Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity

Kun Yang; Xianhe Zhang; Alexandra Harbuzaru; Lei Wang; Yang Wang; Changwoo Koh; Han Guo; Yongqiang Shi; Jianhua Chen; Huiliang Sun; Kui Feng; M. Carmen Ruiz Delgado; Han Young Woo; Rocio Ponce Ortiz; Xugang Guo

doi:10.1021/jacs.9b12683

Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity

Kun Yang, Xianhe Zhang, Alexandra Harbuzaru, Lei Wang, Yang Wang, Changwoo Koh, Han Guo, Yongqiang Shi, Jianhua Chen, Huiliang Sun, Kui Feng, M. Carmen Ruiz Delgado, Han Young Woo, Rocio Ponce Ortiz, Xugang Guo^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

136 Citations (Scopus)

Abstract

Unpaired electrons of organic radicals can offer high electrical conductivity without doping, but they typically suffer from low stability. Herein, we report two organic diradicaloids based on quinoidal oligothiophene derivative (QOT), that is, BTICN and QTICN, with high stability and conductivity by employing imide-bridged fused molecular frameworks. The attachment of a strong electron-withdrawing imide group to the tetracyano-capped QOT backbones enables extremely deeply aligned LUMO levels (from -4.58 to -4.69 eV), cross-conjugated diradical characters, and remarkable ambient stabilities of the diradicaloids with half-lives > 60 days, which are among the highest for QOT diradicals and also the widely explored polyaromatic hydrocarbon (PAH)-based diradicals. Specifically, QTICN based on a tetrathiophene imide exhibits a cross-conjugation assisted self-doping in the film state as revealed by XPS and Raman studies. This property in combination with its ordered packing yields a high electrical conductivity of 0.34 S cm-1 for the QTICN films with substantial ambient stability, which is also among the highest values in organic radical-based undoped conductive materials reported to date. When used as an n-type thermoelectric material, QTICN shows a promising power factor of 1.52 uW m-1 K-2. Our results not only provide new insights into the electron conduction mechanism of the self-doped QOT diradicaloids but also demonstrate the great potential of fused quinoidal oligothiophene imides in developing stable diradicals and high-performance doping-free n-type conductive materials.

Original language	English
Pages (from-to)	4329-4340
Number of pages	12
Journal	Journal of the American Chemical Society
Volume	142
Issue number	9
DOIs	https://doi.org/10.1021/jacs.9b12683
Publication status	Published - 2020 Mar 4

Bibliographical note

Funding Information:
X.G. is grateful to the National Science Foundation of China (no. 51573076). L.W. acknowledges the China Postdoctoral Science Foundation (no. 2018M641626). Research at University of Málaga was supported by Junta de Andalucía (UMA18-FEDERJA-080). H.Y.W. is thankful for the financial support from the NRF of Korea (NRF-2016M1A2A2940911 and 2019R1A6A1A11044070). We would like to thank Dr. Yinhua Yang (MCPC, SUSTech) for the kind help with the ESR and VT-NMR measurements as well as the assistance of the SUSTech Core Research Facilities and the technical support from the Computational Science and Engineering Department of the Southern University of Science and Technology. The authors would like to acknowledge the computer resources, technical expertise, and assistance provided by the Supercomputing and Bioinformatics (SCBI) centre of the University of Málaga.

Publisher Copyright:
© 2020 American Chemical Society.

ASJC Scopus subject areas

Catalysis
General Chemistry
Biochemistry
Colloid and Surface Chemistry

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Yang, K., Zhang, X., Harbuzaru, A., Wang, L., Wang, Y., Koh, C., Guo, H., Shi, Y., Chen, J., Sun, H., Feng, K., Ruiz Delgado, M. C., Woo, H. Y., Ortiz, R. P., & Guo, X. (2020). Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity. Journal of the American Chemical Society, 142(9), 4329-4340. https://doi.org/10.1021/jacs.9b12683

Yang, K, Zhang, X, Harbuzaru, A, Wang, L, Wang, Y, Koh, C, Guo, H, Shi, Y, Chen, J, Sun, H, Feng, K, Ruiz Delgado, MC, Woo, HY, Ortiz, RP & Guo, X 2020, 'Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity', Journal of the American Chemical Society, vol. 142, no. 9, pp. 4329-4340. https://doi.org/10.1021/jacs.9b12683

@article{65f192ad38e54a8abb332748cb9348e5,

title = "Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity",

abstract = "Unpaired electrons of organic radicals can offer high electrical conductivity without doping, but they typically suffer from low stability. Herein, we report two organic diradicaloids based on quinoidal oligothiophene derivative (QOT), that is, BTICN and QTICN, with high stability and conductivity by employing imide-bridged fused molecular frameworks. The attachment of a strong electron-withdrawing imide group to the tetracyano-capped QOT backbones enables extremely deeply aligned LUMO levels (from -4.58 to -4.69 eV), cross-conjugated diradical characters, and remarkable ambient stabilities of the diradicaloids with half-lives > 60 days, which are among the highest for QOT diradicals and also the widely explored polyaromatic hydrocarbon (PAH)-based diradicals. Specifically, QTICN based on a tetrathiophene imide exhibits a cross-conjugation assisted self-doping in the film state as revealed by XPS and Raman studies. This property in combination with its ordered packing yields a high electrical conductivity of 0.34 S cm-1 for the QTICN films with substantial ambient stability, which is also among the highest values in organic radical-based undoped conductive materials reported to date. When used as an n-type thermoelectric material, QTICN shows a promising power factor of 1.52 uW m-1 K-2. Our results not only provide new insights into the electron conduction mechanism of the self-doped QOT diradicaloids but also demonstrate the great potential of fused quinoidal oligothiophene imides in developing stable diradicals and high-performance doping-free n-type conductive materials.",

author = "Kun Yang and Xianhe Zhang and Alexandra Harbuzaru and Lei Wang and Yang Wang and Changwoo Koh and Han Guo and Yongqiang Shi and Jianhua Chen and Huiliang Sun and Kui Feng and \{Ruiz Delgado\}, \{M. Carmen\} and Woo, \{Han Young\} and Ortiz, \{Rocio Ponce\} and Xugang Guo",

note = "Funding Information: X.G. is grateful to the National Science Foundation of China (no. 51573076). L.W. acknowledges the China Postdoctoral Science Foundation (no. 2018M641626). Research at University of M{\'a}laga was supported by Junta de Andaluc{\'i}a (UMA18-FEDERJA-080). H.Y.W. is thankful for the financial support from the NRF of Korea (NRF-2016M1A2A2940911 and 2019R1A6A1A11044070). We would like to thank Dr. Yinhua Yang (MCPC, SUSTech) for the kind help with the ESR and VT-NMR measurements as well as the assistance of the SUSTech Core Research Facilities and the technical support from the Computational Science and Engineering Department of the Southern University of Science and Technology. The authors would like to acknowledge the computer resources, technical expertise, and assistance provided by the Supercomputing and Bioinformatics (SCBI) centre of the University of M{\'a}laga. Publisher Copyright: {\textcopyright} 2020 American Chemical Society.",

year = "2020",

month = mar,

day = "4",

doi = "10.1021/jacs.9b12683",

language = "English",

volume = "142",

pages = "4329--4340",

journal = "Journal of the American Chemical Society",

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TY - JOUR

T1 - Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity

AU - Yang, Kun

AU - Zhang, Xianhe

AU - Harbuzaru, Alexandra

AU - Wang, Lei

AU - Wang, Yang

AU - Koh, Changwoo

AU - Guo, Han

AU - Shi, Yongqiang

AU - Chen, Jianhua

AU - Sun, Huiliang

AU - Feng, Kui

AU - Ruiz Delgado, M. Carmen

AU - Woo, Han Young

AU - Ortiz, Rocio Ponce

AU - Guo, Xugang

N1 - Funding Information: X.G. is grateful to the National Science Foundation of China (no. 51573076). L.W. acknowledges the China Postdoctoral Science Foundation (no. 2018M641626). Research at University of Málaga was supported by Junta de Andalucía (UMA18-FEDERJA-080). H.Y.W. is thankful for the financial support from the NRF of Korea (NRF-2016M1A2A2940911 and 2019R1A6A1A11044070). We would like to thank Dr. Yinhua Yang (MCPC, SUSTech) for the kind help with the ESR and VT-NMR measurements as well as the assistance of the SUSTech Core Research Facilities and the technical support from the Computational Science and Engineering Department of the Southern University of Science and Technology. The authors would like to acknowledge the computer resources, technical expertise, and assistance provided by the Supercomputing and Bioinformatics (SCBI) centre of the University of Málaga. Publisher Copyright: © 2020 American Chemical Society.

PY - 2020/3/4

Y1 - 2020/3/4

N2 - Unpaired electrons of organic radicals can offer high electrical conductivity without doping, but they typically suffer from low stability. Herein, we report two organic diradicaloids based on quinoidal oligothiophene derivative (QOT), that is, BTICN and QTICN, with high stability and conductivity by employing imide-bridged fused molecular frameworks. The attachment of a strong electron-withdrawing imide group to the tetracyano-capped QOT backbones enables extremely deeply aligned LUMO levels (from -4.58 to -4.69 eV), cross-conjugated diradical characters, and remarkable ambient stabilities of the diradicaloids with half-lives > 60 days, which are among the highest for QOT diradicals and also the widely explored polyaromatic hydrocarbon (PAH)-based diradicals. Specifically, QTICN based on a tetrathiophene imide exhibits a cross-conjugation assisted self-doping in the film state as revealed by XPS and Raman studies. This property in combination with its ordered packing yields a high electrical conductivity of 0.34 S cm-1 for the QTICN films with substantial ambient stability, which is also among the highest values in organic radical-based undoped conductive materials reported to date. When used as an n-type thermoelectric material, QTICN shows a promising power factor of 1.52 uW m-1 K-2. Our results not only provide new insights into the electron conduction mechanism of the self-doped QOT diradicaloids but also demonstrate the great potential of fused quinoidal oligothiophene imides in developing stable diradicals and high-performance doping-free n-type conductive materials.

AB - Unpaired electrons of organic radicals can offer high electrical conductivity without doping, but they typically suffer from low stability. Herein, we report two organic diradicaloids based on quinoidal oligothiophene derivative (QOT), that is, BTICN and QTICN, with high stability and conductivity by employing imide-bridged fused molecular frameworks. The attachment of a strong electron-withdrawing imide group to the tetracyano-capped QOT backbones enables extremely deeply aligned LUMO levels (from -4.58 to -4.69 eV), cross-conjugated diradical characters, and remarkable ambient stabilities of the diradicaloids with half-lives > 60 days, which are among the highest for QOT diradicals and also the widely explored polyaromatic hydrocarbon (PAH)-based diradicals. Specifically, QTICN based on a tetrathiophene imide exhibits a cross-conjugation assisted self-doping in the film state as revealed by XPS and Raman studies. This property in combination with its ordered packing yields a high electrical conductivity of 0.34 S cm-1 for the QTICN films with substantial ambient stability, which is also among the highest values in organic radical-based undoped conductive materials reported to date. When used as an n-type thermoelectric material, QTICN shows a promising power factor of 1.52 uW m-1 K-2. Our results not only provide new insights into the electron conduction mechanism of the self-doped QOT diradicaloids but also demonstrate the great potential of fused quinoidal oligothiophene imides in developing stable diradicals and high-performance doping-free n-type conductive materials.

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U2 - 10.1021/jacs.9b12683

DO - 10.1021/jacs.9b12683

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SN - 0002-7863

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EP - 4340

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 9

ER -

Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity

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