An electron-deficient supramolecular macrocyclic host for the selective separation of aromatics and cyclic aliphatics

Abstract

Here, we report the synthesis of 3,3′,4,4′-biphenyltetracarboxylic acid diimide-extended pillar[6]arenes 1 with an electron-deficient nanometer-sized cavity in two steps in 45% yield. With its electron-deficient cavity, host 1 has been successfully used as a gas chromatographic stationary phase to prepare a packed column for the separation of benzene/cyclohexane and toluene/methylcyclohexane. Compared with the traditional capillary chromatographic column, this prepared packed column has the advantages of easy preparation, short column length, low separation temperature and short retention time. Moreover, the single crystal structures of (PhH)₂@1 and Tol₂@1 indicate that the electron-deficient cavity of host 1 enables the prepared packed column to be used in the high-resolution gas chromatographic separation of benzene/cyclohexane and toluene/methylcyclohexane.