A new class of macrobicyclic and cation photosensitive compounds, the anthraceno-cryptands A"" is described. In these ligands, the nitrogen lone pairs form intramolecular exciplexes with the anthracene ring, inducing a dual fluorescence emission (monomer type and exciplex) sensitive to the nature of the solvent. Thus, although A22 displays an intense triple exciplex emission in aprotic solvents, only a strong monomer-type emission is observed in methanol; this behavior is ascribed to hydrogen bonds between the solvent and the nitrogen lone pairs, which maintain an out-out conformation preventing exciplex

The preparation of polystyrene with controlled molar masses and narrow dispersity endcapped with an anthrylmethyl ether group, as well as the study of their photophysical properties, are described. Under irradiation at 336 nm dimerisation of the polystyrene chains is observed. This process results from the formation of a symmetrical head-to-tail photodimer between two anthryl end groups. When irradiated at lower wavelength (1 = 228 nm), the original o-anthrylpolystyrene chains are quantitatively restored. These dimerisatioddissociation cycles can be conducted more than ten times without any detectable degradation of the photosensitive polymer. The fluorescence emission quantum yield and fluorescence lifetime of the o-anthryl moieties and the quantum yield of the dimerisation and of the reverse process have been measured.

No abstract