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161.
Hyungrak Kim 《Journal of solid state chemistry》2005,178(6):1935-1939
The compound Ca14MnP11 crystallizes in the Ca14AlSb11 structure type with the tetragonal space group I41/acd (Z=8) and lattice parameters of , c=20.7565(9) at 90 K. The structure consists of MnP49− tetrahedron, P37− trimer, 4 P3− isolated anions and 14 Ca2+ cations. Similar to other compounds of this structure type containing phosphorous, the P37− trimer has a central P atom that is best modeled in the structure as being equally split between two sites. In addition, there is no additional distortion of the manganese-containing tetrahedron compared with the main group analog, Ca14GaP11, suggesting that the Mn oxidation state is Mn2+. Temperature-dependent magnetic susceptibility shows that the compound is paramagnetic over the entire temperature range measured (2-300 K). The data can be fit with a modified Curie-Weiss law and provide an effective magnetic moment of 5.80 (2) B.M. with a Weiss constant of −2.13(2) K and . This moment is significantly higher than those measured for any of the Mn-containing analogs and is consistent with Mn2+. This result will be discussed in light of the electron counting scheme for Mn compounds of the Ca14AlSb11 structure-type. 相似文献
162.
Sansei Nishibe Kumiko Mitsui-Saitoh Junichi Sakai Takahiko Fujikawa 《Molecules (Basel, Switzerland)》2021,26(8)
Forsythia fruit (Forsythia suspensa Vahl (Oleaceae)) is a common component of Kampo medicines for treating the common cold, influenza, and allergies. The main polyphenolic compounds in the leaves of F. suspensa are pinoresinol β-d-glucoside, phillyrin and forsythiaside, and their levels are higher in the leaves of the plant than in the fruit. It is known that polyphenolic compounds stimulate lipid catabolism in the liver and suppress dyslipidemia, thereby attenuating diet-induced obesity and polyphenolic anti-oxidants might attenuate obesity in animals consuming high-fat diets. Recently, phillyrin was reported as a novel cyclic AMP phosphodiesterase 4 (PDE4) inhibitor derived from forsythia fruit. It was expected that the leaves of F. suspensa might display anti-obesity effects and serve as a health food material. In this review, we summarized our studies on the biological effects of forsythia leaves containing phillyrin and other polyphenolic compounds, particularly against obesity, atopic dermatitis, and influenza A virus infection, and its potential as a phytoestrogen. 相似文献
163.
E. I. Kachibaya R. A. Imnadze T. V. Paikidze R. A. Akhvlediani 《Russian Journal of Electrochemistry》2006,42(11):1224-1234
Extralithiated chromium-doped finely divided lithium-manganese spinels are synthesized as a result of a two-step solid-phase process with use made of the fusion-saturation method. The spinels are intended for application as cathodic materials in lithium-ion batteries. The phase composition and structural characteristics of samples of cathodic materials of the type Li x Mn2?y Cr y O4 are studied. The samples with x = 1.0?1.2 and y = 0?0.5 are characterized by phase purity and cubic syngony with parameter a = 0.817?0.823 nm and a disperseness equal to 1–2 nm. The maximum content of chromium and lithium in Li x Mn2?y Cr y O4 that does not lead to violation of cubic syngony is determined. Lithium excess in the cathodic material that does not exceed 0.2 formula units may be used for compensating the irreversible capacity. Replacing some manganese atoms by chromium may facilitate retention of the structures’s integrity in the course of cycling. 相似文献
164.
E. V. Gert 《Cellulose (London, England)》1996,3(1):217-228
For preparation of various modified forms of microcrystalline cellulose, an optional combination is proposed of hydrolytic activity with other properties of nitric acid such as, adduct forming ability (manifested as Knecht compound formation), oxidizing, bleaching and nitrating. The manifestation of a chosen acid function is reached by variation of the reaction conditions: concentration, temperature, time, etc. The sole-reagent continuous procedure involving several operations made in a predetermined sequence allows the use of a more simple technological scheme and saves energy, time and materials. The features of transformation of fibrous and microcrystalline forms of native cellulose into cellulose-II through the Knecht compound are discussed. Purely acidic transformation schemes of native cellulose into microcrystalline cellulose hydrate and amorphous low-nitrate powder cellulose according to the above scheme are considered. Morphological features as well as distinguishing properties — enhanced hydrophilicity, sorption activity and degree of whiteness — of the prepared materials are pointed out. The possibility of obtaining uniformly oxidized forms of powder cellulose according to this scheme and the outlook for the use of nitrogen(IV) oxide as a multifunctional reagent are discussed. 相似文献
165.
166.
CrystalandMolecularStructureof3,4-diphenyl-5-ethyl-5-methyl-1,3,4-diazaphospholidin-2-thione-4-oxide¥FengKe-Sheng;ChenRu-Yu(I... 相似文献
167.
Eight ionic organotin compounds [R2SnCl2(2-quin)]−(HNEt3)+ have been synthesized by reactions of 2-quinH with R2SnCl2 (R = PhCH21, 2-Cl-C6H4CH22, 4-Cl-C6H4CH23, 2-F-C6H4CH24, 4-F-C6H4CH25, 4-CN-C6H4CH26, Ph 7, 2,4-Cl2-C6H3CH28) in the presence of organic base NEt3, and their structures have been characterized by elemental analysis, IR and multinuclear NMR (1H, 13C, 119Sn) spectroscopies. The structure of [(2,4-Cl2-C6H3CH2)2SnCl2(2-quin)]−(NEt3)+ (8) has been determined by X-ray diffraction study. Studies show that compound 8 has a monomeric structure with the central tin atom six-coordinate in a distorted octahedral configuration and the nitrogen atoms of the 2-quin ligands are coordinating to the tin atom in all the eight compounds. 相似文献
168.
A novel microwave dielectric powder with composition of Ca2Zn4Ti16O38 was synthesized through a citrate sol-gel process. The development of crystalline phases with heat-treating temperature for the gel derived powders was evaluated by using thermo-gravimetric analysis and X-ray powder diffraction analysis techniques. The pure phase of Ca2Zn4Ti16O38 with crichtonite crystal structure was obtained at relatively low temperature of 1000 °C. The synthesized powder has high reactivity and the dense ceramics with single crystalline phase were obtained at low sintering temperature of 1100 °C. Impedance spectroscopy and microwave dielectric measurements on sintered samples showed the present compound to be a modest dielectric insulator with excellent dielectric properties of εr∼47-49, Qf value ∼27,800-31,600 GHz and τf∼+45 to +50 ppm/°C. It shows comparable microwave dielectric properties to other moderate-permittivity microwave dielectrics, but much lower sintering temperature of 1100 °C. 相似文献
169.
Yuan Yang Jinnan Zhang Surong Luo Xiaohong Song Qi Li 《Frontiers of Chemistry in China》2007,2(3):296-302
Two new inclusion compounds (n-C4H9)4N+C18-H13O4
−·B(OH)3 (1) and (n-C4H9)4N+C18H13O4
− (2) were prepared and characterized by X-ray crystallography. Crystal data: compound 1, monoclinic P2(1)/c, a = 1.569 9(1) nm, b = 0.995 5(6) nm, c = 2.293 3(1) nm, β = 109.962(3)°, Z = 4, and R
1 = 0.0434, wR = 0.075 9; compound 2, monoclinic C2/c, a = 1.400 5(3) nm, b = 1,282 1(2) nm, c = 1.765 7(3) nm, β = 100.388(1)°, Z = 4, and R
1 = 0.0584, wR = 0.096 6. In the crystal structure of 1, the tetramers formed by two trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (EADA) anions and two boric acid molecules were connected through
O—H⋯O hydrogen bonds to generate a channel type host lattice. The tetra-n-butylammonium cations were stacked to give two columns within each channel with cross-sectional size of about 2.30 nm × 0.93
nm. In the crystal structure of 2, similar honeycomb host lattices with big size were also formed along the [101] direction
by three-dimensional accumulation of EADA anions. The tetra-n-butylammonium cations were accommodated in a zigzag fashion within each channel.
Translated from Acta Chimica Sinica, 2006, 64(18): 1904–1910 [译自: 化学学报] 相似文献
170.
Simons electrochemical fluorination (ECF) of 1,4-dimethyl-1,4-homopiperazine, methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine was studied. For comparison, ECF of three piperazines with a N-(methoxycarbonylmethyl) group(s) was also studied. ECF of 1,4-dimethyl-1,4-homopiperazine gave a low yield of corresponding perfluoro(1,4-dimethyl-1,4-homopiperazine) together with perfluoro(2,6-diaza-2,6-dimethylheptane) as the major product. Corresponding perfluoro(homopiperazines) with mono- and/or di-(fluorocarbonyldifluoromethyl) groups [CF2C(O)F] at the 1- and/or 4-position were formed in low yields from methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine, respectively. These new seven-membered perfluoro(1,4-dialkyl-1,4-homopiperazines) were accompanied by the formation of mono- and/or di-basic linear perfluoroacid fluorides resulting from the CC bond scission at the 2- and 3-positions of the ring. From mono- and/or di-N-(methoxycarbonylmethyl)-substituted piperazines, corresponding perfluoropeperazines having the acid fluoride group(s) were formed in low yields. 相似文献