Intrazeolite photochemistry. I. Phosphorescence enhancement of aromatic ketones included in silicalite.

1984 ◽  
Vol 62 (3) ◽  
pp. 628-629 ◽  
Author(s):  
H. L. Casal ◽  
J. C. Scaiano
Keyword(s):  
Room Temperature ◽  
Chemical Processes ◽  
Aromatic Ketones ◽  
Triplet Lifetime

The triplet lifetime of β-phenylpropiophenone at room temperature is enhanced by ca. five orders of magnitude upon inclusion in the channels of silicalite, a hydrophobic zeolite. This behaviour is attributed to restrictions to mobility in this medium, and it is suggested that photochemical probes can provide a rather unique insight in the study of intrazeolite chemical processes.

The Merger of CF3SO2Na and Palladium Catalysis to Enable Decarboxylative Cross-Coupling for the Synthesis of Aromatic Ketones under Room Temperature

2021 ◽  
Author(s):  
Pan Xie ◽  
Cheng Xue ◽  
Cancan Wang ◽  
Dongdong Du ◽  
Sanshan Shi
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Palladium Catalysis ◽  
Cross Coupling ◽  
Boronic Acids ◽  
Aromatic Ketones ◽  
Aryl Ketones ◽  
Oxocarboxylic Acids

A CF3SO2Na/Pd(OAc)2 co-catalyzed strategy is developed to produce aryl ketones via visible-light-induced decarboxylative cross-coupling of α-oxocarboxylic acids and aryl boronic acids. This process was perfomed under air at room temperature,...

scholarly journals The Three-Component Synthesis of 4-Sulfonyl-1,2,3-triazoles via a Sequential Aerobic Copper-Catalyzed Sulfonylation and Dimroth Cyclization

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 581
Author(s):  
Max Van Hoof ◽  
Santhini Pulikkal Veettil ◽  
Wim Dehaen
Keyword(s):  
Room Temperature ◽  
Aromatic Ketones ◽  
Three Component Reaction ◽  
Reaction Proceeds

4-Sulfonyl-1,2,3-triazole scaffolds possess promising bioactivities and applications as anion binders. However, these structures remain relatively unexplored and efficient synthetic procedures for their synthesis remain desirable. A practical room-temperature, aerobic copper-catalyzed three-component reaction of aromatic ketones, sodium sulfinates, and azides is reported. This procedure allows for facile access to 4-sulfonyl-1,5-disubstituted-1,2,3-triazoles in yields ranging from 34 to 89%. The reaction proceeds via a sequential aerobic copper(II)chloride-catalyzed oxidative sulfonylation and the Dimroth azide–enolate cycloaddition.

Catalysis at Room Temperature: Perspectives for Future Green Chemical Processes

2015 ◽  
pp. 209-231
Author(s):  
Frank Leung-Yuk Lam ◽  
Michael C.L. Li ◽  
Rock S.L. Chau ◽  
Rick A.D. Arancon ◽  
Xijun Hu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Processes

Room Temperature Chemoselective Deoxygenation of Aromatic Ketones and Aldehydes Promoted by a Tandem Pd/TiO2 + FeCl3 Catalyst

2018 ◽  
Vol 83 (18) ◽  
pp. 11067-11073 ◽  
Author(s):  
Zhenhua Dong ◽  
Jinwei Yuan ◽  
Yongmei Xiao ◽  
Pu Mao ◽  
Wentao Wang
Keyword(s):  
Room Temperature ◽  
Aromatic Ketones

Intrazeolite photochemistry. II. Evidence for site inhomogeneity from studies of aromatic ketone phosphorescence

1985 ◽  
Vol 63 (6) ◽  
pp. 1308-1314 ◽  
Author(s):  
H. L. Casal ◽  
J. C. Scaiano
Keyword(s):  
Energy Transfer ◽  
Luminescent Properties ◽  
Cooperative Effect ◽  
Type Ii ◽  
Oxygen Quenching ◽  
Aromatic Ketones ◽  
Transfer Processes ◽  
Norrish Type ◽  
Triplet Lifetime ◽  
Conformational Restrictions

The luminescent properties of several aromatic ketones included in the hydrophobic zeolite Silicalite have been examined. Acetophenone, benzophenone, and β-phenylpropiophenone show readily detectable phosphorescence; by contrast, valerophenone does not luminesce, but undergoes the Norrish Type II reaction. Thus, irradiated samples of valerophenone in Silicalite show phosphorescence due to the accumulation of acetophenone. In the case of β-phenylpropiophenone the triplet lifetime is ca. 100 000 times longer than the solution value, suggesting severe conformational restrictions. Co-inclusion of acetophenone with various substrates and oxygen quenching studies indicate that Silicalite has at least two distinct classes of inclusion sites. In one of them energy transfer processes are rapid and efficient, suggesting a cooperative effect in the inclusion of ketones in these regions of the Silicalite framework.

Notizen: Triplet Quenching by Oxygen in a Rhodamine 6G Laser

1973 ◽  
Vol 28 (5) ◽  
pp. 792-793 ◽  
Author(s):  
F. P. Schäfer ◽  
L. Ringwelski
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Output Power ◽  
Room Temperature ◽  
Rhodamine 6G ◽  
Laser Output Power ◽  
Simple Theoretical Model ◽  
Best Fit ◽  
Triplet Lifetime ◽  
Quenching By Oxygen

Measurements of dye laser output power vs. oxygen content of the dye solution are reported and compared with a simple theoretical model. The triplet lifetime of rhodamine 6G in oxygen-free methanol at room temperature is seen to lie between 1 and 100 μsec, with 2 μsec giving the best fit of the experimental data.

Designing Advanced Ceramic Structures with Novel Environmental Microscopy and Related Methods

2001 ◽  
Vol 7 (S2) ◽  
pp. 386-387
Author(s):  
Pratibha L. Gai
Keyword(s):  
Phase Transformations ◽  
Room Temperature ◽  
Single Phase ◽  
Atomic Level ◽  
Chemical Processes ◽  
Atomic Resolution ◽  
Vast Array ◽  
Β Phase ◽  
Silica And Titania

Silica and titania based ceramics and their analogs are some of the most fundamental in crystal chemistry and ceramic science Our interests include applications of nanostructures and chemical composites of the ceramics in nanoelectronics, chemical processes and as scaffolds in biotechnologies. Finely divided titania is used in a vast array of products including paper, paint, food and clothing. Novel microscopy methods including dynamic environmental-high resolution transmission EM (EHREM) at the atomic level, FESEM and cathodoluminescence are leading to striking progress in the development of the ceramic nanotechnologies.Phase transformations in the cristobalite form of silica, from the tetragonal a phase (low or room temperature form) to the cubic β phase (high temperature, (270°C) form) result in discontinuous thermal expansion and are not conducive to nanotechnology. Here we report fundamental in situatomic resolution studies of the phase transformations using EHREM and have used the results to design a number of stable, single-phase structures at room temperature (RT).

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