Two-photon fluorescent probe for silver ion derived from twin-cyano-stilbene with large two-photon absorption cross section

A two-photon sensor for silver ion derived from twin-cyano-stilbene as the fluorophore is reported. The sensor exhibits remarkably large two-photon absorption cross sections (δTPA) whose value is as high as 950 GM in MeCN, high sensitivity to and selectivity for silver ion, and emits strong two-photon fluorescence when excited by 790 nm laser photons. The sensor can be used to detect trace Ag+, and its binding constant (log K) for Ag+ is as high as 5.76 ± 0.05. The successful applications of the sensor provide a brilliant prototype for the development of ideal two-photon fluorescence probes.