Intramolecular energy migration in polyesters from 2,6-naphthalene dicarboxylic acid: polarization of fluorescence in the polymers and in bichromophoric model compounds

Abstract

The fluorescence has been measured in dilute solution and in glassy poly(methyl methacrylate) for polyesters in which 2,6-naphthalene dicarboxylate is the rigid unit, and (CH 2) m ( m=2–6) is the flexible spacer. Bichromophoric compounds in which the same flexible spacer connects two molecules of 2-naphthoate were also studied. The anisotropy in the rigid medium demonstrates the existence of intramolecular energy migration, which becomes more important as m decreases from 6 to 2. The Förster radius is ∼ 12 A ̊ in the bichromophoric compounds and 14 Å in the polyesters.