A Modular Synthetic Strategy for Functional Macrocycles

Abstract

Reported here is a molecule‐Lego synthetic strategy for macrocycles with functional skeletons, involving one‐pot and high‐yielding condensation between bis(2,4‐dimethoxyphenyl)arene monomers and paraformaldehyde. By changing the blocks, variously functional units (naphthalene, pyrene, anthraquinone, porphyrin, etc.) can be conveniently introduced into the backbone of macrocycles. Interestingly, the macrocyclization can be tuned by the geometrical configuration of monomeric blocks. Linear (180°) monomer yield cyclic trimers and pentamers, while V‐shaped (120°, 90° and 60°) monomers tend to form dimers. More significantly, even heterogeneous macrocycles are obtained in moderate yield by co‐oligomerization of different monomers. This series of macrocycles have the potential to be prosperous in the near future.

Selective complexation and efficient separation of cis/trans-1,2-dichloroethene isomers by a pillar[5]arene

“…Future work will attempt to achieve more separation of congurational isomers using extended biphen[n] arene 48 and functional macrocycles. 49…”

Multiple Stimuli-Responsive Conformational Exchanges of Biphen[3]arene Macrocycle

“…MeBP3 contains three 2,2 ,4,4 -tetramethoxyl biphenyl sidewalls and three methylene linkers, which is structurally similar to those synthetic macrocyclic arenes like calix[n]arenes [28,30,[47][48][49], resorc [4]arene [50], cyclotribenzylene [51], pillar[n]arenes [52][53][54] and other biphen[n]arenes [40][41][42][43][44][45][46]. Theoretically, there are two representative conformations for MeBP3, due to flipping of the biphenyl sidewalls ( Figure 1a, MeBP3-I and MeBP3-II).…”

“…Suitable guests may efficiently switch the conformations of acceptors [29][30][31][32][33][34][35][36]. According to MeBP3's cavity size (5.43 Å) [40] and π-electron rich characteristics [40][41][42][43][44][45][46], a linear secondary ammonium guest 1 + was chosen to study the binding properties of the macrocycle. As shown in Figure 4, in the 1 H NMR spectrum of host-guest 1:1 mixtures, no signals for MeBP3-II were found, showing that the conformational exchanges were fixed in the presence of 1 + .…”

“…Here, we report the stimuli-responsive conformational exchanges of 2,2',4,4'-tetramethoxyl biphen [3]arene (MeBP3) [40][41][42][43][44][45][46]. The conformational exchanges between two conformers of MeBP3 were slow on the NMR timescale, and we successfully differentiated them in the 1 H NMR and 13 C NMR spectra of MeBP3.…”

Coordination-Driven Poly[2]Pseudorotaxanes in Highly Polar Organic Solvent

“…In the past 10 years, our group focused on the host–guest chemistry of pillararenes and biphenarenes (Li, 2014 ; Ma et al, 2016 ; Li H. et al, 2019 ; Wang Y. et al, 2019 ; Xu et al, 2020 ). The association constant, (7.4 ± 0.3) × 10 2 M −1 , of P 5 A and bis(pyridinium)dicationic guest in DMSO is surprisingly high, leading to the formation of a [2]psdudorotaxane-type complex (Li et al, 2010 ).…”