In this work, through the Suzuki–Miyaura cross-coupling reaction with high yields, new π-conjugated azulene compounds containing diphenylaniline groups at positions 2 and 6 of azulene were synthesized. The obtained diphenylaniline–azulenes have intensely visible-light absorbing and emitting (in the wavelength range from 400 to 600 nm) properties. It has been shown that such unique optical properties, in particular fluorescent emission in the region of blue and green photoluminescence (λem at 495 and 525 nm), which were absent in the original azulene, are the result of the electron donor effect of diphenylaniline groups, which significantly changes the electronic structure of azulene and leads to the allowed HOMO → LUMO electron transition.

The bulletin of Irkutsk State University. Series «Mathematics»

The Knoevenagel condensation of azulenyl ketones with malononitrile resulted in the synthesis of π-conjugated 1-mono- and 1,3-bis(phenyldicyanovinyl)azulenes, and the Kumada cross-coupling reaction of bromazulenes with PhMgBr gave 1-mono- and 1,3-biphenylazulene. The electronic spectra of dicyanovinylated azulenes showed strong absorption bands of intramolecular charge transfer in the visible region, as well as significant bathochromic shifts of the absorption maxima of phenylazulenes.