A Smart Phosphine–Diyne Polymer Displays “Turn-On” Emission with a High Selectivity for Gold(I/III) Ions

A polymeric phosphine sensor is reported that exhibits bright blue fluorescence in the presence of gold­(I/III) ions but is nonemissive with other metal ions. Specifically, solutions of a poly­(p-arylenediethynylene phosphine) copolymer are 35 or 94 times more emissive when treated with solutions of (tht)­AuCl or HAuCl4·3H2O, respectively. Model compound studies confirm phosphine coordination to metals, including gold­(I/III) and rhodium­(I), and the selective “turn-on” fluorescence was investigated using time-dependent density functional theory calculations.