Two Isostructural Flexible Porous Coordination Polymers Showing Contrasting Single-Component and Mixture Adsorption Properties for Propylene/Propane.

Solvothermal reactions of 3-(3-methylpyridin-4-yl)benzoic acid (Hmpba) with Mn(NO) or Co(NO) yielded isostructural porous coordination polymers, [Mn(mpba)]·guest (MCF-56, ) and [Co(mpba)]·guest (MCF-57, ), respectively. X-ray diffraction revealed that and possess similar one-dimensional ultramicroporous channels, and guest-free [Mn(mpba)] () and [Co(mpba)] () possess significantly and slightly contracted channels, respectively. Single-component CH/CH adsorption isotherms and computational simulations showed the typical nonporous-to-porous structural transformations for , in which CH exhibits a significantly lower threshold pressure, and the typical small-pore-to-large-pore structural transformations for , in which CH exhibits a slightly lower threshold pressure. Mixture column breakthrough experiments showed that the CH/CH separation performances of are obviously better than those of , because the latter cannot adsorb CH below the threshold pressure for pore opening, and the pore opened by CH can adsorb CH.