scholarly journals Microwave-Assisted Preparation of Luminescent Inorganic Materials: A Fast Route to Light Conversion and Storage Phosphors

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2882
Author(s):  
José Miranda de Carvalho ◽  
Cássio Cardoso Santos Pedroso ◽  
Matheus Salgado de Nichile Saula ◽  
Maria Claudia França Cunha Felinto ◽  
Hermi Felinto de Brito
Keyword(s):  
Rapid Heating ◽  
Inorganic Materials ◽  
Rapid Screening ◽  
Conventional Heating ◽  
Quantum Yields ◽  
Microwave Assisted Synthesis ◽  
Volumetric Heating ◽  
White Leds ◽  
Microwave Assisted ◽  
And Storage

Luminescent inorganic materials are used in several technological applications such as light-emitting displays, white LEDs for illumination, bioimaging, and photodynamic therapy. Usually, inorganic phosphors (e.g., complex oxides, silicates) need high temperatures and, in some cases, specific atmospheres to be formed or to obtain a homogeneous composition. Low ionic diffusion and high melting points of the precursors lead to long processing times in these solid-state syntheses with a cost in energy consumption when conventional heating methods are applied. Microwave-assisted synthesis relies on selective, volumetric heating attributed to the electromagnetic radiation interaction with the matter. The microwave heating allows for rapid heating rates and small temperature gradients yielding homogeneous, well-formed materials swiftly. Luminescent inorganic materials can benefit significantly from the microwave-assisted synthesis for high homogeneity, diverse morphology, and rapid screening of different compositions. The rapid screening allows for fast material investigation, whereas the benefits of enhanced homogeneity include improvement in the optical properties such as quantum yields and storage capacity.

Microwave-assisted Synthesis of Benzoxazoles Derivatives

2020 ◽  
Vol 7 (3) ◽  
pp. 183-195
Author(s):  
Musa Özil ◽  
Emre Menteşe
Keyword(s):  
Microwave Irradiation ◽  
Reaction Medium ◽  
Pharmaceutical Chemistry ◽  
Conventional Heating ◽  
High Yield ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Optical Brighteners ◽  
Chemistry Research ◽  
Extensive Class

Background: Benzoxazole, containing a 1,3-oxazole system fused with a benzene ring, has a profound effect on medicinal chemistry research owing to its important pharmacological activities. On the other hand, the benzoxazole derivative has exhibited important properties in material science. Especially in recent years, microwave-assisted synthesis is a technique that can be used to increase diversity and quick research in modern chemistry. The utilization of microwave irradiation is beneficial for the synthesis of benzoxazole in recent years. In this focused review, we provide a metaanalysis of studies on benzoxazole in different reaction conditions, catalysts, and starting materials by microwave technique so far, which is different from conventional heating. Methods: Synthesis of different kind of benzoxazole derivatives have been carried out by microwave irradiation. The most used method to obtain benzoxazoles is the condensation of 2-aminophenol or its derivatives with aldehydes, carboxylic acids, nitriles, isocyanates, and aliphatic amines. Results: Benzoxazole system and its derivatives have exhibited a broad range of pharmacological properties. Thus, many scientists have remarked on the importance of the synthesis of different benzoxazole derivatives. Conventional heating is a relatively inefficient and slow method to convey energy in orientation to the reaction medium. However, the microwave-assisted heating technique is a more effective interior heating by straight coupling of microwave energy with the molecules. Conclusion: In this review, different studies were presented on the recent details accessible in the microwave- assisted techniques on the synthesis of the benzoxazole ring. It presents all examples of such compounds that have been reported from 1996 to the present. Benzoxazoles showed an extensive class of chemical substances not only in pharmaceutical chemistry but also in dyestuff, polymer industries, agrochemical, and optical brighteners. Thus the development of fast and efficient achievement of benzoxazoles with a diversity of substituents in high yield is getting more noteworthy. As shown in this review, microwave-assisted synthesis of benzoxazoles is a very effective and useful technique.

scholarly journals Effect of Rapid Heating on Microwave-Assisted Synthesis of SAPO-34 Membranes

2015 ◽  
Vol 41 (4) ◽  
pp. 228-232 ◽  
Author(s):  
Yuichiro Hirota ◽  
Shingo Tamura ◽  
Yusuke Shimoyama ◽  
Akira Ito
Keyword(s):  
Rapid Heating ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted

scholarly journals Microwave-Assisted Synthesis of Tetrahydrocarbazole Linked 1,2-Diazoles in Aqueous-Brønsted Acid Catalytic System

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Zubi Sadiq ◽  
Erum Akbar Hussain ◽  
Narjis Naz ◽  
Ambreen Ghani ◽  
Kausar Yasmeen ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Catalytic System ◽  
Multicomponent Reaction ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Spectroscopic Techniques ◽  
Unsaturated Ketones ◽  
Microwave Assisted ◽  
Michael Type Addition

A new series of tetrahydrocarbazole coupled 1,2-diazoles 4/5/6(a–o) in moderate to excellent yield was synthesized successfully via multicomponent reaction approach by adopting Michael type-addition of hydrazines on in situ generated α,β-unsaturated ketones via aldol type strategy under synthetic microwave radiations and conventional heating. Structural confirmations of all the prepared compounds were achieved by spectroscopic techniques. The best results were achieved when equal amounts of water-acetic acid were used in microwave conditions in 4 minutes.

scholarly journals Fast Microwave-Assisted Synthesis of Wells-Dawson-Type 18-Tungsto-2-Phosphate [P2W18O62]6−

Inorganics ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 23 ◽  
Author(s):  
Vamangi Pandya ◽  
Ali Haider ◽  
Hafiz Qasim ◽  
Ali Mougharbel ◽  
Ulrich Kortz ◽  
...  
Keyword(s):  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Synthetic Procedure

We report on a fast microwave-assisted synthetic procedure of the Wells-Dawson-type 18-tungsto-2-phosphate [P2W18O62]6− with a 35% yield in 24 h, rather than a week using conventional heating.

scholarly journals Microwave assisted synthesis of some new coumarin-pyrazoline hybrids and their antimicrobial activity

2015 ◽  
Vol 80 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Dongamanti Ashok ◽  
Bommidi Lakshmi ◽  
Sidda Ravi ◽  
Arram Ganesh
Keyword(s):  
Antimicrobial Activity ◽  
Sodium Acetate ◽  
Pathogenic Bacteria ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Good Activity ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Microwave Assisted ◽  
Bacteria And Fungi

A series of pyrazolines 4a-g have been synthesized by Michael addition of chalcones 3a-g with hydrazine hydrate in presence of sodium acetate under conventional heating and microwave irradiation. Structures of the newly synthesized chalcones 3a-g and pyrazolines 4a-g have been established on the basis of IR, 1H & 13C NMR and mass spectral data. All the synthesized compounds were screened for their antimicrobial activity. Some of the compounds shown very good activity compared to standard drugs against all pathogenic bacteria and fungi.

scholarly journals Green, Microwave-Assisted Synthesis of O-Perbutyrylated-Alkyl-Glycosides

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 42
Author(s):  
Emmanuel Pérez-Escalante ◽  
Luis Guillermo González-Olivares ◽  
Araceli Castañeda-Ovando ◽  
Verónica Salazar-Pereda ◽  
John F. Trant ◽  
...  
Keyword(s):  
Lewis Acids ◽  
Model Compound ◽  
Traditional Approach ◽  
Reaction Times ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Hydroxyl Groups ◽  
Alkyl Glycosides ◽  
Microwave Assisted ◽  
Synthetic Strategy

Chemical synthesis of carbohydrates is a challenging task. Several protection and deprotection steps of hydroxyl groups are required to ensure regioselective formation of the glycosidic bond. Usually, it is achieved through acylation, where conventional heating is combined with addition of Lewis acids as catalysts. This traditional approach has two drawbacks; it is time consuming and often catalysts are hazardous to the environment. An alternative route relies on application of microwaves and/or other Lewis acids with less or no toxicity. Such combination would reduce reaction times and offer a benign synthetic strategy to obtain peracylated compounds. The current work describes an efficient and environmentally mild synthesis of peracylated glycosides with potential application in enzymatic preparation of carbohydrates. Model compound O-perbutyrylated-phenyl-galactose was synthesized using imidazole as catalyst in the microwave-assisted process. The acylation protocol was optimized, and the target sugar was obtained at 50% yield after 1 h. In conclusion, the combination of imidazole and microwaves provides an excellent alternative to swiftly synthesize peracylated glycosides in a benign way.

scholarly journals Microwave-Assisted Synthesis of Arylidene Acetophenones

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Sheauly Khatun ◽  
M. Z. H. Khan ◽  
Khodeza Khatun ◽  
M. A. Sattar
Keyword(s):  
Microwave Irradiation ◽  
Microwave Heating ◽  
Spectral Data ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Efficient Synthesis ◽  
H Nmr ◽  
Microwave Assisted

An efficient synthesis of arylidene acetophenones have been achieved by using the microwave heating in comparison to the conventional heating. In this work compound 1-phenyle-3-(4-droxyphenyle)-2-propen-1-one, 1-(4-chlorophenyle)-3-phenyle-2-propen-1-one, and 1-(4-chlorophenyle)-3-(4-hydroxyphenyle)-2-propen-1-one have been synthesized by the condensation reaction between aromatic aldehydes and substituted acetophenones under microwave irradiation. The compounds of aldehydes and acetophenones were used as benzaldehyde, parahydroxybenzaldehyde, acetophenone, and parachloroacetophenone. The result shows that the time taken for the reaction was reduced from the conventional 1-2 hours to 60–120 seconds. The yield of the compounds in the conventional heating was moderate while the highest yield of 90–98% was observed in MWI method. The structure of the compounds was characterized by their IR,1H-NMR spectral data.

scholarly journals Microwave assisted synthesis of 2-(2-(tetrazolo[1,5-a]quinolin-4-yl)-2,3-dihydro-1h-benzo[b][1,4]diazepin-4-yl) substituted phenols and evaluation of their antimicrobial activity

2016 ◽  
Vol 81 (8) ◽  
pp. 851-858 ◽  
Author(s):  
Dongamanti Ashok ◽  
Velagapuri Rao ◽  
Rangu Kavitha
Keyword(s):  
Antimicrobial Activity ◽  
Microwave Irradiation ◽  
13C Nmr ◽  
Sodium Acetate ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Substituted Phenols ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Microwave Assisted

A series of new benzodiazepines 4a-h have been synthesized by Michael addition of chalcones 3a-h with o-phenylenediamine (OPDA) in presence of sodium acetate under conventional heating and microwave irradiation. Structures of the newly synthesized benzodiazepines 4a-h have been established on the basis of IR, 1H & 13C NMR and mass spectral data and tested for antimicrobial activity.

scholarly journals Microwave-Assisted Green Synthesis of Carbon Quantum Dots Derived from Calotropis Gigantea as a Fluorescent Probe for Bioimaging

2021 ◽  
Author(s):  
Neetu Sharma ◽  
Indu Sharma ◽  
Milan Kumar Bera
Keyword(s):  
Quantum Dots ◽  
Aqueous Suspension ◽  
Significant Proportion ◽  
Carbon Quantum Dots ◽  
Quantum Yields ◽  
Microwave Assisted Synthesis ◽  
Nuclear Magnetic Resonance Analysis ◽  
Synthetic Dyes ◽  
Calotropis Gigantea ◽  
Microwave Assisted

Abstract In this study, an eco-friendly, cost-effective, and convenient method for preparing biocompatible fluorescent carbon quantum dots (CQDs) by one-pot microwave assisted synthesis from the leaf extract of the medicinal plant Calotropis gigantea, also known as crown flower, has been demonstrated. As-synthesized CQDs demonstrated fluorescence quantum yields up to 4.24 percent. The size distribution of the as-synthesized CQDs varied from 2.7 to 10.4 nm, with a significant proportion of sp2 and sp3 carbon groups verified by nuclear magnetic resonance analysis. The zeta potential of as-synthesized CQDs was measured to be –13.8 mV, indicating the existence of a negatively charged surface with incipient instability in aqueous suspension. Furthermore, as an alternative to organic or synthetic dyes, the development of simple, inexpensive, and non-destructive fluorescence-based staining agents are highly desired. In this regard, as-synthesized CQDs shown remarkable fluorescent staining capabilities in this work and may be utilised as a suitable probe for optical and bio-imaging of bacteria, fungi, and plant cells.

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