Tuning and Directing Energy Transfer in the Whole Visible Spectrum through Linker Installation in Metal–Organic Frameworks

While limited choice of emissive organic linkers with systematic emission tunability presents a great challenge to investigate energy transfer (ET) over the whole visible light range with designable directions, luminescent metal-organic frameworks (LMOFs) may serve as an ideal platform for such study due to their tunable structure and composition. Herein, five Zr₆ cluster-based LMOFs, HIAM-400X (X=0, 1, 2, 3, 4) are prepared using 2,1,3-benzothiadiazole and its derivative-based tetratopic carboxylic acids as organic linkers. The accessible unsaturated metal sites confer HIAM-400X as a pristine scaffold for linker installation. Six full-color emissive 2,1,3-benzothiadiazole and its derivative-based dicarboxylic acids (L) were successfully installed into HIAM-400X matrix to form HIAM-400X-L, in which the ET can be facilely tuned by controlling its direction, either from the inserted linkers to pristine MOFs or from the pristine MOFs to inserted linkers, and over the whole range of visible light. The combination of the pristine MOFs and the second linkers via linker installation creates a powerful two-dimensional space in tuning the emission via ET in LMOFs.