Near-Quantitative Removal of Oxalate and Terephthalate from Water by Precipitation with a Rigid Bis-Amidinium Compound.

A simple, readily-prepared precipitant (1⋅Cl) precipitates oxalate or terephthalate from water with very high efficacy, removing these anions at sub-millimolar concentrations using only one equivalent of precipitant. A simple aqueous base/acid cycle can be used to regenerate 1⋅Cl after use. The resulting precipitates, 1⋅oxalate and 1⋅terephthalate, are anhydrous and closely-packed, with each anion receiving eight charge-assisted hydrogen bonds from amidinium N-H donors.

A three-component hydrogen bonded framework.

A porous three-component hydrogen bonded framework, 1⋅biphen⋅TP, was prepared from a tetra-amidinium component (1) and two different dianions, benzene-1,4-dicarboxylate (terephthalate, TP) and biphenyl-4,4'-dicarboxylate (biphen). Interestingly, when the framework was prepared in ethanol/water, 1⋅biphen⋅TP forms even when an excess of either dicarboxylate is present. However, when only water is used as solvent, only two-component frameworks are formed.

Hydrogen-bonded frameworks containing aliphatic 3D linkers show high-capacity water vapour sorption.

Hydrogen-bonded frameworks were prepared from a tetra-amidinium component and three-dimensional cubane and bicyclopentane dicarboxylate linkers. Despite the incorporation of aliphatic components, the frameworks demonstrate strong and reversible uptake of water vapour, with one of the frameworks showing water uptake at very low relative humidity.

Charge "mis-matched" hydrogen bonded frameworks for cation exchange and dye sorption.

Anionic hydrogen bonded frameworks were synthesised from di or tetra-amidinium hydrogen bond donor components and a charge "mis-matched" tecton possessing a 5- charge but only four hydrogen bond accepting groups. The net negative charge on the framework skeletons necessitates the presence of a cation in the framework channel. In one of the frameworks, the initially incorporated organic cation was rapidly displaced by smaller inorganic cations, or the cationic dye methylene blue.

Correspondence on "Crystalline Porous Organic Salt for Ultrarapid Adsorption/Desorption-Based Atmospheric Water Harvesting by Dual Hydrogen Bond System".

In a recent Research Article, Ben and co-workers reported a hydrogen-bonded framework prepared from a 4 tetra-amidinium component and a 4 tetra-sulfonate component, termed CPOS-6. They showed that CPOS-6 could reversibly adsorb and desorb water over a narrow humidity window, and that this material offered potential for applications in atmospheric water harvesting. This conclusion was supported by experiments that showed the material was stable over 50 adsorption/desorption cycles and that the kinetics of these cycles were very rapid.

Molecular Imprinting Using a Functional Chain Transfer Agent.

This study demonstrates the feasibility of molecular imprinting using a functional chain transfer agent sans a functional monomer. Ethylene glycol dimethacrylate (EGDMA)-based MIPs were synthesised in the presence of thioglycolic acid (TGA) possessing a carboxylic acid group, capable of interacting with the chosen test template ,-(±)-propranolol (PNL) and a labile S-H bond to facilitate an efficient chain transfer reaction. Quantitative H NMR measurements showed high PNL and TGA incorporation within the MIP, indicating an efficient chain transfer process and a favourable interaction between PNL and TGA.

Use of modulators and light to control crystallisation of a hydrogen bonded framework.

The effect of concentration, organic co-solvent, and salt modulators on the crystallisation of a hydrogen bonded framework was studied. The framework contains ∼1.4 nm wide channels and contains a diazobenzene based dicarboxylate anion.

Molecularly Imprinted Polymeric Nanoparticles by Precipitation Polymerization and Characterization by Quantitative NMR Spectroscopy.

An optimized synthetic methodology for the preparation of highly homogeneous MIP nanoparticles by the precipitation method is presented. A quantitative H NMR method that was developed to estimate template incorporation, polymer composition and conversion, and binding capacities and selectivities is also described. While the experiment presented here is exemplified by an MIP formulation using (±)-propranolol as the template, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker, the methods and techniques are applicable to other precipitation MIP systems.