Eu3+ and Tb3+ doped in nanocrystalline InBO3, GdBO3, and LaBO3 having three different morphs of calcite (CaCO3) such as Calcite, Vaterite, and Aragonite, respectively, were synthesized by glycine–nitrate combustion method. Luminescence due to Eu3+ and Tb3+ doped individually as well as simultaneously in these three different morphs of calcite were investigated and compared. Also the effect of concentration of dopant ions on the luminescence was studied. The highest photoluminescence emission intensity was observed for RE0.05M0.95BO3 (RE = Eu3+, Tb3+, M = In, Gd, La) samples. Further increase in doping led to concentration quenching of the luminescence. In case of the co‐doped borates, the energy transfer between the co‐doped rare earth ions was influenced by the host crystal structure. This study reveals that there is remarkable effect of the crystal structure of host and concentration of dopant ions on the luminescence.
In 2 O 3 nanopaticles were synthesized by glycine-nitrate combustion method. The synthesized In 2 O 3 is characterized by the powder X-ray diffraction and transmission electron microscopy. The average crystallite size, as determined by Scherrer's formula, was found to be about 48 nm. A catalytic amount of In 2 O 3 nanopaticles, were used for an efficient synthesis of amidoalkyl naphthols via multicomponent condensation of aryl aldehydes, β-naphthol, and urea or acetamide. In 2 O 3 nanopaticles were found to be highly active for the transformation with excellent yield and purity of the product in a short reaction time.
Background:
Nanocatalysts exhibit several applications in the synthesis of many industrially important organic compounds. They manifest extremely fascinating physical and chemical properties which can be exploited in their catalytic applications.
Method:
A magnetically recyclable Ag@Fe2O3 core-shell structured nanocatalyst was synthesized by a simple sol-gel technique and characterized by x-ray diffraction spectroscopy, field emission scanning electron microscope, high-resolution transmission electron microscopy, fourier transform infrared spectroscopy, vibrating sample magnetometer etc. Nanocatalyst was found to be a highly efficient heterogeneous catalyst for the synthesis of 2-aryl benzimidazoles and benzothiazoles via one-pot condensation of aromatic aldehydes and 1, 2-phenylenediamine, and 2-aminothiophenol.
Results:
Ag@Fe2O3 nanocatalyst provides rapid conversion of the substrate into the desired product at room temperature within just 5-18 min in the presence of C2H5OH with good to excellent yield. The combination of Ag core with magnetic Fe2O3 shell results in improved efficiency, stability, magnetic recovery, and reusability compare to the individual nanoparticles.
Conclusion:
The synthetic protocol is featured with high yield, mild conditions, and simple work-up. Magnetic recovery of the catalyst from reaction systems and its reusability for several runs without loss of catalytic activity are additional advantages.
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