Pillararene-Based Aggregation-Induced-Emission-Active Supramolecular System for Simultaneous Detection and Removal of Mercury(II) in Water.

Supramolecular polymers are polymers based on monomeric units held together with directional and reversible noncovalent interactions. Compared with traditional polymers, they possess better processability and better recycling properties, owing to their reversible monomer-to-polymer transition. Herein, we report the construction of a new supramolecular system through self-assembly of a thymine-substituted copillar[5]arene 1 and a tetraphenylethylene (TPE) derivative 2 in the presence of Hg2+. Copillar[5]arene 1 can coordinate with Hg2+ tightly through T-Hg2+-T pairings. On the other hand, 1 can bind with guest molecule 2 through host-guest interactions between the pillararene cavity and the nitrile moiety of 2. These joint interactions generate crisscrossed networks composed of 1, 2, and Hg2+, which eventually wrap into spherical nanoparticles. Due to the aggregation-induced emission (AIE) properties of 2, the formed supramolecular polymer exhibits strong fluorescence which renders convenient the detection of the Hg2+-containing nanoparticles and the subsequent removal procedure. Furthermore, the polymer precipitate can be readily isolated by simple treatment, and the pseudorotaxane 2 ⊂ 1 can be recycled and reused. Our study has demonstrated a practical strategy for the sensing and removal of heavy metal ions in water by the construction of supramolecular polymers.

Simultaneous saccharification and co-fermentation of dry diluted acid pretreated corn stover at high dry matter loading: Overcoming the inhibitors by non-tolerant yeast.

Dry dilute acid pretreatment (DDAP) is a promising method for lignocellulose bioconversion, although inhibitors generated during the pretreatment impede the fermentation severely. We developed the simultaneous saccharification and co-fermentation (SScF) of DDAP pretreated biomass at high solid loading using xylose fermenting Saccharomyces cerevisiae, SyBE005. Effect of temperature on SScF showed that ethanol yield at 34°C was 10.2% higher than that at 38°C. Ethanol concentration reached 29.5 g/L at 15% (w/w) dry matter loading, while SScF almost ceased at the beginning at 25% (w/w) dry matter loading of DDAP pretreated corn stover. According to the effect of the diluted hydrolysate on the fermentation of strain SyBE005, a fed-batch mode was developed for the SScF of DDAP pretreated corn stover with 25% dry matter loading without detoxification, and 40.0 g/L ethanol was achieved. In addition, high yeast inoculation improved xylose utilization and the final ethanol concentration reached 47.2 g/L.

A prominent bathochromic shift effect of indole-containing diarylethene derivatives.

The potential implication of photochromic materials with absorption and reactivity in the near-infrared region is far-reaching. In this work, three novel bisindole-containing diarylethene derivatives 1o­3o have been successfully synthesized and their photochromic behaviour exhibits a strong bathochromic shift effect compared with bisbenzothiophene diarylethene 4o. These new bisindole-diarylethene compounds 1o­3o are highly sensitive to photo-stimuli both in solution and in poly(methyl methacrylate) films. Besides, 1o­3o exhibit an excellent reversible fluorescence switching behavior modulated by optical stimuli.

Highly efficient enantioselective construction of bispirooxindoles containing three stereocenters through an organocatalytic cascade Michael-cyclization reaction.

Bispirooxindole derivatives containing three stereocenters, including two spiro quaternary centers, were synthesized in a high-yielding, atypically rapid, and stereocontrolled cascade Michael-cyclization reaction between methyleneindolinones and isothiocyanato oxindoles catalyzed by a bi- or multifunctional organocatalyst. Mild conditions were used to construct bispirooxindoles with excellent enantio- and diastereomeric purities within less than 1 min. Catalyst reconfiguration offered access to the opposite enantiomer. This exceptionally highly efficient procedure will allow diversity-oriented syntheses of this intriguing class of compounds with potential biological activities.