Synthesis of first-row transition metal complexes containing halogenated phenanthroline and bipyridine ligands.

Abstract

This thesis describes the development and analysis of several complexes that have the potential to exhibit magnetic bistability, focussing on some complexes that are capable of exhibiting spin-crossover (SCO) and single-molecule magnet (SMM) properties. Magnetic bistability is a property of molecule to exist in two stable electronic states under a external parameter resulting in two different magnetic states being measured Yttrium and dysprosium complexes with and without linkers were synthesised and analysed in the hope of producing a bimetallic complex containing both a transition metal and a lanthanide metal centres, which could display both SCO and SMM properties. Although the dysprosium complexes synthesised have the potential to be SMMs, synthesis of the desired bimetallic complex having both SCO and SMM properties was not achieved. The synthesis of a series of halogenated ligands 5,5'-difluoro-2,2'-bipyridine (5,5'-F2bipy) and 4,4'-difluoro-2,2'-bipyridine (4,4'-F2bipy) 5,5'-dibromo-2,2'-bipyridine (5,5'-Br2bipy) and 3,8-dibromo-1,10-phenantholine (3,8-Br2phen) are reported. The complexes investigated in this thesis with the potential to be SCOs complexes included several iron (II) poly-pyrazoleborato and substituted iron (II) poly-pyrazoleborato complexes, with the above halogenated ligands. The structures, steric and [some of the] electronic properties of these complexes were examined. The findings indicate that the presence of a halogenated ligand influences both the structural and electronic properties of the complexes. This thesis also describes the development and analysis of late first row transition metal (iron, cobalt, nickel, copper and zinc) complexes incorporating a series of halogenated ligands as detailed above and examines their steric and [some of their] electronic properties. The findings suggest that the presence of halogenated bipy ligands cause only structural changes across the transition metal series examined, while the presence of halogenated phenanthroline ligands were seen to produce both structural and electron changes.

Date of Award	1 Aug 2022
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Alan Brisdon (Supervisor) & David Collison (Supervisor)