Mn(II)-based MIL-53 analogues: synthesis using neutral bridging mu2-ligands and application in liquid-phase adsorption and separation of C6-C8 aromatics.

Four Mn(II)-based MIL-53 single crystals were prepared using four neutral pyridine N-oxides as bridging mu(2)-ligands. In the case of 4,4'-bipridine-N,N'-dioxide (BPNO), the infinite manganese oxide chains were further interconnected by BPNO besides BDC, which allows 1D channels to be accessible for guest molecules. The liquid-phase adsorption and separation of C6-C8 aromatics using the evacuated compound as an absorbent were investigated via crystal-to-crystal transformations. Both structural evolution of the compounds and selectivity of C6-C7 aromatics of one evacuated compound could be attributed to noncovalent interactions, especially pi-pi interaction.