Photochemistry of unsaturated ketones in solution. XVIII. Efficiencies of quenching of short-lived excited triplet states of ketones with dienes

Schuster, David I.; Fabian, Arthur C.; Kong, Noland P.; Barringer, William C.; Curran, William V.; Sussman, David H.

doi:10.1021/ja01020a048

Cited by 11 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clearly this is an aspect of this system that needs to be improved if reversible solar energy storage applications based on the norbornadiene to quadricyclane interconversion are to be realized. To investigate the possible involvement of a triplet excited state in the photoconversion, this experiment was also conducted on 4h in the presence of 1,3-cyclohexadiene, a known triplet quencher. Because the results are comparable with (entry 19) and without (entry 7) the quencher, triplet state involvement seems unlikely.…”

Section: Resultsmentioning

confidence: 99%

Substituted Diarylnorbornadienes and Quadricyclanes: Synthesis, Photochemical Properties, and Effect of Substituent on the Kinetic Stability of Quadricyclanes

et al. 2017

View full text Add to dashboard Cite

In this Article, we present a new method for the synthesis of diarylnorbornadiene derivatives. Through the use of a two-step procedure consisting of a tandem alkene insertion-Suzuki coupling reaction followed by a DDQ dehydrogenation, we have been able to synthesize derivatives with a wide variety of substituents. We also present the results of UV-visible spectroscopy studies and kinetics experiments that show the effect of substituent on light absorption properties of the norbornadienes as well as the kinetic stability of the quadricyclanes that result from their photochemical conversion. While substitution on the aromatic rings had comparatively little effect on quadricyclane lability, substitution at a bridgehead position with a methyl group produced a quadricyclane that thermally reverted to the norbornadiene at a rate that was significantly slower than that for the quadricyclane without the methyl substituent. From the results of the kinetics experiments, we determined that the reversion of the quadricyclanes occurs via a free radical mechanism with very little contribution from polar effects. This observation led us to speculate as to whether our data may form the basis for a free radical substituent constant, σ•, analogous to the traditional Hammett σ parameter.

show abstract

Section: Resultsmentioning

confidence: 99%

Substituted Diarylnorbornadienes and Quadricyclanes: Synthesis, Photochemical Properties, and Effect of Substituent on the Kinetic Stability of Quadricyclanes

et al. 2017

View full text Add to dashboard Cite

show abstract

“…19•20 Such selectivity in energy transfer has been observed for other 2,5-cyclohexadienones. 20 From the quantum yield and cyclohexadiene quenching data, assuming18 in dioxane káií = 6.0 X 1091. mol-1 sec-1, values of kT/a and kd/a can be calculated and are given in Table IV.…”

Section: Resultsmentioning

confidence: 99%

Photochemistry of unsaturated ketones in solutions. XXVII. Synthesis and photochemistry of .DELTA.1-4-alkyltestosterones

Schuster¹,

Barringer²

1971

J. Am. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

The identity of 21 from this reaction with an authentic sample was confirmed by comparison of the infrared spectra and melting points.Fluorescence Spectrum of 14a. The emission from a diethyl ether solution, 1.5 X 10~1 2345 M in 14a, was measured with a Cary Model 15 spectrophotometer equipped with a high-powered mercury-Xenon arc lamp and a monochromator adjusted to provide excitation light at 302 nm. A quartz cell was employed, and excitation was perpendicular to the path of the visible light detector of the spectrophotometer.

show abstract

“…There is a discrepancy between our directly measured triplet lifetime of 14 ps and that estimated by Wagner and Bucheck (4) = 0, the k, for 1,3-pentadiene becomes 3.4 x lo9 M -~ s-I. The difference between this value of k, for 1,3-pentadiene and our measured k, value of 8.1 f 0.6 x lo9 M -I s-I for 2,4-hexadien-1-01 is likely due to a difference in quenching efficiencies of the two dienes (10,11). It is felt that quenching by solvent impurity is a less likely alternative explanation for the lifetime discrepancy.…”

mentioning

confidence: 50%

Detection and chemistry of the triplet state of thymine

Szabo¹,

Rlddell²,

Yip³

1970

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

Photochemistry of unsaturated ketones in solution. XVIII. Efficiencies of quenching of short-lived excited triplet states of ketones with dienes

Cited by 11 publications

References 0 publications

Substituted Diarylnorbornadienes and Quadricyclanes: Synthesis, Photochemical Properties, and Effect of Substituent on the Kinetic Stability of Quadricyclanes

Substituted Diarylnorbornadienes and Quadricyclanes: Synthesis, Photochemical Properties, and Effect of Substituent on the Kinetic Stability of Quadricyclanes

Photochemistry of unsaturated ketones in solutions. XXVII. Synthesis and photochemistry of .DELTA.1-4-alkyltestosterones

Detection and chemistry of the triplet state of thymine

Contact Info

Product

Resources

About