Relationship between Electron Affinity and Half-Wave Reduction Potential: A Theoretical Study on Cyclic...

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Materials Science

Background:

• Accurate prediction of electron affinities and reduction potentials is crucial for designing novel materials for organic electronics and redox flow batteries.
• Existing theoretical methods require validation and refinement for reliable application to diverse electron-acceptor systems.

Purpose of the Study:

• To develop and validate a high-level ab initio protocol for computing electron affinities and half-wave reduction potentials.
• To investigate the factors influencing these properties in electron-acceptor compounds.
• To assess the reliability of theoretical predictions against experimental data.

Main Methods:

• Application of the G3(MP2) theoretical approach for ab initio calculations.
• Utilizing a thermodynamic cycle to compute first half-wave reduction potentials.
• Detailed analysis of solvation free energy differences between neutral and anionic species.

Main Results:

• The G3(MP2) protocol demonstrates high accuracy in predicting electron affinities, prompting a re-evaluation of some experimental values.
• Theoretical estimates for half-wave reduction potentials show excellent agreement with experimental data (max deviation of 0.2 V).
• The difference in solvation free energy (ΔΔGsolv) significantly impacts reduction potential predictions and is not constant across related compounds.

Conclusions:

• The validated ab initio protocol provides a reliable tool for electronic property prediction in electron-acceptors.
• Solvation effects are critical for accurate electrochemical property estimation in solution and depend on electron delocalization.
• This work offers insights into the structure-property relationships governing electron-acceptor behavior.