State-Selective Photochemistry of Singlet Oxygen Precursors: Kinetics and Wavelength Dependence of the Photodissociation of Anthracene Endoperoxides

Article abstract of DOI:10.1021/j100412a055

The photochemical behavior of the two isomeric endoperoxides (9,10-PMO2 and 1,4-PMO2) of 1,4-dimethyl-9,10-diphenylanthracene was found to differ in their kinetics and reaction efficiencies.Consistent with the work of Rigaudy et al. and Brauer et al. on a related endoperoxide we find that the generation of ¹O2 is wavelength dependent, occuring from upper excited singlet states of the endoperoxide, whereas bond cleavage of the O-O endoperoxide bond occurs principally from the lowest excited singlet and triplet states.Results of picosecond kinetics and absolute quantum yield measurements are discussed in terms of various concerted and nonconcerted mechanisms for the formation of ¹O2 and the anthracene fragment.