Synthesis Of Cis-and Gem-Tetraphenylethlyene Bicycles With Aggregation Induced Emission And The Fluorescent Testing

In order to further understand the luminescence process and guide the design of an new AIE molecules,accurate understanding the mechanism of AIE has extremely vital significance.So far,for the mechanism of AIE,the most comprehensive and the most widely applicable mechanism is the restriction of intramolecular rotations.Based on the above,four benzene ring of TPE were fixed in the different locations and the cis/gem compounds of TPE were synthesized for the first time to obtain that the specific evidence of an AIE phenomenon caused by the restriction of the excited double bond rotation.(1)A series of new cis-and gem-TPE bicycles were synthesized and characterized by NMR,MS,IR and X-ray single crystal diffraction.(2)The fluorescence test shows that they have the typical AIE properties.However,the cis-TPE bicycle can launch strong fluorescence in solution and the gem-TPE bicycle don’t launch fluorescence.The fluorescence quantum efficiency of the cis-TPE bicycle is more than the gem-TPE bicycle.(3)1H NMR in the room temperature show that the phenyl and the methylene of gem-TPE bicycle are rotating rapidly.When temperature is zero,the rotation of them become slower.However the fluorescence has no much enhancement.When the m-phthalic oxygen groups were lined to TPE,the phenyl and the methylene of the cis-and gemTPE bicycle are all rotating in the room temperature.But the fluorescence quantum efficiency of the cis-TPE bicycle is ten times greater than the gem-TPE bicycle.So the excited double bond is the main reason of the AIE phenomenon.