A new fluorescent sensor selective for Pb2+ in water capable of two-photon-induced fluorescence measurement

Abstract

A new fluorescent sensor (1) for Pb2+ containing a 1,4-dicyano-2,5-bis(styryl)benzene fluorophore and 2-(N,N′-bis(carboxylmethyl))amino-1-carboxylmethoxylbenzene as receptor has been synthesized. The sensor selectively responds to Pb2+ in the aqueous environment, and brings about similar and significant changes in one- and two-photon excited emission spectra: λmax red-shift from 460 (519) to 590 nm. The selective response is pH-independent in a large physiological pH range, and two-photon action cross section (ϕδ) is 51 GM (1 GM = 1×10−50 cm4·s·photon−1·molecule−1) at 740 nm.