Fluorescence ''turn-on'' probe for the selective detection of water in organic solvents based on functionalized mesoporous silica

A fluorescence ''turn-on'' probe, namely, TTA-SBA-15, for the selective detection of water (H₂O) was designed by grafting terthiophene fluorophore onto ethylenediamine functionalized mesoporous SBA-15 silica. The maximum fluorescence emission peak of TTA-SBA-15 ranged from 462 nm (toluene) to 525 nm (methanol) in various organic solvents. No fluorescence was observed in H₂O due to the donor-excited photoinduced electron transfer mechanism, in which terthiophene acted as the donor and the amino group acted as the acceptor. Upon adding trace amounts of H₂O into the TTA-SBA-15 suspensions dispersed in various organic solvents, TTA-SBA-15 was successfully applied as a ''turn-on'' fluorescent probe for the quantitative determination of trace H₂O in organic solvents with high sensitivity and low detection limit. To demonstrate the selective detection mechanism of TTA-SBA-15 for H₂O, the fluorescent spectra of two control materials (TT-SBA-15 and PyA-SBA-15) were also investigated in H₂O and various organic solvents. The experimental results indicated that the terthiophene fluorophore and amine functional group on TTA-SBA-15 contributed to the H₂O selectivity, highlighting the structure-activity relationships in developing organic functionalized mesoporous silica for potential applications.

Circularly polarized luminescence of nanoassemblies via multi-dimensional chiral architecture control

Circularly polarized luminescence (CPL) materials are currently an important class of chiroptical materials that are attracting increasing interest. Nanoassemblies constructed from chiral or achiral building blocks show great potential for achieving CPL-active nanomaterials with high quantum yields and dissymmetry factors, which is crucial for further applications. In nanoassemblies, the dimensional morphology affects the chiroptical properties significantly since the microscopic packing modes will affect the luminescence processes and chirality transfer processes. In this review, we will show some examples for illustrating the relationship between multi-dimensional morphology and chiroptical properties. Furthermore, with dimensional morphology tuning, higher dissymmetry factors would be obtained. We hope to provide a useful and powerful insight into the design and control of CPL-active nanoassemblies via morphology control.

SnCl2-catalyzed synthesis of dihydro-5H-benzo[f]pyrazolo[3,4-b]quinoline and dihydroindeno[2,1-b]pyrazolo[4,3-e]pyridine with high fluorescence and their photophysical properties

A series of pyrazoloquinoline and pyrazolopyridine based derivatives bearing donor–acceptor (D–A) substituent groups on the phenyl ring, was synthesized by a mild reaction condition.

Radical Arylation of Anilines and Pyrroles via Aryldiazotates

The radical arylation of anilines and pyrroles can be achieved under transition-metal- and catalyst-free conditions by using aryldiazotates in strongly alkaline aqueous solutions. The aryldiazotates act as protected diazonium ions, which do not undergo azo coupling with electron-rich aromatic substrates, but can still serve as an aryl radical source at slightly elevated temperatures. Based on an improved preparation of aryldiazotates in aqueous solution, homolytic aromatic substitutions of anilines and pyrroles were conducted with good overall yields and high regioselectivity. Moreover, DFT calculations provided further mechanistic insights.

Aggregation-induced emission enhancement and aggregation-induced circular dichroism of chiral pentaphenylpyrrole derivatives and their helical self-assembly

AIEE-active chiral pentaphenylpyrrole derivatives possess AICD and circularly polarized luminescence features with self-assembling to regular nanofibers.