Showing papers by "Cesar A. Sierra published in 2016"
TL;DR: The optical absorption of UiO-66-NH2 MOF was red-shifted using a diazo-coupling reaction and the degradation performance was found to correlate with the red shift of the absorption edge, suggesting potential applications of these materials in photocatalysis and in dye sensitized solar cells.
42 citations
TL;DR: In this paper, the physical properties of the deep eutectic solvent (DES) such as viscosity, electrical conductivity, density, pH and refractive index were measured and analyzed as a function of temperature.
Abstract: In this work, the low melting mixture sodium acetate trihydrate–urea was synthesized and the eutectic composition was determined and characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The physical properties of the deep eutectic solvent (DES) such as viscosity, electrical conductivity, density, pH and refractive index were measured and analyzed as a function of temperature. To explore the use of this DES as a reaction media, the Biginelli one-pot reaction for the preparation of polyhydroquinoxaline derivatives was studied and unexpectedly methylenebis(3-hydroxy-5,5-dimethylcyclohex-2-enones) and hexahydroxanthene-1,8-diones were obtained when the reaction was performed at 60 °C, and hexahydroacridine-1,8-diones when the reaction was conducted at 100 °C. Our results showed that the nature of the obtained products can be tuned by increasing the temperature of the reaction.
25 citations
TL;DR: In this paper, a simple solvothermal Heck cross-coupling reaction yields a stereospecific 2½ PV system, whose photoluminescence properties were examined and the crystal structure showed the desired anti trans-trans configuration.
8 citations
TL;DR: A definicion de nanomateriales for Colombia que ha adoptado el Consejo Nacional Asesor de Nanociencia and Nanotecnologia adscrito a la Red Colombiana de Nanocencias y Nanotechnologia as discussed by the authors.
Abstract: Debido a la creciente produccion y uso de nanomateriales para actividades de investigacion y desarrollo en Colombia, es necesario establecer una definicion del termino nanomaterial que facilite la toma de decisiones en torno a iniciativas de caracter regulatorio y de normatividad. Se presenta la definicion de nanomateriales para Colombia que ha adoptado el Consejo Nacional Asesor de Nanociencia y Nanotecnologia adscrito a la Red Colombiana de Nanociencia y Nanotecnologia.
6 citations
05 Oct 2016
TL;DR: In this paper, the authors describe the oligomer approach using the Mizoroki-Heck reaction as a synthetic route for oPVs and PPVs, and the importance of an extensive characterization for novel applications, such as photocatalysis and matrix-assisted laser desorption/ionization (MALDI) matrices, where these electronic conjugated systems have very promising applications.
Abstract: Among conducting polymers, poly-p-phenylenevinylenes (PPVs) have attained a special place in polymer electronics. The optoelectronic properties initially exposed by PPVs in organic light-emitting diodes (OLEDs) turned these organic electronic conjugated systems from the solo academic interest into a technologically very promising area. The easiness of the tuning of their optoelectronic properties through synthetic modifications make PPVs an outstanding and suitable compound for technological applications and fundamental science development. Unfortunately, the synthesis and structural optoelectronic characterization of novel PPVs is a long and difficult task that sometimes yields unclear results. However, phenylenevinylene oligomers (oPV) can be synthesized and characterized in a very straightforward manner, and their performance in novel applications can be directly related to their structural analogue polymer, methodology designated as the oligomer approach. Herein, we describe the oligomer approach using the Mizoroki-Heck reaction as a synthetic route for oPVs and PPVs, and the importance of an extensive characterization for novel applications, such as photocatalysis and matrix-assisted laser desorption/ionization (MALDI) matrices, where these electronic conjugated systems have very promising applications.
2 citations
TL;DR: In this article, the title compound 9-(4-hydroxybutyl)-3,3,6,6-tetramethyl-3,4,5, 6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione was synthesized in 72% yield through a simple, convenient and environmentally friendly one-pot reaction between dimedone and 3,4-dihydron-2H-pyran in aqueous citric acid.
Abstract: The title compound 9-(4-hydroxybutyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione was synthesized in 72% yield through a simple, convenient and environmentally friendly one-pot reaction between dimedone and 3,4-dihydro-2H-pyran in aqueous citric acid. Additionally, a plausible reaction mechanism for the formation of the target xanthene is proposed.
1 citations
TL;DR: In this article, the physical properties of the deep eutectic solvent (DES) such as viscosity, electrical conductivity, density, pH and refractive index were measured and analyzed as a function of temperature.
Abstract: In this work, the low melting mixture sodium acetate trihydrate–urea was synthesized and the eutectic composition was determined and characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The physical properties of the deep eutectic solvent (DES) such as viscosity, electrical conductivity, density, pH and refractive index were measured and analyzed as a function of temperature. To explore the use of this DES as a reaction media, the Biginelli one-pot reaction for the preparation of polyhydroquinoxaline derivatives was studied and unexpectedly methylenebis(3-hydroxy-5,5-dimethylcyclohex-2-enones) and hexahydroxanthene-1,8-diones were obtained when the reaction was performed at 60 °C, and hexahydroacridine-1,8-diones when the reaction was conducted at 100 °C. Our results showed that the nature of the obtained products can be tuned by increasing the temperature of the reaction.