Acidity constants of anthracene derivatives in singlet and triplet excited states

Abstract

Acidity constants in the ground state (G) the lowest excited singlet (S₁) and the lowest triplet (T₁) states have been measured for four anthracene derivatives. Even when S₁ and T₁ are both L_a states, the pK of T₁ is intermediate between that of G and S₁ confirming the earlier generalization based on studes of naphthalene derivatives. However, the relatively large change in pK of the upper singlet, as compared with the triplet, which was characteristic of naphthalene derivatives is not found in the anthroic acids.