Dynamic control of circumrotation of a [2]catenane by acid‐base switching

We reports a mechanical interlocking donor-acceptor [2]catenane, which is able to form varying degrees of self-complexed or decomplexed compounds that alter the cavity size of the crown ether and affecting the circumrotation behavior of CBPQT ⋅ 4PF₆ ring of the catenane.

Abstract

Dynamic control of the motion in a catenane remains a big challenge as it requires precise design and sophisticated well-organized structures. This paper reports the design and synthesis of a donor-acceptor [2]catenane through mechanical interlocking, employing a crown ether featuring two dibenzylammonium salts on its side arms as the host and a cyclobis(paraquat-p-phenylene) (CBPQT ⋅ 4PF₆) ring as the guest molecule. By addition of external acid or base, the catenane can form self-complexed or decomplexed compounds to alter the cavity size of the crown ether ring, consequently affecting circumrotation rate of CBPQT ⋅ 4PF₆ ring of the catenane. This study offers insights for the design and exploration of artificial molecular machines with intricate cascading responsive mechanisms.

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