyrins. 相似文献
104.
Masanori Asakura 《K-Theory》2002,27(3):273-280
We construct 0-cycles on a self-product of a curve whose cycle classes are linearly independent in the extension group of arithmetic Hodge structure. This is an extended version of Theorem 4.5 of Asakura's contribution to CMR Lecture Notes Ser. 24 ((2000), pp. 133–154). 相似文献
105.
Masahito Katto Hironari Zushi Wataru Nagaya Shinya Harano Ryota Matsumoto Atushi Yokotani Masanori Kaku Shoichi Kubodera Noriaki Miyanaga 《Applied Physics A: Materials Science & Processing》2010,101(2):297-301
We have developed intense vacuum ultraviolet (VUV) radiation sources for advanced material processing, such as photochemical
surface reactions and precise processing on a nanometer scale. We have constructed a new VUV laser system to generate sub-picosecond
pulses at the wavelength of 126 nm. A seed VUV pulse was generated in Xe as the 7th harmonic of a 882-nm Ti:sapphire laser.
The optimum conversion was achieved at the pressure of 1.2 Torr. The seed pulse will be amplified by the Ar2*\mathrm{Ar}_{2}^{*} media generated by an optical-field-induced ionization Ar plasma produced by the Ti:sapphire laser. We have obtained a gain
coefficient of g=0.16 cm−1. Our developing system will provide VUV ultra-short pulses with sub-μJ energy at a repetition rate of 1 kHz. 相似文献
106.
Abe M Adam W Hara M Hattori M Majima T Nojima M Tachibana K Tojo S 《Journal of the American Chemical Society》2002,124(23):6540-6541
Photodenitrogenation of the diazenes 4 affords exclusively the housanes 5 through intramolecular cyclization of the spectrally detected and characterized singlet diradicals 3. The lifetime of singlet diradical 3, determined by transient absorption measurements, depends on the Y and Z substituents at the para position of the phenyl ring and has the following order: Y, Z = OMe, OMe > OMe, CN > CN, CN > OMe, H > Cl, Cl approximately CN, H approximately Me, Me > H, H. This unprecedented substituent effect reveals stabilization of the singlet 2,2-dimethoxycyclopentane-1,3-diyl diradicals 3 through radical, zwitterionic, pi-bonding, and hyperconjugative structures. 相似文献
107.
We observed a small-signal gain of Ar2* emission at 126 nm by use of a hollow fiber to guide the high-intensity laser propagation in high-pressure Ar. The small-signal gain coefficient was measured to be 0.05 cm(-1) at 126 nm. Kinetic analysis revealed that the electrons produced by the high-intensity laser through an optical-field-induced ionization process initiated the Ar2* production processes. The increase in the emission intensity was measured to be exp(2.5), with an increase in the fiber length. 相似文献
108.
Masanori Yamanaka Shinsuke Honjo Yasuhiro Hatsugai Mahito Kohmoto 《Journal of statistical physics》1996,84(5-6):1133-1208
We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing. 相似文献
109.
110.
Dr. Arlin Jose Amali Dr. Hideto Hoshino Dr. Chun Wu Dr. Masanori Ando Prof. Qiang Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8279-8282
Highly photoluminescent carbon nanodots (CNDs) were synthesized for the first time from metal–organic framework (MOF, ZIF‐8) nanoparticles. Coupled with fluorescence and non‐toxic characteristics, these carbon nanodots could potentially be used in biosafe color patterning. 相似文献