Two ligands have been synthesized by derivatisation of cyanuric chloride: 6-(diethylamino)-2,4-disulfanyl-1,3,5triazine (H 2 SSta) 1 and 6-(diethylamino)-2-hydroxo-4-sulfanyl-1,3,5-triazine (H 2 OSta) 2 have been characterised by X-ray crystallography, which shows intermolecular hydrogen bonding in the solid state, leading to dimers of 1 and ribbons of 2. On reaction with metal salts both ligands undergo oligomerisation reactions. Compound 1 reacts with nickel chloride to form a mononuclear complex, [Ni{(Sta)S(S 2 ta)}] 3. In 3 two triazine ligands have reacted, to form a tetradentate ligand in which two triazine rings are bridged by a sulfur group, with a co-ordinated disulfide group present on one ring and a co-ordinated thiolate on the second. Compound 2 reacts with cobalt() chloride to form a cage complex, [Co 6 NaO(OStaH) This complicated structure contains two polydentate ligands formed by linking triazine groups through a bridging sulfur. The cage contains four cobalt() and two cobalt() sites which are assigned by bond length considerations. The compound [Co(OSta) 3 ] 5 co-crystallises with 4, and its structure has also been determined.

The modes of action of the commercial solvent extractants used in extractive hydrometallurgy are classified according to whether the recovery process involves the transport of metal cations, M(n+), metalate anions, MXx(n-), or metal salts, MXx into a water-immiscible solvent. Well-established principles of coordination chemistry provide an explanation for the remarkable strengths and selectivities shown by most of these extractants. Reagents which achieve high selectivity when transporting metal cations or metal salts into a water-immiscible solvent usually operate in the inner coordination sphere of the metal and provide donor atom types or dispositions which favour the formation of particularly stable neutral complexes that have high solubility in the hydrocarbons commonly used in recovery processes. In the extraction of metalates, the structures of the neutral assemblies formed in the water-immiscible phase are usually not well defined and the cationic reagents can be assumed to operate in the outer coordination spheres. The formation of secondary bonds in the outer sphere using, for example, electrostatic or H-bonding interactions are favoured by the low polarity of the water-immiscible solvents.

A very simple self-assembling system, which produces inclusion complexes with pseudorotaxane geometries, is described. The self-assembly of eight pseudorotaxanes with a range of stoichiometries-I : I , 1 :2, 2:1, and 2:2 (host:guest)-has been Keywords achieved. These pseudorotaxanes self-assemble from readily available componentscrown ethers -dialkylammonium well-known crown ethers, such as dibenzo [24]crown-8 and bis-p-phenylene[34lcrown-salts 9 hydrogen bonding -molecular 10, and secondary dialkylammonium hexafluorophosphate salts, such as (PhCH,),-recognition -pseudorotaxanes * NHiPF; and (nBu),NHlPF;-and have been characterized not only in the solid state, self-assembly but also in solution and in the "gas phase". The pseudorotaxanes are stabilized largely by hydrogen-bonding interactions and, in some instances, by aryl-aryl interactions.

A simple motif for molecular recognition—the binding of disubstituted ammonium salts, for example dibenzyl‐ and di‐n‐butylammonium hexaflurophosphate, with crown ethers like dibenzo[24]crown‐8—results in the self‐assembly of threaded 1:1 complexes 1. The superstructures of these complexes are stabilized by hydrogen bonds, electrostatic pole–dipole interactions, and dispersive interactions.

Waste electrical and electronic equipment (WEEE) such as mobile phones contain a plethora of metals of which gold is by far the most valuable. Here we describe a simple primary amide that achieves the selective separation of gold from a mixture of metals typically found in a mobile phone by extraction into toluene from an aqueous HCl solution; unlike current processes, reverse phase transfer is achieved simply using water. Phase transfer occurs by dynamic assembly of protonated and neutral amides with AuCl4 − anions through hydrogen bonding in the organic phase, as shown by EXAFS, mass spectrometry measurements and computational calculations, and supported by distribution coefficient analysis. We anticipate that the fundamental chemical understanding gained here is integral to the development of metal recovery processes, in particular through the use of dynamic assembly processes to build complexity from simplicity.