In recent years, several novel strategies for speeding up the slow kinetics of the water oxidation reaction have attracted considerable attention for generation of O
2
. This is particularly ...important from the environmental perspective. Here we report a SBA-15 type, 2D-hexagonal functionalized mesoporous organosilica material as support for small Ag nanoparticles (NPs) by grafting the silica surface with 3-aminopropyltriethoxysilane, followed by chemical impregnation of Ag NPs at its surface, to obtain a AgNPs@SBA-NH
2
material. The AgNPs@SBA-NH
2
has been thoroughly characterized using several instrumental tools, such as powder X-ray diffraction, ultra-high resolution transition electron microscopy, N
2
sorption, FT-IR spectroscopy, thermogravimetric and differential thermal analysis and X-ray photoelectron spectroscopy. High Brunauer-Emmett-Teller (BET) surface area and fine dispersion of Ag NPs throughout the surface of the amine-functionalized mesoporous material could enhance the rate of oxygen evolution reaction (OER) activity for AgNPs@SBA-NH
2
in the electrochemical water splitting reaction.
Ag NPs were decorated on the surface of a functionalized SBA-15 material and the resulting AgNPs@SBA-NH
2
material showed excellent OER activity for electrochemical water oxidation under alkaline pH.
CO2 fixation reactions by inserting it in reactive organic compounds are very challenging for the utilization of this abundant and harmful gas present in air and thus to mitigate this greenhouse gas ...responsible for global warming. This can be achieved by appropriate design of functionalized porous nanocatalysts having high surface areas and porosity and good CO2 uptake capacity. Herein, we first report the decoration of silver nanoparticles (NPs) over the surface of a covalent organic framework (COF) material TpPa-1 synthesized through the polycondensation of 2,4,6-triformylphloroglucinol (TFP) and p-phenylenediamine. The resulting material Ag@TpPa-1 was thoroughly characterized by N2 adsorption/desorption, powder X-ray diffraction (PXRD), FE-SEM, TEM, UV-Vis, FT IR and thermogravimetric techniques. This Ag NP decorated porous COF in the presence of DBU exhibited excellent catalytic activity for the synthesis of tetramic acids from a variety of propargylic amine derivatives at 60 °C under atmospheric pressure of carbon dioxide via formation of oxazolidinones, where CO2 acts as a C1 reagent. The Ag@TpPa-1 catalyst exhibited excellent recycling efficiency for the synthesis of tetramic acid with no leaching of Ag from the catalyst surface.
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•A simple and an efficient oxidative conversion of chromenes to flavones.•A very short reaction time and high level of functional group tolerance.•Non precious metal salt, Cu(II) ...bromide is used as a catalyst.•Wide applicability (21 examples) and good to excellent yields (67–94%).
A simple and efficient method has been developed for the facile oxidation of chromenes to the corresponding flavones by tert-butylhydroperoxide (TBHP) in the presence of copper(II) bromide catalyst in toluene at 80°C in a very short time. The reaction demonstrates excellent reactivity, functional group tolerance, and good to excellent yields without using conventional strong oxidizing agents.
The development of drug carriers based on nanomaterials that can selectively carry chemotherapeutic agents to cancer cells has become a major focus in biomedical research. A novel pH-sensitive ...multifunctional envelope-type mesoporous silica nanoparticle (SBA-15) was fabricated for targeted drug delivery to human colorectal carcinoma cells (HCT-116). SBA-15 was functionalized with folic acid (FA), and the material was loaded with the water-insoluble flavonoid, quercetin (QN). Additionally, acid-labile magnetite Fe
3
O
4
nanoparticles were embedded over the FA-functionalized QN-loaded monodisperse SBA-15 to prepare the highly orchestrated material FA-FE-SBA15QN. The
in vitro
and
in vivo
anti-carcinogenic efficacy of FA-FE-SBA15QN was carried out to explore the pH-sensitive QN release with putative mechanistic aspects. FA-FE-SBA15QN caused a marked tumor suppression, and triggered mitochondrial-dependent apoptosis through a redox-regulated cellular signaling system. Furthermore, FA-IO-SBA-15-QN initiated the c-Jun N-terminal Kinase (JNK)-guided H2AX phosphorylation, which relayed the downstream apoptotic signal to the phosphorylate tumor suppressor protein, p53. On the other hand, the selective inhibition of heat shock protein-27 (HSP-27) by FA-FE-SBA15QN augmented the apoptotic fate through JNK/H2AX/p53 axis. The
in vitro
and
in vivo
magnetic resonance imaging (MRI) studies have indicated the theranostic perspective of the composite. Thus, the result suggested that the newly synthesized FA-FE-SBA15QN could be used as a promising chemo theranostic material for the management of carcinoma.
pH-Sensitive quercetin/Fe
3
O
4
NPs loaded functionalized mesoporous SBA-15 fabricated for targeted drug delivery to colorectal carcinoma cells with high anti-carcinogenic efficacy.
The development of a robust, sustainable and inexpensive bifunctional material for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) via electrochemical overall water splitting is ...very challenging and essential for energy generation and conversion processes. Herein, we have developed two 3d transition metals Ni(II) and Cu(II)-porphyrin based conjugated microporous polymeric electrocatalysts having high specific surface areas (1400 and 1350 m2g−1). Both catalysts showed good performance towards overall water splitting under alkaline pH conditions. These metal-coordinated porous polymers Ni-Por-Py and Cu-Por-Py are well characterized using different analytical instruments. Ni-Por-Py and Cu-Por-Py displayed a low overpotential of 213 mV and 250 mV, respectively to attend a current density of 10 mA/cm2 for HER using Ni-foam as substrate. The OER activity under alkaline condition with an overpotentials of 164 and 170 mV for Ni-Por-Py and Cu-Por-Py, respectively were achieved to drive a current density of 10 mA/cm2 under similar conditions. The excellent electrocatalytic activity of Ni-Por-Py and Cu-Por-Py could be attributed to the presence of transition metal coordinated porphyrin building blocks in the π-conjugated polymer skeletons, which facilitates the electron transfer processes along with inherent microporosity and high surface areas.
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CO2 fixation reactions by inserting it in reactive organic compounds are very challenging for the utilization of this abundant and harmful gas present in air and thus to mitigate this greenhouse gas ...responsible for global warming. This can be achieved by appropriate design of functionalized porous nanocatalysts having high surface areas and porosity and good CO2 uptake capacity. Herein, we first report the decoration of silver nanoparticles (NPs) over the surface of a covalent organic framework (COF) material TpPa-1 synthesized through the polycondensation of 2,4,6-triformylphloroglucinol (TFP) and p-phenylenediamine. The resulting material Ag@TpPa-1 was thoroughly characterized by N2 adsorption/desorption, powder X-ray diffraction (PXRD), FE-SEM, TEM, UV-Vis, FT IR and thermogravimetric techniques. This Ag NP decorated porous COF in the presence of DBU exhibited excellent catalytic activity for the synthesis of tetramic acids from a variety of propargylic amine derivatives at 60 °C under atmospheric pressure of carbon dioxide via formation of oxazolidinones, where CO2 acts as a C1 reagent. The Ag@TpPa-1 catalyst exhibited excellent recycling efficiency for the synthesis of tetramic acid with no leaching of Ag from the catalyst surface.
An one pot simple and efficient approach toward the synthesis of dialkyl-3-aryl-3,4-dihydrobenzofquinoline-1,2-dicarboxylate and its dehydro derivatives have been developed through the ...three-component reaction of aromatic aldehydes, 2-naphthylamine, and but-2-ynedioate catalyzed by SbCl3 under reflux in acetonitrile in good to excellent yields.
An unprecedented facile oxidation of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines (DHPs) to the corresponding pyrazoles and pyridines was observed, mediated by ...3,4-dihydro-2H-pyran in air. The reaction showed excellent reactivity, functional group tolerance, and high yield without using any metal and/or halogen based oxidizing agents.
A convenient approach for the synthesis of 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) by an efficient one-pot reaction of aromatic aldehydes, phenylhydrazine, and ethyl acetoacetate ...by using substoichiometric amount of K
2
CO
3
in acetonitrile solvent at room temperature is described. This protocol of one-pot synthesis produced a library of bis-pyrazolylmethane derivatives, a potential bioactive compound in very good to excellent yields.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A wide range of coumarin-3-carboxylic acids can be synthesized quantitatively via Knoevenagel condensation of an ortho-hydroxyaryl aldehydes and active methylene compound in the presence of ordered ...mesoporous γ-Al2O3 as a heterogeneous catalyst.
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•Ordered mesoporous γ-Al2O3 has been synthesized through evaporation induced self-assembly method.•Mesoporous alumina material possesses both surface acidity and basicity.•Efficient Knoevenagel condensation of ortho-hydroxyaryl aldehyde and malononitrile.•A wide range of Knoevenagel condensation products can be synthesized over mesoporous γ-Al2O3.•Mesoporous γ-Al2O3 material showed very high recycling efficiency in the synthesis of coumarin derivatives.
Coumarins are important class of organic compounds and intensively used in agricultural and pharmaceutical industries. We have developed a strategy for the synthesis of coumarin derivatives quantitatively via Knoevenagel condensation reaction of an ortho-hydroxyaryl aldehyde and an activated methylene compounds in the presence of ordered mesoporous γ-Al2O3 as a heterogeneous catalyst. The catalyst has been thoroughly characterized through powder X-ray diffraction, N2 sorption analysis, FTIR spectroscopy, TG/DTA, NH3-TPD and CO2-TPD (temperature programmed desorption) analysis. The material possesses periodicity in mesopores and both surface acidic and basic sites having strengths of 1.47 and 1.11 mmol g−1, respectively, which is highly favorable for carrying out the Knoevenagel condensation reaction for the synthesis of a wide range of condensation product (yields ∼98%) under very mild conditions. This amphoteric catalyst exhibits good surface Lewis acidity/basicity and high recyclability up to sixth reaction cycles without any significant loss in the product yield.
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