1,2,5,6,9-Pentaazacoronenes (PACs) and π-Extended PAC Derivatives: Synthesis, Crystal Structure, and Optical and Redox Properties

Abstract

A novel class of 1,2,5,6,9-pentaazacoronene (PAC, 1) derivatives and π-extended PAC derivatives, chromeno­[2,3,4-ij]­pentaazacoronenes (CPACs, 2), has been successfully synthesized on the basis of intramolecular diazo-coupling reaction and Pictet–Spengler cyclization. Single-crystal analysis demonstrates that 1o (R1 = H) displays a herringbone packing motif while 1s (R1 = C3F7) packs into an S-shaped arrangement. Photophysical and electrochemical studies indicated that the new PAC system manifested significantly red-shifted absorption and emission capacity, larger Stokes shifts, and narrower HOMO–LUMO energy gaps.

Synthesis, crystal structure, and properties of methyl-substituted coronene amide analogue

“…2e and S2, ESI †). [14][15][16]20 Given the structure of 3, alternations of the C-C bond lengths in the central hexagon (1.411-1.441 Å) represented lower aromaticity than that of the benzene ring (Fig. 2d).…”

“…Compound 3 crystallized as a kryptoracemate in the Sohncke space group P2 1 with two enantiomeric molecules in the asymmetric unit (Z 0 ¼ 2). 28,29 Compared to the core of 3 with those of other coronene analogues, [14][15][16][17]19,20 it exhibited low planarity with a maximum distance of 0.304 Å between the peripheral atom of the core and 2D plane based on the central ring (Fig. 2b).…”

“…[5][6][7][8] Doping of heteroatoms in aromatic rings is an effective approach for modulating physico-electrochemical properties, and several synthetic studies of heterocoronenes have been reported. [9][10][11][12][13][14][15][16][17][18][19][20] As a coronene analogue containing amide linkages, the synthesis 17 and application to organic semiconductors 18 of a D 2h symmetric compound 1 have been reported. Recently, our group has synthesized 2, a new C 3 symmetrical coronene analogue with three peripheral amide linkages, by the cyclic trimerization of 2-bromo-4-(isobutylamino)benzoic acid, followed by palladium-mediated intramolecular biarylation.…”