Mechanism for the photodegradation of 9,10-dibutoxyanthracene in the presence of air

The photoreactivity of anthracene has been previously verified for a range of its derivatives. 9,10-Dibutoxyanthracene is commonly used as an electron transfer sensitizer for photopolymerization because of its favorable optical properties. This study experimentally demonstrated that 9,10-dibutoxyanthracene produces an endoperoxide species upon reaction with the oxygen present in air. A secondary decomposition product formed during the photodecomposition of the endoperoxide species was also isolated and identified. The proposed reaction pathway is supported by singlet oxygen scavenger studies and calculations of the singlet–triplet transition energies. Our findings suggest that 9,10-dibutoxyanthracene can be used as a photo-induced oxygen scavenger.