An Ortho-modification Strategy to Develop Brooker's Merocyanine Probe for Precise Monitoring of pH Changes in Urine.

As a non-invasive body fluid, urine pH is one of the important biomarkers for diseases such as the kidneys. Therefore, rapid and accurate detection of urine pH is of great clinical significance. A novel fluorescent probe (SPPH-Cl) was developed based on Brooker's merocyanine skeleton for pH detection. The pKa of SPPH-Cl was adjusted to 6.55 using a phenolic hydroxyl ortho substitution strategy, therefore, the fluorescence response range of SPPH-Cl to pH covers the urine physiological pH range (4.6-8.0). SPPH-Cl has excellent water solubility, stable recoverability, wide anti-interference capability, and sensitive reactions to pH fluctuations in pure aqueous solutions. SPPH-Cl has succeeded in applying to monitor the pH of volunteer urine samples based on a standard curve established in artificially simulated urine, and the detection results have accuracy comparable to pH meters. Therefore, this work provided a powerful molecule tool for detecting pH in urine samples.

Donor-Acceptor Molecule Based High-Performance Photothermal Organic Material for Efficient Water Purification and Electricity Generation.

In this contribution, a unique donor-acceptor conjugated organic-small-molecule photothermal material, namely GDPA-QCN, is presented. Bulky dendritic triphenylamine (GDPA) was grafted onto quinoxaline-6,7-dicarbonitrile (QCN) with a phenyl ring as a bridge to form an "umbrella" architecture. Benefited from the particular molecular structure, in solid state, GDPA-QCN molecules adopted a loose packing mode due to the steric effect of "umbrella head" dendritic triphenylamine and flexible molecular structure feature, which allows efficient intramolecular motions and consequently elevates energy dissipation by taking the pathway of thermal deactivation within broad absorption range. The GDPA-QCN solid has high solar-thermal conversion efficiency with an absorption range from 300 to 1100 nm, which can promote superior water purification and electricity generation performance.

Novel intramolecular charge transfer effect-based ligands and aggregation-induced emission-active europium complexes: synthesis, characterization, and fluorescence properties.

Two novel coumarin derivatives and the corresponding europium complexes were prepared using a simple procedure. The pH response of the ligand and the aggregation-induced emission (AIE) properties of the target europium complex were studied. The ligand had an intramolecular charge transfer (ICT) effect and was linearly and sharply responsive under acidic conditions. The goal europium complexes exhibited excellent AIE performance when subjected to increasing concentrations of target europium complex or proportion of poor solvent. The effect of substituents on fluorescence strength or thermogravimetric and electrochemical properties was further investigated. The target complexes displayed the typical fluorescence of europium. The fluorescence amplitude of the target europium complexes was enhanced by the addition of electron-donating groups to ligands. Thermogravimetric research findings indicated that the target complexes possessed extreme thermal stability. Electrochemistry discovery findings indicated that the highest occupied molecular orbit energy level of EuL1 was greater than EuL2 , but the lowest unoccupied molecular orbit energy level was smaller than that of EuL2 . These complexes could be applied in medicinal chemistry, substance chemistry, and fluorescence labelling areas.

A rare extra-long flexible salamo-based bisoxime as highly efficient and selective probe for fluorescent identification of CO32- ion and mechanism exploration.

A novel extra-long carbon-chain salamo-like fluorescent chemical probe DNS (named as 2,2'-[1,10-(decanedioxy)bis(nitromethyldyne)]dinaphthol) containing ten methylene groups was synthesized based on the 2-hydroxy-1-naphthylaldehyde unit. Research has shown that the fluorescent probe DNS can achieve efficient and selective recognition of CO32- anions, with a detection limit LOD=1.59 × 10-8 M. The binding constant Ka = 3.7 × 104 M-1 and quantification limit is as low as LOQ=4.31 × 10-8 M, respectively. The possible identification mechanism of the fluorescent chemosensor DNS was analyzed and studied through fluorescence titration and nuclear magnetic titration. The results showed that the fluorescence chemical sensor DNS is deprotonated by CO32- anions, enhancing its fluorescence and producing a ICT effect.

Enantioselective Recognition of L-Lysine by ICT Effect with a Novel Binaphthyl-Based Complex.

A novel triazole fluorescent sensor was efficiently synthesized using binaphthol as the starting substrate with 85% total end product yield. This chiral fluorescence sensor was proved to have high specific enantioselectivity for lysine. The fluorescence intensity of R-1 was found to increase linearly when the equivalent amount of L-lysine (0-100 eq.) was gradually increased in the system. The fluorescence intensity of L-lysine to R-1 was significantly enhanced, accompanied by the red-shift of emission wavelength (389 nm to 411 nm), which was attributed to the enhanced electron transfer within the molecular structure, resulting in an ICT effect, while the fluorescence response of D-lysine showed a decreasing trend. The enantioselective fluorescence enhancement ratio for the maximum fluorescence intensity was 31.27 [ef = |(IL - I0)/(ID - I0)|, 20 eq. Lys], thus it can be seen that this fluorescent probe can be used to identify and distinguish between different configurations of lysine.