Benzylidene fluorene ozonolysis under chemiluminescence mimetic conditions in homogeneous and micellar media II. Rate constants of fluorenone quenching by the leaving moiety

Abstract

The rate constants for the quenching of the fluorenone fluorescence by substituted benzaldehydes and benzoic acids (substitutents: p-nitro, p-cyano, p-chloro, p-bromo, p-H, p-methyl, p-methoxy, p-methoxy-m-methyl, and p-dimethylamino) are reported in ethanolic and micellar media. These are compared with the diffusion rate constant and evidence is presented that, under chemiluminescence mimetic conditions, the quenching leaving moiety in close proximity to the emitter is responsible for most of the quenching observed. The binding constants and partition coefficients of the above compounds as well as those of the corresponding substituted 9-benzylidene fluorenes in cetyltrimethylammonium chloride are also reported together with quencher molecules per micelle. The influence of the micellar medium on the quenching rate constants is discussed and the position of the above compounds inside the micelle is reported.