Francoise Mechin

End-to-end cyclization of a pyrene end-capped poly(bisphenol AF-diethylene glycol carbonate) in solution

Abstract A pyrene end-labelled poly(bisphenol AF-diethylene glycol carbonate) has been synthesized. Its molecular weight and end-group composition were determined through a combination of u.v. absorption and fluorescence decay measurements of the pyrene end-groups. Through gel permeation chromatography, several fractions were collected. For each fraction, the cyclization dynamics of the polymer in dilute solutions in acetone and toluene were investigated through studies of intramolecular fluorescent excimer formation. Values for 〈k1〉, the end-to-end cyclization rate constant, as well as for k−1 and kE were calculated.

Cyclization of poly(bisphenol A-diethylene glycol carbonate)—Intramolecular pyrene excimer formation

Abstract A sample of poly(bisphenol A-diethylene glycol carbonate) of M n = 4500 was prepared using phase transfer catalysis, and then labelled at both ends with pyrene groups. The polymer in dilute solution showed intramolecular excimer fluorescence with the intensity ratio, I E I M , very sensitive to solvent. Both viscosity and excluded volume effects are important. Fluorescence decay measurements were difficult to interpret because of polydispersity effects (here M w M n = 1.35 ). The form and magnitude of these polydispersity effects were examined.