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Title: Functional supramolecular metallo-assemblies
Author: Onions, Stuart T.
ISNI:       0000 0001 3459 2479
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 2005
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The formation and characterisation of a novel range of homonuclear [2 x 2] grids are reported. These are formed by metal ion directed self-assembly of selected first row transition metal ions displaying an octahedral coordination preference with a single ligand strand. These assemblies display electronic communication between metal centres, indicated by both electrochemical and magnetic studies. Further manipulation of the ligand strand along with the inert character of the Cr(III) ion allowed the formation of a series heteronuclear [2 x 2] grids displaying magnetic interactions. The attempted preparation of a series of mixed oxidation [2 x 2] grids via controlled potential electrolysis (CPE) is presented along with the successful preparation of a mixed oxidation Mng [3 x 3] molecular grid, which displays antiferromagnetic exchange. This is first time the CPE has been manipulated within a grid-like stnicture to produce mixed oxidation species in a controlled manner. A series of ligand strands with the potential to from [4 x 4] molecular grids are reported. Grid-like structures are structurally characterised with Mn(II) and Pb(II) metal ions some of which suffer from incomplete metal ion coordination. Other structural motifs are observed and rationalised in terms of the encoding within the ligand framework. The magnetic properties are consistent with the structures observed. These assemblies are some of the largest reported with the chosen metal ions and the largest in all cases to formed in a controlled predictable manner. The first ever series of tetrametallic triple stranded helicates are reported which have been characterised in the solid-state and in solution. These display weak magnetic communication between metal centres with mixtures of both ferro- and antiferromagnetic behaviour, which is rationalised by the geometry of bridging ligands. Systematic alteration of the ligand fi-amework produced a Cug circular helicate displaying weak ferromagnetic behaviour, an Mng assembly suffering from incomplete metal ion coordination and a Cuzo assembly displaying strong antiferromagnetic exchange.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available