Water adsorption was investigated in the hydrostable Sc(iii) coordination polymer NOTT-400. This material performed CO2 capture under relative humidity (RH) conditions (20 and 10% RH). The maximum CO2 capture was obtained at 20% RH and 30 °C with a total amount of ∼10.2 wt%, representing a 2.5-fold increase in comparison with anhydrous conditions.

Metal–organic frameworks (MOFs) can act as a platform for the heterogenization of molecular catalysts, providing improved stability, allowing easy catalyst recovery and a route toward structural elucidation of the active catalyst. We have developed a MOF, 1, possessing vacant N,N-chelating sites which are accessible via the porous channels that penetrate the structure. In the present work, cationic rhodium­(I) norbornadiene (NBD) and bis­(ethylene) (ETH) complexes paired with both noncoordinating and coordinating anions have been incorporated into the N,N-chelation sites of 1 via postsynthetic metalation and facile anion exchange. Exploiting the crystallinity of the host framework, the immobilized Rh­(I) complexes were structurally characterized using X-ray crystallography. Ethylene hydrogenation catalysis by 1·[Rh­(NBD)]­X and 1·[Rh­(ETH)2]­X (X = Cl and BF4) was studied in the gas phase (2 bar, 46 °C) to reveal that 1·[Rh­(ETH)2]­(BF4) was the most active catalyst (TOF = 64 h–1); the NBD materials and the chloride salt were notably less active. On the basis of these observations, the activity of the Rh­(I) bis­(ethylene) complexes, 1·[Rh­(ETH)2]­BF4 and 1·[Rh­(ETH)2]­Cl, in butene isomerization was also studied using gas-phase NMR spectroscopy. Under one bar of butene at 46 °C, 1·[Rh­(ETH)2]­BF4 rapidly catalyzes the conversion of 1-butene to 2-butene with a TOF averaging 2000 h–1 over five cycles. Notably, the chloride derivative, 1 [Rh­(ETH)2]Cl displays negligible activity in comparison. XPS analysis of the postcatalysis sample, supported by DFT calculations, suggest that the catalytic activity is inhibited by the strong interactions between a Rh­(III) allyl hydride intermediate and the chloride anion.

CO2 capture of InOF-1 was enhanced 3.6-fold, at 1 bar and 30 °C, by confining EtOH within its pores. Direct visualisation by single crystal X-ray diffraction revealed that EtOH divides InOF-1 channels in wide sections separated by "bottlenecks" caused by EtOH molecules bonded to the μ2-OH functional groups of InOF-1.

Kinetic uptake experiments on InOF-1 confirm a maximum of 5.42 wt% CO2 capture at 30 o C and a significant 2-fold increase (~11 wt %) in CO2 capture under 20% relative humidity of water vapour. InOF-1 captures CO2 under humidity conditions (10% and 20% RH) and relatively high temperatures (40 and 50 o C) without any degradation of the crystalline structure which was corroborated by PXRD.