A Platinum(II)-Based Molecular Cage with Aggregation-Induced Emission for Enzymatic Photocyclization of Alkynylaniline.

Enzymes facilitate chemical conversions through the collective activity of aggregated components, but the marriage of aggregation-induced emission (AIE) with molecular containers to emulate enzymatic conversion remains challenging. Herein, we report a new approach to construct a PtII -based octahedral cage with AIE characteristics for the photocyclization of alkynylaniline by restricting the rotation of the pendant phenyl rings peripheral to the PtII corner. With the presence of water, the C-H⋅⋅⋅π interactions involving the triphenylphosphine fragments resulted in aggregation of the molecular cages into spherical particles and significantly enhanced the PtII -based luminescence. The kinetically inert Pt-NP chelator, with highly differentiated redox potentials in the ground and excited states, and the efficient coordination activation of the platinum corner facilitated excellent catalysis of the photocyclization of alkynylaniline. The enzymatic kinetics and the advantages of binding and activating substrates in an aqueous medium provide a new avenue to develop mimics for efficient photosynthesis.

Encapsulating electron-deficient dyes into metal-organic capsules to achieve high reduction potentials.

The design of artificial supramolecular systems that mimic the structure and functionality of natural enzymes to achieve efficient chemical conversions is a promising subject. In this work, we assembled a novel metal-organic capsule from electron-rich dyes, polyaniline compounds, as ligands by a subcomponent self-assembly strategy. By encapsulating electron-deficient dyes, anthraquinone or 9,10-dicyanoanthracene, into electron-rich pseudo-cubic capsules, we successfully constructed an artificial enzyme-mimicking supramolecular system for the efficient photocatalytic reduction of aryl chlorides with high reduction potentials (Ered < -2.0 V) via multiphoton excitation. Within the confined space of the host, the electron-deficient dyes were forced to come into contact intimately with the electron-rich host walls, which facilitates the photoinduced electron transfer process. Moreover, we achieved quantitative yields in the photocatalytic reduction reaction under mild conditions within 30 minutes, which was rarely reported in the previous literature in terms of reaction efficiency. This study provides a general and valuable strategy for activating inert substrates, which may have potential applications in solar energy conversion and enzyme-mimicking catalysis in the chemical industry.