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241.
Using a sonochemical method, nanoparticles of a new Ce(III) supramolecular compound, (NAMH+)2[Ce4(pydc)6(pydcH)2(H2O)8]·8H2O (1), (H2pydc = 2,6-pyridinedicarboxylic acid, NAM = nicotinamide), have been synthesized. Compound 1 was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analyses, and its structure was determined by X-ray crystallography. It has been revealed that its structure consists of tetra-nuclear building units that extend to a 3D supramolecular network via non-covalent interactions mainly hydrogen bonding. The thermal stability of complex 1 both for its crystals and nanostructures has been studied by the thermal gravimetric (TG) method and compared with each other. The role of ultrasound irradiation power and the concentration of initial reactants on the size and morphology of the nano-structured complex 1, has been investigated. Ceria nanoparticles were obtained upon the calcination of complex 1 at 800 °C under atmospheric air. Furthermore, the fluorescent properties of complex 1 at room temperature were studied. 相似文献
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244.
Jérôme Elhaïk 《Tetrahedron》2007,63(2):291-298
Two routes to 2,6-di(pyrazol-1-yl)-4-hydroxymethylpyridine (1) from 2,6-dihydroxy-isonicotinic acid, in four and six steps, are reported. Reaction of 1 with 48% HBr yields 2,6-di(pyrazol-1-yl)-4-bromomethylpyridine (2), which is a powerful precursor to a range of new tridentate ligands for transition metals functionalised at the pyridine ring. As a proof of principle, we describe the further elaboration of 2 to give two 2,6-di(pyrazol-1-yl)pyridines bearing nucleobase substituents, and the back-to-back ligand 1,2-bis[2,6-di(pyrazol-1-yl)pyrid-4-yl]ethane. Crystal structures of two of these new derivatives are presented. 相似文献
245.
The supramolecular interaction of β-cyclodextrin dimer with berberine hydrochloride was studied in aqueous KH2PO4-H3PO4 buffer solution of pH 2.00 at room temperature by spectrofluorimetry. The apparent association constant of the complex was 1.53 × 104 L mol−1. Based on the significant enhancement of fluorescence intensity of supramolecular sandwich complexes, a spectrofluorimetric method with high sensitivity and selectivity was developed for the determination of berberine hydrochloride in aqueous solution in presence of ethylenediamine linked β-CD dimer. The linear range of the method was 12.8-1.00 × 104 ng mL−1 with the detection limit 3.6 ng mL−1. There was no interference from the normally used in tablets and serum constituents. The proposed method was successfully applied to the determination of berberine hydrochloride in tablets and serum. And then it has a promising potential in therapeutic drug monitoring, pharmokinetis and clinical application. 相似文献
246.
Susobhan Biswas Saikat Sarkar Ian M. Steele Sougata Sarkar Golam Mostafa Bijali Bikash Bhaumik Kamalendu Dey 《Polyhedron》2007
The reaction of phenylmercury(II) acetate and cadmium(II) acetate with a refluxed solution of diacetylmonoxime and morpholine N-thiohydrazide formed a novel phenylmercury(II) complex, [PhHg(Hdammthiol)] (1) and a cadmium(II) complex, [Cd(Hdammthiol)2] (2), respectively (where H2dammthiol is the thiol form of diacetylmonoximemorpholine N-thiohydrazone (Hdammth) formed by the condensation of diacetylmonoxime and morpholine N-thiohydrazide in the presence of phenylmercury(II) and cadmium(II) ions). The complexes were characterised by elemental analyses and spectral data (electronic, infrared and 1H NMR) and also by X-ray crystal structure analysis. The X-ray crystallography shows that the phenylmercury(II) complex attained a tricoordinated distorted T-shaped structure, while the cadmium(II) complex attained a trapezoidal bipyramidal geometry. The phenylmercury(II) complex forms a two-dimensional sheet via C–H?O and O–H?N hydrogen bonding and also forms a two-dimensional supramolecular dimer, having C–H?π synthons. Intermolecular C–H?O and O–H?O hydrogen bonding of the cadmium(II) complex forms a two-dimensional supramolecular sheet along the bc plane and posses an impressively short intermolecular C(sp3)?O(sp3) contact. 相似文献
247.
Two novel photoluminescent coordination polymers of the formula [Cd(Haip)2(H2O)2] · 2H2O (1) and [Zn(aip)(atz)] · 3H2O (2) (H2aip = 5-aminoisophthalic acid; atz = 3-amino-1,2,4-triazole) have been synthesized through the self-assembly of metal(II) ions with H2aip and N-containing ligands [2-amino-5-mercapto-1,3,4-thiadiazole for 1 and 3-amino-1,2,4-triazole for 2, respectively] in the presence of NaOH. These complexes were characterized by FT-IR spectroscopy, thermogravimetric analysis (TG), elemental analysis and X-ray analysis. X-ray crystallographic studies of the complexes reveal that 1 is a first example where only one carboxylate group of the H2aip ligand participates in coordination with the metal(II) ion and it exhibits a two-dimensional framework which further assembles into a three-dimensional supramolecular network via interlayer π–π stacking interactions and strong hydrogen bonds, while 2 exhibits a two-dimensional porous architecture. The extensively strong hydrogen bonds and interlayer π–π stacking interactions in 2 lead to the formation of a three-dimensional supramolecular network. Photoluminescence properties of the compounds 1 and 2 have been examined in the solid state at room temperature. These compounds have been found to exhibit blue photoluminescence and may be good candidates for photoactive materials. 相似文献
248.
The structural similarities and differences between the original DOM and the eight size fractions separated were studied in detail with the pyrolysis technique in combination with gas chromatography and mass spectrometry (Py-GC-MS) using two alkylating reagents: TMAH (tetramethylammonium hydroxide), to find both esterified and free carboxylic acids; and TMAAc (tetramethylammonium acetate), to specify only free carboxylic acids. A statistical analysis of the original multidimensional TMAH and TMAAc pyrograms disclosed that the overall structural compositions of the five most important size fractions, accounting for 84% of the original DOM, greatly resembled each other. The remaining three minor size fractions were not classified as homogeneous associations, but they also contained the same total, covalently bound and free carboxylic acid species as the other size fractions and the original DOM mixture, thus representing some kind of intermediate forms. This fundamental outcome strongly supports the opinion that the native dissolved humic-like macromolecules resemble supramolecular associations of smaller molecular size moieties with similar structural functionalities. The concentrations of free aliphatic and aromatic dicarboxylic acids in the DOM solution were so low that their effects on the potential formation of multiply charged ions in electrospray ionization-MS (ESI-MS) studies are likely insignificant. 相似文献
249.
Krešimir Mol?anov Darko Babi? Biserka Koji?-Prodi? 《Journal of organometallic chemistry》2007,692(18):3874-3881
The double cyclopalladated complex with azobenzene, μ-[(E)-1,2-diphenyldiazene-C2,8, N1,2]-di-[chloro(dimethylsulfoxide)palladium(II)]; (DMSO)PdCl(μ-C6H4NNC6H4)(DMSO)PdCl (1) and its analogous complex with DMF as ancillary ligand, (DMF)PdCl(μ-C6H4NNC6H4)(DMF)PdCl; μ-[(E)-1,2-diphenyldiazene-C2,8,N1,2]-di-[chloro(dimethylformamide)palladium(II)] (2a) were synthesized and the function of cyclopalladated moiety in molecular assembling in the solid state is illustrated by their crystal packings. The polymorphism of 2a and 2b is discussed. The crystal structures reveal assemblies with molecular components self-organized by C-H?Cl-Pd hydrogen bonds, π?π, and C-H?π interactions. The double cyclopalladated complexes of azobenzene, with two Pd-Cl moieties participating in the hydrogen bond formation and π-conjugated system involved in the π?π or C-H?π interactions, represent a new class of building blocks for construction of solid state supramolecular assemblies. 相似文献
250.
Summary: A novel mesoporous organosilica with additional cyclodextrin‐based micropores has been synthesized from tetraethoxysilane (TEOS) and cyclodextrin‐based silane monomer precursors and triblock PEO‐PPO‐PEO (poly(ethylene oxide)‐poly(propylene oxide)‐ poly(ethylene oxide)) copolymer P123 as the structure‐directing template with the aid of sodium chloride and the supramolecular assembly of cyclodextrins with P123.