Structural imposition on the off–on response of naphthalimide based probes for selective thiophenol sensing†
N-Phenyl-1,8-naphthalimide based fluorescent probes are reported with various positions of dinitrobenzenesulfonyl (DNs) quencher on the phenyl ring. The probe with –DNs at the ortho-position was predicted to show better response compared to those with the quencher at the meta and para positions. The probe showed selective and very fast response (response time, tR = 1 min) toward thiophenol with 20-fold off–on fluorescence sensitivity. Thiophenol sensing applications by the probe were demonstrated via water sample analysis and live cell imaging studies.