Products Cited in Publications Worldwide Twofold 6π‐Electrocyclization as a Route Toward Multi‐Heteroatom‐Doped Nanographenes Built on 1, 4‐Dihydropyrrolo [3, 2‐b] pyrrole Core

Twofold 6π‐Electrocyclization as a Route Toward Multi‐Heteroatom‐Doped Nanographenes Built on 1, 4‐Dihydropyrrolo [3, 2‐b] pyrrole Core

Górski, Krzysztof; Pejov, Ljupcho; Jørgensen, Kåre B; Knysh, Iryna; Jacquemin, Denis; Gryko, Daniel T

DOI: PMID:

Abstract

Here we present a highly versatile synthetic strategy based on twofold 6π-electrocyclization accompanied with HBr elimination as a novel approach towards centrosymmetric multi-heteroatom-doped nanographenes build around an electron-rich 1,4-dihydropyrrolo[3,2-b]pyrrole core. A straightforward synthesis from readily available substrates offers a unique possibility of fusing the 1,4-dihydropyrrolo[3,2-b]pyrrole subunit not only with carbocyclic building blocks, such as electron-deficient phenanthrenes, chrysenes, or [4]helicenes, but also with heterocyclic systems, such asbenzo[b]furan and 5-thiatruxene. The clear advantage of this strategy is that there is no requirement to assemble complex scaffolds possessing bromoaryl units since bromine atom is introduced by bromination of 1,4-dihydropyrrolo[3,2-b]pyrrole core which, because of its exceptionally electron-rich character, is straightforward reaction. The obtained χ-shaped and S-shaped nanographenes containing 10or more fused rings, exhibit visible-range emissions characterized by fluorescence quantum yields reaching 48%. Computational studies of the reaction mechanism revealed that the 6π-electrocyclization is kinetically favourable over photo-induced direct arylation. Steadystate UV/Visible spectroscopy reveals that upon photoexcitation, the prepared S-shaped N-doped nanographenes undergo mostly radiative relaxation leading to large fluorescence quantum yields. We anticipate that this chemistry will empower the creation of new materials with various functionalities.

Keywords

Dyes/Pigments ; Photochemistry ; Nanographenes ; Pyrrole ; Fluorescence

Purchased from AmBeed

A13039726465-81-697%

3,3-Dimethyl-2,3-dihydro-1H-inden-1-one

10.0/1g

Detail

A229949113893-08-698%

Benzo[b]thiophen-3-ylboronic acid

108.0/25g

Detail

A3325936287-82-798% (stabilized with Cu+HQ+MgO)

2,3-Dibromobenzo[b]thiophene

15.0/5g

Detail
NBS

A607865128-08-598%

NBS

15.0/25g

Detail