molecules-logo

Journal Browser

Journal Browser

A Fascinating Story of Supramolecular Chemistry: A Themed Issue in Honor of Prof. Harry W. Gibson

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Macromolecular Chemistry".

Deadline for manuscript submissions: closed (15 July 2021) | Viewed by 48420

Special Issue Editor

State Key Laboratory of Chemical Engineering, Zhejiang University, Hangzhou, China
Interests: supramolecular chemistry; supramolecular polymers; nonporous adaptive crystals; pillararenes; supramolecular amphiphiles

Special Issue Information

Dear Colleagues,

Professor Harry W. Gibson (born: Syracuse, New York, USA in 1941) finished his undergraduate education at the Clarkson College of Technology (1962); thereafter, he obtained his PhD under the supervision of Prof. Frank D. Popp at the same university (1965). He spent two years as a post-doctoral fellow at the University of Notre Dame in the research group of Prof. Ernest L. Eliel on the conformational analysis of acyclic systems. During the period 1966–1986, he entered industry, successively including Union Carbide Corporation, Xerox Corporation, and Allied-Signal, as a scientist and embarked on a series of investigations. He then became a Professor of Chemistry at the Virginia Polytechnic Institute & State University. Prof. Gibson has presented >215 invited lectures and co-authored a total of > 660 papers at technical meetings worldwide. He has mentored 47 undergraduate researchers, 12 MS graduates, and 20 PhD graduates to date; additionally, he has directed 29 postdoctoral researchers.

Prof. Gibson has pioneered the synthesis and characterization of a novel polymer architecture: polyrotaxanes, consisting of physically linking cyclic molecules with linear polymeric molecules by “threading”, forming molecular analogs of strings of pearls. The Gibson lab was one of the first worldwide to establish synthesis and analysis protocols for polymeric rotaxanes. Such constructs are currently of great interest as stimuli-responsive systems for applications in sensors, molecular electronics, and artificial molecular machines, such as muscles. Another related objective has been the construction of macromolecular structures from relatively small building blocks through the use of self-assembled threaded or mechanically linked units, so-called “supramolecular polymers”. In the early years, he pursued the utilization of α-aminonitriles and their derivatives (Reissert compounds) as valuable intermediates for the synthesis of novel polymers. Then, polymerized cyclic oligomeric aromatic ethers were designed and prepared to produce high-performance poly(arylene ether)s from low-viscosity monomers. For the past 10 years, Prof. Gibson has contributed his synthetic expertise to the exohedral functionalization of fullerenes to tailor them for various applications, the main one being as diagnostic and radiotherapeutic materials for the treatment of brain tumors and gliomas. Starting in 2007, he devoted his efforts to the design, synthesis, and study of ionic liquids and related polymers for electroactive devices, such as mechanical actuators.

It is with this in mind that we honor Prof. Gibson on the occasion of his retirement for his immense contributions in the areas of macrocycles, pseudorotaxanes, rotaxanes, catenanes, self-assembled structures, fullerene chemistry, and ionic liquids and related polymers. He remains an inspiration to all and we are pleased to invite you to submit an article to this Special Issue of the journal Molecules.

Prof. Feihe Huang
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • heterocyclic polymers via Reissert compounds
  • macrocycles
  • polyketones from aminonitriles
  • pseudorotaxanes
  • rotaxanes
  • catenanes
  • self-assemblies
  • optoelectronic materials and devices
  • fullerene chemistry
  • ionic liquids
  • ionic polymers
  • cryptands

Published Papers (16 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

18 pages, 4809 KiB  
Article
β-Cyclodextrin-Polyacrylamide Hydrogel for Removal of Organic Micropollutants from Water
by Xia Song, Nana Nyarko Mensah, Yuting Wen, Jingling Zhu, Zhongxing Zhang, Wui Siew Tan, Xinwei Chen and Jun Li
Molecules 2021, 26(16), 5031; https://doi.org/10.3390/molecules26165031 - 19 Aug 2021
Cited by 23 | Viewed by 3646
Abstract
Water pollution by various toxic substances remains a serious environmental problem, especially the occurrence of organic micropollutants including endocrine disruptors, pharmaceutical pollutants and naphthol pollutants. Adsorption process has been an effective method for pollutant removal in wastewater treatment. However, the thermal regeneration process [...] Read more.
Water pollution by various toxic substances remains a serious environmental problem, especially the occurrence of organic micropollutants including endocrine disruptors, pharmaceutical pollutants and naphthol pollutants. Adsorption process has been an effective method for pollutant removal in wastewater treatment. However, the thermal regeneration process for the most widely used activated carbon is costly and energy-consuming. Therefore, there has been an increasing need to develop alternative low-cost and effective adsorption materials for pollutant removal. Herein, β-cyclodextrin (β-CD), a cheap and versatile material, was modified with methacrylate groups by reacting with methacryloyl chloride, giving an average degree of substitution of 3 per β-CD molecule. β-CD-methacrylate, which could function as a crosslinker, was then copolymerized with acrylamide monomer via free-radical copolymerization to form β-CD-polyacrylamide (β-CD-PAAm) hydrogel. Interestingly, in the structure of the β-CD-PAAm hydrogel, β-CD is not only a functional unit binding pollutant molecules through inclusion complexation, but also a structural unit crosslinking PAAm leading to the formation of the hydrogel 3D networks. Morphological studies showed that β-CD-PAAm gel had larger pore size than the control PAAm gel, which was synthesized using conventional crosslinker instead of β-CD-methacrylate. This was consistent with the higher swelling ratio of β-CD-PAAm gel than that of PAAm gel (29.4 vs. 12.7). In the kinetic adsorption studies, phenolphthalein, a model dye, and bisphenol A, propranolol hydrochloride, and 2-naphthol were used as model pollutants from different classes. The adsorption data for β-CD-PAAm gel fitted well into the pseudo-second-order model. In addition, the thermodynamic studies revealed that β-CD-PAAm gel was able to effectively adsorb the different dye and pollutants at various concentrations, while the control PAAm gel had very low adsorption, confirming that the pollutant removal was due to the inclusion complexation between β-CD units and pollutant molecules. The adsorption isotherms of the different dye and pollutants by the β-CD-PAAm gel fitted well into the Langmuir model. Furthermore, the β-CD-PAAm gel could be easily recycled by soaking in methanol and reused without compromising its performance for five consecutive adsorption/desorption cycles. Therefore, the β-CD-PAAm gel, which combines the advantage of an easy-to-handle hydrogel platform and the effectiveness of adsorption by β-CD units, could be a promising pollutant removal system for wastewater treatment applications. Full article
Show Figures

Graphical abstract

17 pages, 2007 KiB  
Article
Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block
by Boer Liu, Xi Chen, Glenn A. Spiering, Robert B. Moore and Timothy E. Long
Molecules 2021, 26(15), 4705; https://doi.org/10.3390/molecules26154705 - 03 Aug 2021
Cited by 5 | Viewed by 2948
Abstract
This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate [...] Read more.
This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths. Full article
Show Figures

Graphical abstract

11 pages, 7261 KiB  
Article
Pb2+-Containing Metal-Organic Rotaxane Frameworks (MORFs)
by Ting Xia, Zhi-Yong Yu and Han-Yuan Gong
Molecules 2021, 26(14), 4241; https://doi.org/10.3390/molecules26144241 - 13 Jul 2021
Cited by 3 | Viewed by 1958
Abstract
The metal-organic rotaxane framework (MORF) structures with the advantage of mechanically interlocking molecules (MIMs) have attracted intense interest from the chemical community. In this study, a set of MORFs (i.e., MORF-Pb-1 and MORF-Pb-2) are constructed using Pb2+, a tetraimidazolium macrocycle (Texas-sized [...] Read more.
The metal-organic rotaxane framework (MORF) structures with the advantage of mechanically interlocking molecules (MIMs) have attracted intense interest from the chemical community. In this study, a set of MORFs (i.e., MORF-Pb-1 and MORF-Pb-2) are constructed using Pb2+, a tetraimidazolium macrocycle (Texas-sized molecular box; 14+), and aromatic dicarboxylate (p-phthalate dianions (PTADAs; 2) or 2,6-naphthalene dicarboxylate dianions (3)) via a one-pot three-layer diffusion protocol. In particular, an unusual Pb…Pb weak interaction was shown in MORF-Pb-1 (charactered with distance of 3.656 Å). Full article
Show Figures

Figure 1

12 pages, 1887 KiB  
Communication
Chiroptical Sensing of Amino Acid Derivatives by Host–Guest Complexation with Cyclo[6]aramide
by Xuebin Wang, Jiecheng Ji, Zejiang Liu, Yimin Cai, Jialiang Tang, Yunzhi Shi, Cheng Yang and Lihua Yuan
Molecules 2021, 26(13), 4064; https://doi.org/10.3390/molecules26134064 - 02 Jul 2021
Cited by 6 | Viewed by 2137
Abstract
A hydrogen-bonded (H-bonded) amide macrocycle was found to serve as an effective component in the host–guest assembly for a supramolecular chirality transfer process. Circular dichroism (CD) spectroscopy studies showed that the near-planar macrocycle could produce a CD response when combined with three of [...] Read more.
A hydrogen-bonded (H-bonded) amide macrocycle was found to serve as an effective component in the host–guest assembly for a supramolecular chirality transfer process. Circular dichroism (CD) spectroscopy studies showed that the near-planar macrocycle could produce a CD response when combined with three of the twelve L-α-amino acid esters (all cryptochiral molecules) tested as possible guests. The host–guest complexation between the macrocycle and cationic guests was explored using NMR, revealing the presence of a strong affinity involving the multi-point recognition of guests. This was further corroborated by density functional theory (DFT) calculations. The present work proposes a new strategy for amplifying the CD signals of cryptochiral molecules by means of H-bonded macrocycle-based host–guest association, and is expected to be useful in designing supramolecular chiroptical sensing materials. Full article
Show Figures

Graphical abstract

7 pages, 1404 KiB  
Communication
A Supramolecular Photosensitizer System Based on Nano-Cu/ZIF-8 Capped with Water-Soluble Pillar[6]arene and Methylene Blue Host–Guest Complexations
by Chenhao Hu, Yueyuan Yu, Shuang Chao, Huidan Zhu, Yuxin Pei, Lan Chen and Zhichao Pei
Molecules 2021, 26(13), 3878; https://doi.org/10.3390/molecules26133878 - 25 Jun 2021
Cited by 13 | Viewed by 2544
Abstract
Photodynamic therapy (PDT) as a safe, non-invasive modality for cancer therapy, in which the low oxygen and high glutathione in the tumor microenvironment reduces therapeutic efficiency. In order to overcome these problems, we prepared a supramolecular photosensitive system of O2-Cu/ZIF-8@ZIF-8@WP6–MB (OCZWM), [...] Read more.
Photodynamic therapy (PDT) as a safe, non-invasive modality for cancer therapy, in which the low oxygen and high glutathione in the tumor microenvironment reduces therapeutic efficiency. In order to overcome these problems, we prepared a supramolecular photosensitive system of O2-Cu/ZIF-8@ZIF-8@WP6–MB (OCZWM), which was loaded with oxygen to increase the oxygen concentration in the tumor microenvironment, and the Cu2+ in the system reacted with glutathione (GSH) to reduce the GSH concentration to generate Cu+. It is worth noting that the generated Cu+ can produce the Fenton reaction, thus realizing the combination therapy of PDT and chemodynamic therapy (CDT) to achieve the purpose of significantly improving the anti-cancer efficiency. Full article
Show Figures

Figure 1

11 pages, 3176 KiB  
Article
A Stretchable Pillararene-Containing Supramolecular Polymeric Material with Self-Healing Property
by Meng Zhao, Changjun Li, Xiaotao Shan, Huijing Han, Qiuhua Zhao, Meiran Xie, Jianzhuang Chen and Xiaojuan Liao
Molecules 2021, 26(8), 2191; https://doi.org/10.3390/molecules26082191 - 10 Apr 2021
Cited by 7 | Viewed by 2239
Abstract
Constructing polymeric materials with stretchable and self-healing properties arise increasing interest in the field of tissue engineering, wearable electronics and soft actuators. Herein, a new type of supramolecular cross-linker was constructed through host-guest interaction between pillar[5]arene functionalized acrylate and pyridinium functionalized acrylate, which [...] Read more.
Constructing polymeric materials with stretchable and self-healing properties arise increasing interest in the field of tissue engineering, wearable electronics and soft actuators. Herein, a new type of supramolecular cross-linker was constructed through host-guest interaction between pillar[5]arene functionalized acrylate and pyridinium functionalized acrylate, which could form supramolecular polymeric material via photo-polymerization of n-butyl acrylate (BA). Such material exhibited excellent tensile properties, with maximum tensile strength of 3.4 MPa and strain of 3000%, respectively. Moreover, this material can effectively dissipate energy with the energy absorption efficiency of 93%, which could be applied in the field of energy absorbing materials. In addition, the material showed self-healing property after cut and responded to competitive guest. Full article
Show Figures

Figure 1

9 pages, 15173 KiB  
Communication
Recognition of Hydrophilic Cyclic Compounds by a Water-Soluble Cavitand
by Yun-Hui Wan, Yu-Jie Zhu, Julius Rebek, Jr. and Yang Yu
Molecules 2021, 26(7), 1922; https://doi.org/10.3390/molecules26071922 - 30 Mar 2021
Cited by 5 | Viewed by 2232
Abstract
A water-soluble deep cavitand bearing amides on the upper rim and trimethyl ammonium groups on the feet was synthesized. The open-ended cavity is stabilized by the intramolecular hydrogen bonds formed between the adjacent amides, and the introduction of trimethylammonium imparts to the cavitand [...] Read more.
A water-soluble deep cavitand bearing amides on the upper rim and trimethyl ammonium groups on the feet was synthesized. The open-ended cavity is stabilized by the intramolecular hydrogen bonds formed between the adjacent amides, and the introduction of trimethylammonium imparts to the cavitand good solubility in water. The cavitand exhibits high binding affinity and selectivity to hydrophilic molecules in water. With certain guests, such as cyclohexyl alcohols, amines and acids, the recognition involves the synergistic action of hydrogen bonding with hydrophobic effects. The binding phenomena are interpreted in terms of a fixed solvent cage presented by the host to the guest. Full article
Show Figures

Figure 1

14 pages, 4130 KiB  
Article
Construction of Supramolecular Polymers with Different Topologies by Orthogonal Self-Assembly of Cryptand–Paraquat Recognition and Metal Coordination
by Kai Wang, Yuan-Guang Shao, Feng-Zhi Yan, Zibin Zhang and Shijun Li
Molecules 2021, 26(4), 952; https://doi.org/10.3390/molecules26040952 - 11 Feb 2021
Cited by 3 | Viewed by 2053
Abstract
Recently, metal-coordinated orthogonal self-assembly has been used as a feasible and efficient method in the construction of polymeric materials, which can also provide supramolecular self-assembly complexes with different topologies. Herein, a cryptand with a rigid pyridyl group on the third arm derived from [...] Read more.
Recently, metal-coordinated orthogonal self-assembly has been used as a feasible and efficient method in the construction of polymeric materials, which can also provide supramolecular self-assembly complexes with different topologies. Herein, a cryptand with a rigid pyridyl group on the third arm derived from BMP32C10 was synthesized. Through coordination-driven self-assembly with a bidentate organoplatinum(II) acceptor or tetradentate Pd(BF4)2•4CH3CN, a di-cryptand complex and tetra-cryptand complex were prepared, respectively. Subsequently, through the addition of a di-paraquat guest, linear and cross-linked supramolecular polymers were constructed through orthogonal self-assembly, respectively. By comparing their proton nuclear magnetic resonance (1H NMR) and diffusion-ordered spectroscopy (DOSY) spectra, it was found that the degrees of polymerization were dependent not only on the concentrations of the monomers but also on the topologies of the supramolecular polymers. Full article
Show Figures

Figure 1

13 pages, 5875 KiB  
Communication
Supramolecular Assemblies of Dipyrrolyldiketone CuII Complexes
by Yohei Haketa and Hiromitsu Maeda
Molecules 2021, 26(4), 861; https://doi.org/10.3390/molecules26040861 - 06 Feb 2021
Cited by 3 | Viewed by 2075
Abstract
Dipyrrolyldiketones are essential building units of anion-responsive π-electronic molecules and ion-pairing assemblies. Here, we demonstrated that they form complexes with CuII characterized by planar geometries. The solid-state stacking assembled structures, as revealed by single-crystal X-ray analysis, were modulated by the substitution of [...] Read more.
Dipyrrolyldiketones are essential building units of anion-responsive π-electronic molecules and ion-pairing assemblies. Here, we demonstrated that they form complexes with CuII characterized by planar geometries. The solid-state stacking assembled structures, as revealed by single-crystal X-ray analysis, were modulated by the substitution of pyrrole units. The rectangular shapes of the CuII complexes resulted in the formation of mesophases upon introduction of aliphatic chains. Full article
Show Figures

Graphical abstract

11 pages, 3153 KiB  
Communication
Acid-Activated Motion Switching of DB24C8 between Two Discrete Platinum(II) Metallacycles
by Yi-Xiong Hu, Gui-Yuan Wu, Xu-Qing Wang, Guang-Qiang Yin, Chang-Wei Zhang, Xiaopeng Li, Lin Xu and Hai-Bo Yang
Molecules 2021, 26(3), 716; https://doi.org/10.3390/molecules26030716 - 30 Jan 2021
Cited by 1 | Viewed by 2158
Abstract
The precise operation of molecular motion for constructing complicated mechanically interlocked molecules has received considerable attention and is still an energetic field of supramolecular chemistry. Herein, we reported the construction of two tris[2]pseudorotaxanes metallacycles with acid–base controllable molecular motion through self-sorting strategy and [...] Read more.
The precise operation of molecular motion for constructing complicated mechanically interlocked molecules has received considerable attention and is still an energetic field of supramolecular chemistry. Herein, we reported the construction of two tris[2]pseudorotaxanes metallacycles with acid–base controllable molecular motion through self-sorting strategy and host–guest interaction. Firstly, two hexagonal Pt(II) metallacycles M1 and M2 decorated with different host–guest recognition sites have been constructed via coordination-driven self-assembly strategy. The binding of metallacycles M1 and M2 with dibenzo-24-crown-8 (DB24C8) to form tris[2]pseudorotaxanes complexes TPRM1 and TPRM2 have been investigated. Furthermore, by taking advantage of the strong binding affinity between the protonated metallacycle M2 and DB24C8, the addition of trifluoroacetic acid (TFA) as a stimulus successfully induces an acid-activated motion switching of DB24C8 between the discrete metallacycles M1 and M2. This research not only affords a highly efficient way to construct stimuli-responsive smart supramolecular systems but also offers prospects for precisely control multicomponent cooperative motion. Full article
Show Figures

Figure 1

11 pages, 3429 KiB  
Article
Synthesis of Chiral Helic[1]triptycene[3]arenes and Their Enantioselective Recognition towards Chiral Guests Containing Aminoindan Groups
by Jing Li, Ying Han and Chuan-Feng Chen
Molecules 2021, 26(3), 536; https://doi.org/10.3390/molecules26030536 - 20 Jan 2021
Cited by 7 | Viewed by 2394
Abstract
Starting from the enantiopure precursors, a pair of chiral macrocyclic arenes named helic[1]triptycene[3]arenes were conveniently synthesized. The circular dichroism (CD) spectra of the enantiomeric macrocyclic arenes exhibited mirror images, and the X-ray single crystal structures confirmed their absolute conformations as well. Moreover, the [...] Read more.
Starting from the enantiopure precursors, a pair of chiral macrocyclic arenes named helic[1]triptycene[3]arenes were conveniently synthesized. The circular dichroism (CD) spectra of the enantiomeric macrocyclic arenes exhibited mirror images, and the X-ray single crystal structures confirmed their absolute conformations as well. Moreover, the macrocyclic arenes showed strong complexation with secondary ammonium and primary ammonium salts containing aminoindan groups. In particular, the chiral macrocyclic arenes exhibited enantioselective recognition ability towards the chiral secondary ammonium salts containing aminoindan groups with an enantioselective ratio up to 3.89. Full article
Show Figures

Figure 1

10 pages, 1791 KiB  
Article
Fluorescence Enhancement by Calixarene Supramolecular Aggregate
by Xin-Yue Hu, Yu-Ying Wang, Hua-Bin Li and Dong-Sheng Guo
Molecules 2020, 25(24), 5912; https://doi.org/10.3390/molecules25245912 - 14 Dec 2020
Cited by 4 | Viewed by 2777
Abstract
We herein constructed supramolecular assemblies from guanidinocalixarenes and sulfonatocalixarenes by exploiting multiple salt bridge interactions. They encapsulate six different kinds of fluorescent dyes (both cationic and anionic), leading to a fluorescence enhancement that could not be achieved by either single calixarene. As such, [...] Read more.
We herein constructed supramolecular assemblies from guanidinocalixarenes and sulfonatocalixarenes by exploiting multiple salt bridge interactions. They encapsulate six different kinds of fluorescent dyes (both cationic and anionic), leading to a fluorescence enhancement that could not be achieved by either single calixarene. As such, this study advances the research on high-performance fluorophores. Full article
Show Figures

Graphical abstract

10 pages, 2466 KiB  
Article
Multiple Stimuli-Responsive Conformational Exchanges of Biphen[3]arene Macrocycle
by Yiliang Wang, Liu-Pan Yang, Xiang Zhao, Lei Cui, Jian Li, Xueshun Jia, Jianhui Fang and Chunju Li
Molecules 2020, 25(24), 5780; https://doi.org/10.3390/molecules25245780 - 08 Dec 2020
Viewed by 2290
Abstract
Conformational exchanges of synthetic macrocyclic acceptors are rather fast, which is rarely studied in the absence of guests. Here, we report multiple stimuli-responsive conformational exchanges between two preexisting conformations of 2,2′,4,4′-tetramethoxyl biphen[3]arene (MeBP3) macrocycle. Structures of these two conformations are both observed in [...] Read more.
Conformational exchanges of synthetic macrocyclic acceptors are rather fast, which is rarely studied in the absence of guests. Here, we report multiple stimuli-responsive conformational exchanges between two preexisting conformations of 2,2′,4,4′-tetramethoxyl biphen[3]arene (MeBP3) macrocycle. Structures of these two conformations are both observed in solid state, and characterized by 1H NMR, 13C NMR and 2D NMR in solution. In particular, conformational exchanges can respond to solvents, temperatures, guest binding and acid/base addition. The current system may have a role to play in the construction of molecular switches and other stimuli-responsive systems. Full article
Show Figures

Graphical abstract

Review

Jump to: Research

44 pages, 14475 KiB  
Review
Thiol- and Disulfide-Based Stimulus-Responsive Soft Materials and Self-Assembling Systems
by Danielle M. Beaupre and Richard G. Weiss
Molecules 2021, 26(11), 3332; https://doi.org/10.3390/molecules26113332 - 01 Jun 2021
Cited by 29 | Viewed by 8672
Abstract
Properties and applications of synthetic thiol- and disulfide-based materials, principally polymers, are reviewed. Emphasis is placed on soft and self-assembling materials in which interconversion of the thiol and disulfide groups initiates stimulus-responses and/or self-healing for biomedical and non-biomedical applications. Full article
Show Figures

Figure 1

13 pages, 5084 KiB  
Review
Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials
by Shengda Liu, Jiayun Xu, Xiumei Li, Tengfei Yan, Shuangjiang Yu, Hongcheng Sun and Junqiu Liu
Molecules 2021, 26(11), 3310; https://doi.org/10.3390/molecules26113310 - 31 May 2021
Cited by 9 | Viewed by 3956
Abstract
In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or [...] Read more.
In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or preorganization in order to construct a specific structure before, and then the subsequent removal of previous templates to form a desired structure, on account of the lack of “self-error-correcting” properties of reversible interactions in polymers. The above processes are time-consuming and tedious. A template-free, self-assembled strategy as a “bottom-up” route to fabricate well-defined nano/microstructures remains a challenge. Herein, we introduce the recent progress in template-free, self-assembled nano/microstructures formed by covalent two-dimensional (2D) polymers, such as polymer capsules, polymer films, polymer tubes and polymer rings. Full article
Show Figures

Figure 1

15 pages, 11548 KiB  
Review
“Texas-Sized” Molecular Boxes: From Chemistry to Applications
by Xiaodong Chi, Jinya Tian, Dan Luo, Han-Yuan Gong, Feihe Huang and Jonathan L. Sessler
Molecules 2021, 26(9), 2426; https://doi.org/10.3390/molecules26092426 - 21 Apr 2021
Cited by 13 | Viewed by 2866
Abstract
The design and synthesis of novel macrocyclic host molecules continues to attract attention because such species play important roles in supramolecular chemistry. However, the discovery of new classes of macrocycles presents a considerable challenge due to the need to embody by design effective [...] Read more.
The design and synthesis of novel macrocyclic host molecules continues to attract attention because such species play important roles in supramolecular chemistry. However, the discovery of new classes of macrocycles presents a considerable challenge due to the need to embody by design effective molecular recognition features, as well as ideally the development of synthetic routes that permit further functionalization. In 2010, we reported a new class of macrocyclic hosts: a set of tetracationic imidazolium macrocycles, which we termed “Texas-sized” molecular boxes (TxSBs) in homage to Stoddart’s classic “blue box” (CBPQT4+). Compared with the rigid blue box, the first generation TxSB displayed considerably greater conformational flexibility and a relatively large central cavity, making it a good host for a variety of electron-rich guests. In this review, we provide a comprehensive summary of TxSB chemistry, detailing our recent progress in the area of anion-responsive supramolecular self-assembly and applications of the underlying chemistry to water purification, information storage, and controlled drug release. Our objective is to provide not only a review of the fundamental findings, but also to outline future research directions where TxSBs and their constructs may have a role to play. Full article
Show Figures

Graphical abstract

Back to TopTop