Yanjun Ding

Creating ordered two-dimensional (2D) metal-organic framework (MOF) nanosheets has attracted extensive interest. However, it still remains a great challenge to synthesize ultrathin 2D MOF nanosheets with controlled thickness in high yields. In this work, we demonstrate a novel intercalation and chemical exfoliation approach to obtain MOF nanosheets from intrinsically layered MOF crystals. This approach involves two steps: first, layered porphyrinic MOF crystals are intercalated with 4,4'-dipyridyl disulfide through coordination bonding with the metal nodes; subsequently, selective cleavage of the disulfide bond induces exfoliation of the intercalated MOF crystals, leading to individual freestanding MOF nanosheets. This chemical exfoliation process can proceed efficiently at room temperature to produce ultrathin (∼1 nm) 2D MOF nanosheets in ∼57% overall yield. The obtained ultrathin nanosheets exhibit efficient and far superior heterogeneous photocatalysis performance compared with the corresponding bulk MOF.

A practical Pd(II)/Pd(IV)-catalyzed carboxyl-directed C-H activation/C-O cyclization to construct biaryl lactones has been developed. The synthetic utility of this new reaction was demonstrated in an atom-economical and operationally convenient total synthesis of the natural product cannabinol from commercially available starting materials, with the newly developed method used for two key steps.

. We believe that molecular sorbents that rely on specific molecular recognition events, such as the triangular pores detailed here, will prove useful as next generation sorbents in energy-efficient separations.

Xylene mixtures and the three individual isomers are valuable chemical feedstocks in the chemical industry. Separation of these isomers is a pressing challenge due to their overlapping physicochemical properties. Traditional separation technologies like distillation are energy intensive and laborious and are not appropriate for sustainable development. To reduce the high energy consumption and decrease the environmental impact, adsorption by porous materials has been proposed and proven as an alternative strategy. Intrinsically porous molecular materials (IPMs) are mainly composed of organic macrocycles and cages that possess guest-accessible intrinsic cavities. They have been used for energy-intensive separations because of their high efficiency and low energy consumption. In this review, we provide a comprehensive summary of IPM-based xylene separations, as well as an overview of the challenges associated with the development of the technology and the future industrial translation of this class of materials.

-3-hexene (trans-3-He) in the vapor and liquid state. This allyl-functionalized macrocycle features a deeper cavity compared to the previously reported trianglamine host molecules. Solid-vapor sorption experiments verified the successful separation of 1-He from an equimolar mixture of 1-He and trans-3-He. Single-crystal structures and powder X-ray diffraction patterns suggest that this selective adsorption arises from the formation of a thermodynamically stable host-guest complex between 1-He and P-TA. A reversible transformation between the nonporous guest-free structure and the guest-containing structure shows that 1-He separation can be carried out over multiple cycles without any loss of performance. Significantly, P-TA can separate 1-He directly from a liquid isomeric mixture and thus P-TA modified silica sieves (SBA-15) showed the ability to selectively separate 1-He when utilized as a stationary phase in column chromatography. This capitalizes on the prospects of employing macrocyclic hosts as molecular recognition units in real-life separations for sustainable and energy-efficient industrial practices.