Conjugated polymers containing pendant terpyridine receptors: highly efficient sensory materials for transition-metal ions

摘要

Abstract: Conjugated polymers containing terpyridine receptors have been prepared and characterized which contain unusually high fluorescence sensitivity toward transition metal ions including Fe$+2$PLU$/, Co$+2$PLU$/, and Ni$+2$PLU$/. This unique molecular structure combines inherently fluorescent conjugated polymers with a low lying electronic state formed upon binding between transition metal ions and terpyridine receptors on the polymer. The result is a dramatic fluorescence quenching response of the conjugated polymer. Fluorescence quenching measurements demonstrate quenching rate constants of 10$+$MIN@9$/ M$+$MIN@1$/s$+$MIN@1$/ and as much as 5 percent quenching of the emission at concentrations of 4 $MUL 10$+$MIN@9$/ M in organic solution. The enhanced sensitivity of these structures is explained based on facile energy migration through the conjugated polymer system to any of the pendant excitation trapping sites. Thin films of these materials demonstrate further enhanced quenching efficiencies as well as moderate reversibility. !30