Tailored Charge Transfer Kinetics in Precursors for Organic Radical Batteries: A Joint Synthetic‐Theoretical Approach **

Abstract The development of sustainable energy storage devices is crucial for the transformation of our energy management. In this scope, organic batteries attracted considerable attention. To overcome the shortcomings of typically applied materials from the classes of redox‐active conjugated polymers (i. e., unstable cell voltages) and soft matter‐embedded stable organic radicals (i. e., low conductivity), a novel design concept was introduced, integrating such stable radicals within a conductive polymer backbone. In the present theory‐driven design approach, redox‐active (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyls (TEMPOs) were incorporated in thiophene‐based polymer model systems, while structure‐property relationships governing the thermodynamic properties as well as the charge transfer kinetics underlying the charging and discharging processes were investigated in a systematical approach. Thereby, the impact of the substitution pattern, the length as well as the nature of the chemical linker, and the ratio of TEMPO and thiophene units was studied using state‐of‐the‐art quantum chemical and quantum dynamical simulations for a set of six molecular model systems. Finally, two promising candidates were synthesized and electrochemically characterized, paving the way to applications in the frame of novel organic radical batteries.Radical approach : Molecular models of stable organic radicals incorporated in a conjugated backbone, with application in the field of organic radical batteries, are investigated by means of multiconfigurational methods. The theory‐guided design allows to tune the charge transfer kinetics as well as the underlying thermodynamics. Auspicious systems are synthesized and characterized electrochemically. imag

Tailored Charge Transfer Kinetics in Organic Radical Batteries – A Joint Synthetic-Theoretical Approach

The development of sustainable energy storage devices is crucial for the transformation of our energy management. In this scope, organic batteries attracted considerable attention. To overcome the shortcomings of typically applied materials from the classes of redox-active conjugated polymers, i.e., unstable cell voltages, and soft matter embedded stable organic radicals, i.e., low conductivity, we introduce a novel design concept integrating such stable radicals within a conductive polymer backbone. In our present theory-driven design approach redox-active TEMPOs were incorporated in thiophene-based polymer model systems, while structure-property relationships governing the thermodynamic properties as well as the charge transfer kinetics underlying the charging and discharging processes were investigated in a systematical approach. Thereby, the impact of the substitution pattern, the length as well as the nature of the chemical linker and the ratio of TEMPO and thiophene units was studied using state-of-the-art quantum chemical and quantum dynamical simulations for a set of six molecular model systems. Finally, two promising candidates were synthesized and electrochemically characterized – paving the way to applications in the frame of novel organic radical batteries

Iron(0)‐Mediated Stereoselective (3+2)‐Cycloaddition of Thiochalcones via a Diradical Intermediate

Reactions of α,β‐unsaturated aromatic thioketones 1 (thiochalcones) with Fe 3 (CO) 12 leading to η 4 ‐1‐thia‐1,3‐diene iron tricarbonyl complexes  2 , [FeFe] hydrogenase mimics 3 , and the thiopyrane adduct 4 are described. Obtained products have been characterized by X‐ray crystallography and by computational methods. Completely regio‐ and diastereoselective formation of the five‐membered ring system in products  3 , containing four stereogenic centers, can be explained by an unprecedented, stepwise (3+2)‐cycloaddition of two thiochalcone molecules mediated by Fe 3 (CO) 12 . Quantum chemical calculations aimed at elucidation of the reaction mechanism, suggest that the formal (3+2)‐cycloaddition proceeds via sequential intramolecular radical transfer events upon homolytic cleavage of one carbon‐sulfur bond leading to a diradical intermediate.Making the rounds : A series of new cyclopentenes was obtained from thiochalcones via a Fe 0 ‐mediated formal (3+2)‐cycloaddition. Reactions occurred diastereoselectively and the postulated reaction mechanism was elucidated by a combined experimental and theoretical approach. imag