Depolymerization-Induced Electrochemiluminescence of Insoluble Porphyrin in Aqueous Phase

Abstract

Exploring efficient and robust electrochemiluminescence (ECL) performance of liposoluble porphyrins in aqueous phase for analytical purposes especially for important biological targets is still very challenging. In this work, a novel depolymerization-induced electrochemiluminescence (DIECL) of porphyrin and β-cyclodextrin (β-CD) self-assembly through a coreactant route was discovered. Among the studied meso-tetrasubstituted porphyrins, self-assembly of 5,10,15,20-tetrakis­(4-hydroxyphenyl) porphyrin (THPP) and β-CD (THPP@β-CD) exhibits the best DIECL behavior with high efficiency (21.8%) as well as good reproducibility and stability. A mechanistic study suggests that the facile complexation of porphyrins with amphiphilic β-CD via hydrogen bonding interaction greatly improves the water insolubility and the aggregation-caused deficient ECL of liposoluble porphyrins in aqueous solution. Furthermore, because of the strong hydrogen bonding between the hydroxyl groups on THPP@β-CD and a highly electronegative substrate, such THPP@β-CD is found to serve as an efficient luminophore for recognition of most electronegative fluoride (F–) in the aqueous phase with high sensitivity and selectivity, together with a low limit of detection (0.74 μΜ). The simplicity of this THPP@β-CD and its unique DIECL property in current work provides a new guide for the ECL applications of liposoluble porphyrins in aqueous phase.

Switching the Photoluminescence and Electrochemiluminescence of Liposoluble Porphyrin in Aqueous Phase by Molecular Regulation

“…1] and SO 4 .− [Eq. 2] coexist in appreciable quantities [19] . An electron transfer reaction between ATPP‐TPE .− and SO 4 .− occurs in the vicinity of the electrode to generate an excited state [ATPP‐TPE*, Eq.…”

“…For example, by facile complexation of porphyrin with amphiphilic β‐cyclodextrin (β‐CD), Wu et al. recently found an efficient depolymerization‐induced ECL strategy for applying liposoluble porphyrins in aqueous phase and recognition of fluoride [19] . On the other hand, the structural modification is considered as another promising approach for improving photophysical properties of luminophores in the aggregated state, innovated as aggregation‐induced emission (AIE) or aggregation‐induced emission enhancement (AIEE).…”

Switching the Photoluminescence and Electrochemiluminescence of Liposoluble Porphyrin in Aqueous Phase by Molecular Regulation

“…(2)] coexist in appreciable quantities. [19] An electron transfer reaction between ATPP-TPEC À and SO 4 C À occurs in the vicinity of the electrode to generate an excited state [ATPP-TPE*, Eq. 3],r esulting in ECL when the excited state returns to the ground state [Eq.…”

“…[18] Therefore,two judicious strategies have been explored to preserve or even improve photophysical properties of porphyrins in the aggregated state.O nt he one hand, much effort has been devoted to preventing the aggregation of porphyrins in aqueous phase by increasing their hydrophilicity.F or example,b yf acile complexation of porphyrin with amphiphilic b-cyclodextrin (b-CD), Wu et al recently found an efficient depolymerization-induced ECL strategy for applying liposoluble porphyrins in aqueous phase and recognition of fluoride. [19] On the other hand, the structural modification is considered as another promising approach for improving photophysical properties of luminophores in the aggregated state,innovated as aggregation-induced emission (AIE) or aggregation-induced emission enhancement (AIEE). Yuan and co-workers successfully changed the ACQ behavior of triphenylamine (TPA) to AIE one by smart structural modification of TPAc ore with tetraphenylethene (TPE) peripheral moiety,and the fluorescence quantum yield of this new created TPA-TPE can reach 100 %.…”

Aggregation-Induced Electrochemiluminescence of Tetraphenylbenzosilole Derivatives in an Aqueous Phase System for Ultrasensitive Detection of Hexavalent Chromium

“…Electrochemiluminescence (ECL) as a powerful and promising analytical technique is a phenomenon triggered by electrochemical processes involving electron transfers near the electrode surface. ECL combines the advantages of chemiluminescence and electrochemical technologies, which provide outstanding merits of high sensitivity, simple operation, rapid response, and good stability. − As we all know, an emitter is arguably a critical role in the ECL technique. The conventional chromophores often encounter a severe aggregation quenching effect, which resulted in faint ECL signals when applied to aqueous ECL, owing to the strong π–π interactions between aromatic rings.…”