Photochemistry of the T2 State of Anthracene

Article abstract of DOI:10.1021/j100104a018

The chemistry of the anthracene T2 state in room-temperature acetonitrile solution in the presence of a variety of quenchers has been investigated by two-laser flash photolysis.The decay of T2 in the presence of ethyl bromoacetate, which is capable of undergoing reductive dehalogenation, is via electron transfer as evidenced by the detection of the anthracene radical cation, λ_max 720 nm.Indirect evidence shows that in benzonitrile, T2 decay is primarily by electron transfer with a minor contribution due to energy transfer (T2 -> benzonitrile T1).The failure to detect the cation radical indicates that back electron transfer, either following ISC or within the geminate triplet radical ion pair, is faster than cage escape.T2 also reacts with acrylonitrile and fumaronitrile partially via 4 + 2 cycloaddition at the anthracene 9 and 10 positions.Again, indirect evidence suggests that triplet-triplet energy transfer and electron transfer also contribute to T2 decay.