Fluorescent supramolecular polymers of barbiturate dyes with thiophene-cored twisted π-systems

Kawaura, Maika; Aizawa, Takumi; Takahashi, Sho; Miyasaka, Hiroshi; Sotome, Hikaru; Yagai, Shiki

doi:10.1039/d1sc06246h

Cited by 17 publications

(9 citation statements)

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“…To validate our interpretations, we also conducted a time-resolved fluorescence analysis by observing their anisotropy change. While DSS is primarily sensitive to energy relaxation, fluorescence anisotropy can detect changes in the orientation of the transition dipole moment. ,,, Our curved supramolecular polymers, which form through the helical stacking of rosettes with six π-conjugated arms, inherently feature a rotated orientation of the π-conjugated chromophores relative to the adjacent chromophore. This arrangement implies that sequential exciton transfer across chromophores should be accompanied by rotation of the transition dipole moment during exciton diffusion (Figure h).…”

Section: Resultsmentioning

confidence: 99%

Impact of Ring-Closing on the Photophysical Properties of One-Dimensional π-Conjugated Molecular Aggregate

Takahashi,

Matsumoto,

Hollamby

et al. 2024

J. Am. Chem. Soc.

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The self-assembled state of molecules plays a pivotal role in determining how inherent molecular properties transform and give rise to supramolecular functionalities and has long attracted attention. However, understanding the influence of morphologies spanning the nano-to mesoscopic scales of supramolecular assemblies derived from identical intermolecular interactions has been notoriously challenging due to dynamic structural change and monomer exchange of assemblies in solution.In this study, we demonstrate that curved one-dimensional molecular assemblies (supramolecular polymers) of lengths of around 70−200 nm, originating from the same luminescent molecule, exhibit distinct photoluminescent properties when they form closed circular structures (toroids) versus when they possess chain termini in solution (random coils). By exploiting the difference in kinetic stability between the toroids and random coils, we developed a dialysis protocol to selectively purify the former. It was revealed that these terminus-free closed structures manifest higher energy and more efficient luminescence compared with their mixed state with random coils. Time-resolved fluorescence measurements unveiled that random coils, due to their dynamic structural fluctuation in solution, generate local defects throughout the main chain, leading to luminescence from lower energy levels. In mixtures of the two assemblies, luminescence was exclusively observed from such a lower energy level of random coils, a result attributed to energy transfer between the assemblies. This work emphasizes that for identical supramolecular assemblies, only averaged properties have traditionally been considered, but their structures at the nano-to mesoscopic scale are important especially if they have a certain degree of shape persistency even in solution.

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Section: Resultsmentioning

confidence: 99%

Impact of Ring-Closing on the Photophysical Properties of One-Dimensional π-Conjugated Molecular Aggregate

Takahashi,

Matsumoto,

Hollamby

et al. 2024

J. Am. Chem. Soc.

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“…As the solutions are cooled from a high temperature, the monomers start to associate via hydrogen bonding to form diverse supramolecular motifs including cyclic and open-ended oligomers. Among these, the concentration of six-membered cyclic oligomers (“rosettes”), which are discrete rather than open-ended hydrogen-bonded motifs, , is high, and therefore they stack via π–π interactions to form the “nuclei” of supramolecular polymers. Hence, the stacking property of rosettes is the key to the supramolecular polymerization of the bar-π-wedge molecules …”

Section: General Propertiesmentioning

confidence: 99%

Nanoengineering of Curved Supramolecular Polymers: Toward Single-Chain Mesoscale Materials

2022

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Metrics & MoreArticle Recommendations CONSPECTUS: Recently, supramolecular polymers (SPs), which depend on the formation of reversible bonds between monomers, have attracted attention as a class of materials that can overcome the potential environmental problems of conventional polymeric materials. The development of various supramolecular polymers is important not only for their direct application as materials but also because their unique polymerization processes and dynamic properties have a profound influence on the development of polymeric and small-molecule-based functional materials. In other words, by limiting the dimensionality of molecular assemblies to one dimension, we can discover the essential aspects of selfassembly and self-organization. In particular, supramolecular polymerization, in which π-electron-rich planar molecules are stacked one-dimensionally via multiple interactions, is interesting because it gives "π-stacked SPs" with one-dimensional crystal-like order. The excellent intrinsic (internal) structural order of π-stacked SPs is difficult to observe in higher-order structures that exhibit only a monotonous linear structure. However, our research has shown that when internal structural order intrinsically generates curvature, the curvature appears as a major feature of the entire polymer chain. This intrinsic curvature allows the formation of diverse topologies such as toroids, random coils, waves, spirals, and helicoids using π-stacked SPs and also allows structural changes at the single-polymer-chain level along a topology-dependent energy landscape. In other words, π-stacked SP-based nanomaterials could enable free control of the structure at the single-polymer-chain level. This Account will focus on our research into curved supramolecular polymers (CSPs) during the last five years. CSPs are formed by the hydrogen bonding between barbituratecontaining π-conjugated molecules to produce giant supramolecular monomers. We first give an overview of the molecular design of the monomers required for the formation of CSPs, the unique energy landscape of CSPs, and their evaluation and analysis methods, before describing the four specific properties of CSPs. The first is structural controllability via the introduction of photoresponsive units such as azobenzene and diarylethene moieties. The isomerization of these photochromic molecules within the CSP main chain has a local effect on the curvature and allows photocontrol of their entire topology. The second is the copolymerization of different molecules via the formation of rosettes. Here, two extreme examples, block and alternating copolymerization, are discussed. Third, we describe a structural transition that involves the rearrangement of hydrogen bonds. This is a new property, which enables a structural transition from a soft and highly soluble supramolecular polymer to a hard and poorly soluble crystalline structure and thus expands the applicability of CSPs to environmentally important and electronic materials. Finally, self-assembled polyc...

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“…A wide variety of donor and acceptor units, as well as π-conjugated spacers, have been combined during the last decades for the construction of push-pull molecules. In this context, the pseudoaromatic 2-thioxodihydropyrimidine-4,6(1H,5H)-dione ring of thiobarbituric acid and its N-alkylated derivatives has been extensively employed as an electron-withdrawing moiety in push-pull chromophores [6][7][8][9]. Representative examples are dyes 3a,b, recently described by Dumur and co-workers, featuring p-methoxyphenyl and p-dimethylaminophenyl donor groups connected to the barbituric acid skeleton through a 1,3-butadiene chain spacer (Scheme 1), which showed a marked solvatochromic Citation: Francos, J.; Cadierno, V. A wide variety of donor and acceptor units, as well as π-conjugated spacers, have been combined during the last decades for the construction of push-pull molecules.…”

Section: Introductionmentioning

confidence: 99%

“…Representative examples are dyes 3a,b, recently described by Dumur and co-workers, featuring p-methoxyphenyl and p-dimethylaminophenyl donor groups connected to the barbituric acid skeleton through a 1,3-butadiene chain spacer (Scheme 1), which showed a marked solvatochromic Citation: Francos, J.; Cadierno, V. A wide variety of donor and acceptor units, as well as π-conjugated spacers, have been combined during the last decades for the construction of push-pull molecules. In this context, the pseudoaromatic 2-thioxodihydropyrimidine-4,6(1H,5H)-dione ring of thiobarbituric acid and its N-alkylated derivatives has been extensively employed as an electronwithdrawing moiety in push-pull chromophores [6][7][8][9]. Representative examples are dyes 3a,b, recently described by Dumur and co-workers, featuring p-methoxyphenyl and pdimethylaminophenyl donor groups connected to the barbituric acid skeleton through a 1,3-butadiene chain spacer (Scheme 1), which showed a marked solvatochromic behavior in solution [10,11].…”

Section: Introductionmentioning

confidence: 99%

One-Pot Synthesis of Push–Pull Butadienes from 1,3-Diethyl-2-thiobarbituric Acid and Propargylic Alcohols

Francos

Cadierno

2022

Molbank

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A new synthetic procedure for obtaining two previously reported donor-acceptor butadiene dyes, namely 5-(3,3-bis(4-methoxyphenyl)allylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione and 5-(3,3-bis(4-(dimethylamino)phenyl)allylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, based on the InCl3-catalyzed coupling 1,3-diethyl-2-thiobarbituric acid with 1,1-bis(4-methoxyphenyl)prop-2-yn-1-ol and 1,1-bis(4-(dimethylamino)phenyl)prop-2-yn-1-ol, respectively, is presented. The reactions, which cleanly proceed in water under MW irradiation, involve the initial generation of the corresponding enals by Meyer-Schuster rearrangement of the alkynols and their subsequent Knoevenagel condensation with the 2-thiobarbituric acid derivative. By following the same approach, the novel butadiene 5-(3,3-bi([1,1′-biphenyl]-4-yl)allylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, which was characterized by 1H and 13C{1H} NMR, IR, UV-Vis, elemental analysis and HRMS, was synthesized in 79% yield.

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Fluorescent supramolecular polymers of barbiturate dyes with thiophene-cored twisted π-systems

Abstract: Because supramolecular polymerization of emissive p-conjugated molecules depends strongly on p–pstacking interaction, the formation of well-defined one-dimensional nanostructures often results in decrease or only small increase of emission efficiency. This is also true...

Cited by 17 publications

References 71 publications

Impact of Ring-Closing on the Photophysical Properties of One-Dimensional π-Conjugated Molecular Aggregate

Impact of Ring-Closing on the Photophysical Properties of One-Dimensional π-Conjugated Molecular Aggregate

Nanoengineering of Curved Supramolecular Polymers: Toward Single-Chain Mesoscale Materials

One-Pot Synthesis of Push–Pull Butadienes from 1,3-Diethyl-2-thiobarbituric Acid and Propargylic Alcohols

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