Ligand Chromophore Modification Approach for Predictive Incremental Tuning of Metal-Organic Framework Color

Color-tunable metal-organic frameworks (MOFs) are emerging materials for light harvesting, molecular sensing, biological imaging, and lighting applications, and their continued development necessitates straightforward and predictive approaches for adjusting the MOF optical absorption across the visible spectrum. We report a strategy for facile diversification of MOF color that combines (i) postsynthetic modification (PSM) of the chromophoric linkers of an amino-functionalized UiO-68 MOF and (ii) computationally guided selection of specific linker modifiers to rationally tune chromophore band gap. This approach is used to identify and generate a family of seven new modified MOFs having incrementally red-shifted absorption spectra spanning ∼400-650 nm. This combination of experiment and computation provides a relatively simple pathway for the rational and facile tuning of MOF color and the creation of new families of light-responsive materials.