Fine-Tuning the Electronic Properties of Azo Chromophore-Incorporated Perylene Bisimide Dyads

Abstract

Perylene bisimide (PBI) and azo-compounds are fascinating molecules with interesting optical properties. Here, we combine the two chromophores to prepare nonconjugated and conjugated stable azo-PBI dyes. The detailed structural characterization, comparison of properties, and solid-state self-assembly of the compounds are discussed. The incorporation of azo groups at the bay side of PBI led to significant changes in optical properties as compared to the model PBIs (M 1 and M 2 ). All new azo-PBIs showed photoinduced isomerization, which caused disaggregation and enhancement in fluorescence. The amine-incorporated azo-PBIs (3 and 6) reduced chloroauric acid into gold nanoparticles. The current study offers a simple synthetic strategy and comparison of the properties of conjugated and nonconjugated azo-PBIs, which could be useful in photoelectronic devices.

Rigid Bay-Conjugated Perylene Bisimide Rotors: Solvent-Induced Excited-State Symmetry Breaking and Resonance-Enhanced Two-Photon Absorption

“…Three absorption bands for dilute PCBP-EPE and PCBP-EE became less resolved obviously with the decreased ratios of A 0‑0 / A 0‑1 to 0.9–1.0, as well as decreased oscillator strength f (Figures b, S6, S7, and Table S7). Relatively decreased ratios were indicative of increased cofacially H-type aggregates and strong exciton coupling between the adjacent PBIs . To our surprise, PCBP-EPE and PCBP-EE displayed obvious red-shift and broad emission peaks above 600 nm (Figure b) .…”

“…Relatively decreased ratios were indicative of increased cofacially H-type aggregates and strong exciton coupling between the adjacent PBIs. 22 To our surprise, PCBP-EPE and PCBP-EE displayed obvious red-shift and broad emission peaks above 600 nm (Figure 1b). 23 They also exhibited biexponential decay traces with fluorescence lifetimes for monomer and dimer states (Table S7).…”

Multiple Azoarenes Based Systems – Photoswitching, Supramolecular Chemistry and Application Prospects

“…Photoisomerization of the azobenzene units not only modulated the optoelectronic properties of the derivatives A‐36 a – c and A‐37 a – c , but also brought significant changes to the supramolecular assembly (Figure 7). [31a] The non‐conjugated azo‐PBI hybrids A‐37 a – c showed a wider band gap than the conjugated azo‐PBI hybrids A‐36 a – c . On isomerization of A‐37 c , a 150‐fold higher fluorescence intensity was observed along with an enhanced fluorescence lifetime, as well as an improved fluorescence quantum yield and increase in the Franck‐Condon ratio.…”

Synthesis, structural characterization, in vitro biological activity, and DFT calculations of Cu(II) complex

“…Because hydrazones are tautomers of azo compounds, they can be made from azo compounds that have a labile proton in the position conjugated with an azo group 3,4 . Well‐known chemicals called hydrazones have a variety of pharmacological effects, including antitumoral, 5 antifungal, 6 and antibacterial behaviur 7,8 . Moreover, they have demonstrated strong antioxidant properties in terms of scavenging free radicals 9 .…”