A Superphane-based carcerand for arsenic detoxification via imprisoning arsenate

Carcerands, special molecular constructs with enclosed interiors as a new phase of matter, have attracted immense interest because of their unique structures, physicochemical properties, and potential applications in many aspects, e.g., targeted drug delivery. However, carcerands for imprisoning, inter alia, anions of interest represent an unmet challenge. Herein, we report the design and synthesis of a superphane-based carcerand 1, featuring up to 18 anion binding sites and a fully enclosed interior space. Carcerand 1 is found capable of incarcerating H2PO4− anion, yielding an anion carceplex 5, as inferred from crystallographic analysis, 1H nuclear magnetic resonance (NMR) spectroscopy, and diffusion-ordered NMR spectroscopy (DOSY), as well as molecular dynamics simulations. More importantly, highly toxic arsenate anion was also imprisoned within carcerand 1, offering the arsenate carceplex 6 that proved nontoxic compared with free arsenate or peripherally bound arsenate in the HEK293T cell line.