N-oxide-functionalized pillared Cd(II) porous metal−organic frameworks: Gas sorption and luminescent behavior

Abstract

Two similar N-Oxide-functionalized pillared Cd(II) metal-organic frameworks (MOFs), {[Cd(dpdcdo)(bpe)0.5(H2O)]·DMF·H2O}n (1) and {[Cd(dpdcdo)(bpe)0.5(H2O)]·DMA}n (2) [DMF ​= ​N,N-dimethylformamide, DMA ​= ​N,N-dimethylacetamide], have been obtained based on axially chiral 2,2′-dipyridine-3,3′-dicarboxylate-1,1′-dioxide (H2dpdcdo) ligand and rigid trans-1,2-bis(4-pyridyl)ethene (bpe) pillar. The N-Oxide group decorated in the channel of the Cd(II)-MOFs could provide effective “open donor sites” to enhance their affinity toward CO2 molecule. The gas adsorption properties of the Cd(II) framework have been investigated by N2, H2, CH4, and CO2 gases, and it reveals good CO2 uptake, CO2 sorption affinity, and sorption selectivity of CO2 over CH4 at ambient temperature. In addition, the solid-state luminescence properties of MOFs 1 and 2 have been conducted at room temperature, and they exhibit luminescent emission upon H2dpdcdo ligand.