Mechanochemical Synthesis of Boroxine-linked Covalent Organic Frameworks.

We report a rapid, room-temperature mechanochemical synthesis of 2- and 3-dimensional boroxine covalent organic frameworks (COFs), enabled by using trimethylboroxine as a dehydrating additive to overcome the hydrolytic sensitivity of boroxine-based COFs. The resulting COFs display high porosity and crystallinity, with COF-102 being the first example of a mechanochemically prepared 3D COF, exhibiting a surface area of ca. 2,500 m g.

Halogen bonding with carbon: directional assembly of non-derivatised aromatic carbon systems into robust supramolecular ladder architectures.

Carbon, although the central element in organic chemistry, has been traditionally neglected as a target for directional supramolecular interactions. The design of supramolecular structures involving carbon-rich molecules, such as arene hydrocarbons, has been limited almost exclusively to non-directional π-stacking, or derivatisation with heteroatoms to introduce molecular assembly recognition sites. As a result, the predictable assembly of non-derivatised, carbon-only π-systems using directional non-covalent interactions remains an unsolved fundamental challenge of solid-state supramolecular chemistry.

Three-in-One: Dye-Volatile Cocrystals Exhibiting Intensity-Dependent Photochromic, Photomechanical, and Photocarving Response.

Cocrystallization of a -azobenzene dye with volatile molecules, such as pyrazine and dioxane, leads to materials that exhibit at least three different light-intensity-dependent responses upon irradiation with low-power visible light. The halogen-bond-driven assembly of the dye -(-iodoperfluorophenyl)azobenzene with volatile halogen bond acceptors produces cocrystals whose light-induced behavior varies significantly depending on the intensity of the light applied. Low-intensity (<1 mW·cm) light irradiation leads to a color change associated with low levels of → isomerization.

Direct mechanocatalysis by resonant acoustic mixing (RAM).

We demonstrate the use of a metal surface to directly catalyse copper-catalysed alkyne-azide click-coupling (CuAAC) reactions under the conditions of Resonant Acoustic Mixing (RAM) - a recently introduced and scalable mechanochemical methodology that uniquely eliminates the need for bulk solvent, as well as milling media. By using a simple copper coil as a catalyst, this work shows that direct mechanocatalysis can occur in an impact-free environment, relying solely on high-speed mixing of reagents against a metal surface, without the need for specially designed milling containers and media. By introducing an experimental setup that enables real-time Raman spectroscopy monitoring of RAM processes, we demonstrate 0th-order reaction kinetics for several selected CuAAC reactions, supporting surface-based catalysis.

The "-sweet-spot" () in liquid-assisted mechanochemistry: polymorph control and the role of a liquid additive as either a catalyst or an inhibitor in resonant acoustic mixing (RAM).

Resonant acoustic mixing (RAM) offers a simple, efficient route for mechanochemical synthesis in the absence of milling media or bulk solvents. Here, we show the use of RAM to conduct the copper-catalysed coupling of sulfonamides and carbodiimides. This coupling was previously reported to take place only by mechanochemical ball milling, while in conventional solution environments it is not efficient, or does not take place at all.

Solid-State Enzymatic Hydrolysis of Mixed PET/Cotton Textiles.

Waste polyester textiles are not recycled due to separation challenges and partial structural degradation during use and recycling. Chemical recycling of polyethylene terephthalate (PET) textiles through depolymerization can provide a feedstock of recycled monomers to make "as-new" polymers. While enzymatic PET recycling is a more selective and more sustainable approach, methods in development, however, have thus far been limited to clean, high-quality PET feedstocks, and require an energy-intensive melt-amorphization step ahead of enzymatic treatment.

After 200 Years: The Structure of Bleach and Characterization of Hypohalite Ions by Single-Crystal X-Ray Diffraction*.

We report the first X-ray single crystal structures of hypochlorite (ClO ) and hypobromite (BrO ) salts, including hydrated sodium hypochlorite, a staple of the chlorine industry and ubiquitous bleaching and disinfection agent for almost 200 years. The structures, supported by variable-temperature Raman spectroscopy on individual crystals and periodic density-functional theory (DFT) calculations, provide insight into solid-state geometry and supramolecular chemistry of hypohalite ions.

Crystal structure of octane-1,8-diaminium 4,4'-(diazene-1,2-di-yl)dibenzoate monohydrate.

The title salt, CHN·CHNO·HO, represents a pseudo-polymer ionic material, resulting from the self-organizing behavior of 4,4'-azinodibenzoate dianions and doubly protonated, 1,8-diaminium-octane cations in aqueous solution. The asymmetric unit consists of two halves of octane 1,8-diaminium cations (the complete cations are both generated by crystallographic inversion symmetry), a 4,4'-azinodibenzoate anion [dihedral angle between the aromatic rings = 10.22 (4)°] and a water mol-ecule of crystallization.

Using isotopically-coded hydrogen peroxide as a surface modification reagent for the structural characterization of prion protein aggregates.

Unlabelled: The conversion of the cellular prion protein (PrP(C)) into aggregated ß-oligomeric (PrP(ß)) and fibril (PrP(Sc)) forms is the central element in the development of prion diseases. Here we report the first use of isotopically-coded hydrogen peroxide surface modification combined with mass spectrometry (MS) for the differential characterization of PrP(C) and PrP(β). (16)O and (18)O hydrogen peroxide were used to oxidize methionine and tryptophan residues in PrP(C) and PrP(β), allowing for the relative quantitation of the extent of modification of each form of the prion protein.