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41.
Masaoki Oku Toetsu Shishido Takeshi Shinohara Qiang Sun Yoshiyuki Kawazoe Kazuo Nakajima Kazuaki Wagatsuma 《Journal of solid state chemistry》2004,177(2):457-460
The solid solutions of ScBRh3-ScRh3 and CeBRh3-CeRh3 are synthesized by the arc melting method, where RBRh3 and RRh3 (R=rare earth element) have perovskite and AuCu3 type structures, respectively. The binding energy of Sc 2p3/2 for ScBxRh3 increases with the boron concentration. The Knight shift of 45Sc observed by nuclear magnetic resonance spectroscopy decreases with increase of boron concentration. The decrement of the Knight shift corresponds the Sc 4s electron density at the Fermi level. The intensity ratio of f2: f1: f0 of Ce 3d XPS spectrum changes with boron concentration of CeBxRh3. It is concluded that in both cases of ScBxRh3 and CeBxRh3 the charge on the atoms on A-site changes with the concentration of the atoms on B-site, where the atoms are not directly bound. 相似文献
42.
Five-coordinate and six-coordinate 2-methyl-2-propanethiolato complexes of zirconium, [Li(DME)(3)][Zr(SCMe(3))(5)] (1) and [(THF)Li](2)Zr(SCMe(3))(6) (2), were obtained from the ZrCl(4)/LiSCMe(3) reaction system. The control of the Zr coordination number, by the ether ligands, THF or DME, bound to Li, is demonstrated by the conversion of 2 into 1 upon dissolution in DME. 1 and 2 were crystallographically characterized. The structures are extensively disordered. Crystal data follow: 1, hexagonal P6(3)/m, a = b = 12.496(3) ?, c = 17.561(9) ?, Z = 2, V = 2375(1) ?(3), R = 5.0%, R(w) = 6.8%; 2, trigonal R32, a = b = 11.813(3) ?, c = 28.37(1) ?, Z = 3, V = 3428(1) ?(3), R = 5.2%, R(w) = 6.4%. 相似文献
43.
Hiroatsu Matsuura Yoshiyuki Kawashima Chiaki Hirose 《Journal of Molecular Structure》1974,20(2):205-212
The rotational constant B and the l-type doubling constant q were determined for the v5, v3+v6 and v2, states of CH2I from the microwave transition frequencies, in combination with the infrared data previously reported. Since these vibrational states were coupled through the Fermi resonance and the xy-type E-E and A1-E Coriolis resonances, the analysis was made by setting up and solving the complete form of the secular determinants of the energy matrices. The rotational and l-type doubling constants were determined as B5, = 0.250 173 cm?1, B36 = 0.247 600 cm?1, B2 = 0.249 369 cm?1, q5 = ?0.000 027 cm?1 and q36 = ?0.000 179 cm?1, which are unperturbed by Fermi and Coriolis interactions. Other band constants for v5 and v3+v6 were also refined in accordance with the new values of B5 and B36. The present study indicated that the combined analysis of microwave and infrared spectral data was useful for the precise determination of vibration-rotation, levels in the perturbed system. 相似文献
44.
Tomio Shimizu Yoshiyuki Hayashi Takehiro Taniguchi Kazuhiro Teramura 《Tetrahedron》1985,41(4):727-738
A variety of symmetrically or unsymmetrically 3,4-disubstituttd furoxans such as dicyano, dialkyl, diacyl, bis(phenylsulfonyl), N.N'-dialkyldicarbamoyl, 3(or 4)-methyl-4(or -3)-phenyl(or nitro, ethoxy, phenoxy, phenylthio, pyrrolidinyl, phenylsulfonyl), 3(or 4)-ethyl-4(or -3)phcnyl, and 3(or 4)-ethoxy-4(or -3)-phenylsulfonylruroxan reacted with dipolarophiles in toluene or xylene at the refluxing temperature to give nitrone-type 1,3-dipolar cycloadducts, 5-substituted 1-aza-2,8-dioxabicyclo-[3.3.0]octanes and/or 3-substituted 2-isoxazoline 2-oxides. On the other hand, some of the furoxans gave 2-isoxazolines via nitrile oxide 1,3-dipolar cycloaddition in a toluene (or xylene)-DMF solvent at the refluxing temperature. 相似文献
45.
Hwa-Jin Jeong Yoshiyuki Oishi Masa-Aki Kakimoto Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1990,28(12):3293-3301
A new highly phenylated heterocyclic diamine, 3,4-bis(4-aminophenyl)-2,5-diphenylfuran, was synthesized in three steps from 4–-nitrodeoxybenzoin. The low temperature solution polycondensation of the diamine with various aromatic diacid chlorides afforded tetraphenylfuran-containing aromatic polyamides with inherent viscosities of 0.2–0.8 dL/g. Copolyterephthalamides were obtained from the diamine and 4,4′-oxydianiline. The polyamides were generally soluble in a wide range of solvents that included N,N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, and m-cresol. Glass transition temperatures of the polyamides and copolyamides ranged from 302–342°C, and 10% weight loss was observed above 480°C in nitrogen. 相似文献
46.
Yoshiyuki Tanaka Makoto Arakawa Yohei Yamaguchi Chieko Hori Masahiro Ueno Takeyuki Tanaka Tatsushi Imahori Yoshinori Kondo 《化学:亚洲杂志》2006,1(4):581-585
A metal‐free acetylide was observed by using NMR spectroscopy. Metal‐free acetylides are closely related to reactive intermediates (carbanions) in solution; therefore, they have been regarded as unobservable species. However, we generated this highly reactive and unstable species through the deprotonation of phenylacetylene by using the strong nonmetallic phosphazene base tBu‐P4. In the presence of tBu‐P4, the J coupling between the ethynyl carbon and hydrogen nuclei (1JC,H) of phenylacetylene disappeared; this indicates the deprotonation of the alkyne terminal. Furthermore, a large low‐field shift (approximately 90 ppm) of the alkyne carbon resonance was observed. We concluded that we have observed a metal‐free carbanion with a formal charge on an sp‐hybridized carbon atom for the first time. 相似文献
47.
The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R2UPh type and -thioureas of the R2TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments. 相似文献
48.
Che S Lim S Kaneda M Yoshitake H Terasaki O Tatsumi T 《Journal of the American Chemical Society》2002,124(47):13962-13963
The presence of various counteranions at the interfacial region of the silicate-surfactant mesophase introduces opportunities for manipulation of the phase structure. Well-ordered 3D-hexagonal P63/mmc, cubic Pmn, 2D-hexagonal p6mm, and cubic Iad mesoporous materials have been synthesized with the same surfactant, cetyltriethylammonium bromide, in the presence of various acids. The counteranions of acidic media have resulted in increasing the surfactant packing parameter g in the order SO42- < Cl- < Br- < NO3-, which leads to the different time course of formation of mesostructures. The effect of counteranions on the formation of mesostructures is explained in terms of not only the adsorption strength on the headgroups of the surfactant micelle but also the rate of silica condensation affecting the charge density matching between the surfactant and silica. It has been found that the mesophase is always transformed from the larger g parameter into the smaller one. The distinct morphologies of the 3D-hexagonal P63/mmc mesophases have been rationally explained by supposing this particular mesostructure. The cubic Iad phase has been first synthesized under acidic conditions. 相似文献
49.
50.
Masao Kato Takao Shiraga Tatsumi Kimura Takashi Fukuda Hiro Matsuda Hachiro Nakanishi 《先进技术聚合物》2002,13(2):120-126
We synthesized some novel rigid NLO‐active maleimide copolymers bearing DR‐1 moieties ( PMPD , PHSD and PHND ). All copolymers exhibited high Tg's (190~197 °C), good solubilities for common solvents and excellent film‐forming properties. Dependence of film thickness on the d33 value for the poled copolymer films induced by corona poling was investigated and it was demonstrated that in less than thickness of 0.3 µm decrease of the thickness gives rise to remarkable increase in the d33 value. The poled copolymer films exhibited large d33 values (270 × 10?9 esu (film thickness 0.13 µm) for PMPD , 290 × 10?9 esu (0.12 µm) for PHSD and 350 × 10?9 esu (0.08 µm) for PHND ) as well as large r33 values (51.0 pmV?1 for PMPD and 60.4 pmV?1 for PHND ) which are significantly large compared to the value of LiNbO3 (31 pmV?1) as a typical EO material. The d33 values of the poled copolymers were kept constant even after standing 1000h at 80 °C, although a small decrease was observed at an initial stage. Further, the d33 values did not change up to ca. 123 °C upon heating at the rate of 10 °C/min in all cases. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献