A model for decomposing the Le Bahers, Adamo, and Ciofini Charge Transfer (CT) Excitations global indexes (J. Chem. Theory Comput. 2011, 7, 2498-2506) into molecular subdomains contributions is presented and a software, DOCTRINE (atomic group Decomposition Of the Charge TRansfer INdExes) for the implementation of this novel model has been coded. Although our method applies to any fuzzy or to any disjoint exhaustive partitioning of the real space, it is here applied using a definition of chemically relevant molecular subdomains based on the Atoms in Molecules Bader basins. This choice has the relevant advantage of associating intra or inter subdomain contributions to rigorously defined quantum objects, yet bearing a clear chemical meaning. Our method allows for a quantitative evaluation of the subdomain contributions to the charge transfer, the charge transfer excitation length and the dipole moment change upon excitation. All these global indexes may be obtained either from the electron density increment or the electron density depletion upon excitation. However, the subdomain contributions obtained from the two distributions generally differ, therefore allowing to distinguish whether the contribution to a given property of a given subdomain is dominated by one of the two distributions or if both are playing a significant role. As a toy system for the first application of our model, a typical [D-pi-A, pi = conjugated bridge] compound belonging to the merocyanine dyes family is selected, and the first four excited states of this compound in a strongly polar protic solvent and in a weakly polar solvent are thoroughly investigated.

This article presents the electrochemical properties of a series of phenothiazine and phenoxazine dimers, by involving an aromatic central core, efficiently synthesized in a single step through a Buckwald–Hartwig coupling reaction. A synergistic approach combining experimental and quantum chemical studies was used in view of providing a thorough characterization of their capabilities as electrodes in the context of electrochemical energy storage applications. A detailed study of the electrochemical activity was then conducted with the aim of optimizing performance, i.e., achieving a specific capacity of around 100 mAh.g ⁻¹ , close to the theoretical values at a potential of 3.6 V relative to Li metal. The dimerization strategy also emerged as an interesting methodology, since it gives rise to molecular materials having specific solubility properties. This finding opens up the possibility of recovering the active material from the electrode at the end of its life, thus paving the way for improved organic electrodes and batteries, especially with respect to their recyclable character.

Understanding structure–property relationship in redox-active molecular species is of central importance in various fields, including many medicinal and chemical applications. The quest for performant organic electrodes in the context of energy storage calls for pioneering studies to develop new and possibly optimal materials. Beyond modifying the molecular design of the existing compounds through functionalization, expansion of the search enabling the advent of efficient new backbones can potentially lead to breakthroughs in this research area. The number of already identified families able to constitute negative organic electrodes is much lower than that of their positive counterparts, which calls for finding ways to bridge this gap. To expand the dataset of known predicted redox potentials and in view of reaching an educated guess about the abilities of some eventual new redox active electrodes, we examined the properties of pyrazine N,N′-dioxide (PZDO) and its fully methylated functionalized derivative (TeMePzDO). The aspects and mechanisms driving the various features characteristic of these compounds were unraveled through molecular and periodic DFT calculations combined with accurate electronic structure analysis. The predicted molecular redox/crystalline intercalation potentials lead to the classification of PZDO and TeMePzDO systems within the class of negative electrodes, with features that are significantly appealing compared to those of some existing systems with backbones suited for such kind of application.