Construction of Helically Stacked π‐Electron Systems in Poly(quinolylene‐2,3‐methylene) Stabilized by Intramolecular Hydrogen Bonds

Kataoka, Yuki; Kanbayashi, Naoya; Fujii, Naoka; Okamura, Taka‐aki; Haino, Takeharu; Onitsuka, Kiyotaka

doi:10.1002/anie.202002734

Cited by 17 publications

(16 citation statements)

References 49 publications

(14 reference statements)

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“…This simplification does not necessarily imply poor accuracy: good to excellent agreement between calculated and experimental aggregate ECD spectra may be observed (Figure ), which is a necessary condition to make these full-QM approaches useful for a wide scope. Possible applications are multiple: accurate determination of helical handedness, including validation of exciton-based qualitative approaches; − structural assessments by employing multiple geometries, obtained by systematic variations or MD sampling; ,− interpretation of aggregate ECD spectra, for example, disentangling intrachain vs interchain mechanisms ,, or monomer chirality vs supramolecular chirality; role of short-range vs long-range couplings; , visualization of electron–hole pair densities . Furthermore, full QM calculations of vibronic spectra are feasible with the inclusion of multiple vibrational modes. ,, Finally, and very importantly, the effect of environment may be modeled accurately …”

Section: Chiroptical Spectroscopies: Survey and Basic Conceptsmentioning

confidence: 99%

Chiroptical Properties in Thin Films of π-Conjugated Systems

2020

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Chiral π-conjugated molecules provide new materials with outstanding features for current and perspective applications, especially in the field of optoelectronic devices. In thin films, processes such as charge conduction, light absorption, and emission are governed not only by the structure of the individual molecules but also by their supramolecular structures and intermolecular interactions to a large extent. Electronic circular dichroism, ECD, and its emission counterpart, circularly polarized luminescence, CPL, provide tools for studying aggregated states and the key properties to be sought for designing innovative devices. In this review, we shall present a comprehensive coverage of chiroptical properties measured on thin films of organic π-conjugated molecules. In the first part, we shall discuss some general concepts of ECD, CPL, and other chiroptical spectroscopies, with a focus on their applications to thin film samples. In the following, we will overview the existing literature on chiral π-conjugated systems whose thin films have been characterized by ECD and/or CPL, as well other chiroptical spectroscopies. Special emphasis will be put on systems with large dissymmetry factors (g abs and g lum) and on the application of ECD and CPL to derive structural information on aggregated states.

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Section: Chiroptical Spectroscopies: Survey and Basic Conceptsmentioning

confidence: 99%

Chiroptical Properties in Thin Films of π-Conjugated Systems

2020

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“…Similar to supramolecular polymers, noncovalent interactions among π-conjugated units embedded in the flexible backbones of oligomer scaffolds can be exploited to tune the electronic properties of nanoscale objects. − This principle has been used to engineer, for example, foldamers whose optical functions are regulated by the structural properties of the flexible chains linking the more rigid, redox-active units. − Solvent polarity and temperature are the two primary experimental handles used to parameterize noncovalent interactions between the π-conjugated units. Seminal work by Iverson and others has shown the emergence of photophysical properties unique to folding states in oligomers built from naphthalene diimide (NDI) electron-acceptor and pyrene electron donor units. − In contrast, only a few studies have explored the extent to which chemical linkages modulate the redox properties of flexible oligomers .…”

Section: Introductionmentioning

confidence: 99%

Molecular Engineering of Water-Soluble Oligomers to Elucidate Radical π–Anion Interactions in n-Doped Nanoscale Objects

et al. 2021

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Modulating, by design, the electronic properties of nanoscale objects that are water-compatible is at the forefront to develop redox-responsive materials capable of interfacing and probing living organisms. In the present work, we report the synthesis and structural and electronic characterizations of two novel water-soluble naphthalene diimide (NDI) oligomers that differ in the nature of the flexible chemical linkages tethering the πconjugated cores. Ground-state electronic absorption spectroscopy experiments, performed as a function of oligomer concentration in an aqueous medium, reveal negligible interactions between oligomer chains but significant interactions among NDI units that comprise a single oligomer chain. Contrasting the monomer controls, which demonstrate well-resolved first and second reduction processes, the NDI oligomers exhibit complex redox processes suggesting the screening of injected charges in the oligomer chains. We show that the flexible chemical linkages offer a synthetic handle to stabilize the first reduction potentials by more than 325 mV when compared to monomer controls. Because the electronic structures of these water-soluble oligomers are characterized by low-lying reduction potentials (E 0/-= −0.025 V vs SCE), biologically relevant sacrificial electron donors, sodium ascorbate and sodium hydrosulfide, possess sufficient driving force to incrementally n-dope the NDI oligomers. Further supported by spectroelectrochemical measurements and time-dependent density functional theory (TD-DFT) calculations, the spectroscopic properties of the reduced NDI units indicate the emergence of novel spectroscopic states diagnostic of radical π−anion interactions. The existence of delocalized electron spin density is unraveled by electron paramagnetic resonance spectroscopy and is shown to be dependent on the strength of the sacrificial electron donors used to n-dope the NDI oligomer chains. Our results not only deliver new insights into the spectroscopic signatures that allow for tracking π−anion interactions in NDI-derived superstructures but also provide new avenues to tune electron spin properties in water-soluble nanoscale objects.

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“…These outstanding chemical, and thermal stabilities could be associated with the π−π interactions between the conjugated TPC. 60 TmTPC-1@PVDF Membrane Fabrication. The bulk powder form of TmTPC-1 is not desirable for real-world applications, for example, radiation dosimetry and medical imaging, which require the materials to be processed into certain shapes.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…In addition, PXRD studies further revealed that the structure of TmTPC-1 remains intact under different relative humidity conditions (35%, 55%, 75%, and 95%) and temperatures (100, 200, and 300 °C) (Figures S8 and S9). These outstanding chemical, radiolytic, and thermal stabilities could be associated with the π–π interactions between the conjugated TPC …”

Section: Resultsmentioning

confidence: 99%

Achieving UV and X-ray Dual Photochromism in a Metal–Organic Hybrid via Structural Modulation

Zheng

et al. 2021

ACS Appl. Mater. Interfaces

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Rational design and synthesis of new photochromic sensors have been active research areas of inquiry, particularly on how to predict and tailor their properties and functionalities. Herein, two thulium 2,2′:6′,2′′-terpyridine-4′-carboxylate (TPC)-functionalized metal–organic hybrids, Tm(TPC)2(HCOO)(H2O) (TmTPC-1) and Tm(TPC)(HCOO)2 (TmTPC-2) with different photochromic response behaviors, have been successfully prepared, allowing for straightforward investigations of the structure–property correlation. Single-crystal X-ray diffraction and electron paramagnetic resonance analyses revealed that the incorporation of a unique dangling decorating TPC unit in TmTPC-1 offers a shorter and more accessible π–π interaction pathway between the adjacent TPC moieties than that in TmTPC-2. Such a structural feature leads to the production of radical species via a photoinduced intermolecular electron-transfer (IeMCT) process upon UV or X-ray irradiation, which ultimately endows TmTPC-1 with a rather unusual UV and X-ray dual photochromism. A linear relationship between the change of UV–vis absorbance intensity and X-ray dose was established, making TmTPC-1 a promising dosimeter for X-ray radiation with an extremely high energy threshold (30 kGy). To advance the development for real-world application, we have fabricated polyvinylidene fluoride (PVDF) membranes incorporating TmTPC-1 for functioning either as a UV imager or as an X-ray radiation indicator. Lastly, TmTPC-1 exhibits high thermal stability (up to 400 °C) and radioresistance (at least 900 kGy), and also excellent reversibility of photochromic transformation (at least 5 cycles).

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Construction of Helically Stacked π‐Electron Systems in Poly(quinolylene‐2,3‐methylene) Stabilized by Intramolecular Hydrogen Bonds

Cited by 17 publications

References 49 publications

Chiroptical Properties in Thin Films of π-Conjugated Systems

Chiroptical Properties in Thin Films of π-Conjugated Systems

Molecular Engineering of Water-Soluble Oligomers to Elucidate Radical π–Anion Interactions in n-Doped Nanoscale Objects

Achieving UV and X-ray Dual Photochromism in a Metal–Organic Hybrid via Structural Modulation

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