Luminescent Properties of Water-Soluble Conjugated Metallopolymers and Their Application to Fluorescent Nitric Oxide Detection

Water-soluble π-conjugated polymers (CPs) incorporating 5,5‘-(2,2‘-dipyridyl) (CP1) or 6,6‘-(2,2‘-dipyridyl) (CP2) units within the π-conjugated backbone were prepared as scaffolds for macromolecular metal complexation. The response of CP emission to a range of metal ions was investigated in water, 10 mM aqueous sodium dodecyl sulfate, and acetonitrile/water (95:5). Cupric ions are the most efficient quenchers of CP emission, with K_SV = 1.1 × 10⁵ and 5.2 × 10⁴ M^-1 in water for CP1a (40% bipyridyl monomer units) and CP1b (20% bipyridyl monomer units), respectively. Quenching is approximately twice as effective in acetonitrile/water (95:5) (K_SV = 3.1 × 10⁵ M^-1 for CP1a and 1.1 × 10⁵ M^-1 for CP1b). Partial restoration of emission was observed upon exposure of Cu(II)−CP solutions to excess NO(g) in acetonitrile/water (95:5) or 10 mM SDS(aq).