Achieving highly sensitive detection of Cu2+ based on AIE and FRET strategy in aqueous solution

Recent Development on Copper-Sensor and its Biological Applications: A Review

Metal ion recognition is one of the most prospective research topics in the field of chemical sensors due to its wide range of clinical, biological and environmental applications. In this context, hydrazones are well known compounds that exhibit metal sensing and several biological properties due to the presence of N=CH- bond. Some of the biological properties includes anti-cancer, anti-tumor, anti-oxidant, anti-microbial activities. Hydrazones are also used as a ligand to detect metal ion as well as to generate metal complexes that exhibit medicinal properties. Thus, in recent years, many attempts were made to develop novel ligands with enhanced metal sensing and medicinal properties. In this review, some of the recent development on the hydrazones and their copper complexes are covered from the last few years from 2015-2023. These includes significance of copper ions, synthesis, biological properties, mechanism and metal sensing properties of some of the copper complexes were discussed.

A novel carbazole-based fluorometric and colorimetric sensor for the highly sensitive and specific detection of Cu2+ in aqueous solution

Based on the typical Suzuki coupling reaction and Schiff base reaction, a novel fluorescent molecular PCBW is synthesized and applied as a fluorescence and colorimetric sensor to detect Cu2+ in aqueous solution. The PCBW sensor presents the aggregation-caused quenching (ACQ) effect and at 1 × 10-5 mol L-1 it emits the strongest turquoise fluorescence in the DMSO-H2O system (fw = 40%). The sensor exhibits a 'turn-off' fluorescent characteristic by adding Cu2+, and its fluorescent intensity shows a reliable linear relationship with the Cu2+ concentration in the range of 0-6 × 10-6 mol L-1, with a detection limit of 1.19 × 10-8 mol L-1. Meanwhile, the PCBW sensor also exhibits the colorimetric sensing from colorless to light yellow. The sensor has good selectivity and anti-interference and its pH application range can be extended from 5 to 10. The intramolecular charge transfer (ICT) is speculated as the main fluorescence mechanism of PCBW. In addition, the sensor presents good reusability and is practicable to detect Cu2+ in diverse aqueous samples.

Exciplex formation between a pair of synthesized AIEgens leads to white light generation: a spectroscopic exploration

Compounds BIMP and ECPA show aggregation promoted ESIPT and AIE emissions, respectively. The BIMP–ECPA ensemble behaves as a white light emitter through exciplex formation.

Rationally introduce AIE into chemosensor: A novel and efficient way to achieving ultrasensitive multi-guest sensing

Recently, ultrasensitive detection and multi-guest sensing have received extensive attention due to their high sensitivity and efficiency. Herein, we report a novel approach to achieve ultrasensitive detection of multi-analyte. This approach is concluded as "rationally introduce Aggregation-Induced Emission (AIE) into chemosensor". According to this approach, by rationally introducing self-assembly moiety, the obtained chemosensor DNS could serve as a novel AIEgen and show strong AIE in DMSO/H₂O (water fraction 80%) binary solution. Interestingly, a simple fluorescent sensor array based on the DNS has been developed. This sensor array could selectively sense Fe³⁺, Al³⁺, H₂PO₄^- and L-Arg in water solution. More importantly, this sensor array shows ultrasensitive detection for Fe³⁺, Al³⁺ and L-Arg. The LODs of the sensor array for Fe³⁺, Al³⁺ and L-Arg are in the range of 3.54×10^-9M to 9.42×10^-9M. Moreover, H₂PO₄^- could realize the reversible detection of Fe³⁺ in the DMSO/H₂O (water fraction 80%) solution. Meanwhile, DNS-based test papers and thin films were prepared, which could serve as test kits for convenient detection Fe³⁺, Al³⁺, and L-Arg in water. In addition, they could also act as efficient erasable fluorescent display materials.

Exploring the hidden potential of a methoxy substituted HBT derivative as an efficient example of coupling of AIE and ESIPT processes and as an energy harvesting platform

A methoxy substituted HBT derivative 2-(benzo[d]thiazol-2-yl)-6-methoxyphenol (TMP) showed coupling of AIE and ESIPT, underwent FRET with Rhodamine B and detected Sulfide in pure water by ratiometry.