Novel conjugated polyelectrolytes based on polythiophene bearing phosphonium side groups

Abstract

The synthesis and photophysical properties of poly{3-[6-(triethylphosphonium)hexyl]-thiophene-2,5-diyl bromide} and poly{3-[6-(triphenylphosphonium)hexyl]-thiophene-2,5-diyl bromide} are reported in the present contribution. Three various polymer precursors (poly[3-(6-bromohexyl)thiophene-2,5-diyl]s) with molecular weights 7.2, 11.8 and 13.2kgmol−1 respectively and head to tail regioregularity from 62% to 94% were prepared and consecutively transformed into the corresponding polyelectrolytes by a simple quaternization reaction with appropriate phosphines. Synthesized polyelectrolytes exhibited solvatochromism. Detailed aggregation experiments via changing water/DMSO ratio have been performed. Photoluminiscence spectra of the polyelectrolyte solutions indicate that the emission maxima are red-shifted gradually with the increasing solvent polarity. Fluorescence quenching has been studied by interaction with model quenchers: K4[Fe(CN)6] and K3[Fe(CN)6] in water using Stern-Volmer methodology.