Our group is interested in these iminium ion derivatives and their pseudobases for their potential to catalyze water oxidation. These derivatives could offer inexpensive and environmental friendly water oxidation catalysts for solar fuel cells. A good understanding of the excited-state behaviors of these pseudobases would be conducive to the catalysis mechanism study.The excited-state behavior of N(5)-ethyl-4a-hydroxyflavin (Et-FlOH) and 9-hydroxy-10-methy1-9-phenyl-9,10-di-hydroacridine (AcrPhOH) are studied. Using femtosecond pump-probe spectroscopy, we found that the excited states of Et-FlOH and AcrPhOH exhibit multi-exponential dynamics. We propose that the fast decay in Et-FlOH is caused by S1 ?S0 internal conversion, initiated by the excited-state nitrogen planarization (sp3?sp2 hybridization change at the N(5)-atom of Et-FlOH S1 state) coupled with an out-of-plane distortion of the pyrimidine moiety of flavin. The decay in AcrPhOH is due to the excited-state hemolytic/heterolytic carbon oxygen bond breaking that produces AcrPh+ or AcrPh. .

Ultrafast transient absorption study of iminium ion derivatives and their pseudobases

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.