Synthesis And Application Of Reactive Fluorescent Probe Based On Triphenylamine / Naphthalimide

Organic fluorescent probes are widely used in the detection of micro environment,such as biological ions,amino acid molecules,protein molecules,cell viscosity,p H,etc.The level of ions in organism plays an important role in maintaining the cell homeostasis and normal operation of physiological mechanism.When the concentration of ions is too high or too low,the cell environment can not be regulated normally,causing cell environment disorder or even death,which leads to various biological diseases.Therefore,it is of great significance to develop a more simple and efficient method to detect the ion level in micro environment.In this paper,we designed and synthesized reactive fluorescent probes for ion detection by using triphenylamine or naphthalimide as the fluorescent group,and explored its application.The specific research work of this paper is as follows(1)The triphenylamine derivative TPA containing aldehyde group was synthesized by using triphenylamine as luminescent group and electron withdrawing N-methyl-4-vinylpyridinium salt as modifying group.Then the small molecule fluorescent probe THP was synthesized by condensation with hydroxylamine hydrochloride.The Nano-THP was further coated by m PEG-DSPE-2000.The results of UV visible and fluorescence spectra show that THP can only identify ClO^-,while Nano-THP can detect ClO^-,which is highly selective in pure water,and is not interfered by other ions.The mechanism of THP response to ClO^-,indicated that oxime of THP may be oxidized to-C(?)N⁺-O^-under the action of ClO^-.Confocal fluorescence imaging showed that Nano-THP could turn on the fluorescence imaging of exogenic ClO^-display in cells.(2)The small molecule TM with formyl structure was synthesized by using triphenylamine as luminescent group and 4-methoxystyrene as electron donor group.The Schiff base fluorescent probes TMN,TMC and TMS were synthesized by the reaction of TM with diaminomaleonitrile,coumarin hydrazide and salicylhydrazide,respectively.Their ion detection performance was studied.The results show that TMN can recognize ClO^-and Hg²⁺in ethanol water(1:1,v:v)and is a dual detection fluorescent probe.TMN showed a"turn on"fluorescence response to ClO^-and a significant color change(from yellow to brown)in response to Hg²⁺.The recognition mechanism of TMN for ClO^-is that TMN is oxidized by ClO^-and cyclized in molecule,then the imidazole structure is formed.Fluorescence confocal imaging showed that TMN could detect exogenous ClO^-in cells,and it could also be used to detect Hg²⁺in naked eyes.In pure DMF solution,the probe TMC showed a highly selective"turn on"fluorescence response to ClO^-and could be used for cell imaging.The recognition mechanism of TMC to ClO^-showed that-CH=N-of TMC was broken and oxidized to carboxyl group under the action of ClO^-.TMS has highly selective recognition of Cu²⁺in ethanol water(2:3,v:v).The presence of Cu²⁺makes the fluorescence quenching of TMS solution accompanied by obvious color change(from light yellow to bright yellow),which can be made into a test paper for naked eye detection of Cu²⁺.The recognition mechanism is that TMS is hydrolyzed to aldehydes in the presence of Cu²⁺.(3)In addition to the above probe,we tried to synthesize Cu NI by the reaction of naphthalimide with hydrazide.N-(morpholinpropyl)-4-formylphenyl-1,8-naphthalimide(MFNI)was synthesized from 4-br-1,8-naphthalene dicarboxylic anhydride by introducing morpholine ring and 4-formylphenyl into naphthalimide.MFNI has aggregation induced emission(AIE)in pure aqueous solution and emits bright blue fluorescence.A typical schiff base compound Cu NI was obtained by the reaction of MFNI with 2-pyridyl hydrazide.The ion recognition performance of Cu NI shows that Cu NI can recognize Cu²⁺with high selectivity in pure aqueous solution and presents"turn on"fluorescence response.The results showed that Cu NI was hydrolyzed to aldehyde(MFNI)with the participation of Cu²⁺.The results showed that the probe Cu NI had excellent cytocompatibility and could accurately target Cu²⁺in lysosomes.