Selective Formation of a Mixed‐Valence State from Linearly Bridged Oligo(aromatic diamines): Drastic Structural Change into a Folded Columnar Stack for Half‐filled Polycations

Abstract

Am ethod to obtain an organic mixed-valence state with long-range delocalization is proposed, which enables the selectivegeneration of half-filled (n/2-charged) polycationsf rom linearly bridgedo ligomers with n electron-donating units. When p-extended phenylenediamineu nits are connected by meta-xylylene-type spacers, the resultingo ligomers adopt non-folded structures in the neutrals tate owing to the non-conjugatinga nd flexible nature of the spacer,w hereas the structure shows ad rastic change into a one-dimensional columnar stack upon oxidation to the corresponding half-filled polycations. Although they are nanosized discrete molecules, they can mimic the electronic structure of crystalline organic conductors in am ixed-valence state. The key for the oligomerd esign is adoption of the best-matched spacert hat facilitates formation of the singlyc harged pimeri nt he dichromophoric system whereas the corresponding doubly charged p-dimerisd isfavored. Figure 1. Stable carbene-basedc ation radical (I), bis(dimethoxybenzene) derivative(II), and BIC dimers (III and IV)s tudied previously.[a] W. Figure 5. 1D columnar stacko fthe dicationdiradical of tetramer 4 determined by X-raya nalysis of its (SbCl 6 À ) 2 salt:a )top view,b)side view.

Preparation, Spectroscopic Characterization and Theoretical Study of a Three-Dimensional Conjugated 70 π-Electron Thiophene 6-mer Radical Cation π-Dimer

“…An attractive intermolecular π-dimerization has been applied to the control of intramolecular motion and the construction of various supramolecular structures . Radical ions derived from bipyridiniums, oligo aromatic diamines, tetracyanoquino­dimethanes, and tetrathia­fulvalenes , are sufficiently stable for use in the construction of supramolecular π-dimers. However, except for end-capped oligothiophenes and several macrocyclic thiophene oligomers, oligothiophene radical cations are labile and, as a result, they have found limited use as building blocks of functional materials.…”

Domino‐Redox Reaction Induced by An Electrochemically Triggered Conformational Change

“…This process is akin to the domino process, however, A could undergo only two‐electron (2e) oxidation, and thus the first ET only facilitates the second ET but could not continue the process, so that it is not a domino process. In addition, organic systems constructed by the assembly of multiple redox‐active units (electrophores) are attracting much attention since it could exhibit superior charge transport properties based on their potential to interconvert with multivalent ionic species [16–28] …”

“…In addition, organic systems constructed by the assembly of multiple redox-active units (electrophores) are attracting much attention since it could exhibit superior charge transport properties based on their potential to interconvert with multivalent ionic species. [16][17][18][19][20][21][22][23][24][25][26][27][28] To realize domino-redox reactions in multi-redox systems consisting of the same kinds of electrophores, some novel mechanism is necessary, so that the initial redox reaction in one electrophore facilitates the subsequent redox reaction of the neighboring unit (Figure 1c and Schemes S3 and S4). As the simplest model of the multi-chromophoric systems, we recently studied octaarylbisquinodimethane (BQD) derivatives B, which have two units of the foldedshaped quinodimethane (QD) connected by a rigid π-linker (Figure 2 and Scheme S2).…”

Bridging the Gap between Small Molecular π-Interactions and Their Effect on Phenothiazine-Based Redox Polymers in Organic Batteries

“…Although the ability of phenothiazine to undergo π-interactions has been studied before by Kochi and co-workers and an effect on the electrochemistry of PVMPT was already observed in the early 1980s by Morishima et al, their impact on redox polymers for energy storage is hardly understood. From other examples of redox-active groups, it is known that pimer formation can cause tremendous structural changes within a polymer, − which suggests a huge influence on the properties of energy storage materials. Weak interactions between redox-active groups have also influenced battery performance in other cases …”