Host-Guest Chemistry of a Tetracationic
Cyclophane, Namely, Cyclobis (paraquatp-phenylene)
3
Hao Li, Tianyu Jiao, and Libo Shen
Contents
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.2 Structural Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.3 Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.4 Guest Recognition Ability of CBPQT Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.4.1 Guest Recognition Ability of CBPQT
4+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.4.2 Guest Recognition Ability of CBPQT
2(•+) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.5 Mechanically Interlocked Molecules Containing CBPQT
4+ Ring . . . . . . . . . . . . . . . . . . . . . . . . 61
3.5.1 Catenanes Containing CBPQT
4+ Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.5.2 Rotaxanes Containing CBPQT
4+ Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.6 Molecular Machines and Molecular Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.7 Extended Derivatives of CBPQT
4+ Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
3.8 Conclusions and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
3.1
Introduction
Since Pedersen’s seminal report [1] of the synthesis and guest recognition behaviors
of crown ether in the year of 1967, the research on host-guest recognition began to
represent one of the major focuses in the field of supramolecular chemistry [2]. In the
early stage, supramolecular chemistry was often referred to as host-guest chemistry
[3], because of the following reasons. On the one hand, host molecules often exist in
the form of macrocycles, which have many convergent binding sites that point
into their cavities. The implication is that the host is able to accommodate a guest
within its pocket where multiple noncovalent interactions could occur simultaneously in a cooperative manner. These supramolecular driving forces include labile
coordination bond [4], π-electron interactions in the form of either donor-acceptor
H. Li (*) · T. Jiao · L. Shen
Department of Chemistry, Zhejiang University, Hangzhou, China
e-mail: lihao2015@zju.edu.cn
© Springer Nature Singapore Pte Ltd. 2020
Y. Liu et al. (eds.), Handbook of Macrocyclic Supramolecular Assembly,
https://doi.org/10.1007/978-981-15-2686-2_4
49