Luminescent Trityl-based Diradicaloids: A Theoretical and Experimental Assessment of Charge-Resonance in Low-Lying Excited States
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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866908499671252992 |
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| author | Mesto, Davide Orza, Michele Bardi, Brunella Punzi, Angela Ratera, Imma Veciana, Jaume Farinola, Gianluca Painelli, Anna Terenziani, Francesca Blasi, Davide Negri, Fabrizia |
| author_facet | Mesto, Davide Orza, Michele Bardi, Brunella Punzi, Angela Ratera, Imma Veciana, Jaume Farinola, Gianluca Painelli, Anna Terenziani, Francesca Blasi, Davide Negri, Fabrizia |
| contents | The tris(2,4,6-trichlorophenyl)methyl radical (TTM) has inspired the synthesis of several luminescent diradicals and diradicaloids, providing an extraordinary opportunity to control the nature of the low-lying excited states by fine-tuning the diradical character. However, the photophysical properties of TTM-derived diradicals remain not fully understood yet. Here we present a combined theoretical and experimental investigation on TTM-derived diradicals to elucidate the origin of their luminescence. The theoretical analysis focuses on a series of symmetric TTM-derived diradicals with singlet ground state, featuring radical moieties linked by pi-conjugated spacers of different length. The nature of the lowest excited electronic states that control their photophysical behaviour is discussed in detail. The study is complemented by a complete spectroscopic characterization of the TTM-TTM diradical, synthesized using a novel, simpler and more efficient procedure exploiting the unique reactivity of TTM. The lowest excited states of the diradicals differ qualitatively from those of TTM: two novel low-lying states emerge in the diradical, due to charge resonance (CR) between the two radical units. The lowest CR state is a dark state for symmetric diradicals. The CR nature explains the blue-shifted emission observed by increasing the distance between the radical centres as seen in TTM-ph-TTM. This insight suggests different design strategies to improve the luminescence properties of TTM-derived diradicals |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_18638 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Luminescent Trityl-based Diradicaloids: A Theoretical and Experimental Assessment of Charge-Resonance in Low-Lying Excited States Mesto, Davide Orza, Michele Bardi, Brunella Punzi, Angela Ratera, Imma Veciana, Jaume Farinola, Gianluca Painelli, Anna Terenziani, Francesca Blasi, Davide Negri, Fabrizia Chemical Physics Materials Science The tris(2,4,6-trichlorophenyl)methyl radical (TTM) has inspired the synthesis of several luminescent diradicals and diradicaloids, providing an extraordinary opportunity to control the nature of the low-lying excited states by fine-tuning the diradical character. However, the photophysical properties of TTM-derived diradicals remain not fully understood yet. Here we present a combined theoretical and experimental investigation on TTM-derived diradicals to elucidate the origin of their luminescence. The theoretical analysis focuses on a series of symmetric TTM-derived diradicals with singlet ground state, featuring radical moieties linked by pi-conjugated spacers of different length. The nature of the lowest excited electronic states that control their photophysical behaviour is discussed in detail. The study is complemented by a complete spectroscopic characterization of the TTM-TTM diradical, synthesized using a novel, simpler and more efficient procedure exploiting the unique reactivity of TTM. The lowest excited states of the diradicals differ qualitatively from those of TTM: two novel low-lying states emerge in the diradical, due to charge resonance (CR) between the two radical units. The lowest CR state is a dark state for symmetric diradicals. The CR nature explains the blue-shifted emission observed by increasing the distance between the radical centres as seen in TTM-ph-TTM. This insight suggests different design strategies to improve the luminescence properties of TTM-derived diradicals |
| title | Luminescent Trityl-based Diradicaloids: A Theoretical and Experimental Assessment of Charge-Resonance in Low-Lying Excited States |
| topic | Chemical Physics Materials Science |
| url | https://arxiv.org/abs/2412.18638 |