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n-Dopants Based on Dimers of Benzimidazoline Radicals: Structures and Mechanism of Redox Reactions.
- Source :
- Chemistry - A European Journal; 7/20/2015, Vol. 21 Issue 30, p10878-10885, 8p
- Publication Year :
- 2015
-
Abstract
- Dimers of 2-substituted N,N′-dimethylbenzimidazoline radicals, (2-Y-DMBI)<subscript>2</subscript> (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 CC bond for (2-Cyc-DMBI)<subscript>2</subscript> than (2-Fc-DMBI)<subscript>2</subscript>, 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 (D<subscript>2</subscript>) dissociation and of D<subscript>2</subscript>-to-A electron transfer, D<subscript>2</subscript> reacts with A to form D<superscript>+</superscript> and A<superscript>−</superscript> by either of two mechanisms, differing in whether the first step is endergonic dissociation or endergonic electron transfer. However, the D<superscript>+</superscript>/0.5 D<subscript>2</subscript> redox potentials-the effective reducing strengths of the dimers-vary little within the series (ca. −1.9 V vs. FeCp<subscript>2</subscript><superscript>+/0</superscript>) (Cp=cyclopentadienyl) due to cancelation of trends in the D<superscript>+/0</superscript> potential and D<subscript>2</subscript> dissociation energy. The implications of these findings for use of these dimers as n-dopants, and for future dopant design, are discussed. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09476539
- Volume :
- 21
- Issue :
- 30
- Database :
- Complementary Index
- Journal :
- Chemistry - A European Journal
- Publication Type :
- Academic Journal
- Accession number :
- 108355100
- Full Text :
- https://doi.org/10.1002/chem.201500611