In addition, 36 and 37 could be deprotected by reaction with excess BBr 3 , indicating
the facile functionalization of biphen[n]arene’s family. As for molecular recognition
properties of biphen[n]arenes, 37 exhibits preeminent guest-friendly property and is
capable of interacting with not only cationic guests but also neutral species. Furthermore, the molecular recognition properties of hydroxylated biphen[4]arene
toward 2,7-dibutyldiazapyrenium and some other guests were also investigated in
their following work [51].
In 2015, the first water-soluble biphen[3]arene, i.e., carboxylated biphen[3]arene
(38), was introduced by Huang and coworkers, and meanwhile, a new supramolecular amphiphilic assembly of 38 and 1-cetylethylammonium chloride was successfully constructed [52]. Similarly, Yu and coworkers synthesized the first cationic
water-soluble biphen[3]arene in 2016, which was further used to alter the aggregation behavior of the amphiphilic guest (sodium 1-hexanesulfonate) in water [53].
Very recently, Li and coworkers successfully designed and synthesized a new family
of biphen[n]arenes derivatives, namely, 2,2-biphen[n]arenes [54]. Compared to the
traditional biphenarenes (4,4
0 -biphen[n]arenes), 2,2
0 -biphen[n]arenes possess a
higher total synthetic yield. Meanwhile, not only cyclic tetramers, high-order macrocycles including cyclic pentamers, hexamers, heptamers, and octamers were also
easily synthesized and separated.
7.3.3 Cyanostar
Cyanostar (40), a C 5 -symmetric star-shaped macrocycle, was first introduced by
Flood and coworkers in 2013 [55, 56]. 40 could be obtained through a one-step
Knoevenagel self-condensation by reaction of the meta-substituted difunctional
phenylene (39) in a good yield of 81% (Fig. 6a). In the crystalloid state, 40 prefers
to stay as π-stacked dimers constituted of chiral P and M enantiomers (Fig. 6c). In the
solution, 40 exhibits outstanding binding properties toward PF 6
À , BF 4
À , and ClO 4
À ,
endowing 40 with great potentials in the detection and separation of electronegative
species. Moreover, owning to its anionic preference and shape-persistent features, a
phosphate-templated [3]rotaxane could be synthesized in a high yield through click
chemistry (Fig. 6b). The efficient synthetic step cooperates with the outstanding
ionic recognition property bringing cyanostar all kinds of applications in supramolecular chemistry and other related fields [57–59].
7.3.4 Campestarenes
Campestarenes (41–44), a family of modifiable macrocycles based on Schiff base,
were first introduced by MacLachlan and coworkers in 2011 [60]. Hydroxyl groups
in this fivefold symmetrical macrocycle guaranteed its flat conformation and stabilized the imine moieties via hydrogen bond interactions (Fig. 7a). Theoretical
calculation of 44 demonstrated that an enol-imine tautomeric state is predominant
in the gas phase or nonpolar solvents, while a keto-enamine tautomeric state is
190
D. Dai et al.
the facile functionalization of biphen[n]arene’s family. As for molecular recognition
properties of biphen[n]arenes, 37 exhibits preeminent guest-friendly property and is
capable of interacting with not only cationic guests but also neutral species. Furthermore, the molecular recognition properties of hydroxylated biphen[4]arene
toward 2,7-dibutyldiazapyrenium and some other guests were also investigated in
their following work [51].
In 2015, the first water-soluble biphen[3]arene, i.e., carboxylated biphen[3]arene
(38), was introduced by Huang and coworkers, and meanwhile, a new supramolecular amphiphilic assembly of 38 and 1-cetylethylammonium chloride was successfully constructed [52]. Similarly, Yu and coworkers synthesized the first cationic
water-soluble biphen[3]arene in 2016, which was further used to alter the aggregation behavior of the amphiphilic guest (sodium 1-hexanesulfonate) in water [53].
Very recently, Li and coworkers successfully designed and synthesized a new family
of biphen[n]arenes derivatives, namely, 2,2-biphen[n]arenes [54]. Compared to the
traditional biphenarenes (4,4
0 -biphen[n]arenes), 2,2
0 -biphen[n]arenes possess a
higher total synthetic yield. Meanwhile, not only cyclic tetramers, high-order macrocycles including cyclic pentamers, hexamers, heptamers, and octamers were also
easily synthesized and separated.
7.3.3 Cyanostar
Cyanostar (40), a C 5 -symmetric star-shaped macrocycle, was first introduced by
Flood and coworkers in 2013 [55, 56]. 40 could be obtained through a one-step
Knoevenagel self-condensation by reaction of the meta-substituted difunctional
phenylene (39) in a good yield of 81% (Fig. 6a). In the crystalloid state, 40 prefers
to stay as π-stacked dimers constituted of chiral P and M enantiomers (Fig. 6c). In the
solution, 40 exhibits outstanding binding properties toward PF 6
À , BF 4
À , and ClO 4
À ,
endowing 40 with great potentials in the detection and separation of electronegative
species. Moreover, owning to its anionic preference and shape-persistent features, a
phosphate-templated [3]rotaxane could be synthesized in a high yield through click
chemistry (Fig. 6b). The efficient synthetic step cooperates with the outstanding
ionic recognition property bringing cyanostar all kinds of applications in supramolecular chemistry and other related fields [57–59].
7.3.4 Campestarenes
Campestarenes (41–44), a family of modifiable macrocycles based on Schiff base,
were first introduced by MacLachlan and coworkers in 2011 [60]. Hydroxyl groups
in this fivefold symmetrical macrocycle guaranteed its flat conformation and stabilized the imine moieties via hydrogen bond interactions (Fig. 7a). Theoretical
calculation of 44 demonstrated that an enol-imine tautomeric state is predominant
in the gas phase or nonpolar solvents, while a keto-enamine tautomeric state is
190
D. Dai et al.