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51.
52.
Kotaro Shirane Takayuki Tokimoto Osamu Tanimoto 《Zeitschrift für Physik B Condensed Matter》1992,89(2):243-246
Many chemical reactions in vivo are self-controlled by fluxes of chemical energy and matter through biological systems, so the induction of such reactions can be governed by changes in the control parameters of the rate equation. A potential of a system is assumed to be given by Gibbs' functionG(T, P, x), which is continuously differentiable, and the rate equation can be derived from the differential (–G/x) of Taylor's expansion ofG
(T,P)(x) for the order parameterx, which corresponds to the product number, at around the critical pointC(T
C, PC). The equation is described bydx/dt=(x)–k1x–k2x3, andk
2>0. In this equation,k
1 andk
2 are functions of the control parameters, temperatureT and pressureP, andk
1 is allowed to have a positive or negative values as (T, P). Thenk
1 is an important factor that decides the induction conditions of the reactions with a phase transition in the steady statex=0. Because bothk
1 (the transition parameter) andG are the quantity of state, they are given by the total differential, and functions that decideG andk
1 are related to a mutual inverse function. From the above relation, the rate of change ink
1 by G, which corresponds to the reaction energy of the system, is uniquely determined by a function ofk
1, [f(k
1
±
)] andf(k
1
±
) is described approximately by ±1
k
1
±
in the transient process thatk
1 approaches zero, where 1 implies 1/RT. These results indicate that internal driving forces caused by a stimulus in a system are proportional tok
1
±
and that the system is regulated by competition of the forces. an approximate function fork
1 in the transient process is described by tanh (G/RT) and Arrhenius' law is elucidated from this theory.Decreased January 19, 1992 相似文献
53.
Kenshu Fujiwara Masanori Kobayashi Fuyuki Yamamoto Yu-ichi Aki Mariko Kawamura Daisuke Awakura Seiji Amano Azusa Okano Akio Murai Hidetoshi Kawai Takanori Suzuki 《Tetrahedron letters》2005,46(30):5067-5069
The common left-half [C31-C33(OC1-C7)-C40] part of pectenotoxins has been synthesized convergently from the C31-C35, C36-C40, and C1-C7 parts. The C31-C35 part, prepared via a new route shorter than our previous route, was coupled with the C36-C40 part through reductive lithiation and addition reactions to give an adduct stereoselectively, which was converted to a cyclic acetal corresponding to the C31-C40 part. The left-half was synthesized by a three-step process including esterification of the C31-C40 part with the C1-C7 part. 相似文献
54.
Chromatographic separation of styrene-methyl methacrylate (MMA) copolymers depending on the chemical composition was studied using liquefied carbon dioxide as an adsorption promoting solvent, and tetrahydrofuran, chloroform containing ethanol as a desorption promoting solvent in the mobile phase and the column packed non-bonded silica gel by a solvent gradient method. With the increase of MMA content, the elution was retarded indicating that the typical normal-phase type of adsorption occurred. The effects of type of desorption solvents, molecular mass of sample, and column temperature on the elution were investigated. 相似文献
55.
Ruthenium‐Catalyzed Cycloisomerization of 2,2′‐Diethynyl‐ biphenyls Involving Cleavage of a Carbon–Carbon Triple Bond
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Prof. Dr. Takanori Matsuda Kotaro Kato Tsuyoshi Goya Shingo Shimada Prof. Dr. Masahiro Murakami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1941-1943
A ruthenium complex catalyzes a new cycloisomerization reaction of 2,2′‐diethynylbiphenyls to form 9‐ethynylphenanthrenes, thereby cleaving the carbon–carbon triple bond of the original ethynyl group. A metal–vinylidene complex is generated from one of the two ethynyl groups, and its carbon–carbon double bond undergoes a [2+2] cycloaddition with the other ethynyl group to form a cyclobutene. The phenanthrene skeleton is constructed by the subsequent electrocyclic ring opening of the cyclobutene moiety. 相似文献
56.
Akihiko Ishii Masashi Saitoh Tetsuhiko Kawai Masami Murata Juzo Nakayama 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2025-2026
The reaction of isolable dithiirane 1-oxides with (Ph 3 P) 2 Pt( m 2 -C 2 H 4 ) provided the title complexes in high yields. 31 P NMR spectroscopy of the phosphine ligands of the complexes and x-ray crystallographic analysis of a complex were reported. 相似文献
57.
58.
Green organogelators with a sulfide linkage and free amino groups were synthesized via phase transfer catalysis using a N-benzylcinchonidinium bromide catalyst. Their self-assemblies in various common solvents were examined. These compounds exhibit high gelation ability especially in aromatic and highly polar solvents with a low critical gelation of 0.1 wt %. The organogels were analyzed by 1H nuclear magnetic resonance (1H NMR) and Fourier transfer-infrared spectroscopies (FT-IR), and their phase transition temperatures were determined by differential scanning calorimetry. The homogeneity of the gel networks was examined by field emission scanning electron microscopy and transmission electron microscopy (TEM). A lamellar structure was also confirmed by X-ray diffraction analysis. The organogels were employed as soft-templates for the in situ generation of stable gold nanoparticles dispersed in the gel matrix, and the resulting GNP dispersions were studied by 1H NMR and UV–vis absorption. Transmission electron microscopy showed that GNPs assemble into a thin membrane-like structure. 相似文献
59.
60.
Prof. Dr. Tomoaki Tanase Dr. Kanako Nakamae Yume Okawa Mami Hamada Dr. Arimasa Matsumoto Prof. Dr. Takayuki Nakajima Prof. Dr. Takuya Nakashima Prof. Dr. Tsuyoshi Kawai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104060
A P-stereogenic linear tetraphosphine tetraoxide, (R,R)- or (S,S)-dpmppm(=O)4, was synthesized to prepare C2 dinuclear M(hfa)3 complexes (M=Eu, Tb, Y) as the first example of lanthanide(III) complexes with P-chiral multidentate phosphine oxides. The mononuclear M(hfa)3 complexes (M=Eu, Y) with a P-chiral diphosphine dioxide, tpdpb(=O)2, were also prepared, and comparison of their photophysical properties for the EuIII complexes revealed that significant chiral induction from the P-chiral centers arises on the achiral M(hfa)3 units through intramolecular π-π stacking constraint in the dinuclear system. 相似文献