Fluorescence quantum yields of trans-stilbene-d0 and -d2 in n-hexane and n-tetradecane: medium and deuterium isotope effects on decay processes

1993 ◽  
Vol 97 (11) ◽  
pp. 2516-2522 ◽  
Author(s):  
Jack Saltiel ◽  
Andrew S. Waller ◽  
Donald F. Sears ◽  
Christopher Z. Garrett
Keyword(s):  
Isotope Effects ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Trans Stilbene ◽  
Deuterium Isotope Effects

The photodissociation of ammonia in the absorption system. Part I. Deuterium isotope effects in the photodissociation

1977 ◽  
Vol 55 (8) ◽  
pp. 1380-1386 ◽  
Author(s):  
S. Koda ◽  
R. A. Back
Keyword(s):  
Hydrogen Atom ◽  
Isotope Effect ◽  
Isotope Effects ◽  
Quantum Yields ◽  
Absorption System ◽  
System Part ◽  
Deuterium Isotope Effects

The photolyses of mixtures of NH3, NH2D, NHD2, and ND3 have been studied at wave lengths of 2144, 2139, 2062, and 1850 Å in the presence of C3H8 as a hydrogen atom scavenger. Quantum yields of dissociation have the same values for all four species, presumably unity. Analysis of the H2 and HD produced permitted evaluation of intramolecular deuterium isotope effects in the photodissociation of NH2D and ND2H. At the two shortest wavelengths dissociation of H was favored by a factor of 2 or 3, while at 2144 and 2139 Å the isotope effect was much larger. Implications for the mechanism of the predissociation of the Ã-state of ammonia are discussed briefly. The system does not appear to be useful for the photochemical separation of deuterium.

Mechanism of hydration and isomerisation of 4-ethylidene-2,6-di-tert-butyl-2,5-cyclohexadien-1-one. Kinetics, acid-base catalysis and solvent deuterium isotope effects

1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček
Keyword(s):  
Aqueous Medium ◽  
Rate Equation ◽  
Kinetic Data ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quinone Methide ◽  
Reaction Products ◽  
Acid Base ◽  
Deuterium Isotope Effects ◽  
Hydroxybenzyl Alcohol

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.

Regioselective Oxidative Cross-Coupling Reaction: Synthesis of Imidazo[1,2-a]pyridine Fluorophores

Synthesis ◽  
2021 ◽  
Author(s):  
Xianglong Chu ◽  
Yadi Niu ◽  
Chen Ma ◽  
Xiaodong Wang ◽  
Yunliang Lin ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Cross Coupling Reaction ◽  
Color Tunable ◽  
Palladium Catalyzed ◽  
Structure Relationship ◽  
High Fluorescence

AbstractA rapid access to a series of N-heteroarene fluorophores has been developed on the basis of the palladium-catalyzed direct oxidative C–H/C–H coupling of imidazo[1,2-a]pyridines with thiophenes/furans. The photophysical properties–structure relationship was systematically investigated. The resulting N-heteroarene fluorophores present color-tunable emissions (λem: 431–507 nm in CH2Cl2) and high fluorescence quantum yields (up to 91% in CH2Cl2).

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