A multi-responsive photochromic Cd-MOF with photoswitchable luminescence, inkless and erasable printing, and UO22+-selective sensing

Stimuli-responsive metal-organic frameworks (MOFs) with unique advantages and motivating application prospects have gained development rapidly in recent years. Thus, it is of great significance to develop stimuliresponsive MOFs with multi-functional properties. Here, a four-fold interpenetrated 3D (three-dimensional) framework Cd(II)-MOF is developed from an extended viologen carboxylate ligand. The MOF shows reversible photochromism due to the formation of extend viologen radicals through photoinduced electron transfer. In addition, the fluorescence can be regulated reversibly in the photochromic process. The MOF also shows potential application prospects in erasable inkless printing and sensing UO22+ ions. The luminescence quenching is mainly attributed to the energy resonance transfer mechanism. This work provides a possible path for developing stimuli-responsive MOFs and potential applications in the field of optical devices and luminescent sensors.