Gold
nanoclusters (AuNCs) represent an emerging type of engineered
nanomaterials with intrinsic enzymatic activity for both chemical
and biological applications, but the catalytic activity of most reported
AuNCs remains rather limited. Herein, we report a new, efficient strategy
of promoting the peroxidase-mimic activity of AuNCs by tailoring their
catalytic interfaces via small molecule-mediated weak interactions.
Inspired by the presence of imidazole structures in many biocatalytic
centers, we screened a series of imidazole-containing small molecules
to evaluate their impact on the enzymatic activity of AuNCs. Through
monitoring the absorbance change of 3,3′,5,5′-tetramethylbenzidine,
1-methyl-2-imidazolecarboxaldehyde (MCA) was identified to possess
the most significant effect on enhancing the peroxidase-mimic activity
of glutathione-stabilized AuNCs (GSH-AuNCs) among all the examined
molecules. Interestingly, the enhancement effect of MCA on the catalytic
activity of these AuNCs was found to be highly reversible and can
be switched on/off by simply adding MCA/dialysis treatment. Molecular
dynamics simulations and further experimental analysis confirmed that
these MCA molecules were adsorbed on the surface of GSH-AuNCs through
weak non-covalent interactions. The underlying mechanism analysis
suggested that the presence of MCA can efficiently promote the production
of •OH in the GSH-AuNC system. As a proof of example, we then
demonstrated that the presence of MCA can greatly increase the bioanalytical
performance of AuNC-based peroxidase mimics, as evidenced by a 65-fold
lower LOD for glucose detection of AuNCs@MCA than that using AuNCs
only. Finally, the present system has been successfully applied for
sensing the blood glucose level of both healthy people and diabetics
with promising results.
We have developed a new radical-mediated alkoxypolyhaloalkylation of styrene with polychloroalkanes and alcohols for the facile synthesis of complex polyhaloalkanes. 4-Methoxybenzenediazonium tetrafluoroborate is a good radical initiator for this transformation....
A three-component photoredox 1,2-alkylamination of styrenes involving functionalization of C(sp3)–H bonds in alkyl halides instead of functionalization of C-halogen bonds is disclosed.
Owing to their easy availability and cheapness, simple alkyl chlorides are good raw materials for introducing complex polychlorinated groups. Polychlorinated hydrocarbons units, such as di‐ or trichloromethyl groups, not only widely found in pesticide and bioactive molecule, but also can be as a precursor to converted into different functional groups such as −COOH, −CHO and −CO. The direct polychloroalkylation reaction by using simple alkyl chlrides has been considered to be an important tool for synthesizing complex polychlorinated compounds. This review summarizes recent developments, especially free radical strategies, in the polychloroalkylation of different substrates (such as 2‐acylpyridines, benzyl tertiary amines, alkenes, imine and 1,n‐enynes). We hope that this review provides a new perspective on this field and also provides a reference to develop environmentally friendly and sustainable methods.
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