Emission from the solvatochromic fluorophore benzo[b]fluorenone (BF) is much less quenched by alcohols than emission from the structurally related ketone 9-fluorenone (9-FL) [1]. Previously, the quenching effect of alcohols on 9-FL has been examined in terms of a model scheme involving hydrogen bonding to 9-FL in both ground and excited states. Equilibrium constants for 9-FL association with alcohols in ground and excited state 9-FL for some binary mixtures have also been reported. Here, we investigate the effect of ethanol and 2,2,2-trifluoroethanol on BF absorption in binary cyclohexane, methylene chloride, and acetonitrile mixtures. Equilibrium constants for the association of ethanol and trifluoroethanol with ground state BF in these solvents were then determined where possible.

[1] J. L. Jamison, L. Davenport, B. W. Williams, Chem. Phys. Lett. 422 (2006) 30-35.