SYNTHESIS AND PHOTOPHYSICAL PROPERTIES OF NEW DIPHENYLACRYLONITRILE-BEARING ALDEHYDES

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Background: The cyano group is well-known for its strong electron-withdrawing properties, Effective in producing acrylonitrile when added to ?-conjugated alkene structures. The twisted structures of acrylonitrile help avoid the ACQ phenomenon and induce AIE properties, making acrylonitrile units important in various applications. Aims: Synthesis of acrylonitrile units via cyano aldol condensation by temperature control and study of AIE activity. Methods: The synthesis of diphenyl acrylonitrile units took place in two steps: 1- By o-arylation, linear aldehydes were synthesized, 2- Gradually adding p-ansiyl cyanide to the linear aldehydes in a round flask containing methanol and KOH. Results: Diphenyl acrylonitrile units were synthesized, and their structures were identified using IR, 1HNMR, 13CNMR, and mass techniques. The photophysical results indicated that diphenylacrylonitrile-bearing aldehyde compounds have fluorescence with a wavelength ranging between 400-500 nm and moderate AIE activity. Discussion: The prepared diphenylacrylonitrile-bearing aldehydes units showed moderate AIE activity in the aggregation state, where the fluorescence intensity increases with increasing water percentage in the THF/H2O mixture and reaches its peak at 80%. The reason lies in the fact that the cyano group forms acrylonitrile with twisted structures, which avoids ACQ and enhances the AIE properties. Conclusions: by controlling the temperature and through a facile aldol condensation, phenylacrylonitrile units were synthesized in good yields. Their photophysical properties were studied, and they were found to have moderate AIE activity.