Formation Of Supramolecular Polymers Research Articles

Strong thickening performance and mechanism of supramolecular system constructed by β-cyclodextrin polymer included adamantane polymer

Introducing supramolecular interactions into polymer systems to improve their properties has recently become a hot topic. However, the formation of supramolecular polymers through host–guest interactions using two types of polymers is rarely reported. In this paper, a novel supramolecular system (ABMN) is prepared by host–guest inclusion of β-cyclodextrin polymer (PAAB) and adamantane polymer (PAMN). Subsequently, the thickening ability and viscoelasticity of ABMN are investigated. The microstructure of ABMN is studied by dynamic light scattering (DLS), atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM). The results show that at the molar ratio of PAAB: PAMN = 1:1 the optimal inclusion is observed with the binding constant between β-cyclodextrin group and adamantane group of 575.33 L/mol. The thickening ability of ABMN is greatly improved when compared to the original polymers. At 90℃ and 32868 mg/L, the viscosity of the ABMN system at 2000 mg/L can reach 38.5 mPa s. The microstructure results evidence that a larger hydrodynamic radius and denser spatial network structures in the ABMN system are formed through the host–guest inclusion interactions. Therefore, the supramolecular system exhibits strong thickening properties and demonstrates exceptional resistance to both temperature and salt, rendering it an optimal candidate for employment in EOR in high-temperature and high-salinity reservoirs.

AIE interfacial supramolecular polymers

High monomer concentration is a requisite for engendering the aggregation-induced emssion (AIE) phenomenon as well as the formation of supramolecular polymers. Therefore, this is supposed to ensure the generation of AIE supramolecular polymers, wherein the monomer soluability takes effect. Nevertheless, parts of supramolecular monomers are considered as poessessing different soluability towards the same sovlent, through which the polymerzation process is thus hard to proceed. Interfacial polymerzation gets over the soluabilty restriction, providing a facile method for propelling the reaction of thesemonomers. Herein, we had prepared M1 containing tetraphenylethene (TPE) functionalized with two terpyridine derivatives, then making M1 dissolving in CHCl3 to give solutions. Cu2+ solutions were fabricated through dissolving CuCl2 into H2O. Towards mixing those solutions, AIE interfacial supramolecular polymers (AIEISPs) displaying green fluorescence were generated at the interface of two phases on the basis of metal-coordination between terpyridine and Cu2+. These AIEISPs were certificated to possess the stimuli-responsiveness, for which the excessive addition of tetrabutylammonium hydroxide would cause the structure destruction owing to the stronger bonding ability with Cu2+ than that of terpyridine. These fabricated AIEISPs had provided a new avenue to prepare AIE supramolecular polymers.

Stimuli-Responsive Designer Supramolecular Polymer Gel

This paper reports a stimuli-responsive designer supramolecular polymer gel in dimethylsulphoxide (DMSO)/water (1:2) based on a dipeptide amphiphile and β-cyclodextrin (β-CD) The dipeptide amphiphile contains caproic acid at the N terminus and methyl ester at the C terminus. From X-ray single crystal diffraction, the amphiphile adopts a kink-like conformation. The amphiphile self-assembled to form a parallel sheet-like structure stabilized by multiple intermolecular hydrogen bonds. Moreover, the parallel sheet-like structure is also stabilized by edge-to-edge π–π stacking interactions. In higher-order packing, it forms a corrugated sheet-like structure stabilized by hydrophobic interactions. The dipeptide amphiphile interacts with β-cyclodextrin and forms gel through supramolecular polymer formation in (DMSO)/water (1:2) by a simple heating-cooling cycle. The sol-to-gel transformation is because of a host–guest complex between compound 1 and β-CD and the formation of supramolecular polymer accompanied by microstructure changes from nanofibers to microrods. The gel is temperature responsive with a Tgel of 70 °C. The supramolecular polymer gel is also responsive to stimuli such aspicric acid and HCl. The extensive spectroscopic studies show that the aromatic hydrophobic side chain of compound 1 forms a host–guest complex with β-CD. These results will be helpful for the design of advanced programable eco-friendly functional materials.

High-efficiency gold recovery by additive-induced supramolecular polymerization of β-cyclodextrin

Developing an eco-friendly, efficient, and highly selective gold-recovery technology is urgently needed in order to maintain sustainable environments and improve the utilization of resources. Here we report an additive-induced gold recovery paradigm based on precisely controlling the reciprocal transformation and instantaneous assembly of the second-sphere coordinated adducts formed between β-cyclodextrin and tetrabromoaurate anions. The additives initiate a rapid assembly process by co-occupying the binding cavity of β-cyclodextrin along with the tetrabromoaurate anions, leading to the formation of supramolecular polymers that precipitate from aqueous solutions as cocrystals. The efficiency of gold recovery reaches 99.8% when dibutyl carbitol is deployed as the additive. This cocrystallization is highly selective for square-planar tetrabromoaurate anions. In a laboratory-scale gold-recovery protocol, over 94% of gold in electronic waste was recovered at gold concentrations as low as 9.3 ppm. This simple protocol constitutes a promising paradigm for the sustainable recovery of gold, featuring reduced energy consumption, low cost inputs, and the avoidance of environmental pollution.

Aggregation‐induced emission polymer systems with circularly polarized luminescence

AbstractFunctional materials with circularly polarized luminescence (CPL) have attracted tremendous attention due to their promising applications in three‐dimensional displays, chiral recognition and catalysis, photoelectronic devices, contrast imaging, information encryption, and other fields. Among various CPL‐active materials, polymeric systems with aggregation‐induced emission (AIE) have emerged as excellent candidates because of their efficient aggregate‐state fluorescence, large solid‐state dissymmetry factor, excellent processibility, diversified self‐assembly behaviors, and readily switchable CPL properties. This review summarizes and discusses the recent progress as well as future perspective of diverse AIE polymer systems with CPL, including CPL‐active covalent AIE polymers, CPL‐active supramolecular AIE polymers, and AIEgen/polymer composites with CPL. According to the location or introduction method of AIEgen in polymer structures, this review further divides CPL‐active covalent AIE polymers into three categories, including polymers with AIEgen in main chains, polymers with AIEgen in side chains, and CPL‐active polymers with clusterization‐triggered emission. CPL‐active supramolecular AIE polymers are discussed based on the driving force for the formation of supramolecular polymers, including host–guest interactions, metal coordination, and other non‐covalent interactions. Moreover, examples on the construction of CPL‐active AIEgen/polymer composites by physically mixing AIEgens with chiral (supra)polymers are also presented. This review is anticipated to provide readers with an overall view on the design strategies of CPL‐active AIE polymers, and facilitate further research on the development of CPL materials and AIE polymers with advanced applications.

Solvent-dependent self-assembly of N-annulated perylene diimides. From dimers to supramolecular polymers.

The synthesis and self-assembling features of the N-annulated perylene diimide (NPBI) 1 in different solvents are reported. Compound 1 possesses two chiral linkers, derived from (S)-(+)-alaninol, that connect the central aromatic NPBI segment and the peripheral trialkoxybenzamide units. The Ala-based linker has been demonstrated to strongly favor the formation of intramolecularly H-bonded seven-membered pseudocycles. NPBI 1 shows a strong tendency to self-assemble even in a good solvent like CHCl3 and the formation of chiral dimers is detected in this good solvent. Both experimental techniques and theoretical calculations reveal that the intramolecular H-bonded pseudocycles are very robust and the formation of chiral dimers is driven by the π-stacking of two units of the NPBI core. Unexpectedly, an efficient transfer of the asymmetry of the point chirality at the linker to the aromatic moiety is observed in the molecularly dissolved state. Changing the solvent to more apolar methylcyclohexane modifies the self-assembly process and the formation of chiral supramolecular polymers is detected. The supramolecular polymerization of 1 is demonstrated to follow an isodesmic mechanism unlike previous referable systems. In the formation of the supramolecular polymers of 1, the combination of experimental and computational data indicates that the H-bonded pseudocycles are also present in the aggregated state and the rope-like, columnar aggregates formed by the self-assembly of 1 rely on the π-stacking of the NPBI backbones.

Introduction of Ferrocene as a Facilitator for the Construction of Supramolecular Polymers.

Proper monomer design is the key to enhancing the strength of noncovalent interactions between the molecules toward the efficient formation of supramolecular polymers (SPs). We have designed and synthesized 1,n'-disubstituted ferrocene-azobenzene-long alkyl chains, Fc(CONH-Azo-TDP)2 , to afford SPs with a high probability. The design exploits the ''molecular ball-bearing'' property of the ferrocene core, which allows two azobenzene arms to rotate in the planes of cyclopentadienyl rings, generating the most suitable molecular conformation required for SP formation. This ferrocene monomer formed a supergel consisting of SPs supported by strong intermolecular (H-bonding and π-π stacking) interactions and higher enthalpy gain than the reference molecules, where the central ferrocene core was replaced by flexible aliphatic as well as rigid benzene linkers. The molecular conformation involved in SPs, the strength of noncovalent interactions, and the process of supramolecular polymerization were investigated through NMR, UV-Vis, XRD and TEM studies. The results demonstrate that ferrocene may act as a good modulator for constructing efficient SPs.

Exploiting Hydrogen Bonding to Direct Supramolecular Polymerization at the Air/Water Interface

AbstractFluid interfaces provide an advanced platform for directed self‐assembly of organic composites and formation of supramolecular polymers (SPs). Intermolecular interactions govern the supramolecular polymerization processes, with hydrogen bonding (H‐bonding) as a key interaction in supramolecular chemistry and biology. Two purposefully designed supra‐amphiphiles for assessing the role of H‐bonding were designed and their supramolecular polymerization (SP) at the air/water interface was compared. H‐bonding was confirmed by in situ experimental and computational techniques as the required intermolecular interaction for attaining SPs with well‐defined molecular arrangement. Control of H‐bonding as opposite to traditionally considered interactions (e. g., π‐π stacking) is proposed as a successful strategy for SP at fluid interfaces.

Dual liquid Crystalline/Gel behavior with AIE effect promoted by Self-assembly of pyrazole dendrons

This work describes the rich self-assembly behavior obtained by grafting a pyrazole-derived platform at the focal point of poly(benzyl ether) dendrons. Liquid crystals and supergels made out of fibers are obtained by supramolecular organization of non-discoid entities, and they notably increment the photoluminescence in these aggregated states (Aggregation-Induced Emission, AIE). The novel focal point, which is derived from 3,5-dimethyl-4-phenyl-1H-pyrazole, shows great tendency to arrange both wedge-shaped or cone-shaped dendrons in columnar arrangements by the formation of supramolecular polymers by hydrogen-bonding following the cylinder model. Two different linkers, amide or ether groups, connecting with the pyrazole-based apex are investigated, obtaining similar mesomorphic behavior, but different luminescent properties. A combined study of NMR, IR and X-ray diffraction allows establishing analogies between the fiber mesoscopic organization and the columnar organization in the liquid crystalline phase.

Direct Participation of Solvent Molecules in the Formation of Supramolecular Polymers.

This article reports supramolecular polymerization of two bis-amide functionalized naphthalene-diimide (NDI) building blocks (NDI-L and NDI-C) in two solvents, namely n-heptane (Hep) and methylcyclohexane (MCH). NDI-L and NDI-C differ only by the peripheral hydrocarbon wedges, consisting of linear C7 chains or cyclic methylcyclohexane rings, respectively. UV/Vis and FTIR spectroscopy studies reveal distinct internal order and H-bonding pattern for NDI-L and NDI-C aggregates irrespective of the solvent system, indicating the dominant role of the intrinsic packing parameters of the individual building block, possibly influenced by the peripheral steric crowding. However, NDI-L produces a significantly stronger gel in Hep compared to MCH as evident from the rheological and thermal properties. In contrast, NDI-C exhibits a clear preference for MCH, producing gel with moderate strength but in Hep it fails to produce 1D morphology or gelation. All-atom molecular dynamics (MD) simulation studies corroborate with the experimental observation and provide the rationale for the observed solvent-shape effect by revealing a quantitative estimate regarding the thermodynamics of self-assembly in these four combinations. Such clear-cut shape-matching effect (between the peripheral hydrocarbon wedge and the solvent system) unambiguously support a direct participation of the solvent molecules during supramolecular polymerization and presence of a closely-adhered solvent shell around the supramolecular polymers, similar to the first layer of water molecules around the protein surface. Solvent induced CD experiments support this hypothesis as induced CD band was observed only from a chiral co-solvent of matching shape. This is reconfirmed by the higher de-solvation temperature of the shape-matching NDI/solvent system combination compared to the shape mis-match combination in variable temperature UV/Vis experiments, revealing transformation to a different aggregate at higher temperatures rather than disassembly to the monomer for all four combinations.

Supramolecular polymers based on host-guest interactions for the construction of artificial light-harvesting systems

In the present work, artificial light-harvesting systems with a fluorescence resonance energy transfer (FRET) process were successfully obtained in the aqueous solution. We designed and synthesized an amphiphilic pyrene derivative with two 4-vinylpyridium arms (Pmvb), which can interact with cucurbit[8]uril (CB[8]) to form supramolecular polymer through host-guest interactions in aqueous solution. The formation of supramolecular polymers results in a significant enhancement of fluorescence, which makes Pmvb-CB[8] an ideal energy donor to construct artificial light-harvesting systems in the aqueous solution. Subsequently, two different fluorescence dyes Rhodamine B (RhB) and Sulforhodamine 101 (SR101) were introduced as energy acceptors into the solution of Pmvb-CB[8] respectively, to fabricate two different artificial light-harvesting systems. The obtained artificial light-harvesting systems can achieve an efficient energy transfer process from Pmvb-CB[8] to RhB or SR101 with high energy transfer efficiency.

Metal-Ligand Interactions and Oligo(p-phenylene vinylene) Derivatives Based Supramolecular Polymer Possessing Variable Fluorescence Colors.

Fluorescent supramolecular polymers combine the benefits of supramolecular polymers in terms of dynamic nature with the optoelectronic features of incorporated fluorophores. However, the majority of fluorescent supramolecular polymers can only exhibit a single fluorescent state, restricting their applications. Incorporating J-type dyes into supramolecular monomers is expected to impart supramolecular polymers with variable fluorescence colors, because the aggregation mode of J-type dyes is closely related to the formation of supramolecular polymers. Herein, the authors report a supramolecular polymer [M1·Zn(OTf)2 ]n , in which the monomer M1 contains a J-type dye, oligo(p-phenylene vinylene) derivative, and two terpyridine ends. The M1 + Zn(OTf)2 solutions exhibit fluorescence color changes varying from cyan to yellow-green in the monomer concentration ranging from 0.04 to 1.00mm. Moreover, based on the outputs from laser scanning confocal microscopy, the fluorescence color transition during the formation of supramolecular polymers is intuitively proven. Additionally, considering the close relationship between the supramolecular polymer structure and the fluorescence color, the fluorescence color can be regulated by introducing tetraethylammonium hydroxide that can bind with Zn2+ competitively to break up the structure of the supramolecular polymer.

Supramolecular Polymerization Powered by Escherichia coli : Fabricating a Near-Infrared Photothermal Antibacterial Agent in Situ

Supramolecular Polymerization Powered by <i>Escherichia coli</i> : Fabricating a Near-Infrared Photothermal Antibacterial Agent in Situ

Spontaneous chiral self-assembly of CdSe@CdS nanorods

Spontaneous chiral self-assembly of CdSe@CdS nanorods

Control of self-assembly pathways toward conglomerate and racemic supramolecular polymers

Homo- and heterochiral aggregation during crystallization of organic molecules has significance both for fundamental questions related to the origin of life as well as for the separation of homochiral compounds from their racemates in industrial processes. Herein, we analyse these phenomena at the lowest level of hierarchy – that is the self-assembly of a racemic mixture of (R,R)- and (S,S)-PBI into 1D supramolecular polymers. By a combination of UV/vis and NMR spectroscopy as well as atomic force microscopy, we demonstrate that homochiral aggregation of the racemic mixture leads to the formation of two types of supramolecular conglomerates under kinetic control, while under thermodynamic control heterochiral aggregation is preferred, affording a racemic supramolecular polymer. FT-IR spectroscopy and quantum-chemical calculations reveal unique packing arrangements and hydrogen-bonding patterns within these supramolecular polymers. Time-, concentration- and temperature-dependent UV/vis experiments provide further insights into the kinetic and thermodynamic control of the conglomerate and racemic supramolecular polymer formation.

Formation of Supramolecular Polymers from Porphyrin Tripods

A porphyrin tripod (PZnT) composed of three zinc porphyrin wings connected via triazole bridges was prepared as a monomeric building block for a supramolecular polymer. PZnT formed long fibrous sup...

Supramolecular Polymeric Radicals: Highly Promoted Formation and Stabilization of Naphthalenediimide Radical Anions.

The supramolecular polymeric radicals are developed to promote the generation efficiency and stability of naphthalenediimide (NDI) radical anions. To this end, a water-soluble bifunctional monomer bearing two naphthalene-viologen end groups and a NDI center is designed and synthesized. The supramolecular polymeric NDI radical anions are fabricated on the basis of host-guest complexation between the NDI-containing bifunctional monomer and cucurbit[8]uril (CB[8]) and followed by the photoinduced electron transfer process under UV light irradiation. The electrostatic effect of CB[8] and the bulky and rigid structure of supramolecular polymer are combined to stabilize the excited state of NDIs and NDI radical anions, contributing to the high enhancement of the formation of NDI radical anions with excellent stability. It is found that the highest occupied molecular orbital energy and lowest unoccupied molecular orbital energy of NDI are also lowered by the formation of supramolecular polymer. In addition, the supramolecular polymeric NDI radical anions could be utilized as a supramolecular photoreducing agent to reduce cytochrome C with a higher efficiency. It is anticipated that other radicals can also be stabilized through this strategy, and this line of research may lead to the development of novel polymeric radical materials.

Guest induced morphology transitions of star shaped pillar[5]arene trimer via endo host-guest and “exo-wall” electron-transfer interactions

Star shape bridged pillar[5]arene trimer (C3-PLT) based on benzene-1,3,5-tricarboxamide (BTAs) was successfully synthesized, which exhibited outstanding guest responsive morphology transition properties. The morphology tuning studies was efficiently achieved with the addition of competitive guest molecules G1 and G2 by various self-assembly mechanisms. C3-PLT itself displays nanofiber morphology through H-type π-π stacking, and this nanofiber morphology can be completely transformed into spherical vesicles by host-guest interaction G1, while upon addition of G2 into C3-PLT by means of “exo-wall” electron-transfer interactions, sheet superstructures can be observed. SEM, 1H NMR, DOSY, fluorescence spectroscopy, and viscosity have verified the formation of supramolecular polymers and morphological transitions between C3-PLT with both guests.

Synthesis and characterization of a hydrogen bonded metal-organic cocrystal: Exploration of its DNA binding study

A metal-organic cocrystal, [Co(2-quin)2(3-ata)2]·[Co(2-quin)2(H2O)2] (1) (H-2-quin = 2-quinalidic acid and 3-ata = 3-amino-1,2,4-triazole), has been synthesized and characterized by elemental analysis as well as the single-crystal X-ray diffraction (SCXRD) technique. Compound 1 crystallizes in the triclinic space group Pī and shows significant hydrogen bonding interactions, leading to the formation of supramolecular polymers. Hirshfeld surfaces analysis has been performed to investigate the non-covalent interactions in the crystal packing. The cocrystal shows a good in vitro binding propensity with ctDNA, which was reflected by its high binding constant (Kb) value of 2412 M−1. A docking study has also been carried out to corroborate the experimental findings.

Concurring Chalcogen- and Halogen-Bonding Interactions in Supramolecular Polymers for Crystal Engineering Applications.

The engineering of crystalline molecular solids through the simultaneous combination of distinctive non-covalent interactions is an important field of research, as it could allow chemist to prepare materials depicting multi-responsive properties. It is in this context that, pushed by a will to expand the chemical space of chalcogen-bonding interactions, a concept is put forward for which chalcogen- and halogen-bonding interactions can be used simultaneously to engineer multicomponent co-crystals. Through the rational design of crystallizable molecules, chalcogenazolo pyridine scaffold (CGP) modules were prepared that, bearing either a halogen-bond acceptor or donor at the 2-position, can interact with suitable complementary molecular modules undergoing formation of supramolecular polymers at the solid state. The recognition reliability of the CGP moiety to form chalcogen-bonded dimers allows the formation of heteromolecular supramolecular polymers through halogen-bonding interactions, as confirmed by single-crystal X-ray diffraction analysis.