Effect of the mismatch structure on crystal packing, physical properties and third-order nonlinearity of unsymmetrical twistacenes

•Five-membered ring-embedded unsymmetrical twistacenes were prepared.•The formed molecules show high thermal stability and strong blue, green and yellow fluorescence.•These molecules exhibited large third-order nonlinearity, which could be utilized in optical devices.

A novel family of unsymmetrical twistacene analogues were synthesized in a palladium-promoted cross-coupling reaction and fully characterized, where five-membered ring was embedded into the main skeleton in these molecules. The formed all-carbon compounds appreciate a series of promising photophysical properties such as good thermal stability and photostability than that of acenes consisting of all six-membered rings. All of them emitted strong solution fluorescence covered a wide range from cyan to yellow. In addition, the nonlinear optical properties were further investigated through the top-hat Z-scan technique at 515 nm, which indicates that all of them presented excellent third-order nonlinear absorption effects.

Graphical abstractFive-membered ring-embedded unsymmetrical twistacenes were prepared that presented large third-order nonlinearity.Figure optionsDownload full-size imageDownload as PowerPoint slide