Photophysical Properties Of D-A Structure Containing Heteroatom Restricted Triphenylamine

As a extensively studied organic fluorophore,triphenylamine is a typical electron donor and combines with different types of acceptors to form D-A systems for intramolecular charge transfer reactions.It has applications in various fields such as solar cells,fluorescent probes and organic light-emitting diodes.In order to make these organic fluorescent molecules have more excellent optical properties,this paper will utilize triphenylamine as the parent and use different heteroatoms to link the benzene ring to restrict the triphenylamine structure,adjust theπ-conjugation strength and electron donating ability,and then combine with different acceptors to make these derivatives with different intramolecular charge transfer（ICT）properties,expecting them to have more meaningful applications in a wider range of fields.The specific contents are as follows:（1）A series of nitro compounds with efficient fluorescence were synthesized by oxygen-bridged restricted triphenylamine structures,and the photophysical properties were investigated.Nitro group is a typically fluorescent bursting group,which limits its application in various fields.Therefore,revealing the pathway to photoluminescence and overcoming the inherent quenching properties of nitroaromatics are essential for the development of nitro compounds capable of fluorescence in the field of optoelectronics.We designed a series of trinitro compounds based on the triphenylamine structures TPA-NO₂,PXZ-NO₂and TOTA-NO₂.Fluorescent nitro compounds with high fluorescence quantum yields were successfully developed by limiting the rotation of the triphenylamine benzene ring through oxygen bridges to expand theπ-conjugation strength and improve the electron giving ability.（2）The D-π-A structural compounds PXZPy,PTZPy,PXZPy-CH3 and PTZPy-CH3weredesignedandsynthesizedwith N-phenylphenoxazine/phenothiazine as the electron donor and pyridine/pyridine salt as the electron acceptor linked by carbon-carbon double bonds.These compounds have a stronger electron donor unit than triphenylamine allowing for a more pronounced intramolecular charge transfer effect,as well as a more rigid structure.Among them,PXZPy and PTZPy-CH₃can successfully enter Hpe G2 human liver cancer cells for biological cell imaging due to their good AIE properties and reactive oxygen yield.