| Autor: |
Das A; Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad 500046, India., Elvers BJ; Institut für Biochemie, Universität Greifswald, Greifswald D-17489, Germany., Chrysochos N; Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad 500046, India., Uddin SI; Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad 500046, India., Gangber T; Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad 500046, India., Krummenacher I; Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany., Borah D; Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India., Mishra A; Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad 500046, India., Shanmugam M; Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India., Yildiz CB; Department of Aromatic and Medicinal Plants, Aksaray University, Aksaray 68100, Turkey., Braunschweig H; Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany., Schulzke C; Institut für Biochemie, Universität Greifswald, Greifswald D-17489, Germany., Jana A; Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad 500046, India. |
| Abstrakt: |
Herein, we report the syntheses and electronic structures of crystalline dianionic as well as neutral diboron-centered classical diradicaloids as boron analogues of classical Thiele, Chichibabin, and Müller (this only for dianionic diradicaloids!) hydrocarbons. These are based on borane radical anion and NHC-stabilized boryl radical spin carriers, respectively. All these dianionic diboron-centered diradicaloids exhibit triplet population at room temperature regardless of the π-conjugated spacer: p -phenylene, p , p' -biphenylene, or p , p″ -terphenylene. In the case of neutral diboron-centered diradicaloids, the employed π-conjugated spacer plays a crucial role for the triplet population at room temperature: EPR inactive for p -phenylene vs EPR active for p , p' -biphenylene. The findings emphasize the importance of the spin carriers for the resulting ground-state: borane radical anion vs NHC-stabilized boryl radical along with the pivotal role of the π-conjugated spacer as spin-coupler between two spins. Notably, 100 years (a century) after the first report by Krause of the triphenyl borane radical-anion, being isoelectronic to the triphenylmethyl radical, we convey borane radical anion-based diradicaloids. Furthermore, while donor-stabilized boryl radicals were introduced in the 1980s by Giles and Roberts, said concept is herewith being extended to NHC-stabilized boryl radical-based diradicaloids. |
