Sensory Responses in Solution vs Solid State: A Fluorescence Quenching Study of Poly(iptycenebutadiynylene)s

A new series of poly(p-phenylenebutadiynylene)s has been synthesized with unique polymer structural features. In these systems each of the p-phenylene units in the conjugated backbone is the core of a rigid three-dimensional iptycene scaffold. The fluorescence quenching properties of these polymers in response to a series of electron-deficient arom. compds. have been investigated in both soln. and the solid state. It was found that in soln. these polymers displayed higher quenching sensitivity toward studied quenchers compared to a more open-structure iptycene-contg. poly(p-phenyleneethynylene). The quenching behaviors of the conjugated polymer were shown to be strongly influenced by the configuration of the incorporated iptycences. The thin films investigations revealed differences in both the fluorescence quenching and the recovery processes. Distinct behaviors indicated that the fluorescence quenching in the solid state is dictated by different factors than those in soln. Our results further suggest that poly(p-phenylenebutadiynylene)s contg. large iptycene scaffolds that introduce porosity have the ability to efficiently sequester the quencher mols. within thin films as these materials display slow fluorescence recoveries. [on SciFinder(R)]