n-Dopants Based on Dimers of Benzimidazoline Radicals: Structures and Mechanism of Redox Reactions
| Autor: | Zhenan Bao, Sean Parkin, Siyuan Zhang, Benjamin D. Naab, Glenn L. Millhauser, Tatiana V. Timofeeva, Stephen Barlow, Jean-Luc Brédas, Seth R. Marder, Eric G.B. Evans, Chad Risko, Evgheni V. Jucov |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Models
Molecular Free Radicals Naphthacenes Dimer Radical Photochemistry Crystallography X-Ray Redox Catalysis Dissociation (chemistry) Article Electron Transport chemistry.chemical_compound Electron transfer Cyclopentadienyl complex Benzene Derivatives Benzimidazoline Imidazolines Chemistry Organic Chemistry General Chemistry Bond-dissociation energy Semiconductors Quantum Theory Thermodynamics Dimerization Oxidation-Reduction |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany). 21(30) |
| ISSN: | 1521-3765 |
| Popis: | Dimers of 2-substituted N,N'-dimethylbenzimidazoline radicals, (2-Y-DMBI)2 (Y=cyclohexyl (Cyc), ferrocenyl (Fc), ruthenocenyl (Rc)), have recently been reported as n-dopants for organic semiconductors. Here their structural and energetic characteristics are reported, along with the mechanisms by which they react with acceptors, A (PCBM, TIPS-pentacene), in solution. X-ray data and DFT calculations both indicate a longer C-C bond for (2-Cyc-DMBI)2 than (2-Fc-DMBI)2 , yet DFT and ESR data show that the latter dissociates more readily due to stabilization of the radical by Fc. Depending on the energetics of dimer (D2 ) dissociation and of D2 -to-A electron transfer, D2 reacts with A to form D(+) and A(-) by either of two mechanisms, differing in whether the first step is endergonic dissociation or endergonic electron transfer. However, the D(+) /0.5 D2 redox potentials-the effective reducing strengths of the dimers-vary little within the series (ca. -1.9 V vs. FeCp2 (+/0) ) (Cp=cyclopentadienyl) due to cancelation of trends in the D(+/0) potential and D2 dissociation energy. The implications of these findings for use of these dimers as n-dopants, and for future dopant design, are discussed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
| Nepřihlášeným uživatelům se plný text nezobrazuje | K zobrazení výsledku je třeba se přihlásit. |