Wavelength Selective Single Molecule Photobase/Photoacid Generator Enabling Dynamic Control of Soft Matter Materials Functions

Abstract

Photoremovable protecting groups (PRPGs) enable precise spatiotemporal control over molecular release and functional activation. Recent advances have introduced wavelength-selective systems for sequential deprotection, broadening applications in drug delivery, material synthesis, and photopolymerization. In parallel, PRPGs play a crucial role in photobase generators (PBGs) and photoacid generators (PAGs), enabling oxygen-tolerant, spatially controlled polymerization and depolymerization through light-induced base and acid release. Herein, we present a novel benzophenazine-based photocleavable system capable of the sequential, wavelength-selective release of both a base and an acid. This design integrates 1,1,3,3-tetramethylguanidine (TMG) and p-toluene sulfonic acid functionalities, which are independently uncaged upon irradiation with blue (≥ 410 nm) and UV (≥ 310 nm) light, respectively. We demonstrated the versatility of this dual-responsive system in modulating soft matter properties, including wavelength-selective polymer crosslinking, degradation, and debonding-on-demand adhesives. This work establishes a new platform for advanced photochemical control over polymeric transformations, with broader implications in responsive soft matter engineering.