Features of a truxene-based stationary phase in capillary gas chromatography for separation of some challenging isomers.

Herein we report the first example of exploring truxene-based derivatives for gas chromatographic (GC) separations. The fabricated thiophene-functionalized truxene (TFT) column exhibited weak polarity and efficiencies as high as 4000plates/m for 0.250mm i.d. columns. TFT column showed preferential retention for halogenated and alkyl benzene analytes, and especially, high resolving capability for the xylene isomers, di- and trichlorobiphenyls (di-CB and tri-CB) isomers. Interestingly, its unique retentions for the latter analytes were found to be closely related with their dihedral angles and the locations of chlorine atoms. This finding on the retention trend has not been reported in GC separations, which may provide a new perspective in elucidating retention behaviours for specific analytes. Moreover, TFT column exhibited high thermal stability up to 320°C and excellent repeatability. This work demonstrates the promising future of truxene derivatives in the separation science.

Rational design of asymmetric red fluorescent probes for live cell imaging with high AIE effects and large two-photon absorption cross sections using tunable terminal groups.

In this work, we report the synthesis of a family of donor-acceptor (D-A) π-conjugated aggregation-induced red emission materials (TPABT, DTPABT, TPEBT and DTPEBT) with the same core 2,2-(2,2-diphenylethene-1,1-diyl)dithiophene (DPDT) and different amounts and different strengths of electron-donating terminal moieties. Interestingly, TPABT and TPEBT, which have asymmetric structures, give obviously higher solid fluorescence quantum efficiencies in comparison with those of the corresponding symmetric structures, DTPABT and DTPEBT, respectively. In particular, the thin film of TPEBT exhibited the highest fluorescence quantum efficiency of ca. 38% with the highest αAIE. Moreover, TPEBT and DTPEBT with TPE groups showed two-photon absorption cross-sections of (δ) 1.75 × 103 GM and 1.94 × 103 GM at 780 nm, respectively, which are obviously higher than the other two red fluorescent materials with triphenylamine groups. Then, the one-photon and two-photon fluorescence imaging of MCF-7 breast cancer cells and Hela cells, and cytotoxicity experiments, were carried out with these red fluorescent materials. Intense intracellular red fluorescence was observed for all the molecules using one-photon excitation and for TPABT using two-photon excitation in the cell cytoplasm. Finally, TPEBT is biocompatible and functions well in mouse brain blood vascular visualization. It is indicated that these materials can be used as a specific stain fluorescent probe for live cell imaging.

Hexaphenylbenzene-Based, π-Conjugated Snowflake-Shaped Luminophores: Tunable Aggregation-Induced Emission Effect and Piezofluorochromism.

In this work, two rigid, multiple tetraphenylethene (TPE)-substituted, π-conjugated, snowflake-shaped luminophores BT and BPT were facilely synthesized by using a 6-fold Suzuki coupling reaction. These molecules are constructed based on the nonplanar structure of propeller-shaped hexaphenylbenzene (HPB) or benzene as core groups and TPE as end groups. As a result, they reserve the intrinsic aggregation-induced emission (AIE) property of the TPE moiety. Meanwhile, both fluorescence quantum yield and piezochromic behavior in the solid state can be tuned or switched by inserting the phenyl bridges through changing the twisting conformation. The more extended structure BPT showed a much stronger AIE effect and higher ΦF,f in the solid state in comparison with that of BT. Furthermore, an excellent optical waveguide application of these molecules was achieved. However, the revisable piezofluorochromic behavior has only appeared when BT was ground using a pestle and treated with solvent.