Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings
Polycyclic hydrocarbon with a singlet biradical ground state has recently become a hot topic among various studies on π-conjugated systems and it is of importance to understand the fundamental structure–biradical character–physical properties relationship. In this work, we found that after incorpora...
| Main Authors: | , , , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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2018
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| Online Access: | https://hdl.handle.net/10356/88285 http://hdl.handle.net/10220/45712 |
| _version_ | 1811697710114275328 |
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| author | Zeng, Zebing Lee, Sangsu Zafra, José L. Ishida, Masatoshi Bao, Nina Webster, Richard David López Navarrete, Juan T. Ding, Jun Casado, Juan Kim, Dongho Wu, Jishan |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Zeng, Zebing Lee, Sangsu Zafra, José L. Ishida, Masatoshi Bao, Nina Webster, Richard David López Navarrete, Juan T. Ding, Jun Casado, Juan Kim, Dongho Wu, Jishan |
| author_sort | Zeng, Zebing |
| collection | NTU |
| description | Polycyclic hydrocarbon with a singlet biradical ground state has recently become a hot topic among various studies on π-conjugated systems and it is of importance to understand the fundamental structure–biradical character–physical properties relationship. In this work, we found that after incorporation of two additional thiophene rings into the closed-shell tetracyano-perylene (Per-CN) and quaterrylenequinodimethanes (QR-CN), the obtained new quinoidal compounds QDTP and QDTQ became a singlet biradical in the ground state due to the recovery of aromaticity of the thiophene rings in the biradical form and additional steric repulsion between the thiophene rings and the rylene unit. The ground state geometries and electronic structures of QDTP and QDTQ were systematically studied by variable-temperature nuclear magnetic resonance, electron spin resonance, superconducting quantum interference device measurements and FT Raman spectroscopy, assisted by density functional theory calculations. Both compounds were found to be a singlet biradical in the ground state with a small singlet–triplet energy gap and the biradical character was enlarged by elongation of the π-conjugation length. Strong one-photon absorption and large two-photon absorption cross-sections were observed for both compounds in the near-infrared region. Our studies demonstrated that a slight structural modification could significantly change the ground state and the electronic, optical and magnetic properties of a pro-aromatic π-conjugated system, and finally lead to new materials with unique properties. |
| first_indexed | 2024-10-01T07:59:35Z |
| format | Journal Article |
| id | ntu-10356/88285 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T07:59:35Z |
| publishDate | 2018 |
| record_format | dspace |
| spelling | ntu-10356/882852023-02-28T19:34:57Z Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings Zeng, Zebing Lee, Sangsu Zafra, José L. Ishida, Masatoshi Bao, Nina Webster, Richard David López Navarrete, Juan T. Ding, Jun Casado, Juan Kim, Dongho Wu, Jishan School of Physical and Mathematical Sciences DRNTU::Science::Chemistry Thiophene Ground State Geometry Polycyclic hydrocarbon with a singlet biradical ground state has recently become a hot topic among various studies on π-conjugated systems and it is of importance to understand the fundamental structure–biradical character–physical properties relationship. In this work, we found that after incorporation of two additional thiophene rings into the closed-shell tetracyano-perylene (Per-CN) and quaterrylenequinodimethanes (QR-CN), the obtained new quinoidal compounds QDTP and QDTQ became a singlet biradical in the ground state due to the recovery of aromaticity of the thiophene rings in the biradical form and additional steric repulsion between the thiophene rings and the rylene unit. The ground state geometries and electronic structures of QDTP and QDTQ were systematically studied by variable-temperature nuclear magnetic resonance, electron spin resonance, superconducting quantum interference device measurements and FT Raman spectroscopy, assisted by density functional theory calculations. Both compounds were found to be a singlet biradical in the ground state with a small singlet–triplet energy gap and the biradical character was enlarged by elongation of the π-conjugation length. Strong one-photon absorption and large two-photon absorption cross-sections were observed for both compounds in the near-infrared region. Our studies demonstrated that a slight structural modification could significantly change the ground state and the electronic, optical and magnetic properties of a pro-aromatic π-conjugated system, and finally lead to new materials with unique properties. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) Accepted version 2018-08-29T03:37:41Z 2019-12-06T16:59:51Z 2018-08-29T03:37:41Z 2019-12-06T16:59:51Z 2014 Journal Article Zeng, Z., Lee, S., Zafra, J. L., Ishida, M., Bao, N., Webster, R. D., . . . Wu, J. (2014). Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings. ChemIcal Science, 5(8), 3072-3080. doi:10.1039/C4SC00659C 2041-6520 https://hdl.handle.net/10356/88285 http://hdl.handle.net/10220/45712 10.1039/C4SC00659C en Chemical Science application/pdf |
| spellingShingle | DRNTU::Science::Chemistry Thiophene Ground State Geometry Zeng, Zebing Lee, Sangsu Zafra, José L. Ishida, Masatoshi Bao, Nina Webster, Richard David López Navarrete, Juan T. Ding, Jun Casado, Juan Kim, Dongho Wu, Jishan Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| title | Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| title_full | Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| title_fullStr | Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| title_full_unstemmed | Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| title_short | Turning on the biradical state of tetracyano-perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| title_sort | turning on the biradical state of tetracyano perylene and quaterrylenequinodimethanes by incorporation of additional thiophene rings |
| topic | DRNTU::Science::Chemistry Thiophene Ground State Geometry |
| url | https://hdl.handle.net/10356/88285 http://hdl.handle.net/10220/45712 |
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