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Bifunctional Ligand (bifunctional + ligand)
Selected AbstractsHighly Stereoselective Synthesis of Novel Multistereogenic Bis - Bifunctional Ligands Based on [2.2]Paracyclophane- 4,7-quinone, their Structure Elucidation and Application in Asymmetric CatalysisADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2005Natalia Vorontsova Abstract Bis - bifunctional cis -4,7-diarylsubstituted-4,7-dihydroxy-4,7-dihydro[2.2]paracyclophanes 3,6 were synthesized by a highly diastereoselective reaction of ortho -substituted aryllithium reagents with [2.2]paracyclophane-4,7-quinone (1). Enantiomerically pure diols 3,5 were tested as chiral inductors in the enantioselective addition of diethylzinc to benzaldehyde (up to 93.5% ee). Acid dehydration of cis -4,7-di(2-methoxyphenyl)-4,7-dihydroxy-4,7-dihydro[2.2]paracyclophane (3) results in 4,7-dihydro-7,8-di(2-methoxyphenyl)[2.2]paracyclophane-4-one (8) , a planar chiral cyclohexadienone of the [2.2]paracyclophane series with a para -semiquinoid substructure. X-Ray investigations of compounds 3, 4 and 8 were performed. [source] Systematic Hydrothermal Investigation of Metal Phosphonatobenzenesulfonates by High-Throughput MethodsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2010Palanikumar Maniam Abstract A high-throughput (HT) investigation using the rigid bifunctional ligand 4-phosphonobenzenesulfonic acid, H2O3P-C6H4 -SO3H (H3L), generated five new phosphonatobenzenesulfonates with copper(II) or lead(II) ions. A comprehensive HT study comprising the screenings of different metal ions, metal salt types and the synthesis optimization were conducted whereby the influence of pH and molar ratios M2+/H3L were investigated. The HT-study led to five new compounds Pb2[(O3P-C6H4 -SO3)(OH)] (1), Cu1.5[(O3P-C6H4 -SO3)(H2O)] (2), NaCu(O3P-C6H4 -SO3)(H2O)3 (3), Cu2[(O3P-C6H4 -SO3)(OH)(H2O)] (4) and Cu3[(O3P-C6H4 -SO3)2(H2O)2] (5). Metal ion screening showed lead(II) and copper(II) to be suitable metal ions. The utilization of discovery and focused arrays allowed to determine the optimal formation fields of the respective compounds. The crystal structures were determined from single-crystal X-ray diffraction and revealed the presence of various MOx polyhedra that form clusters, chains or layers which are connected through the organic linker. IR spectra, thermogravimetric studies, magnetic susceptibility measurements and elemental analyses were conducted to further characterize the compounds 1, 3, 4 and 5. [source] [Ru(0)]@SiO2 and [RuO2]@SiO2 Hybrid Nanomaterials: From Their Synthesis to Their Application as Catalytic Filters for Gas SensorsADVANCED FUNCTIONAL MATERIALS, Issue 23 2009Victor Matsura Abstract [Ru(0)]@SiO2 and [RuO2]@SiO2 hybrid nanomaterials are produced following a facile method consisting of the synthesis of size-controlled ruthenium nanoparticles as elemental bricks. This route takes advantage of the organometallic approach and the use of a bifunctional ligand for the synthesis of ruthenium nanoparticles from [Ru(COD)(COT)](COD,=,1,3-cyclooctadiene, COT,=,1,3,5-cyclooctatriene) as metal precursor and (PhCH2)2N(CH2)11O(CH2)3Si(OEt)3 (benzenemethanamine) as stabilizer. Hydrolysis and polycondensation steps via a sol,gel approach lead to the formation of the silica materials containing the metal nanoparticles. A final calcination step in air at 400,°C yields the [RuO2]@SiO2 nanocomposites. Such hybrid nanomaterials display a good dispersion of the nanoparticles inside the silica matrix and interesting porosity properties making them attractive materials for catalytic applications. This is shown by using [RuO2]@SiO2 hybrid nanomaterials as catalytic filters for gas sensors. [source] Synthesis and biological evaluation of a novel asymmetrical 99mTc-nitrido complex of metronidazole derivativeJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 13 2007Dejing Kong Abstract The novel dithiocarbamate derivative of metronidazole, potassium 2-(2-methyl-5-nitro-1H -imidazolyl)-ethyl-dithiocarbamate (MNIE-DTC), was synthesized as the pharmacophore-containing bifunctional ligand. The corresponding asymmetrical 99mTc-nitrido complex, expected as a tumor hypoxia marker, had been successfully obtained by the addition of the biphosphine ligand PNP5 (PNP5 = N -ethoxethyl- N,N -bis[2-(bis(3-methoxypropyl)phosphino)ethyl]-amine) and the dithiocarbamate ligand (MNIE-DTC) to the 99mTc-nitrido precursor solution at 100°C for 15 min. The radiochemical purity of the product was above 95% as measured by thin-layer chromatography and high-performance liquid chromatography. In vitro studies showed that the complex possessed good stability under physiological conditions. Its partition coefficient studies indicated that it was a lipophilic complex. The electrophoresis results showed that the complex was cationic. Biological evaluation of the complex [99mTcN(PNP5)(MNIE-DTC)]+ performed in Kunming mice bearing H22 tumor showed that the complex had a moderate tumor uptake (0.57±0.06%ID/g at 1h), and the ratios of tumor/blood and tumor/muscle were 2.46 and 1.31 at 1h p.i., and reached 4.52 and 2.86 at 4h p.i., respectively. Copyright © 2007 John Wiley & Sons, Ltd. [source] 3-D Water-Soluble Reversible Neodymium(III) and Lanthanum(III) Coordination PolymersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2004Tina Vermonden Abstract The formation of soluble supramolecular 3-D coordination polymers with Nd3+ and La3+ in aqueous solution has been studied for two bifunctional ligands consisting of two pyridine-2,6-dicarboxylate groups connected at the 4-position by O(CH2CH2O)4 and O(CH2CH2O)6 spacers (C4 and C6, respectively). Viscosity measurements were used to monitor the network formation as a function of the ligand concentration, and the ratio between metal ions and ligands. For corresponding conditions C4 solutions with Nd3+ always gave much higher viscosities than C6 solutions with Nd3+. C6 is long, and flexible enough to bind with both chelating groups to only one metal ion (ring formation). This causes the polymers to stop growing, resulting in smaller average sizes of the 3-D polymers. The ring-structures could be demonstrated by 1H NMR spectroscopy using C6 and La3+ at low concentrations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] | ||||||||||