Systematically tuning the conductivity of metal−organic frameworks (MOFs) is key to synergizing their attractive synthetic control and porosity with electrochemical attributes useful in energy and sensing technologies. A priori control of charge transfer is possible by exploiting the solid-solution properties of MOFs together with electronic self-exchange enabled by redox pendants. Here we introduce a new strategy for preparing redox-active MOF thin-film electrodes with finely tuned redox pendant content. Varying the ratios of alkylferrocene containing redox-active and inactive links during MOF synthesis enabled the fabrication of electrodes with tunable redox conductivity. The prepared MOF electrodes display maximum electron conductivity of 1.10 mS m −1 , with crystallographic and electrochemical stability upon thousands of redox cycles. Electroanalytical studies demonstrated that the conductivity follows solution-like diffusion-controlled behavior with nonlinear electron diffusion coefficients consistent with charge hopping and percolation models of spatially fixed redox centers. Our studies create new prospects in the design and synthesis of redox-active MOFs with targeted properties for the design of advanced electrochemical devices.

J-dimer emission is an emergent property that occurs when pairs of ground-state fluorophores associate within multivariate MOFs producing tunable red shifted emission.

A library of 12 dibenzo- and naphtho-fluoranthene polycyclic aromatic hydrocarbons (PAHs) with MW = 302 (CH) was synthesized via a Pd-catalyzed fluoranthene ring-closing reaction. By understanding the various modes by which the palladium migrates during the transformation, structural rearrangements were bypassed, obtaining pure PAHs in high yields. Spectroscopic and electrochemical characterization demonstrated the profound diversity in the electronic structures between isomers. Highlighting the significant differences in emission of visible light, this library of PAHs will enable their standardization for toxicological assessment and potential use as optoelectronic materials.

The separation of xenon and krypton from their mixtures has been an enduring and complex venture due to their similar sizes and unreactive nature. Metal−organic frameworks (MOFs) have shown the potential to complete these challenging separations by utilizing pressure-swing adsorption (PSA) as a sustainable alternative to current cryogenic distillation techniques. To rationally design materials to better realize this goal, two main approaches have emerged: pore-size optimized and polarizability-based separations. To ascertain the efficacy of these strategies, we designed a series of UiO-type MOFs with terphenyl linkers that systematically varied their steric and electronic properties, including −Me, −F, −TMS, and −I functionalities, to assess their interactions with xenon and krypton. The prepared MOFs are all isoreticular and have similar pore size distributions, allowing us to directly evaluate the effects imposed by the functional groups. We found that the xenon uptake could be increased with greater polarizability of the functional group (−F < −Me ≈ −TMS < −I), whereas the selectivities seem to follow a trend more related to pore-steric effects (−TMS < −I < −Me < −F).