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101.
Koichi KikuchiHiroyuki Nishikawa Isao IkemotoTakashi Toita Hiroki AkutsuShin'ichi Nakatsuji Jun-ichi Yamada 《Journal of solid state chemistry》2002,168(2):503-508
Three FeCl4 salts based on non-tetrathiafulvalene (TTF) donors, 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH-TTP) and 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), have been prepared and characterized as κ-(BDH-TTP)2FeCl4, β-(BDA-TTP)2FeCl4, and (BDA-TTP)3FeCl4 · PhCl. The κ-(BDH-TTP)2FeCl4 salt, with a room-temperature conductivity (σrt) of 39 S cm−1, is metallic down to 1.5 K, and its magnetic susceptibility obeys the Curie-Weiss law with a Curie constant (C) of 4.25 emu K mol−1 and a Weiss constant (θ) of 0.041 K. β-(BDA-TTP)2FeCl4 exhibits metallic behavior (σrt=9.4 S cm−1) with a sharp metal-to-insulator (MI) transition (TMI=113 K) and antiferromagnetic ordering with the Néel temperature of near 8.5 K, whereas the solvated (BDA-TTP)3FeCl4 · PhCl salt is a semiconductor with a thermal activation energy of 0.11 eV (σrt=2.0× 10−2 S cm−1) and exhibits Curie-Weiss behavior (C=4.42 emu K mol−1, θ=−0.35 K). 相似文献
102.
Exposure of tertiary thioamides to (E)-1-hexenyl(phenyl)-lambda 3-iodane results in vinylic SN2 reaction to give the inverted (Z)-S-vinylthioimidonium salts, which under alkaline hydrolysis (Na2CO3 or K2CO3) selectively afford amides, while (Z)-S-vinyl thioesters are obtained in high yields via the hydrolysis under acidic conditions (HCl). 相似文献
103.
Periodic mesoporous benzene-silicas with large pores of 6.0 to 7.4 nm in diameter are synthesized using triblock copolymer as a template. These mesoporous materials have a well-defined hexagonal rod morphology and high thermal stability up to 823 K in air. 相似文献
104.
[structure: see text] 8,11-Dideoxytetrodotoxin, an unnatural tetrodotoxin analogue, was synthesized in a highly stereoselective manner from a common intermediate in our synthetic studies on tetrodotoxin. The synthesis features neighboring group participation of trichloroacetamide for stereoselective hydroxylation, protection of ortho ester, and guanidine installation with Boc-protected isothiourea. 相似文献
105.
[reaction: see text] Treatment of 1,6-enynes with tetramethallylchromate induces a cyclization reaction with concurrent introduction of a methallyl group. A catalytic amount of CrCl(3) combined with methallylmagnesium chloride also achieves this cyclization process. The resultant cyclic organometallic species undergo further functionalization upon reaction with electrophiles. 相似文献
106.
Sulfuric acid-functionalized mesoporous benzene-silica with a molecular-scale periodicity in the walls 总被引:2,自引:0,他引:2
Novel sulfuric acid-functionalized mesoporous benzene-silicas with a molecular-scale periodicity in the walls were derived from the mesoporous benzene-silica possessing mercaptopropyl groups by the oxidative transformation of -SH into -SO3H. 相似文献
107.
The off-resonant fifth-order response functions for two-dimensional (2D) Raman spectroscopy of molecular liquids CS2 and H2O are investigated by using molecular dynamics calculation. This spectroscopy, able to deal with a phase space dynamics, shows the existence of nodal lines in several polarization tensor elements [see L. Kaufman et al., Phys. Rev. Lett. 88, 207402 (2002) for experimental results]. The nodal property is found to arise from the dynamical couplings among rotational modes, not accounted for in a normal mode picture. The effects of anharmonicities and "mode coupling through polarizability" are also investigated by comparing the 2D Raman signal with a constant temperature velocity reassignment echo method. 相似文献
108.
Electronic states of P donors in Si nanocrystals (nc-Si) embedded in insulating glass matrices have been studied by electron spin resonance. Doping of P donors into nc-Si was demonstrated by the observation of optical absorption in the infrared region due to intraconduction band transitions. P hyperfine structure (hfs) was successfully observed at low temperatures. The observed splitting of the hfs was found to be much larger than that of the bulk Si:P and depended strongly on the size of nc-Si. The observed strong size dependence indicates that the enhancement of the hyperfine splitting is caused by the quantum confinement of P donors in nc-Si. 相似文献
109.
Koga T Seo YS Zhang Y Shin K Kusano K Nishikawa K Rafailovich MH Sokolov JC Chu B Peiffer D Occhiogrosso R Satija SK 《Physical review letters》2002,89(12):125506
We report an anomalous swelling of polymer thin films in carbon dioxide (CO(2)) which is associated (in both locus and form) with the density fluctuation ridge that forms along the extension of the coexistence curve of gas and liquid in the P-T phase diagram. Neutron reflectivity results showed that CO(2) could be sorbed to a large extent ( approximately 60%) in thin polymer films even when the bulk miscibility of the polymer with CO(2) is very poor. The anomalous swelling is found to scale with the polymer radius of gyration (R(g)) and extends to a distance approximately 10 R(g). 相似文献
110.
Shinji Fushiya Yoshikazu Sato Shigeo Nozoe Kyosuke Nomoto Tsunematsu Takemoto Sei-ichi Takagi 《Tetrahedron letters》1980,21(32):3071-3072
A new amino acid derivative possessing an iron chelating activity was isolated from root washings of water cultured under iron deficient conditions. The structure of this compound, avenic acid A has been determined as 2(S),3′(S),3″(S)-N-[3-(3-hydroxy-3-carboxypropylamino)-3-carboxypropyl]-homoserine (1) on the basis of chemical and spectroscopic evidence. 相似文献