Noncovalently bound and mechanically interlocked systems using pillar[<i>n</i>]arenes

Kato, Kenichi; Fa, Shixin; Ohtani, Shunsuke; Shi, Tan‐Hao; Brouwer, Albert M.; Ogoshi, Tomoki

doi:10.1039/d2cs00169a

Cited by 90 publications

(52 citation statements)

References 222 publications

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“…Inspired by Pedersen's first discovery of wholly synthetic macrocyclic polyethers named crown ethers in the mid-1960s, 19 has been listed as one of the most influential synthetic macrocyclic receptors among the well-established ones. 20 Due to their synthetic accessibility, facile functionalization, preorganized π-electron-rich cavities, and predictable noncovalent interactions, pillarene chemistry created a boom in many research fields during the past decade or so, including smart and stimuli-responsive host−guest systems, 16−18 molecular devices and machines, 21 porous and nonporous adsorption materials, 22−24 and many others. 25−29 While the synthetic method, host−guest chemistry, and diversified application exploration of the traditional pillarenes have been wildly investigated, new macrocyclic compounds inspired by pillarenes are being unearthed continuously and reported on today, 1−4,30−39 aiming to break through some bottleneck scientific problems which cannot be well resolved or explained by traditional pillarenes.…”

Section: Introductionmentioning

confidence: 99%

Pillararene-Inspired Macrocycles: From Extended Pillar[n]arenes to Geminiarenes

Yang

2022

Acc. Chem. Res.

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Conspectus Macrocyclic compounds have been the primary tools in supramolecular chemistry since their establishment due to their innate functional features of molecular recognition and complexation. The rapid development of modern supramolecular chemistry has also significantly benefited from creating new macrocycles with distinctive geometries and properties. For instance, pillar[n]arenes (pillarenes), a relatively young generation of star macrocyclic hosts among the well-established ones (e.g., crown ethers, cyclodextrins, cucurbiturils, and calixarenes), promoted a phenomenal research hotspot all over the world in the past decade. Although the synthesis, host–guest properties, and various supramolecular functions of pillarenes have been intensively studied, many objective limitations and challenges still cannot be ignored. For example, high-level pillar[n]arenes (n > 7) usually do not possess applicable large-sized cavities due to structural folding and cannot be synthesized on a large scale because of the uncompetitive cyclization process. Furthermore, two functional groups must be covalently para-connected to each repeating phenylene unit, which severely limits their structural diversity and flexibility. In this context, we have developed a series of pillarene-inspired macrocycles (PIMs) using a versatile and modular synthetic strategy during the past few years, aiming to break through the synthetic limitations in traditional pillarenes and find new opportunities and challenges in supramolecular chemistry and beyond. Specifically, by grafting biphenyl units into the pillarene backbones, extended pillar[n]arenes with rigid and nanometer-sized cavities could be obtained with reasonable synthetic yields by selectively removing hydroxy/alkoxy substitutes on pillarene backbones, leaning pillar[6]arenes and leggero pillar[n]arenes with enhanced structural flexibility and cavity adaptability were obtained. By combining the two types of bridging modes in pillarenes and calixarenes, a smart macrocyclic receptor with two different but interconvertible conformational features, namely geminiarene, was discovered. Benefiting from the synthetic accessibility, facile functionalization, and superior host–guest properties in solution or the solid state, this new family of macrocycles has exhibited a broad range of applications, including but not limited to supramolecular assembly/gelation/polymers, pollutant detection and separation, porous organic polymers, crystalline/amorphous molecular materials, hybrid materials, and controlled drug delivery. Thus, in this Account, we summarize our research efforts on these PIMs. We first present an overview of their design and modular synthesis and a summary of their derivatization strategies. Thereafter, particular attention is paid to their structural features, supramolecular functions, and application exploration. Finally, the remaining challenges and perspectives are outlined for their future development. We hope that this Account and our works can stimulate further advance...

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Section: Introductionmentioning

confidence: 99%

Pillararene-Inspired Macrocycles: From Extended Pillar[n]arenes to Geminiarenes

Yang

2022

Acc. Chem. Res.

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“…Modern supramolecular chemistry has also significantly benefited from the development of novel macrocyclic receptors with preorganized cavity structures and intriguing host–guest properties [ 4 ]. For example, pillar[n]arenes (pillararenes), a family of influential synthetic macrocycles first introduced by Ogoshi et al in 2008 [ 5 , 6 ], have experienced rapid development during the past years and created a boom in many cross-disciplinary research fields, including but not limited to molecular devices and machines [ 7 ], stimuli-responsive supramolecular/host–guest systems [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ], porous/nonporous materials [ 15 , 16 , 17 ], organic–inorganic hybrid systems [ 18 , 19 , 20 , 21 ], catalysis [ 22 , 23 , 24 ] and cancer theranostics [ 25 , 26 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

A Water-Soluble Leggero Pillar[5]arene

Cai

et al. 2022

Molecules

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The study of aqueous-phase molecular recognition of artificial receptors is one of the frontiers in supramolecular chemistry since most biochemical processes and reactions take place in an aqueous medium and heavily rely on it. In this work, a water-soluble version of leggero pillar[5]arene bearing eight positively charged pyridinium moieties (CWP[5]L) was designed and synthesized, which exhibited good binding affinities with certain aliphatic sulfonate species in aqueous solutions. Significantly, control experiments demonstrate that the guest binding performance of CWP[5]L is superior to its counterpart water-soluble macrocyclic receptor in traditional pillararenes.

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“…Such hybrid macrocycles have particular structural characteristics, e.g., "fused" hybrid macrocyclic cavities "double-bridged" 81 by aromatic rigid linkers with unique planar chirality. 82 Furthermore, it provides the opportunity to raise another supramolecular issue, i.e., the fabrication of mechanically interlocked molecules. 82 For example, 83 1,4-dimethoxypillar [4]arene [1]hydroquinone P1 (Scheme 2) was used as the previous piece to react with the "bridging group"-1,5-diuoro-2,4-dinitrobenzene F1 (Scheme 2) in the presence of triethylamine as the catalyst in THF solutions under N 2 atmosphere to produce 2,4-dinitro-5-uorophenyl difunctionalized pillar [5]arene P2 (Scheme 2) using the classic nucleophilic aromatic substitution (S N Ar) yielding 90%.…”

Section: Introductionmentioning

confidence: 99%

“…82 Furthermore, it provides the opportunity to raise another supramolecular issue, i.e., the fabrication of mechanically interlocked molecules. 82 For example, 83 1,4-dimethoxypillar [4]arene [1]hydroquinone P1 (Scheme 2) was used as the previous piece to react with the "bridging group"-1,5-diuoro-2,4-dinitrobenzene F1 (Scheme 2) in the presence of triethylamine as the catalyst in THF solutions under N 2 atmosphere to produce 2,4-dinitro-5-uorophenyl difunctionalized pillar [5]arene P2 (Scheme 2) using the classic nucleophilic aromatic substitution (S N Ar) yielding 90%. Then, P2 was dissolved in DMF to promote its solubility under K 2 CO 3 condition and prepare another nitrophenyl difunctionalized pillar [5]arene P3 (Scheme 2), yielding 99%.…”

Section: Introductionmentioning

confidence: 99%