A highly selective and sensitive fluorescence probe with A-π-D-π-A structure for detection of Ag+

A novel triphenylamine derivative, 4,4′ -bis-([1,10]phenanthrolin-2-yl) imidazo -triphenylamine (IPTPA) with an A-π-D-π-A structure, has been synthesized and characterized. The UV absorption , single and two-photon fluorescence spectra showed that IPTPA was highly sensitive to Ag + with a lower detection limit of 3.97 nmoL/L and a moderate binding constant of 2.16 × 10 5 /M at room temperature . The two-photon active cross-section of IPTPA was calculated with a value of 94.68 GM at 800 nm in the tris-HCl buffer solution. The binding mechanism between IPTPA and Ag + were explored by the Job plot, ESI-MS and 1 H NMR. The A-π-D-π-A structure of IPTPA was substituted by the A-π-D-π-D structure of IPTPA-Ag to improve the fluorescence. Furthermore, the fluorescence microscopy images indicated that IPTPA could detect Ag + in living cells.