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101.
Influence of Intermolecular Interactions on Valence Tautomeric Behaviors in Two Polymorphic Dinuclear Cobalt Complexes
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Guo‐Ling Li Dr. Shinji Kanegawa Dr. Zi‐Shuo Yao Dr. Sheng‐Qun Su Shu‐Qi Wu Dr. You‐Gui Huang Dr. Soonchul Kang Prof. Dr. Osamu Sato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17130-17135
Two polymorphic structures have been well determined in a valence tautomeric (VT) dinuclear cobalt complex. These polymorphs showed distinct thermal‐ and photomagnetic behavior, and are thus ideal for studying the “pure” intermolecular factors to VT transitions. In polymorph 1A , the VT cations are arranged head‐to‐waist with their neighbors and exhibit weak π???π interactions, resulting in a gradual and incomplete thermal VT transition. In contrast, the cations in polymorph 1B are arranged head‐to‐tail and exhibit relatively strong π???π interactions, leading to an abrupt and complete thermal VT transition with adjustable hysteresis loop at around room temperature. The VT process for both polymorphs can be induced by light, but the light‐excited state of 1B? 2H2O has a higher thermal relaxation temperature than that of 1A? 3H2O. 相似文献
102.
Syuji Fujii Shinji Yamashita Yuichi Kakigi Kodai Aono Sho Hamasaki Shin-ichi Yusa Yoshinobu Nakamura 《Colloid and polymer science》2013,291(5):1171-1180
Hydroxy-functional macrodisulfides have been synthesized by atom transfer radical polymerization of 2-hydroxyethyl methacrylate or 2-hydroxypropyl methacrylate in 2-propanol. Mean degrees of polymerization of the polymer chains beside the disulfide were fixed at 30, 60, and 90; since ATRP has reasonably good living character, the molecular weight distribution is relatively narrow. Furthermore, the macrodisulfides were reduced to synthesize corresponding thiol-terminated polymers with relatively narrow molecular weight distributions. 1H nuclear magnetic resonance and gel permeation chromatography were used to characterize the macrodisulfides and thiol-terminated polymers in terms of their chemical structure, molecular weight, and polydispersity, respectively. Dispersion polymerizations of styrene using the thiol-terminated hydroxy-functional polymers as a transtab (chain transfer agent + colloidal stabilizer) in ethanol resulted in colloidally stable submicrometer-sized polystyrene latex particles. Scanning electron microscopy, Fourier transform infrared spectroscopy, and elemental microanalysis were used to characterize the particles in terms of their morphologies, particle sizes and their distributions, and chemical compositions. 相似文献
103.
Shinji Nakaya Daisuke Segawa Toshikazu Kadota Yoshiaki Nagashima Tomoya Furuta 《Proceedings of the Combustion Institute》2011,33(2):2031-2038
The burning and sooting behaviors of isolated fuel droplets for ethanol and n-decane are examined in high concentration of the ambient carbon dioxide under microgravity. A quartz fiber with the diameter of 50 μm maintains the droplet in the center of the combustion chamber and the range in the initial droplet diameter is from 0.30 to 0.80 mm. The ambience consists of oxygen, nitrogen and carbon dioxide. The concentration of oxygen is 21% in volume, and that of carbon dioxide is varied from 0% to 60% in volume. Detail measurements of the projected image of the droplet are conducted by using a high speed video camera and the effective droplet diameter squared are calculated from the surface area of the rotating body of the projected object. From evolutions of the droplet diameter squared, the instantaneous burning rates are calculated. Time history of the instantaneous burning rate clearly represents the droplet combustion events, such as the initial thermal expansion, ignition and following combustion. The instantaneous burning rate for n-decane shows an increasing trend during combustion, while that for non-sooting ethanol remains almost constant or shows a decreasing trend. A slight stepwise increase in the instantaneous burning rate is observed for larger n-decane droplets in air, which may be attributed to soot accumulation. However, this behavior of the burning rate disappears in higher concentration of carbon dioxide. Direct observation of the droplet flame indicates suppression of soot production in higher concentration of carbon dioxide and the suppression is enhanced for smaller droplet. 相似文献
104.
105.
T. Suzuki T. Hatsushika M. Miyake 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The cation-exchange characteristics between Pb2+ ions of aqueous solutions containing counter-anions (F?, C1?) and Ca2+ ions of synthetic hydroxyapatite samples have been investigated in detail under the conditions of low pH values (3.0, 4.0 and 5.0) by a normal batch method. Even at the low pH value of 3.0 the apatite structure in a solution containing F? or C1? ions was maintained via a concurrent ion-exchange effect of Pb2+ ions together with F? or C1?ions, which are known to be exchangeable with OH- ions of the apatite. Moreover, it was found that Ca2+ ions in the apatite sample can easily be exchanged for Pb2+ ions almost without distinction between MI and M2 sites, assisted by the loosening effect of protons even at room temperature. Next, it was found that the hydroxyapatite samples are transformed into amorphous states by the reactions between Ca 2+ ions in the samples and Sn 2+ ions in the SnC12 acidic aqueous solutions with pH of 3.0 or below with a molar ratio of Sn2+/Ca2+ -1.0. The existence of hydroxyapatite as amorphism in acidic aqueous solutions such as SnC12 is quite interesting, because in general the hydroxyapatite has been found to be dissolved in acidic aqueous solutions. Moreover, the obtained amorphism are found to be stable up to at least 500 to 6OO°C but to be unstable in alkaline solutions. The characteristics of Sn2+ ions are found to have been found to form crystalline Pb 2+ apatite even in be quite different from those of homologous Pb2+ ions which have been found to form crystalline pb2+ apatite even in such an acidic atmosphere. 相似文献
106.
Kazuyuki Kubo Hiroshi Nakazawa Hiroyasu Inagaki Tomoyuki Miyake Tsutomu Mizuta Katsuhiko Miyoshi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2159-2160
Treatment of [Cp*(CO) 2 M{P(NHPh)(OMe) 2 }]PF 6 (M = Fe and Ru) with NaNH 2 gives metallaiminophosphoranes, Cp*(CO) 2 M{P(NPh)(OMe) 2 }. The x-ray structures and reactivity of the complexes are reported. 相似文献
107.
Tatsuro Ouchi Shinji Kitazaki Akinobu Kobayashi Minoru Imoto 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):1045-1059
The radical polymerization of methyl methacrylate (MMA) was carried out with the system of imidazole (Im), copper(n) chloride, and water at 85°C. The effects of the amount of each component on the conversion of MMA were investigated. The polymerization proceeded through a radical mechanism. The overall activation energy was estimated to be 28.7 kJ/mole. The conversion of MMA showed a maximum at pH 8-9 of the aqueous solution. The formation of a complex of CuCl2 with Im, water, and MMA was confirmed by electronic spectra. An initiation mechanism was proposed. 相似文献
108.
Abstract Postpolymerization of vinyl monomers initiated by pendant peroxycarbonate groups of grafted polymer chains on carbon black (CB) was investigated. The grafting of polymers having pendant peroxycarbonate groups onto CB was achieved by the trapping of polymer radicals formed by the thermal decomposition of copolymers of t-butylperoxy-2-methacryloyloxyethyl-carbonate (HEPO) with vinyl monomers such as vinyl acetate (VAc), styrene (St) and methyl methacrylate (MMA). The copolymers having pendant peroxycarbonate groups were prepared by copolym-erization of HEPO with vinyl monomers using azo initiator under irradiation of UV light at room temperature. The amount of remaining pendant peroxycarbonate groups of the poly(VAc-co-HEPO)-grafted CB obtained from the reaction at 90°C was maximum and decreased above the temperature. Furthermore, the postpolymerization of vinyl monomers, such as St, MMA, and VAc was initiated in the presence of poly(VAc-co-HEPO)-grafted and poly(St-co-HEPO)-grafted CB and the corresponding polymers were postgrafted onto CB to give branched polymer-grafted CB. The percentage of poly(St)-postgrafting (proportion of post-grafted poly(St) to poly(MMA-co-HEPO)-grafted CB used) increased with increasing polymerization time, but became constant at 20% after 4 hours. 相似文献
109.
Hiroki Matsunaga Hiroto Habu Atsumi Miyake 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1387-1394
Ammonium dinitramide (ADN) is one of the several promising new solid propellant oxidizers. ADN is of interest because its oxygen balance and energy content are high, and it also halogen-free. One of the most important characteristics of a propellant oxidizer, however, is stability and ADN is known to degrade to ammonium nitrate (AN) during storage, which will affect its performance. This study focused on the effects of aging on the thermal decomposition mechanism of ADN. The thermal behaviors of ADN and ADN/AN mixtures were studied, as were the gases evolved during their decomposition, using differential scanning calorimetry (DSC), thermogravimetry–differential thermal analysis-infrared spectrometry (TG–DTA-IR), and thermogravimetry–differential thermal analysis-mass spectrometry (TG–DTA-MS). The results of these analyses demonstrated that the decomposition of ADN occurs via a series of distinct stages in the condensed phase. The gases evolved from ADN decomposition were N2O, NO2, N2, and H2O. In contrast, ADN mixed with AN (to simulate aging) did not exhibit the same initial reaction. We conclude that aging inhibits early stage, low temperature decomposition reactions of ADN. Two possible reasons were proposed, these being either a decrease in the acidity of the material due to the presence of AN, or inhibition of the acidic dissociation of dinitramic acid by NO 3 ? . 相似文献
110.
Kazumasa Inoue Masahiro Hosoda Shinji Tokonami Tetsuo Ishikawa Masahiro Fukushi 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(3):2009-2015
The temporal variation of the radon concentration, and the radon and thoron concentrations every 3 months for a year were measured using two types of devices in a landmark skyscraper, the Tokyo Metropolitan Government Daiichi Building. In the measurement of temporal variation of the radon concentration using a pulse type ionization chamber, the average radon concentration was 21 ± 13 Bq m?3 (2–68 Bq m?3). The measured indoor radon concentration had a strong relationship with the operation of the mechanical ventilation system and the activities of the office workers. The radon concentration also increased together with temperature. Other environmental parameters, such as air pressure and relative humidity, were not related to the radon concentration. In the long-term measurements using a passive radon and thoron discriminative monitor, no seasonal variation was observed. The annual average concentrations of radon and thoron were 16 ± 8 and 16 ± 7 Bq m?3, respectively. There was also no relationship between the two concentrations. The annual average effective dose for office workers in this skyscraper was estimated to be 0.08 mSv y?1 for 2000 working hours per year. When considering the indoor radon exposure received from their residential dwellings using the annual mean radon concentration indoors in Japan (15.5 Bq m?3), the annual average effective dose was estimated to be 0.37 mSv y?1. This value was 31 % of the worldwide average annual effective dose. 相似文献