Discrete and Continuous One-Dimensional Channels Based on Pillar[n]arenes

One-dimensional (1D) channel structures, have spaces, entrances, and exits of specific sizes, therefore guest molecules can travel through the channel from the entrance to the exit. Such 1D channel structures are therefore ideal platforms for transporting molecules. In this mini-review, we will discuss the preparation of molecular-scale continuous 1D channels from pillar[n]arenes by using non-covalent interactions and covalent bonding. Because of their highly symmetrical structures, pillar[n]arenes are suitable building blocks for constructing 1D channel structures. Continuous 1D channels can be prepared by connecting both pillar[n]arene rims via physical interactions. Pillar[5]arenes with different rims can be used to produce discrete 1D channels, e.g., dimers and trimers, via non-covalent bonds. Non-covalent 1D channels can be produced by complexation between pillar[n]arene wheels and polymeric axles. Continuous and discrete 1D channels can also be produced by connecting pillar[n]arene units via covalent bonds. We will also discuss the characteristic features and potential uses of these 1D channels in material applications. In this mini-review, we discuss the preparation of molecular scale one-dimensional (1D) channels by using non-covalent interactions and covalent bonds between pillar[n]arenes. Connecting both pillar[n]arene rims via physical interactions or covalent bonds, enables preparation of continuous and discrete 1D channels. Non-covalent 1D channels can also be produced by complexation between pillar[n]arene wheels and polymeric axles.