Minimalistic Artificial Catalysts with Esterase-Like Activity from Multivalent Nanofibers Formed by the Self-Assembly of Dipeptides.

Imitating and incorporating the multiple key structural features observed in natural enzymes into a minimalistic molecule to develop an artificial catalyst with outstanding catalytic efficiency is an attractive topic for chemists. Herein, we designed and synthesized one class of minimalistic dipeptide molecules containing a terminal -SH group and a terminal His-Phe dipeptide head linked by a hydrophobic alkyl chain with different lengths, marked as HS-C n+1-His-Phe (n = 4, 7, 11, 15, and 17; n + 1 represents the carbon atom number of the alkyl chain). The His (-imidazole), Phe (-CO2 -) moieties, the terminal -SH group, and a long hydrophobic alkyl chain were found to have important contributions to achieve high binding ability leading to outstanding absolute catalytic efficiency (k cat/K M) toward the hydrolysis reactions of carboxylic ester substrates.

Ferrocene-Boronic Acid-Fructose Binding Based on Dual-Plate Generator-Collector Voltammetry and Square-Wave Voltammetry.

The interaction of ferrocene-boronic acid with fructose is investigated in aqueous 0.1 m phosphate buffer at pH 7, 8 and 9. Two voltammetric methods, based on 1) a dual-plate generator-collector micro-trench electrode (steady state) and 2) a square-wave voltammetry (transient) method, are applied and compared in terms of mechanistic resolution. A combination of experimental data is employed to obtain new insights into the binding rates and the cumulative binding constants for both the reduced ferrocene-boronic acid (pH dependent and weakly binding) and for the oxidised ferrocene-boronic acid (pH independent and strongly binding).

Synthesis and evaluation of a boronate-tagged 1,8-naphthalimide probe for fluoride recognition.

A biocompatible fluoride receptor has been developed where the interaction between the boronic acid ester and amine (NH) results in fluoride ion selectivity and enhanced fluorescence quenching.

Colorimetric enantioselective recognition of chiral secondary alcohols via hydrogen bonding to a chiral metallocene containing chemosensor.

An operationally simple colorimetric method for enantioselective detection of chiral secondary alcohols via hydrogen bonding interactions using a chiral ferrocene derivative is reported.

"Integrated" and "insulated" boronate-based fluorescent probes for the detection of hydrogen peroxide.

Integrated and insulated boronate-based fluorescent probes have been evaluated for the detection of hydrogen peroxide in the presence of saccharides.

A simple visual sensor with the potential for determining the concentration of fluoride in water at environmentally significant levels.

We have developed a simple and robust fluorescence based boronic-acid molecular sensor for determining the concentration of fluoride in water at environmentally significant levels. The simplicity of the method and the ability to measure fluoride in water between 0.1 and 1.5 ppm is particularly noteworthy given the WHO requirements for detecting levels of fluoride in drinking water below 1.5 ppm.

Supramolecular aggregation/disaggregation-based molecular sensing: a review focused on investigations from China.

Supramolecular aggregation and disaggregation induced by external stimuli can impact the optical or electrical signals of the aggregates/constituting units (receptors). Therefore, manipulating supramolecular aggregation/disaggregation has recently been employed to construct novel and promising photoluminescence (PL)-based sensing and recognition systems. The sensing systems were capable of substantially enhancing the sensitivity, relying on cooperative interactions occurring in the assembly/disassembly processes (mostly operating in emission turned-on or emission-enhanced mode). This review focuses mainly on recent advances in the new emerging PL-based sensing platforms, based on manipulating the behaviours of supramolecular aggregation/disaggregation, including aggregation-induced emission (AIE), metallophilic interactions-related sensing (metallophilic interactions-induced aggregation/disaggregation), metal coordination polymers-related sensing, and other sensing systems involving supramolecular aggregation/disaggregation. In particular, those sensing systems developed by scientists in China are summarized and highlighted.

Ordered honeycomb microporous films from self-assembly of alkylated guanosine derivatives.

Ordered honeycomb microporous films have previously been fabricated from polymeric macromolecules. We report here the successful fabrication of them from the supramolecular self-assembly of small molecules, alkylated guanosine derivatives. The ribbonlike self-assembly of the guanosines in CHCl3 is found to be the intrinsic structure that forms regular microporous structure via Bénard-Maragoni convection. Factors such as substrate, solvents, guanosine concentration, and solvent evaporation temperature are revealed to be able to control the size of the formed micropores, which in turn allows for the wettability of the honeycomb film surface to be modulated. These microporous materials exhibit excellent ability of loading organic dyes that eventually leads to the fabrication of luminescent honeycomb films. As structures of both the small molecules that can assemble and their self-assemblies can be varied and controlled, extended applications of this supramolecular method are expected to lead to microporous films of interesting functions.

Enhanced saccharide sensing based on simple phenylboronic acid receptor by coupling to Suzuki homocoupling reaction.

Substantially enhanced monosaccharide fluorescent sensing in aqueous solutions using a simple phenylboronic acid receptor is achieved by coupling the classic strategy based on saccharide-boronic acid interaction with catalytic Suzuki homocoupling reaction.

Two new xanthones from Premna microphylla.

Two new xanthones have been isolated from the EtOAc extract of the roots of Premna microphylla Turcz. Based on spectral and chemical evidences, their structures were elucidated as 1-hydroxy-2,3-methylenedioxy-6-methoxycarbonyl-7-acetylxanthone 1 and 1,3-dihydroxy-2-methoxy-6-methoxycarbonyl-7-acetylxanthone 2. This is the first report on isolation of xanthones from this plant.

Four new isoflavones from Ampelopsis grossedentata.

Four new isoflavones have been isolated from the BuOH extract of Ampelopsis grossedentata Hand.-Mazz. Based on spectral and chemical methods, their structures were elucidated as 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 1; 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 6-O-beta-D-glucopyranoside 2; 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 6-O-alpha-L-rhamnopyranoside 3; 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 6-O-beta-D-xylopyranosyl-(1-6)-beta-D-glucopyranoside 4. This is the first report on isolation of isoflavones from this plant.