[MIII2MII3] n+ trigonal bipyramidal cages based on diamagnetic and paramagnetic metalloligands.

A family of five [MIII2MII3] n+ trigonal bipyramidal cages (MIII = Fe, Cr and Al; MII = Co, Zn and Pd; n = 0 for 1-3 and n = 6 for 4-5) of formulae [Fe2Co3L6Cl6] (1), [Fe2Zn3L6Br6] (2), [Cr2Zn3L6Br6] (3), [Cr2Pd3L6(dppp)3](OTf)6 (4) and [Al2Pd3L6(dppp)3](OTf)6 (5) (where HL is 1-(4-pyridyl)butane-1,3-dione and dppp is 1,3-bis(diphenylphosphino)propane) are reported. Neutral cages 1-3 were synthesised using the tritopic [MIIIL3] metalloligand in combination with the salts CoIICl2 and ZnIIBr2, which both act as tetrahedral linkers. The assembly of the cis-protected [PdII(dppp)(OTf)2] with [MIIIL3] afforded the anionic cages 4-5 of general formula [MIII2PdII3](OTf)6. The metallic skeleton of all cages describes a trigonal bipyramid with the MIII ions occupying the two axial sites and the MII ions sitting in the three equatorial positions. Direct current (DC) magnetic susceptibility, magnetisation and heat capacity measurements on 1 reveal weak antiferromagnetic exchange between the FeIII and CoII ions. EPR spectroscopy demonstrates that the distortion imposed on the {MO6} coordination sphere of [MIIIL3] by complexation in the {MIII2MII3} supramolecules results in a small, but measurable, increase of the zero field splitting at MIII. Complete active space self-consistent field (CASSCF) calculations on the three unique CoII sites of 1 suggest DCo ≈ -14 cm-1 and E/D ≈ 0.1, consistent with the magnetothermal and spectroscopic data.

Non-equilibrium cobalt(iii) "click" capsules.

Cobalt(iii) tetrahedral capsules have been prepared using an assembly-followed-by-oxidation protocol from a cobalt(ii) precursor and a readily derivatizable pyridyl-triazole ligand system. Experiments designed to probe the constitutional dynamics show that these architectures are in a non-equilibrium state. A preliminary investigation into the host-guest chemistry of a water-soluble derivative shows it can bind and differentiate a range of different neutral organic molecules. The stability of this ensemble also permits the study of guest-binding at high salt concentrations.

A truncated [Mn(III)12] tetrahedron from oxime-based [Mn(III)3O] building blocks.

The use of the novel pro-ligand H4L combining the complimentary phenolic oxime and diethanolamine moieties in one organic framework, results in the formation of the first example of a [Mn(III)12] truncated tetrahedron and an extremely rare example of a Mn cage conforming to an Archimedean solid.

Syntheses and structures of M(L)(X)BPh4 complexes (M = Co(II), Zn(II); L = cis-1,3,5-tris[3-(2-furyl)prop-2-enylideneamino]cyclohexane, X = OAc, NO3) n: structural models of the active site of carbonic anhydrase.

The metal coordination geometries in the structures of the zinc(II) and cobalt(II) complexes of the ligand cis-1,3,5-tris[3-(2-furyl)prop-2-enylideneamino]cyclohexane (fr-protach) and with the anions nitrate and acetate are structural models for the active site of carbonic anhydrase. The acetate structures show a striking structural correlation with the metal coordination environments in the known bicarbonate forms of the enzyme. Such structures provide a basis for understanding the marked effect of different metal substitution on the catalytic rate of the enzyme.