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.