High capacity, high selectivity, and low-cost regeneration conditions are the most important criteria by which new adsorbents for post-combustion carbon dioxide capture will be judged. The incorporation of N,N′-dimethylethylenediamine (mmen) into H₃[(Cu₄Cl)₃(BTTri)₈ (CuBTTri; H₃BTTri = 1,3,5-tri(1H-1,2,3-triazol-4-yl)benzene), a water-stable, triazolate-bridged framework, is shown to drastically enhance CO₂ adsorption, resulting in one of the best performing metal–organic frameworks for CO₂ separation reported to date. High porosity was maintained despite stoichiometric attachment of mmen to the open metal sites of the framework, resulting in a BET surface area of 870 m² g⁻¹. At 25 °C under a 0.15 bar CO₂/0.75 bar N₂ mixture, mmen-CuBTTri adsorbs 2.38 mmol CO₂ g⁻¹ (9.5 wt%) with a selectivity of 327, as determined using Ideal Adsorbed Solution Theory (IAST). The high capacity and selectivity are consequences of the exceptionally large isosteric heat of CO₂ adsorption, calculated to be −96 kJ mol⁻¹ at zero coverage. Infrared spectra support chemisorption between amines and CO₂ as one of the primary mechanisms of uptake. Despite the large initial heat of adsorption, the CO₂ uptake was fully reversible and the framework could be easily regenerated at 60 °C, enabling a cycling time of just 27 min with no loss of capacity over the course of 72 adsorption/desorption cycles.

Of the many thousands of new metal–organic frameworks (MOFs) that are now discovered each year, many possess potential redox activity arising from the constituent metal ions and/or organic ligands, or the guest molecules located within their porous structures. Those redox states that can be accessed via postsynthetic redox modulation often possess distinct physical properties; if harnessed, these provide a basis for applications including microporous conductors, electrocatalysts, energy storage devices and electrochemical sensors, amongst others. This feature article highlights the latest developments in experimental, theoretical and computational concepts relevant to redox-active MOFs, including new solid state electrochemical and spectroelectrochemical techniques that have great utility in this field. A particular emphasis is on current and emerging trends at the fundamental level which underscore the importance of this promising class of electroactive materials for a wide range of technologically- and industrially-relevant applications.

Defect concentrations and their compensating groups have been systematically tuned within UiO-66 frameworks and are found to have a pronounced effect on CO ₂ and H ₂ O adsorption at low and high pressure.