Torsional Bias as a Strategy To Tune Singlet–Triplet Gaps in Organic Diradicals
| Autor: | Guzmán López-Espejo, Justin R. DeFrancisco, Reid E. Messersmith, José L. Zafra, John D. Tovar, Henrik Ottosson, Juan Casado, Carlos J. Gómez-García, Sangeeta Yadav |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Diradical Aromaticity 02 engineering and technology Annulene 010402 general chemistry 021001 nanoscience & nanotechnology Ring (chemistry) Resonance (chemistry) 01 natural sciences Small molecule 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials General Energy Chemical physics Molecule Singlet state Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | The Journal of Physical Chemistry C. 122:12148-12157 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/acs.jpcc.8b01905 |
| Popis: | Quinoidal compounds with proaromatic structures possess differing degrees of diradical character, where the open-shell diradical resonance form has restored aromaticity throughout the compound. Methods to tune the diradical character of these compounds have traditionally focused on altering the length and the molecular composition of the π-conjugated backbones. However, other molecular design strategies to tune the singlet–triplet gap of π-conjugated quinoidal molecules have not been extensively explored. We previously reported a strikingly small energy gap between the quinoidal and diradical states of a quinoidal small molecule containing methano[10]annulene (TMTQ) that was dictated in large part by the unusual aromaticity of the central annulene ring. Here, we report on two alkylated derivatives of TMTQ that present substantially different torsional biases to the planarity of the TMTQ π-system. Using a combination of electronic and vibrational spectroscopies, magnetic measurements, and quantum chemical ... |
| Databáze: | OpenAIRE |
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