Photophysical and Electrochemical Properties of Thiophene‐Based 2‐Arylpyridines

Abstract

Two families of thiophene‐based 2‐arylpyridines, in which aryl is phenyl and 2,4‐difluorophenyl, have been developed. The pyridine ring of the new compounds is substituted at the 4‐position with π‐conjugated electron‐rich and electron‐poor thiophene‐based fragments to tune the optical and energetic properties. The high‐yielding synthetic access, which consists of two sequential Suzuki coupling reactions, the first of which is completely regioselective, is of wide applicability and allows access to a large variety of derivatives. The absorption/emission and redox features, as well as the HOMO and LUMO energy levels, have been investigated; the results show that the optical and electronic properties can be tuned over a broad range. The diversity of the characteristics may be effectively exploited by using the thiophene‐substituted 2‐arylpyridines as ligands in cyclometalated sensitizers for dye‐sensitized solar cells and other optoelectronic applications.

Synthesis and two-photon absorption property of new π -conjugated donor–acceptor polymers carrying different heteroaromatics

“…This is originated due to the presence of thiophene ring in the polymer P2 which has enhanced the electron delocalization in the polymer. Further, the appearance of shoulder peak in polymer P3 at 475 nm has been attributed to the intramolecular charge-transfer (ICT) transition between the thiophene and pyridine moieties, 34,35 and its absorption maximum at 350 nm is due to the π-π* transition. The fluorescence emission spectra of polymers P1, P2 and P3 in THF showed emission peaks at 554, 566, and 552 nm, respectively as shown in figure 7.…”

Site Selective Synthesis of Pentaarylpyridines via Multiple Suzuki–Miyaura Cross‐Coupling Reactions

“…The absorption wavelengths of 3 are in the UV region of λ 1–4abs =227–316 nm and exhibit four conspicuous transitions (λ 1–4abs ) (Figure 2); The absorption maxima of compound 3e , bearing electron‐donating methoxy substituents, are red‐shifted, which indicates a more pronounced π‐electron delocalization relative to unsubstituted derivative 3a (λ abs2–4 ); In contrast, compound 3i , bearing electron‐withdrawing trifluoromethyl groups, caused no significant shift of the transitions. Furthermore, the position of the high‐energy band located at 227–228 nm is to some extent independent of the substitution pattern and can be assigned to local π‐π* transitions involving the arylpyridine core 18. However, the lower energy transitions strongly depend on the presence of the substituent attached to the arylpyridine moiety.…”

Steering Scholl Oxidative Heterocoupling by Tuning Topology and Electronics for Building Thiananographenes and Their Functional N−/C−Congeners

“…The cyclic voltammogram (CV, Figures S70-S104) of DPTs and PTs showed only reversible oxidation waves, probably due to incorporating electron-rich thiophene. [61] The oxidation potential of DPTs decreases with the strength of electrondonating substituents. PTs oxidize at a relatively higher potential when compared to the corresponding DPTs due to shorter conjugation.…”