Synthesis And Luminescent Properties Of Tetraphenylethene Probes Containing N And O Coordination Sites

The traditional chromophores exhibits aggregation-caused quenching(ACQ)in aggregated state,which greatly limits the application of fluorescent/phosphorescent materials.Therefore,the development of high-efficiency solid-state light-emitting materials has been research hotspot in recent years.Until the discovery of aggregation-induced emission(AIE),which overcomes the defects of the optical performance of traditional materials,it also promotes the application and development of high-efficiency luminescent materials..Therefore,the development of AIE materials has received high attention from experts.In this type of material,the typical AIE characteristics of tetraphenylethylene(TPE)have excellent luminescence performance in the aggregated state,and is simple to synthesize and easy to be functionalized,which is convenient to combine with other chromophores to obtain luminescent materials with excellent performance.In this paper,two types of molecules with AIE properties were synthesized based on tetraphenylethylene groups.Their photophysical properties and applications in chemical sensing were studied.The main contents are as follows:1.A series of metal probes TPE(OH)-8HQ,Tri PE(OH)-8HQ and TPE(OCH₃)-8HQ were obtained by constructing tetraphenylethylene/triphenylethylene derivatives and then reacting with 2-methyl-8hydroxyquinoline.The luminescence properties of aggregation induced emission under different water contents were explored which showed that the molecules have AIEE properties.The results of fluorescence spectra showed that TPE(OH)-8HQ and Tri PE(OH)-8HQ can specifically recognize Zn²⁺,which can be used as an excellent red chemsensor,and the probe was found to have a large Stokes shift(289 nm),Which can effectively avoid the interference of the excitation light during the test.TPE(OH)-8HQ has better AIE characteristics than Tri PE(OH)-8HQ,which has better fluorescence enhancement effect,and has a lower detection limit is 1.64×10^-7M for Zn²⁺.During the ion interference test of TPE(OH)-8HQ,it was found that except for Co²⁺and Cu²⁺ions,there was less interference from other ions(no effect on the recognition of Zn²⁺in the living system),and it could work stably in the p H range of 6?13;Fluorescence/ultraviolet titration was used to detect the binding process with metal ions,and it was found that the intensity of the fluorescence spectrum and the absorption spectrum showed a good linear relationship with the increase of Zn²⁺concentration;Job's mapping method and ¹H NMR titration determined that the combinated method and the binding ratio of probe molecule to Zn²⁺is 2:1;from the cell imaging results of probe TPE(OH)-8HQ,it showed that the red fluorescence in tracellular was gradually increasing with the increase of Zn²⁺concentration,it showed that the probe as a red chemsensor cound detected Zn²⁺in cells excellently.2.Base on different diamine molecules(1,3-propanediamine,1,2-cyclohexanediamine,o-phenylenediamine)as bridging groups,three tetraphenylethylene Schiff base ligands 1a,2a,3a with the[O,N,N,O]binding site were designed and synthesized,it in order to explore the effects of different twisting bridging groups on the overall molecular structure and optical properties.The results show that the fluorescence intensity of the ligand at different water contents indicates that the molecule has AIEE properties.It was found that the bridging group has effect on the overall distortion of the ligand gradually decreases to weaken the AIE effect.The phenyl group in 3a restricts intramolecular distortion which causes the AIE effect to be insignificant.The single crystal structure of 3a was obtained by the solvent volatilization method.The arrangement of the crystals and the intermolecular forces were studied.The[O,N,N,O]binding sites of 3a are on a plane.It makes it possible to better react with Pt²⁺,and shows that 3a can be used as a fluorescent/phosphorescence sensor for Pt²⁺specific recognition and achieve change from yellow-green fluorescence to red phosphorescence,which has the function of visual recognition and excellent anti-interference ability.The anion binding experiment confirmed that can effectively distinguish OH^-from other anions the ligand with strong yellow-green fluorescence,mechanism research proves that the reason for the enhanced fluorescence is different from the AIE phenomenon because a new hydrogen bond is formed between the ligand and OH^-.Finally,a preliminary study on the photophysical properties of the metal platinum complex was found to have aggregation-induced phosphorescence properties.