Search

Abstract: Tetraphenylethylene (TPE) foldamers with double hairpin‐turn linkers showing an aggregation‐induced emission (AIE) effect have been synthesized for the first time. A crystal structure of a foldamer–TNT complex has been obtained, enabling unprecedented direct observation of the interactions between TNT molecules and the chromophores of the foldamer. Instead of π–π stacking interactions, which have often been considered to be the key mechanism in the binding of TNT by chromophoric receptors, strong n–π interactions between the nitro groups of TNT and the aromatic rings of the foldamer have been found. Exceptionally, by addition of 1 % NaF to a suspension of the foldamer in H2O/THF (95:5), the fluorescence quenching efficiency by TNT vapor significantly increased from about 20 % to more than 90 %. Even after diluting TNT‐saturated air at 25 °C by a factor of 2×104, an obvious quenching response was observed, indicating that ultratrace TNT vapor (down to 3.4 fg per mL of air) could be detected. [ABSTRACT FROM AUTHOR]

Tetraphenylethylene (TPE) and its derivatives are the most typical and most widely studied organic compounds showing aggregation-induced emission (AIE). Due to their propeller-like structures, V-like clefts exist between the aryl rings, which make them promising host compounds. However, such a possibility is seldom explored. Herein, it is reported that TPE derivatives bearing two or four pyridine rings at the para positions of the phenyl rings (TPE-Pys) can selectively include triangular (Δ-like) m-phthalic acid from a mixture of o-, m-, and p-phthalic acids due to their shape complementary to form host-guest co-crystals, which showed redder emission than the TPE-Pys themselves. The emission of co-crystals 1- 5 could be reversibly switched between yellow and red by alternating exposure to HCl and ammonia vapor. The host-guest co-crystals not only exhibited great potential for selectively recognizing and separating m-phthalic acid and as multicolor emission materials, but are also suitable for use as secret ink due to their reversible color change on varying the host-guest interactions. [ABSTRACT FROM AUTHOR]

A tetraphenylethylene (TPE) Schiff-base macrocycle showing an aggregation-induced emission (AIE) effect has been synthesized, which could aggregate into nanospheres and emit yellow fluorescence in aqueous media. By virtue of its AIE effect, the macrocycle showed a sensitive and selective response to 2,4,6-trinitrophenol (TNP) and 2,4-dinitrophenol (DNP) among a number of nitroaromatic compounds, which could be used to detect TNP and DNP at nanomolar levels. Moreover, it exhibited a superamplified quenching effect with DNP but not with TNP, providing a possible means of discriminating these two compounds. In comparison with open-chain TPE Schiff-bases, the cavity of the macrocycle is essential for the selectivity for DNP over TNP. In addition, quantitative analyses of both DNP and TNP in real water samples and qualitative detection of these two analytes in the solid state by the macrocycle have been tested. The reliability of the quantitative analysis has been confirmed by HPLC. Our findings demonstrate that the TPE Schiff-base macrocycle has great potential as an excellent sensor for DNP and TNP. [ABSTRACT FROM AUTHOR]

Itwas found for the first time that neutral amphiphilc tetraphenylethylene(TPE) derivatives showed an enhanced monomer emission and a decreasedaggregate emission when they were included in the cavity of γ-cyclodextrin.This result provided a new insight into the aggregation-induced emission(AIE) effect. [ABSTRACT FROM AUTHOR]