ISSN:
0894-3230
Keywords:
Organic Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The acid-catalysed rate constants (kH+) for the photohydration of 18 meta- and para-substituted styrenes and phenylacetylenes were determined in H2SO4 solutions by means of fluorescence quenching measurements and the standard Stern-Volmer approach. Singlet lifetimes of the substrates were determined in the reference solution (water at pH 7) by single photon counting. The log kH+ values obtained did not correlate well with any previously reported σ scales, and were used to try to establish a σhν scale (for H-, p-F, m-F, p-Me, m-Me, p-Et, m-Et, p-OMe and m-OMe substituents) for possible use in other photochemical reactions. Correlation of all available literature data versus the new σhv scale gave reasonable correlations (r = 0.957-0.966). The problems associated with establishing linear free energy relationships for photoreactions are discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/poc.610040402
