Z/E PHOTOISOMERIZATION OF UROCANIC ACID* |
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| Authors: | H. Morrison,&dagger ,D. Avnir,,C. Bernasconi, G. Fagan |
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| Affiliation: | Department of Chemistry, Purdue University, W. Lafayette, IN 47907, USA |
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| Abstract: | The E ? Z photoisomerization of the title compound (UA) (a naturally occurring sunscreen) has been studied in aqueous solution. At a UA concentration of 6mM and using 313nm excitation, φE→z= 0.52, φZ→E= 0.47 and the photostationary state is 34% E. Under these conditions, loss of UA is minimal. Low energy triplet quenchers fail to impede the isomerization, but the reaction can be induced by several triplet sensitizers. The ET for UA is estimated to be approximately 55 kcal/mol. |
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