Synthesis and photoluminescent properties of conjugated aryl–vinyl dioctyl 2,6-dimethylbenzofuro[5,6-b]furan-3,7-dicarboxylate derivatives

• Highly fluorescent heterocyclic compounds.
• An efficient synthetic approach to conjugated linear benzodifurans.
• Modern synthetic method using efficient catalysts for the Heck coupling reaction.
• QM calculations for HOMO/LUMO orbitals levels.

The synthesis of highly fluorescent conjugated benzodifuran aryl–vinyl systems, containing four double bonds and at least four phenyl rings, is described. The ethyl groups of diethyl 2,6-dimethylbenzofuro[5,6-b]furan-3,7-dicarboxylate, obtained by the Michael type condensation of p-benzoquinone and ethyl acetoacetate, were replaced by octyl groups via the transesterification reaction to improve the desired product solubility in common organic solvents. The dioctyl ester was brominated and used for the Wittig reaction with stilbene aldehydes, obtained by the Heck reaction of 4-bromobenzaldehyde and an appropriate styrene. The products, obtained in 48–92% yield, exhibit the UV–Vis fluorescence with high quantum yields, 58–69%.

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