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991.
Prof. Dr. Shoichi Kutsumizu Akane Kawafuchi Prof. Dr. Yasuhisa Yamamura Dr. Taro Udagawa Takashi Otaki Masaki Masuda Prof. Dr. Yohei Miwa Prof. Dr. Kazuya Saito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10293-10302
A recent intriguing finding that a helical network arrangement forms the bicontinuous cubic phase is attracting great attention for the possibility of new routes to asymmetric synthesis by achiral molecules. However, the design of the molecular structure for the cubic phase is still unrevealed. In this work, a nonsymmetric core molecule with larger naphthalene and smaller benzene moieties at each side of the central linkage and the same disiloxanyldecyloxy terminal at both terminals is shown to be the first example of molecule forming both single-layered and double-layered core assembly modes in the Ia3d phase as a single molecule system. The molecule forms the former mode at high temperatures as a thermodynamically stable phase, similarly to the symmetric naphthalene core system, whereas, on cooling below a temperature (∼350 K), a metastable Ia3d phase forms a double-layered core state down to room temperature, which is common to the benzene core system. As another effect of the nonsymmetric core, the cubic phase is maintained at room temperature for more than 100 days with slight distortion. Infrared spectral studies and quantum chemical calculations suggested the easy transformation between the two core assembly modes. The core nonsymmetry can be a versatile fine-tuning of the core assembly mode and phase stability for the cubic phase molecules. 相似文献
992.
Dr. Tomohiro Ichitsuka Shingo Komatsuzaki Dr. Koichiro Masuda Dr. Nagatoshi Koumura Dr. Kazuhiko Sato Prof. Dr. Shū Kobayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(42):10844-10848
The N-arylation of chiral amino acid esters with minimal racemization is a challenging transformation because of the sensitivity of the α-stereocenter. A versatile synthetic method was developed to prepare N-arylated amino acid esters using cyclohexanones as aryl sources under continuous-flow conditions. The designed flow system, which consists of a coil reactor and a packed-bed reactor containing a Pd(OH)2/C catalyst, efficiently afforded the desired N-arylated amino acids without significant racemization, accompanied by only small amounts of easily removable co-products (i. e., H2O and alkanes). The efficiency and robustness of this method allowed for the continuous synthesis of the desired product in very high yield and enantiopurity with high space-time yield (74.1 g L−1 h−1) and turnover frequency (5.9 h−1) for at least 3 days. 相似文献
993.
Masayuki Kurokuzu Shinji Kitao Yasuhiro Kobayashi Makina Saito Ryo Masuda Takaya Mitsui Yoshitaka Yoda Makoto Seto 《Hyperfine Interactions》2014,226(1-3):687-691
The Mössbauer spectra of the 35.49 keV excited state of 125Te were observed in the energy domain using synchrotron radiation for the first time. The obtained isomer shifts and Debye temperature agree with previous experiments. These results show that this method will be applicable to various compounds. 相似文献
994.
Takayuki Masuda 《Geometriae Dedicata》2016,182(1):249-262
995.
996.
Takahiro Hosokawa Toshihiro Sugafuji Toshio Yamanaka Shun-Ichi Murahashi 《Journal of organometallic chemistry》1994,470(1-2)
Exclusive elimination of β-Pd-OH takes place in the oxypalladation intermediate derived from methyl (α-hydroxymethyl)acrylate and alcohols with PdCl2 catalyst, and no β-Pd-H elimination occurs. 相似文献
997.
998.
999.
Toshio Mikami 《Journal of multivariate analysis》2004,90(2):257-268
We modify and generalize the idea of covariance kernels for Borel probability measures on Rd, and study the relation between the central limit theorem in the total variation distance and the convergence of covariance kernels. 相似文献
1000.
Doping in amorphous silicon has been studied by P, B and Si implantation in evaporated silicon films made by electron beam evaporations. After double implantation of P and B, a compensation effect has been observed in implanted amorphous silicon layer. 相似文献