The excited state dynamics of triplet 1,8-dichloroanthraquinone in solutions at room temperature

Abstract

The transient absorption spectra of the title compound (1,8-DCAQ) in solutions at room temperature have been measured by the picosecond laser photolysis, and the buildup and decay of a new absorption were observed on a picosecond time scale. The decay of this absorption was accompanied by a rate matching increase in the triplet–triplet absorption of the lowest triplet state of a ππ* character. Since the addition of 2,5-dimethyl-2,4-hexadiene (1 M) or triethylamine (2 M), as a triplet energy acceptor, quenched the new absorption, it was assigned to the second nπ* triplet state of 1,8-DCAQ with an intramolecular charge–transfer character between the chlorine and oxygen atoms.