Two viologen-based photoluminescent compounds: excitation-wavelength-dependent and photoirradiation-time-dependent photoluminescent switches

Solid-state materials with adjustable luminescence properties have always been a research hotspot due to their potential applications in optical data recording, display and ink-free printing. Further research on the multiform light-controlled luminescent switches will create a new perspective. We synthesized two isostructural compounds, namely [Me(ipbp)Cl] H2O (ipbp = 1-(3,5-dicarboxyphenyl)-4,4′-bipyridinium, Me = Cd (1), Me = Zn (2)). In the solid-state, they not only show excitation-wavelength-dependent photoluminescence emission in a wide spectral range but also exhibit good time-dependent photoluminescence emission. This study could provide a broad perspective for the development of multiform light-controlled luminescent switches.