Gareth W. Bates

Anion binding vs.sulfonamide deprotonation in functionalised ureas

Sulfonamide groups, commonly used as neutral hydrogen bond donors in a wide variety of anion receptors, deprotonate upon addition of certain basic anionic guests in two simple functionalised ureas.

Ionic liquid–calix[4]pyrrole complexes: pyridinium inclusion in the calixpyrrole cup

Pyridinium based ionic liquids form complexes with meso-octamethylcalix[4]pyrrole with both the anion and cation binding to the tetrapyrrole macrocycle.

An Introduction to Anion Receptors Based on Organic Frameworks

This review article provides a broad overview to the area of anion coordination by synthetic organic receptors and includes examples of different functional groups used to bind anions. The first section examines neutral anion receptors containing amide-, sulfonamide-, urea- and thiourea-based receptors. Then aromatics such as pyrrole, carbazole and indole are discussed before concluding the discussion of neutral systems with examples of hydroxy OH donors. A brief overview of charged systems is also provided.

Interactions of Organic Halide and Nitrate Salts with meso-Octamethylcalix[4]pyrrole

Proton NMR titrations have been performed with meso-octamethylcalix[4]pyrrole and a variety of organic chloride and bromide salts in dichloromethane-d 2 . The results show apparently increasing chloride stability constants within each set of anion salts (tetrabutylammonium < imidazolium < pyridinium). Addition of 1-ethyl-3-methylimidaolium (EMIM) nitrate to dichloromethane-d 2 solutions of calix[4]pyrrole caused significantly larger downfield shifts of the pyrrole NH protons of calix[4]pyrrole than addition of equimolar quantities of tetrabutylammonium nitrate. The first crystal structure of a nitrate complex of a calix[4]pyrrole is also presented.

Organic salt inclusion: the first crystal structures of anion complexes of N-confused calix[4]pyrrole

The first crystal structures of anion complexes of N-confused calix[4]pyrrole are presented showing chloride binding to the three ‘unconfused’ pyrrole NH groups and imidazolium inclusion in the calixpyrrole cup.

A dual host approach to NiSO4extraction

This paper reports the synthesis of sulphate extractants, N,N′-bis-(2-dibutylamino-ethyl)-isophthalamide (1), pyridine-2,6-dicarboxylic acid bis-[(2-dibutylamino-ethyl)-amide] (2) and 3,4-diphenyl-1H-pyrrole-2,5-dicarboxylic acid bis-[(2-dibutylamino-ethyl)-amide] (3), and demonstrates that, in combination with a commercially available oxime extractant 2-hydroxy-5-nonyl benzaldehyde oxime (P50), these dual host systems are better extractants for nickel(II) sulphate than the metal salt extractant, 5-nonyl-3-dihexylaminomethyl-2-hydroxy-benzaldehyde oxime (4).