π-Conjugated Discrete Oligomers Containing Planar and Nonplanar Aromatic Motifs

Abstract

A new family of π-conjugated oligomers featuring a nonplanar polycyclic aromatic hydrocarbon, corannulene, and a planar aromatic unit, thiophene, is synthesized through an iterative metal-catalyzed coupling protocol. The two structural motifs are connected through an acetylene linkage. In the shorter oligomers, a thiophene unit is attached to one or two corannulenes. In the higher analogues, two, three, and four thiophene units are placed in an alternating fashion with three, four, and five corannulene units, respectively. Photophysical studies reveal extended π-effects that initially increase and then attenuate as a function of the oligomer length. Notably, longer oligomers are found to be highly active for nonlinear absorption and emission properties. The oligomer with three corannulene and two thiophene units exhibits a two-photon absorption cross section of 600 GM and two-photon-excited intense green luminescence. This work, therefore, introduces the concept of combining planar and nonplanar aromatic motifs in the design of π-conjugated discrete oligomers, establishes synthetic feasibility of such hybrid materials, reports on their photophysical properties that is anticipated to have significant implications for future research targets, and features the discovery that corannulene derivatives can exhibit excellent nonlinear optical activity when extended through π-bridges.

Geodesic‐Planar Conjugates: Substituted Buckybowls—Synthesis, Photoluminescence and Electrochemistry

“…[10,11] During the last decades the chemistry andp hysics of CA-derived buckybowl derivatives was thoroughlys tudied. [12][13][14][15][16][17][18] However,c omparably less work has been carried out in the field of Idpc and its derivatives.T he first synthetic approach towards Idpc by palladium catalyzed cyclization of suitable precursors was reported already in 2000, but lacked generality. [19] The aluminium-oxide mediated cove-regionr ing-closure through CÀF bond activation of fluoroarenes [20] towards pristine Idpc and other bowl-shaped PAHs developed by Amsharov et al in 2012 constituted am ajor breakthrough.…”

“…During the last decades the chemistry and physics of CA‐derived buckybowl derivatives was thoroughly studied [12–18] . However, comparably less work has been carried out in the field of Idpc and its derivatives.…”

Corannulene Chalcogenides

“…Finally, single‐stranded macromolecular architectures are prepared through metal‐catalyzed coupling reactions [43,44] . In the first instance, Stille coupling is employed to prepare a linear polymer (Scheme 11).…”

Bowl-Shaped Naphthalimide-Annulated Corannulene as Nonfullerene Acceptor in Organic Solar Cells

“…13,14 Its derivatives have been applied in organic field-effect transistors, [15][16][17] organic light-emitting diodes, 18,19 and nonlinear optics. 20 Due to its structural similarity to fullerenes, which are still the state-of-the-art acceptor materials in OPVs, 21 OSCs using corannulene and its derivatives have been fabricated by different groups. 22 By substituting the phenyl group in the widely used phenyl-C 61butyric acid methyl ester (PC 61 BM) with corannulene, a new fullerene-corannulene dyad has been successfully synthesized.…”