Dumbbell-Shaped Bi-component Mesoporous Janus Solid Nanoparticles for Biphasic Interface Catalysis.

There is a strong desire to design and synthesize catalysts that assemble at the oil-water interface to improve the efficiency of biphasic reactions. Anisotropic dumbbell-shaped bi-component mesoporous carbon-organosilica Janus particles with asymmetric wettability are synthesized through a one-step compartmentalized growth of a mesoporous organosilica sphere attached to a mesoporous resorcinol-formaldehyde (RF) sphere. A library was prepared of tunable Janus particles possessing diverse hollow structures with various functionalities. As a proof of concept, the Janus particle-derived catalyst can assemble at the oil-water interface to stabilize Pickering emulsions. Owing to the increased reaction interface area, the Janus catalyst exhibits a more than three-fold increase in catalytic efficiency compared to the Pt loaded carbon sphere catalyst in aqueous hydrogenation reactions.

Compartmentalization of incompatible reagents within Pickering emulsion droplets for one-pot cascade reactions.

It is a dream that future synthetic chemistry can mimic living systems to process multistep cascade reactions in a one-pot fashion. One of the key challenges is the mutual destruction of incompatible or opposing reagents, for example, acid and base, oxidants and reductants. A conceptually novel strategy is developed here to address this challenge. This strategy is based on a layered Pickering emulsion system, which is obtained through lamination of Pickering emulsions. In this working Pickering emulsion, the dispersed phase can separately compartmentalize the incompatible reagents to avoid their mutual destruction, while the continuous phase allows other reagent molecules to diffuse freely to access the compartmentalized reagents for chemical reactions. The compartmentalization effects and molecular transport ability of the Pickering emulsion were investigated. The deacetalization-reduction, deacetalization-Knoevenagel, deacetalization-Henry and diazotization-iodization cascade reactions demonstrate well the versatility and flexibility of our strategy in processing the one-pot cascade reactions involving mutually destructive reagents.