Rate constants for the decay and reactions of the lowest electronically excited singlet state of molecular oxygen in solution

1981 ◽  
Vol 10 (4) ◽  
pp. 809-999 ◽  
Author(s):  
Francis Wilkinson ◽  
James G. Brummer
Keyword(s):  
Molecular Oxygen ◽  
Rate Constants ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Electronically Excited

Quenching of Fluorescence of Chloropentafluoroacetone by Saturated Hydrocarbons

1972 ◽  
Vol 50 (9) ◽  
pp. 1429-1432 ◽  
Author(s):  
A. J. Yarwood
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Singlet State ◽  
Fluorescence Yield ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Quenching Rate ◽  
Saturated Hydrocarbons ◽  
Phase Measurements ◽  
Electronically Excited

Saturated hydrocarbons can quench the electronically excited singlet state of a simple ketone in the gas phase. Measurements on the quenching of the fluorescence yield of chloropentafluoroacetone at 23 °C show that different saturated hydrocarbons can deactivate the excited singlet state with varying efficiencies. The quenching rate constants are reported and possible relationships considered.

Combined Experimental and Theoretical Study of the Transient IR Spectroscopy of 7-Hydroxyquinoline in the First Electronically Excited Singlet State

2016 ◽  
Vol 120 (47) ◽  
pp. 9378-9389 ◽  
Author(s):  
Felix Hoffmann ◽  
Maria Ekimova ◽  
Gül Bekçioğlu-Neff ◽  
Erik T. J. Nibbering ◽  
Daniel Sebastiani
Keyword(s):  
Ir Spectroscopy ◽  
Theoretical Study ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Electronically Excited

The structure, photochemical reactivity, and photophysical properties of adamantyl X-substituted aryl ethers and a comparison with the alkyl groups, methyl, tert-butyl, and allyl

2005 ◽  
Vol 83 (9) ◽  
pp. 1237-1252 ◽  
Author(s):  
A L Pincock ◽  
J A Pincock
Keyword(s):  
Excited State ◽  
Rate Constants ◽  
Singlet State ◽  
Bond Cleavage ◽  
Photophysical Properties ◽  
Excited Singlet State ◽  
Quantum Yields ◽  
Aryl Ether ◽  
Excited Singlet ◽  
Aryl Ethers

The structure, photophysical properties, and photochemistry of the adamantyl aryl ethers 1 in both methanol and cyclohexane have been examined. UV absorption spectra, 13C NMR chemical shifts, X-ray structures, and Gaussian calculations (B3LYP/6-31G(d)) indicate that these ethers adopt a 90° conformer in the ground state. In contrast, fluorescence spectra, excited singlet state lifetimes, and calculations (TDDFT) indicated a 0° conformer is preferred in the first excited singlet state S1. Irradiation in either solvent results in the formation of adamantane and the corresponding phenol as the major products, both derived from radical intermediates generated by homolytic cleavage of the ether bond. The 4-cyano substituted ether 1j was the only one to form the ion-derived product, 1-methoxyadamantane (16% yield), on irradiation in methanol. Rate constants of bond cleavage for these ethers from S1 were estimated by two different methods by comparison with the unreactive anisoles 2, but the effect of substituents was too small to determine structure–reactivity correlations. The temperature dependence of the quantum yields of the fluorescence of the unsub stituted, 4-methoxy and 4-cyano derivatives of 1 and 2 were also determined. These results indicated that the activated process for 1 was mainly bond cleavage for the 4-cyano substrate whereas for 2, it was internal conversion and intersystem crossing. Key words: aryl ether photochemistry, fluorescence, excited-state rate constants, excited-state temperature effects.

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