Biao Jiang

A novel barium-based carbon-to-chemical process with CO₂ capture.

Phosphorus-doped activated carbon is reported for the first time as a highly selective catalyst for n-hexane dehydroaromatization to benzene and hydrogen with 100% n-hexane conversion and 97% benzene selectivity. The weak/medium-strength acidic centres composed of (CO)(C)–P(O)(OH) units on the catalyst surface would be the catalytic active sites. This work provides a new alternative in the preparation of metal-free catalysts for the highly selective functionalization of C–H bonds of n-alkanes.

This report describes a facile method by which, without using any surface-assisted growth or pre-organisation, free-standing two-dimensional (2D) covalent organic monolayers (COMs) were synthesised through condensation reactions of planar tri-aldehydes with A1/A2-diamino-substituted pillar[5]arene (DAP5). In the as-formed monolayers (DAP5-COM-1 and DAP5-COM-2), the tubular pentagonal pillar[5]arene units positioned out of the 2D polymer planes suppress efficiently the interlayer π-π stacking interactions. Both DAP5-COM-1 and DAP5-COM-2 can be transferred onto solid surfaces for further characterisation and were found to possess unusual fluorescence up-conversion property.

The pyrolysis of 1,2-dichloroethane (EDC) is the most popular commercialized way of producing vinyl chloride monomers (VCM); however, it is plagued by high-energy consumption and the resulting coke formation. Here, a series of nitrogen-doped (N-doped) activated carbon catalysts (N-AC) were prepared conveniently for EDC dehydrochlorination. The structural and textural properties of N-doped catalysts were characterized by X-ray diffraction, transmission electron microscopy, Raman spectra, temperature-programmed desorption of VCM and EDC, and X-ray photoelectron spectroscopy. The results revealed that doping N into activated carbon supports introduced basicity sites and caused partial graphitization on the catalyst surfaces. Thus, an improved absorption capacity to EDC and VCM and an accelerated desorption rate were obtained, which greatly enhanced EDC conversion and VCM selectivity. EDC was almost completely dehydrochlorided into vinyl chloride at a temperature of 300 °C and an EDC liquid hourly space velocity of 0.313 h^–1. The high catalytic activity and selectivity as well as good stability suggested that the N-AC catalyst would be a promising dehydrochlorination catalyst on an industrial scale.

Correction for ‘Guest-regulated chirality switching of planar chiral pseudo[1]catenanes’ by Ya-Fen Yang et al., Org. Biomol. Chem., 2018, DOI: 10.1039/c8ob00156a.

A supramolecular organic framework, P5-bpy-SOF, made of perhydroxyl-pillar[5]arene (P5) and 4,4-bipyridine (bpy) and prepared by using a co-crystallization approach, showed a different hydrogen bonding pattern and a 3D molecular arrangement from that in the perhydroxyl-pillar[5]arene-based supramolecular organic framework (P5-SOF). TGA analyses, powder X-ray diffraction and gas absorption study confirmed P5-bpy-SOF's structural stability, permanent porosity, and, especially, selectivity of absorption of CO₂ over N₂.

pseudo[1]Catenane 3 is in a self-included conformation in chloroform, but in dichloromethane, it exists in an equilibrium between the self-included conformational state and a de-threading one. The planar chirality inversion of 3 can be triggered by the host–guest complexation of 3 with adiponitrile G, but the extent of such chiral switching depends on the length of self-included bis(pyrazin-2-yloxy)alkane chains in 3 – longer chains are more favored than shorter ones in the inversion.

Pillar[5]arene–Py–Cu gel, a supramolecular metallo(organo)gel, was made from an A1/A2‐bipyridyl‐functionalized pillar[5]arene ligand (L) through metal–ligand complexation. The xerogel obtained from pillar[5]arene–Py–Cu gel has a hydrangea‐flower‐like rugate layered structure, and a sheet‐like structured gel‐precipitate was formed from pillar[5]arene–Py–Cu gel under shaking or sonication. Both the xerogel and the gel‐precipitate can extract Sudan III from its ethanol solution.

Multicavity macrocyclic hosts are host molecules comprising more than one macrocyclic guest binding components connected through multipoint linkages. Macrocycles, such as crown ethers, pillar[n]arenes, calix[n]arenes, and calix[4]pyrroles, have been used to fabricate multicavity hosts, either homotopic or heterotopic. This review is mainly focused on the molecular structures and host–guest behaviors of multicavity macrocyclic host molecules and their applications in the assembly of sophisticated supramolecular architectures.

Pseudorotaxane type host–guest complex of a secondary ammonium salt and oxacalixcrown with the polyether linker as short as five ethylene glycol units was created. While an axle containing both ammonium and carbamate stations was installed in an oxacalixcrown‐6‐based [2]rotaxane through a threading‐followed‐by‐stoppering approach, translocation of the oxacalixcrown‐6 component of the [2]rotaxane from the secondary ammonium station to the carbamate station of the thread was achieved through blocking the amino moiety with a bulky Boc group.