Poly [p-(phenyleneethynylene)-alt-(thienyleneethynylene)] polymers with oligopyridine pendant groups:: Highly sensitive chemosensors for transition metal ions

We report the synthesis and characterization of a series of luminescent chemosensory materials that have the conjugated polymer poly [p-(phenyleneethynylene)-alt-(thienyleneethnylene)] (PPETE) as a backbone and oligopyridine pendant sites as receptors. These polymers are soluble in common organic solvents and highly emissive. Investigations reveal that these polymers are highly sensitive to transition metal ions such as Ni2+. For the terpyridine-receptor polymer ttp-PPETE, we observed similar to5% initial emission quenching by Ni2+ concentration as low as 4 x 10(-9) M. The polymers also show selectivity to different transition metal ions. The ether-linked polymer ttp-O-PPETE is also prepared which successfully demonstrates that complete conjugation is not required for emission quenching. However, the vinylene-linked ttp-PPETE was found to have a higher quenching efficiency.