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101.
102.
[Structure: see text]. Molecular devices incorporating azobenzene units represent active components of smart systems, as they are capable of exhibiting photoregulated cooperative molecular motion. Herein, we describe the synthesis, X-ray crystal analysis, and photochemical and thermal studies of a xanthene based cyclic azobenzene dimer and its precursor. The trans-trans isomer of the azobenzene dimer upon photoirradiation transforms to the cis-cis isomer through an intermediate trans-cis isomer. The X-ray crystal structures of the trans-trans isomer (open) and the cis-cis isomer (closed) provide unambiguous proof for the hinge-like molecular motion in this class of molecules. The inferences drawn from photochemical and thermal studies shed light on the effect of varied substitution and cyclic structures on the different transitions. The lifetime of the cis-cis isomer is estimated to be 6.43 years, whereas the trans-cis isomer is short-lived (2.73 min) at 303 K. A rational explanation for the relative stability of the different isomers is derived from the isokinetic plot and theoretical calculations. 相似文献
103.
The total synthesis of (±)-dithiathromboxane A2 sodium salt 1 was accomplished in 26 steps from methyl 4,4-dimethoxyactoacetate. 相似文献
104.
Nobuyuki Kenmochi 《Israel Journal of Mathematics》1975,22(3-4):304-331
In this paper we study initial value problems for nonlinear parabolic variational inequalities involving time-dependent subdifferentials of convex functions on a Hilbert space. We shall show the existence of a solution by a semi-discretisation method with respect to the time. 相似文献
105.
(+)-11a-methano-9,11-thiathiromboxane A2(1) was synthesized from prostaglandin A2 and prostaglandin E2. 相似文献
106.
Shinji Nishitani Nobuyuki Kurata Yoshiteru Sakata Soichi Misumi Masahito Migita Tadashi Okada Noboru Mataga 《Tetrahedron letters》1981,22(22):2099-2102
To clarify the primary process of photosynthesis, a series of model compounds, in which an octaethylporphyrin and a benzoquinone ring are connected with different lengths of a polymethylene chain, were synthesized and their photophysical properties were investigated. 相似文献
107.
Particle times of flight in incident shock flow were determined experimentally by marking several positions of the test gas (mainly Ar) in the shock tube with an infrared emitting gas (NO or CO2). From the local particle velocity, derived from the particle flight times, temperature and pressure changes behind the shock front were evaluated. Several experimental data were found to be correctly described by Mirels's formulations when used properly. The limitations of the formulations are discussed. It is found to be advisable to evaluate boundary-layer effects on shock-tube flow by experiments, rather than theory, in carrying out chemical kinetics studies. 相似文献
108.
109.
Seki S Kobayashi Y Miyashiro H Ohno Y Usami A Mita Y Kihira N Watanabe M Terada N 《The journal of physical chemistry. B》2006,110(21):10228-10230
Highly reversible, safe lithium secondary batteries that use imidazolium-cation-based room-temperature ionic liquid as an electrolyte and lithium metal as an anode material were realized by the molecular design. To achieve higher reduction stability, an electron-donating substituent was introduced to promote charge delocalization in the imidazolium cation of room-temperature ionic liquids. 相似文献
110.
Seki S Kobayashi Y Miyashiro H Ohno Y Usami A Mita Y Watanabe M Terada N 《Chemical communications (Cambridge, England)》2006,(5):544-545
For the purpose of realizing high-voltage, high-capacity, long-life and safe rechargeable batteries, a lithium secondary battery that uses high-voltage stable ZrO2-coated LiCoO2 cathode powder and a nonvolatile high-safety room temperature ionic liquid was fabricated. 相似文献