RESUMO
Resumen En este artículo se reporta la síntesis de nanopartículas de paladio soportadas en hidroxisales de acetato de zinc y modificadas con un surfactante (LHS-Zn-Ac/Pd0 y LHS-Zn-Suf/Pd0 respectivamente), mediante inserción de [PdCl4]2- y su posterior reducción con etanol en reflujo. Con la inserción de surfactante, la distancia interlaminar de la hidroxisal de partida (LHS-Zn-Ac) se incrementó de 13,8 Å a 29,8 Å, mientras que los materiales finales, que contenían paladio metálico registraron distancias interlaminares de 22,4 Å y 29,4 Å para LHS-Zn-Ac/Pd0 y LHS-Zn-Suf/Pd0 respectivamente. Las hidroxisales de acetato de zinc y de surfactante con nanopartículas metálicas de paladio incorporadas fueron ensayadas como potenciales catalizadores en la reacción de Sonogashira partiendo de fenilacetileno y yoduros de arilo, particularmente yodobenceno o 2-yodofenol, dando lugar a difenilacetileno (32% de rendimiento de producto aislado y purificado) o 2-fenilbenzofurano (18%). Todos los materiales inorgánicos fueron caracterizados mediante las siguientes técnicas: difracción de rayos X (XRD), microscopia electrónica de barrido (SEM y SEM-EDS), microscopia electrónica de transmisión (TEM) y espectroscopía de Infrarrojo con Transformada de Fourier (FT-IR). Por su parte los compuestos orgánicos se caracterizaron por resonancia magnética nuclear (1H-NMR y 13C-NMR) y cromatografía de gases acoplada a espectrometría de masas (GC-MS).
Abstract This article reports the synthesis of palladium nanoparticles supported on zinc acetate hydroxysalts and modified with a surfactant (LHS-Zn-Ac/Pd0 and LHS-Zn-Suf/Pd0 respectively), by insertion of [PdCl4]2- and its subsequent reduction with ethanol at reflux. With the surfactant insertion, the interlaminar distance of the starting hydroxysalt (LHS-Zn-Ac) increased from 13.8 Å to 29.8 Å, while the final materials containing palladium metal registered interlaminar distances of 22.4 Å and 29.4 Å for LHS-Zn-Ac/Pd0 and LHS-Zn-Suf/Pd0 respectively. Zinc acetate hydroxysalt and surfactant with incorporated palladium metal nanoparticles were tested as potential catalysts in the Sonogashira reaction starting from phenylacetylene and aryl iodides, particularly iodobenzene or 2-iodophenol, giving diphenylacetylene (32% yield of isolated and purified product) or 2-phenylbenzofuran (18%). All inorganic materials were characterized by the following techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM and SEM-EDS), transmission electron microscopy (TEM) and Fourier transformed infrared spectroscopy (FT-IR). The organic compounds were characterized by nuclear magnetic resonance (1H-NTMR and 13C-NMR) and gas chromatography coupled to mass spectrometry (GC-MS).
Resumo Neste artigo se reporta a síntese de nanopartículas de paládio suportadas em hidroxisais de acetato de zinco e modificadas com um surfactante (LHS-Zn-Ac/Pd0 e LHS-Zn-Suf/Pd0 respectivamente), mediante inserção de [PdCl4]2- para depois fazer uma redução com etanol em refluxo. Com a inserção do surfactante, a distância interlaminar da hidroxisal inicial (LHS-Zn-Ac) aumentou de 13,8 Å até 29,8 Å, enquanto que os materiais finais que continham paládio metálico registraram distâncias interlaminares de 22,4 Å até 29,4 Å para LHS-Zn-Ac/Pd0 e LHS-Zn-Suf/Pd0 respectivamente. As hidroxisais do acetato de zinco e do surfactante com nanopartículas metálicas de paládio incorporadas foram testados como potenciais catalisadores na reação de Sonogashira a partir de fenilacetileno e iodetos de arilo, particularmente iodobenzeno ou 2-iodofenol, levando respectivamente difenilacetileno (32% de rendimento de produto isolado e purificado) ou 2-fenilbenzofurano (18%). Todos os materiais inorgânicos foram caracterizados pelas seguintes técnicas: difração de raios X (XRD), microscopia eletrônica de varredura (SEM e SEM-EDS), Microscopia Eletrônica de Transmissão (TEM) e espectroscopia de infravermelho com transformada de Fourier (FT-IR). Por outro lado, os compostos orgânicos foram caracterizados por ressonância magnética nuclear (1H-NMR y 13C-NMR) e cromatografia gasosa acoplada à massa (GC-MS).
RESUMO
To improve the sensitivity of molecularly imprinted electrochemical sensors, a Pd nanoparticles-modified molecularly imprinted polymer (MIP) film for the determination of trimethoprim (TMP) was developed by thermal polymerization with N, N′-methylene diacrylamide as a functional monomer, Pd nanoparticle as a dopant and ethylene glycol maleic rosinate acrylate as a crosslinking agent.The morphologies and chemical structures of the Pd nano-materials and the imprinted films were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy, respectively.The electrochemical properties of the nano-doped and undoped MIP sensors were investigated by cyclic voltammetry and electrochemical impedance spectroscopy.Results showed that the morphologies and chemical structures and the electrochemical properties of the doped molecularly imprinted sensor were remarkably different from those of the undoped imprinted sensor.Linear responses of the imprinted sensor to TMP were observed for concentrations ranging from 5.0×10-7 mol/L to 4.0×10-3 mol/L (R=0.9995), with a detection limit of 3.2×10-8 mol/L (S/N=3).The Pd nanoparticle doped MIP sensors exhibited high selectivity.The chronoamperometry showed that no interference from potential interfering species such as sulfamethoxazole, sulfadiazine, glucose, and urea were noted.The proposed electrochemical sensor was used to determine TMP in actual samples, with average recoveries of 96.8%-102.0%.
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The fourth generation poly( amidoamine) dendrimers ( G4. 0 PAMAM) functionalized multiwalled carbon nanotube ( G4 . 0-MWCNTs ) was prepared by amidation between carboxylated multiwalled carbon nanotube (MWCNTs) and G4. 0 PAMAM. Then a novel hydrogen peroxide (H2O2) sensor was fabricated by electrodepositing Pd nanoparticles (NPs) on a glassy carbon electrode (GCE) modified with G4. 0-MWCNTs composites. The modified electrode was characterized by field emission scanning electron microscopy ( FESEM) , cyclic voltammetry ( CV) and electrochemical impedance spectroscopy ( EIS) . A large amounts of highly dispersion PdNPs could be well loaded on the surface of the G4. 0-MWCNTs, and the modified electrode exhibited excellent electrocatalytic activity towards the reduction of H2 O2 . Under the optimized conditions, the reduction peak currents of H2 O2 were linear to their concentrations in the range from 1. 0 × 10-9 mol/L to 1. 0×10-3 mol/L and the limit of detection of 2. 3×10-8 mol/L was obtained. The recovery of standard addition for human serum samples was 96 . 7%-103 . 1%.