Linear Positional Isomer Sorting in Nonporous Adaptive Crystals of a Pillar[5]arene

Here we show a new adsorptive separation approach using nonporous adaptive crystals of a pillar[5]­arene. Desolvated perethylated pillar[5]­arene crystals (<b>EtP5</b>α) with a nonporous character selectively adsorb 1-pentene (<b>1-Pe</b>) over its positional isomer 2-pentene (<b>2-Pe</b>), leading to a structural change from <b>EtP5</b>α to <b>1-Pe</b> loaded structure (<b>1-Pe</b>@<b>EtP5</b>). The purity of <b>1-Pe</b> reaches 98.7% in just one cycle and <b>EtP5</b>α can be reused without losing separation performance.