Calixarenes are concave molecules consisting of phenol units and linking methylenes. Due to facile modification and controllable conformations, calixarenes are regarded as the third generation of host molecules. At molecular level, chiral calixarenes can be classified into calixarenes with chiral subunits, inherently chiral calixarenes, and bridging chiral calixarenes, according to the structural feature of the chirality elements. At supramolecular level, calixarenes can self-assemble or assemble with other molecules or ions into nanoscale aggregates of diverse topologies in solution, solid state, and two-dimensional surface, through non-covalent bonds. The study on chiral calixarenes and their supramolecular chirality not only has theoretical significance in chiral structures, origin of chirality, and so on, but also shows great potential in chiral sensors, chiral catalysts, chiral separation materials, chiral vehicles, and chiral nano-materials etc. This review focuses on the progress in the design, synthesis, structure, and function of representative calixarenes with molecular chirality and supramolecular chirality in the last decade. Emphasis is laid on the advantages of calixarene skeletons in forming novel molecular chirality and supramolecular chirality as well as in realizing specific and novel functions. It is expected that more exceptional chiral calixarene molecules and chiral calixarene supramolecular materials will be obtained as advancement of synthetic technology and supramolecular designs in calixarene studies.
Contents
1 Introduction
2 Calixarenes with chiral subunits
2.1 As solvating reagents
2.2 As gelators
2.3 As asymmetric catalysts
3 Inherently chiral calixarenes
3.1 Upper rim/Lower rim-substituted
3.2 Meta-substituted
3.3 Calixarenes containing chiral methylene bridge carbon
4 Calixarene supramolecular chirality
4.1 Supramolecular chirality driven by acid-base reaction
4.2 Supramolecular chirality driven by electrostatic attraction
4.3 Supramolecular chirality driven by hydrogen bonding
4.4 Supramolecular chirality driven by coordination
4.5 Supramolecular chirality driven by van der Waals interaction
4.6 Supramolecular chirality driven by π-π interaction
4.7 Supramolecular chirality driven by inclusion
5 Conclusion and outlook