Synthesis and Properties of New Multiple TCNE Adducts from Dialkynyl‐N‐(het)arylpyrroles

Abstract

We report the synthetic routes to mono‐ and di‐TCBD adducts onto N‐(het)arylpyrrole derivatives. We present herein two series of panchromatic chromophores bearing different combinations of donor–acceptor moieties. Additionally, we observe an impact of the nature of the central core. Cyclic voltammograms show very different behaviors at negative potentials between the two series. Particularly, four waves are observed for symmetrical di‐TCDB adducts, thus indicating a communication through the central unit despite the non‐planarity of these molecules.

Synthesis and Photophysical Evaluation of Dialkynyl‐N‐(het)arylpyrroles: Promising Key Compounds in Fluorescence Chemistry

“…These distinctions can be attributed to differences in their electronic structures, incorporating different substituents. These precursors present absorption maxima around 300 nm, as reported in the literature concerning similar derivatives [3a] . In addition, high molar absorptivity coefficient values (ϵ~10 4 cm −1 M −1 ) suggest allowed 1 π →π* electronic transitions.…”

“…The selection of solvents was made considering potential interactions with fluorophores, encompassing aromatic, non‐polar, polar protic, and aprotic solvents. It is worth noting that, while the photophysics of ullazines is relatively well‐described and defined in the literature, [13a,c,d,17] very little research has been conducted on their precursors, [3a] such as those obtained in this study. The rigid core of ‐(het)arylpyrroles and the extended conjugation provided by alkynyl groups containing substituted or unsubstituted phenyls are of great photophysical interest, as they may exhibit interesting absorption or emission characteristics that can be explored in various future applications Figures 3 and 4 show the photophysical characterization in the respective ground and excited states of specific compounds chosen for their electronic properties.…”

Calamitic-Type Dipolar and Quadrupolar Chromophores with a Twisted Peripheral Handle: Structure–Property Outlook as Nonfullerene Acceptors for Binary Solar Cells

“…the decrease of the HOMO−LUMO levels to realize the acceptor character of the molecules. 69 As per the DFT structure, the HOMO wave functions of 14 and 15 are delocalized throughout the electron-rich πconjugated backbone, which is typical of quadrupolar molecules (Figure 5). 70−72 For dipolar molecules (16 and 17), the π-delocalization is aligned mainly on the electron-rich portions of phenylethynyl and the neighboring thienyl groups.…”

“…As shown in Figure , the optimized structure of all chromophores displayed a dihedral angle ( θ ) of ∼−81° between the two adjacent C­(CN) 2 groups, thereby confirming the orthogonal conformation (− syn -clinal). While this nonplanarity could obstruct effective π-conjugation, inclusion of TCBD benefits the decrease of the HOMO–LUMO levels to realize the acceptor character of the molecules …”

Azulene Bridged π‐Distorted Chromophores: The Influence of Structural Symmetry on Optoelectrochemical and Photovoltaic Parameters

“…Though this deviation from co-planarity could hamper an effective π-delocalization, [31] the TCBD group could potentially influence the decrease of πorbital energies to contribute for the acceptor character. [32] On the other hand, the CÀ C single bond linking the 2-thienyl and =C(CN) 2 group in TATC1 (1.36 Å) is shorter than that in TATC2 (1.53 Å). The shorter bond distance in TATC1 over TATC2 is suggestive of enhanced electronic communication via strong ICT, a feature of dipolar chromophores.…”