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991.
A facile two-step procedure for the synthesis of 6-(trifluoromethyl)-1,4,5,6-tetrahydropyrazolo[3,4-b]pyran derivatives (4) from the reaction of 4-arylidene-3-methyl-1-phenyl-5-pyrazolones (1) with ethyl trifluoroacetoacetate (2), a versatile fluorinated building-block, was presented. Furthermore, to increase the efficiency of this reaction, the more convenient one-pot three-component process was also developed with a slightly lower yield. Treatment of 4 with P2O5, conc. H2SO4, POCl3/Py or p-TsOH under the drastic conditions did not afford the corresponding dehydrated products. 相似文献
992.
George Eng Xueqing Song Angel C. de Dios Robert D. Pike 《Journal of organometallic chemistry》2007,692(6):1398-1404
A series of triorganotin 2-(p-chlorophenyl)-3-methylbutyrates, (R3SnO2CCH(CH(CH3)2)C6H4Cl-4), where R = methyl, ethyl, n-propyl, n-butyl, phenyl and cyclo-hexyl, have been synthesized. Elemental analyses, Mössbauer, Infrared and NMR spectroscopies have been used to characterize their structures. Based on the spectroscopic results, all the complexes with the exception of the tricyclohexyl compound were found to be five-coordinated in the solid state while the tricyclohexyltin derivative was determined to be four-coordinated. Structural assignments based on spectroscopic data are supported by the crystallographic results of four of the triorganotin butyrates (trimethyl-, tri-n-propyl-, tri-n-butyl- and tricyclohexyltin 2-(p-chlorophenyl)-3-methylbutyrate). Multinuclear NMR spectroscopy studies indicated that all the complexes were tetrahedral in solution. Larvicidal activities of the complexes were evaluated against the 2nd instar stage of the Anopheles stephensi, Aedes aegypti and Culex pipiens quinquefasciatus mosquitoes. The toxicity data indicate that there does not appear to be any significant differences of the compounds towards the different mosquito species based on their averaged toxicity values. In addition, the toxicity of the triorganotin compounds towards the mosquito larvae was concluded to be dependent on both the compound and the species of mosquito larvae. 相似文献
993.
Yanfei Qi Hua Jin Zhiming Zhang Xinglong Wang Song Chang 《Journal of solid state chemistry》2007,180(1):382-389
Two novel organic-inorganic hybrid arsenic-vanadates, [{Ni(en)2}4(4,4′-bipy)4{Ni(H2O)2}]2[As8V14O42(NO3)]4·16H2O 1 and [Ni(en)2(H2O)2]2[{Ni(en)2(H2O)}2As8V14O42(NO3)][{Ni(en)2}As8V14O42(NO3)]·6H2O 2 are reported in this study. Crystal data for compound 1: Tetragonal, I4/m, a=27.507(4) Å, b=27.507(4) Å, c=22.101(4) Å; V=16722(5) Å3, Z=2, R(final)=0.0508. Crystal data for compound 2: Triclinic, P-1, a=11.530(2) Å, b=14.883(3) Å, c=21.330(4) Å, α=76.94(3)°, β=76.58(3)°, γ=69.54(3)°, V=3293.4(1) Å3, Z=1, R(final)=0.0559. The boxlike structure of compound 1 is designed from [{Ni(en)2}4(4,4′-bipy)4{Ni(H2O)2}] sheets pillared by [α-As8V14O42] clusters, which represents the first mixed-organic ligand-decorated tetrameric As-V-O cluster. Compound 2 is constructed from the rarely [β-As8V14O42] clusters and Ni coordination complex fragments. The electrochemical property and magnetic property of compound 1 have been studied. 相似文献
994.
Nanosized aluminum nitride hollow spheres were synthesized by simply heating aluminum nanoparticles in ammonia at 1000 °C. The as-synthesized sphere shells are polycrystalline with cavity diameters ranging from 15 to 100 nm and shell thickness from 5 to 15 nm. The formation mechanism can be explained by the nanoscale Kirkendall effect, which results from the difference in diffusion rates between aluminum and nitrogen. The Al nanoparticles served as both reactant and templates for the hollow sphere formation. The effects of precursor particle size and temperature were also investigated in terms of product morphology. Room temperature cathode luminescence spectrum of the nanosized hollow spheres showed a broad emission band centered at 415 nm, which is originated from oxygen related luminescence centers. The hollow structure survived a 4-h heat treatment at 1200 °C, exhibiting excellent thermal stability. 相似文献
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含铋金属氧簇结构的多样性和多功能性使其在诸多领域有着非常广泛的应用。本文总结了已报道的50多个含铋金属氧簇化合物,根据Bi(Ⅲ)在金属氧簇中所充当的作用,可将含铋金属氧簇分成4大类:(1)Bi(Ⅲ)作为中心杂原子;(2)Bi(Ⅲ)作为取代原子;(3)Bi(Ⅲ)作为桥联原子;(4)Bi(Ⅲ)作为终端原子,分别对其合成和结构的发展现状进行总结。同时,介绍了含铋金属氧簇在催化、磁性、光学、药物等方面的应用,并对其前景进行了展望。通过本文可以很好了解含铋金属氧簇的合成、性能及发展,对多金属氧簇的拓展研究有重要意义。 相似文献
1000.
Jingen Wang Xihe Huang Changcang Huang Haiyan Song Duoping Yang 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(12):m583-m585
In the title complex, poly[triaquabis(dimethylformamide)di‐μ3‐oxalato‐μ2‐oxalato‐dilanthanum(III)], [La2(C2O4)3(C3H7NO)(H2O)3]n, both La ions are coordinated by nine O atoms, forming slightly distorted tricapped trigonal prisms. The two La ions, the terminal water O atom, and the O and N atoms of the dimethylformamide molecule reside on twofold rotation axes, giving the two La‐centered coordination geometries twofold or pseudo‐twofold symmetries. The two oxalate ligands, one of which rests on a center of inversion at the mid‐point of the C—C bond, adopt different bridging modes, connecting with the La ions to form two types of lanthanide oxalate chains, i.e. anionic {[La(C2O4)2(DMF)(H2O)2]n−}n (DMF is dimethylformamide) and cationic zigzag {[La(C2O4)(H2O)]n+}n, respectively. Each zigzag cationic chain is linked to four adjacent anionic chains via the bridging oxalate anions, and each anionic chain connects with four zigzag cationic chains, constructing a three‐dimensional neutral framework. 相似文献