Dihedral‐Angle‐Controlled Crossover from Static Hole Delocalization to Dynamic Hopping in Biaryl Cation Radicals. (29th November 2016)

• Record Type: Journal Article
• Authors: Talipov, Marat R.; Navale, Tushar S.; Hossain, Mohammad M.; Shukla, Ruchi; Ivanov, Maxim V.; Rathore, Rajendra
• Is Part Of: Angewandte Chemie. Volume 129:Number 1(2017)
• Page Start: 272
• Page End: 275
• Publication Date: 2016-11-29
• Subjects: Delokalisierung -- Elektronische Kopplung -- Inkohärentes Hopping -- Ladungstransfer -- Radikalkationen; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201609695
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: In cases of coherent charge‐transfer mechanism in biaryl compounds the rates follow a squared cosine trend with varying dihedral angle. Herein we demonstrate using a series of biaryl cation radicals with varying dihedral angles that the hole stabilization shows two different regimes where the mechanism of the hole stabilization switches over from (static) delocalization over both aryl rings to (dynamic) hopping. The experimental data and DFT calculations of biaryls with different dihedral angles unequivocally support that a crossover from delocalization to hopping occurs at a unique dihedral angle where the electronic coupling ( H ab ) is one half of reorganization ( λ ), that is, H ab = λ /2. The implication of this finding in non‐coherent charge‐transfer rates is being investigated. Abstract : Landungstransport in Biarylen : Abhängig vom Diederwinkel wechselt der Elektronentransfermechanismus in kationischen Biarylradikalen von einer statischen Delokalisierung zu dynamischem Hopping (siehe Bild). Experimentelle Daten und DFT‐Rechnungen belegen, dass der Übergang bei einem charakteristischen Diederwinkel stattfindet, bei dem die elektronische Kopplung genau halb so groß ist wie die Reorganisationsenergie.