Search

A chiral, octahedral M12L12 cage, which is charge neutral and contains an internal void of about 2000 Å3, is reported. The cage was synthesised as an enantiopure complex by virtue of amino‐acid‐based dicarboxylate ligands, which assemble around copper paddlewheels at the vertices of the octahedron. The cage persists in solution with retention of the fluorescence properties of the parent acid. The solid‐state structure contains large pores both within and between the cages, and displays permanent porosity for the sorption of gases with retention of crystallinity. Initial tests show some enantioselectivity of the cage towards guests in solution. [ABSTRACT FROM AUTHOR]

The need for effective CO2 capture systems remains high, and due to their tunability, metallosupramolecular architectures are an attractive option for gas sorption. While the use of extended metal organic frameworks for gas adsorption has been extensively explored, the exploitation of discrete metallocage architectures to bind gases remains in its infancy. Herein the solid state gas adsorption properties of a series of [Pd2( L)4]4+ lantern shaped coordination cages ( L = variants of 2,6-bis(pyridin-3-ylethynyl)pyridine), which had solvent accessible internal cavities suitable for gas binding, have been investigated. The cages showed little interaction with dinitrogen gas but were able to take up CO2. The best performing cage reversibly sorbed 1.4 mol CO2 per mol cage at 298 K, and 2.3 mol CO2 per mol cage at 258 K (1 bar). The enthalpy of binding was calculated to be 25-35 kJ mol−1, across the number of equivalents bound, while DFT calculations on the CO2 binding in the cage gave Δ E for the cage-CO2 interaction of 23-28 kJ mol−1, across the same range. DFT modelling suggested that the binding mode is a hydrogen bond between the carbonyl oxygen of CO2 and the internally directed hydrogen atoms of the cage. [ABSTRACT FROM AUTHOR]

Caging carbon dioxide: Self ‐ assembled discrete palladium(II) [Pd2(L)4]4+ cages with 2,6 ‐ bis(pyridin ‐ 3 ‐ ylethynyl)pyridine) ligands (L) have cavities, which bind guests containing carbonyl groups through hydrogen bonding interactions. In the solid state these cages have now been shown to bind up to four CO2 molecules, with selectivity over N2. Long ‐ range order in the packing of the molecules in powdered samples of the compound does not appear to be necessary for their activity, making their preparation easy. Additionally, the cages can be readily functionalized, opening up avenues for selective guest binding and gas separations. More information can be found in the Full Paper by B. F. Abrahams, J. D. Crowley et al. on page 10559. [ABSTRACT FROM AUTHOR]