Development of a quantum chemical descriptor expressing aromatic/quinoidal character for designing narrow-bandgap π-conjugated polymers

Hayashi, Yoshihiro; Kawauchi, Susumu

doi:10.1039/c9py00987f

Cited by 14 publications

(9 citation statements)

References 81 publications

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“…5 In some recent computational study, the correlation between the quinoidal character and bandgaps of conjugated copolymers was explored with new quantum chemical descriptors that possess higher compatibility and universality than the simple BLA parameter. 6,7 Apart from BLA, the backbone conformations are often different between a quinoidal conjugated polymer and its aromatic analogue. 9 On account of the double-bond connections between cyclic π-units, a quinoidal structure often exhibits higher coplanarity and rigidity, while its aromatic counterpart possesses a higher degree of freedom for torsional rotation about the single bond linkages.…”

Section: Lei Fangmentioning

confidence: 99%

Quinoidal conjugated polymers with open-shell character

Fang

2021

Polym. Chem.

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Section: Lei Fangmentioning

confidence: 99%

Quinoidal conjugated polymers with open-shell character

Fang

2021

Polym. Chem.

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“…Recently, Hayashi and Kawauchi investigated the design of copolymers of 14 different heteroconjugated units using their quinoid stabilization energy descriptor and obtained band gaps as low as 0.5 eV for an alternating sulfur containing copolymer . This line of research follows that of Bérubé et al, Brédas, and others, which emphasized the reduction of the bond length alternation (BLA) parameter to obtain a reduction of the band gap, while Kertesz and others emphasized both the BLA parameter and the relaxation energy associated with BLA in order to achieve a realistic description of the reduced band gap in π-conjugated oligomers and polymers …”

Section: Introductionmentioning

confidence: 85%

Quinonoid versus Aromatic π-Conjugated Oligomers and Polymers and Their Diradical Characters

2022

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Quinonoid elements in π-conjugated oligomers and polymers have promising characteristics by providing unique structures and electronic properties, including varying degrees of ground state open shell diradical character and small band gaps. So far, quinonoid ground state polymers were rarely identified, and one of the goals of this work was to expand the portfolio of such systems in which over 17 different repeat units were considered, about half preferred a quinonoid and half preferred aromatic structures plus several with the alternating A-Q composition were also included. The dependency of the diradical character as a function of size and composition opens a rich space to discover trends affecting the aromaticity and diradical character. Herein, we show that the diradical character is a useful parameter to classify a wide variety of polymers based on their ground states in a systematic study of a large number of homo- and hetero-systems. Homo-polymers with quinonoid ground states show a high diradical character, while those with the aromatic ground state behave as closed-shell systems with no or a very small diradical character. The diradical character of quinonoid systems depends strongly on the size, which increases with the size of the oligomer. We found a correlation between the diradical character and the interring C–C distance as well as the singlet–triplet energy gaps. In alternating copolymers mixing quinonoid and aromatic subunits, we found open-shell hetero-polymers with moderate to high diradical characters.

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“…A polymer is one of the most challenging analytical subjects since it is composed of a huge number of atoms and the assembled or higher-order structure is also crucial to determine the net properties. Such complicated polymer structures could not be assessed by previous computational descriptors which only represent “monomer” or “oligomer” structures based on atomic composition, molecular dynamic simulation 1 , quantum chemical calculation 2 , string notation (e.g., SMILES), and graph representation 3 – 6 . In contrast, experimental investigations of polymers can be conducted by various analytical techniques that target primary, secondary, higher-order, and large-scale structures, respectively.…”

Section: Introductionmentioning

confidence: 99%

Integrative measurement analysis via machine learning descriptor selection for investigating physical properties of biopolymers in hairs

Takamura

Tsukamoto

Sakata

et al. 2021

Sci Rep

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Integrative measurement analysis of complex subjects, such as polymers is a major challenge to obtain comprehensive understanding of the properties. In this study, we describe analytical strategies to extract and selectively associate compositional information measured by multiple analytical techniques, aiming to reveal their relationships with physical properties of biopolymers derived from hair. Hair samples were analyzed by multiple techniques, including solid-state nuclear magnetic resonance (NMR), time-domain NMR, Fourier transform infrared spectroscopy, and thermogravimetric and differential thermal analysis. The measured data were processed by different processing techniques, such as spectral differentiation and deconvolution, and then converted into a variety of “measurement descriptors” with different compositional information. The descriptors were associated with the mechanical properties of hair by constructing prediction models using machine learning algorithms. Herein, the stepwise model refinement via selection of adopted descriptors based on importance evaluation identified the most contributive descriptors, which provided an integrative interpretation about the compositional factors, such as α-helix keratins in cortex; and bounded water and thermal resistant components in cuticle. These results demonstrated the efficacy of the present strategy to generate and select descriptors from manifold measured data for investigating the nature of sophisticated subjects, such as hair.

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Development of a quantum chemical descriptor expressing aromatic/quinoidal character for designing narrow-bandgap π-conjugated polymers

Abstract: Guidance for designing narrow-bandgap copolymers was established by developing a chemical descriptor (QSE) that considers only the monomer and linking sites.

Cited by 14 publications

References 81 publications

Quinoidal conjugated polymers with open-shell character

Quinoidal conjugated polymers with open-shell character

Quinonoid versus Aromatic π-Conjugated Oligomers and Polymers and Their Diradical Characters

Integrative measurement analysis via machine learning descriptor selection for investigating physical properties of biopolymers in hairs

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