LaFeO~3超微粒子的制备及性质的研究

本文使用溶胶-凝胶法制备了平均粒径为12~75nm的LaFeO~3超微粒子。从凝胶至超微粒子的过程中, 失重达90%。纯相晶态的LaFeO~3超微粒子的最低生成温度为600℃。粒子平均粒径随着灼烧温度的升高而显著增大, 通过对不同粒径的LaFeO~3超微粒子表面光电压光谱的研究发现, 随着粒子粒径的增大, 粒子内部逐渐形成长程有序的晶体结构和完整的能带结构。粒子粒径越小, 表面特性越明显。     

Synthesis and properties of 4-amino-3-cyanofurazan

Deoximation of the amidoxime of 4-aminofurazan-3-carboxylic acid and dehydration of 4-aminofurazan-3-carboxamide gave 4-amino-3-cyanofurazan. Reactions of the cyano and amino groups were studied.Latvian Institute of Organic Chemistry, Riga, LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 693–696, May, 1994.     

Synthesis and properties of 3-formyl-4H-pyrans

The Vilsmeier formylation of 4H-pyrans afforded 3-formyl-4H-pyrans. These were converted to 3-formylpyrylium salts, from which pyridine or pyridine salts with an aldehyde group at C₍₃₎ were obtained. The reaction between 3-formyl-4-allyl-4H-pyran and methyltrifluoromethanesulfonate proceeded via a Koop rearrangement.Translated from Khimiya Geterotsiklicheskii Soedinenii, No. 5, pp. 603–607, May, 1990.     

3-cyclobutyl-3-ferrocenylcyclopropene and 3-cyclobutylidene-3-ferrocenylpropyne Synthesis and chemical properties

3-Cyclobutyl-3-ferrocenylcyclopropene was synthesized by the reactions of mono- or dibromoferrocenylcyclopropanes with Bu^tOK in DMSO. Treatment of dibromoferro-cenylcyclopropane with Bu^tOK in THF afforded 3-cyclobutylidene-3-ferrocenylpropyne in 52% yield. Heterolysis of the C-C bond in the three-membered ring of 3-cyclobutyl-3-ferrocenylcyclopropene at low and high temperatures was studied. Hydrolysis yielded 3-cyclobutyl-1H-cyclopentaferrocene and products with linear structures,viz., 3-cyclobutylidene-3-ferrocenylpropene,E- andZ-I-ferrocenyl-1-cyclobutylpropenes, and 1-cyclobutylidene-1-ferrocenylacetone. Cyclopropene reacts with 1,3-diphenylisobenzofuran to form two Diels-Alder adducts, while the enyne does not react with 1,3-diphenylbenzofuran. Facultad de Quimica, Universidad Nacional Autónoma de México, Cd. Universitaria, C.P. 04510, México D. F., México. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2177–2181, November, 1999.     

5,7-dihydroxy-3-phenoxychromones: Synthesis and properties

A series of 5,7-dihydroxy-3-phenoxychromones and their 2-methyl analogs has been obtained by the heterocyclization of α-aryloxy-2,4,6-trihydroxyacetophenones. Their acylation, alkylation, and aminoacylation reactions have been studied. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 466–474, July–August, 1998.     

Synthesis and properties of substituted indolo-3-cyanine dyes

Indolo-3,3-mono- and indolo-3,3-trimethylidynecyanines that contain substituents in the indole rings and in the polymethine chain (in the case of trimethylidynecyanines) were synthesized by condensation of 2-alkyl- and 2-arylin-doles, respectively, with ethyl orthoformate and tetraalkylacetals of substituted malonic dialdehydes in anhydrous benzene in the presence of acetyl chloride or thionyl chloride. The colors of the products were studied, and the polarographic potentials of the oxidation and reduction half waves were determined. A relationship between the indicated characteristics of indolo-3-cyanines and their structure was established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1067–1071, August, 1971.     

Synthesis and magnetic properties of colloidal MnPt3 nanocrystals

The colloidal synthesis and magnetic properties of MnPt(3) nanocrystals are reported. The nanocrystal size depended on the Mn reactant used, but the Mn:Pt stoichiometry was always 1:3. As synthesized, the nanocrystals are compositionally disordered with the face-centered cubic (fcc) A1 phase. Annealing at 580 degrees C changed the MnPt(3) crystal structure to the compositionally ordered L1(2) phase (AuCu(3) structure) with higher magnetocrystalline anisotropy. Magnetization measurements showed that the A1 nanocrystals are paramagnetic and the L1(2) MnPt(3) nanocrystals are superparamagnetic.     

Synthesis and properties of (3-quinuclidyl)diarylcarbinols

The reaction of 3-ethoxycarbonyl-, 3-ethoxycarbonylmethyl-, and 3-benzoylquinuclidines with organometallic compounds was studied. General methods for the preparation of (3-quinuclidyl)-diarylcarbinols were developed, and the properties of these compounds were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 935–939, July, 1976.     

Synthesis and conformational properties of 2,6-bis-anilino-3-nitropyridines

The synthesis of 2,6-bis-anilino-3-nitropyridines that are alkylated or acylated at the anilino nitrogen atoms is described. These derivatives show characteristic differences in the 1H-NMR spectra compared with the unsubstituted parent compound. These differences are used to determine structure-conformation relationships of this type of compounds. The conclusions drawn from the 1H-NMR spectra in this respect are supported by X-ray crystallographic data and by 1H-NMR data of conformationally restricted analogues. Preliminary investigations indicate that these relationships can in principle be extended to other diarylamines.     

Synthesis and some properties of 1-amino-3-nitroindazole

By treating 3-nitroindazole with hydroxylamine-O-sulfonic acid in basis medium, we have obtained its 1-amino derivative. We have observed that in chloroform solution in the presence of triethylamine, it is slowly converted to 1-ethylideneamino-3-nitroindazole. We discuss a possible mechanism for this unexpected reaction.Scientific-Research Institute of Physical and Organic Chemistry, Rostov State University. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1343–1346, October, 1996.     

Synthesis and spectral properties of 3-furyl-4-hydroxycoumarins

3-(5-Ethoxycarbonyl-2-furyl)-4-hydroxy-6-R-7-methoxycoumarins and their 4-acyl derivatives have been synthesized. Their¹H and¹³C NMR and IR spectra, and also their absorption and fluorescence spectra, have been studied. It has been shown that some of the substances synthesized can be used as fluorescent probes in the study of membranes and of protein preparations.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 45–51, January–February, 1998.     

Synthesis and some properties of 2,4,6-trihydroxy-3-methylbenzoic acid

Russian Chemical Bulletin - 2,4,6-Trihydroxy-3-methylbenzoic acid was obtained by NaHCO3 carboxylation of 2,4,6-trihydroxytoluene. The heterocyclization and esterification of the above acid were...     

Synthesis and properties of 2-isopropyl-3-aryl-4-quinazolones

A number of N-isobutyrylanthranilic acid arylamides (I) were obtained. Under the influence of phosphorus trichloride, I are cyclized to 2-isopropyl-3-aryl-4-quinazolones. The UV and IR spectra and biological activity of the quinazolone compounds were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1000–1002, July, 1972.     

Synthesis and properties of Au-Fe3O4 heterostructured nanoparticles

Au-Fe(3)O(4) composite nanoparticles have received much research interest due to their promising biomedical applications. In this work, Au-Fe(3)O(4) composites with well-defined dimer-like nanostructure were synthesized via thermal decomposition route. The surfactant 1,2-hexandicandiol has proved to be critical for the formation of the Au-Fe(3)O(4) hetero-dimers. The hetero-dimers production yield could be significantly improved to be 90% when the 1,2-hexandicandiol concentration was optimized at 0.6 M. The obtained Au-Fe(3)O(4) hetero-dimers possess dual-functionalities of plasmon resonance and magnetization. Moreover, the Fe(3)O(4) domain of the hetero-dimers can be tuned readily by adjusting the molar ratio between Fe and Au sources. Furthermore, it was demonstrated that these Au-Fe(3)O(4) hetero-dimers could be further developed into star-like Au-Fe(3)O(4) nanoparticles which showed plasmon absorption at NIR region.     

Synthesis and properties of 1-dinitromethyl-3-R-1,2,4-triazoles

Reductive denitration of 1-trinitromethyl-3-R-1,2,4-triazoles by KI or NH₂OH followed by the treatment of the formed 1-dinitromethyl-3-R-1,2,4-triazoles salts with sulfuric acid yielded dinitromethyl compounds (R = H, N₃, Cl, NO₂), sufficiently strong CH-acids (pK_a 1.37–0.12) whose typical reactions are similar to those of gem-dinitrocompounds from the aliphatic series. The spectral data and the analysis of correlation relations between pK_a of 1-dinitromethyl-3-R-1,2,4-triazoles and the substituent constants confirm that their structure is analogous to that of the majority of compounds belonging to the mentioned series.     

Synthesis and properties of 2-ethoxycarbonyl-3-amino-2,3-dehydroquinuclidine

The reduction of 2-ethoxycarbonyl-3-oxoquinuclidine oxime hydrochloride leads to 2-ethoxycarbonyl-3-amino-2,3-dehydroquinuclidine, from which pyrimido[5,4-b]quinuclidine derivatives were obtained by reaction with formamide, methyl isocyanate, and phenyl isothiocyanate. It is shown that 7-hydroxypyrazolo[4,3-b]quinuclidine is formed in the reaction of 2-ethoxycarbonyl-3-acetamido-2,3-dehydroquinuclidine with hydrazine hydrate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 971–974, July, 1983.     

Synthesis and properties of novel C3-symmetric coplanar chromophores

New synthetic pathways for novel C(3)-symmetric molecules featured with a thiophene-fused six-five-five carbon-bridged coplanar core structure have been established. The incorporation of thiophene as the constituent of a C(3)-symmetric core provides effective modulation of the physical properties and imparts extra flexibility for π-conjugated functionalization stemming from either the embedded thiophene or pendant aryl substitutions.     

Synthesis, structure and magnetic properties of nanocrystalline YMnO3

Nanocrystalline YMnO(3) has been prepared by wet chemical synthesis routes to obtain crystallites with sizes from 20 nm to bulk material. The crystal structure of hexagonal YMnO(3) nanocrystallites smaller than 80 nm deviates from bulk material in terms of unit cell distortion and unit cell volume. The ferrielectric displacements of Y(3+) cations along the polar c-axis decays progressively with decreasing size below 100 nm. Indications of weak ferromagnetism in the form of a narrow hysteresis loop and enhanced magnetic susceptibility below 43 K in 20 nm YMnO(3) nanoparticles is attributed to extrinsic effects. Low-temperature annealing of the 20 nm crystallites in an oxidizing atmosphere removed all traces of ferromagnetism, showing that this is not a size-induced property. Finally, formation of the competing metastable orthorhombic phase and the thermodynamically stable hexagonal phase is discussed with respect to oxidizing or reducing conditions during synthesis.