cantenane via host-guest interaction, temperature, and ions could be potentially
applied in the area of chiral switches or sensors.
As a class of topological superstructures which are designed at a molecular resolution, pseudo[1]cantenanes have vast potential applications in the area of supramolecular
area. Our group [42] also reported a protocol to fabricate mechanically self-locked
molecules via a one-step reaction. A pseudorotaxane based on two carboxyl units
modified pillar[5]arene threaded by a,o-diaminoalkane was first constructed. Then
amidation reaction could take place between one or two pseudorotaxanes and in this
way monomeric and dimeric pseudo[1]catenanes could be easily obtained, as shown in
Fig. 20. Due to the fixed planar chirality of pillar[5]arene, the chiral dimeric pseudo[1]
catenanes were isolated and fully characterized by both experiments (circular dichroism
spectroscopy and X-ray crystallography) and DFT calculations. We call this kind of
dimeric pseudo[1]catenanes “gemini-catenane.” We believe this convenient protocol for
the synthesis of chiral pseudo[1]catenanes and gemini-catenanes could efficiently
facilitate the practical applications of such kind of masterly chiral architectures.
4.4
Molecular Figures-of-Eight
Different from the pseudo[1]catenane structure, of which both ends of the axle
part connected to the same segment of the macrocycle, a self-threaded molecular
8 architecture connected two portions of the axle to different regions of the macrocycle.
Vogtle et al. [43] first constructed a class of self-threaded molecular 8 architectures
in 2001, and due to multiple connection sites on the macrocyclic molecule, three
Fig. 19 (a) Conformation transformation of a chiral pseudo[1]cantenane upon the addition
and removal of the competitive guest [39]; (b) structure of pseudo[1]cantenane based on pillar[5]
arene and crown ether [40]; (c) conformation transformation of a chiral pseudo[1]cantenane
upon the addition of ClO 4
À and S
2À [41]
4 Mechanically Self-Locked Molecules
99
applied in the area of chiral switches or sensors.
As a class of topological superstructures which are designed at a molecular resolution, pseudo[1]cantenanes have vast potential applications in the area of supramolecular
area. Our group [42] also reported a protocol to fabricate mechanically self-locked
molecules via a one-step reaction. A pseudorotaxane based on two carboxyl units
modified pillar[5]arene threaded by a,o-diaminoalkane was first constructed. Then
amidation reaction could take place between one or two pseudorotaxanes and in this
way monomeric and dimeric pseudo[1]catenanes could be easily obtained, as shown in
Fig. 20. Due to the fixed planar chirality of pillar[5]arene, the chiral dimeric pseudo[1]
catenanes were isolated and fully characterized by both experiments (circular dichroism
spectroscopy and X-ray crystallography) and DFT calculations. We call this kind of
dimeric pseudo[1]catenanes “gemini-catenane.” We believe this convenient protocol for
the synthesis of chiral pseudo[1]catenanes and gemini-catenanes could efficiently
facilitate the practical applications of such kind of masterly chiral architectures.
4.4
Molecular Figures-of-Eight
Different from the pseudo[1]catenane structure, of which both ends of the axle
part connected to the same segment of the macrocycle, a self-threaded molecular
8 architecture connected two portions of the axle to different regions of the macrocycle.
Vogtle et al. [43] first constructed a class of self-threaded molecular 8 architectures
in 2001, and due to multiple connection sites on the macrocyclic molecule, three
Fig. 19 (a) Conformation transformation of a chiral pseudo[1]cantenane upon the addition
and removal of the competitive guest [39]; (b) structure of pseudo[1]cantenane based on pillar[5]
arene and crown ether [40]; (c) conformation transformation of a chiral pseudo[1]cantenane
upon the addition of ClO 4
À and S
2À [41]
4 Mechanically Self-Locked Molecules
99