Functional supramolecular metallo-assemblies

Onions, ST, 2005. Functional supramolecular metallo-assemblies. PhD, Nottingham Trent University.

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Abstract

The formation and characterization 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 centers, 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 Mn9 [3 x 3] molecular grid, which displays antiferromagnetic exchange. This is first time the CPE has been manipulated within a grid-like structure 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 characterized with Mn(II) and Pb(II) metal ions some of which suffer from incomplete metal ion coordination. Other structural motifs are observed and rationalized 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 characterized in the solid-state and in solution. These display weak magnetic communication between metal centres with mixtures of both ferro- and antiferromagnetic behavior, which is rationalized by the geometry of bridging ligands. Systematic alteration of the ligand framework produced a Cu8 circular helicate displaying weak ferromagnetic behavior, an Mn6 assembly suffering from incomplete metal ion coordination and a Cu2o assembly displaying strong antiferromagnetic exchange.

Item Type:	Thesis
Creators:	Onions, S.T.
Date:	2005
ISBN:	9781369314472
Identifiers:	Number Type PQ10183171 Other
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	18 Sep 2020 13:45
Last Modified:	27 Jul 2023 09:14
URI:	https://irep.ntu.ac.uk/id/eprint/40821

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