Designing two-photon fluorescent probes based on the target-induced enhancement of the absorption cross-section†
Abstract
We have reported a new strategy to design two-photon (2P) fluorescent probes for simultaneous elevation of the 2P absorption cross-section (δ) and quantum yield (ϕ). The target-induced hydrogen bond-chelated ring enhances molecular planarity, leading to the enhancement of δ; meanwhile, the photo-induced electron transfer (PET) “on–off” process modulates ϕ.