Electrode

Organic chemistry

Ring (chemistry)

Stereochemistry

Crystallography

Crystal structure

Conjugated system

Physical chemistry

Medicinal chemistry

Annulene

Chemistry

Bicyclic molecule

Pyridine

Azulene

Pyrrole

Polymer

Electrochemistry

Photochemistry

Journal of the American Chemical Society

Azulene, a nonbenzenoid bicyclic aromatic hydrocarbon with unique electronic structure, is a promising building block for constructing nonbenzenoid π-conjugated systems. However, azulene-fused (hetero)aromatics remain rare as a result of limited synthetic methods. We report herein the unexpected synthesis of azulene- and pyridine-fused heteroaromatics Az-Py-1, a seven fused ring system with 30π electrons, by reductive cyclization of a 1-nitroazulene. The structure of Az-Py-1 was unambiguously confirmed by single-crystal X-ray analysis, and analogues Az-Py-2-Az-Py-6 were also synthesized, demonstrating that this is an effective method for constructing azulene- and pyridine-fused heteroaromatics. Theoretical calculations and photophysical and electrochemical studies of Az-Py-1-Az-Py-6 suggest their potential as semiconductors, and the single-crystal ribbons of Az-Py-1 show high hole mobilities up to 0.29 cm2 V-1 s-1.

Azulene–Pyridine-Fused Heteroaromatics