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Title: Design of new spin-crossover materials for surface deposition
Author: Capel Berdiell, Izar
ISNI:       0000 0004 8500 8967
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2019
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This thesis comprises the synthesis and characterization of a variety of compounds and systems whose magnetic behaviour has been tested orienting into the spin crossover phenomenon (SCO). The first chapter is an introduction of generic knowledge related to spin crossover, including the techniques used to determine SCO and the stimuli which are relevant and contribute to it. The modification of the 2,6-bis(pyrazol-1-yl)pyridine (1-bpp) scaffold was proposed as an easier alternative way to produce iron(II) SCO complexes. A new family of iron(II) mononuclear complexes of 2,4-di(pyrazol-1-yl)-1,3,5-triazine based ligands, with different substituents in the 6-position of the triazinyl ring or at the pyrazolyl group are studied (Chapter 2), DFT calculations highlight the nature of these HS compounds is due to a geometric factor. New heterometallic coordination polymer gels (CPGs) with different first row transition metal complexes of 2,4,6-tris(pyrazol-1-yl)-1,3,5-triazine (TPT) combined with silver(I) salts are characterized in the following study. Production of SCO CPGs is attempted by modification of the TPT ligand. Related coordination polymers of silver(I) salts and a linear iron(III) trimer bridged by fluorine are also described at chapter 3. Various polymeric and polymetallic compounds assembled from 1,3,5-triazine and 1,3-pyrimidine based ligands acting as bisbidentate ligands (Chapter 4). Modification of the ligands affects the coordination type and the magnetic properties of such assemblies. Moreover, a second modification of 1-bpp family of ligands is studied together in chapter 5 with the magnetic behaviour of their iron(II) mononuclear complexes. Geometric isomers of 2,6-di(1,2,3-triazol-yl)pyridine based behave differently. DFT calculations of the free ligands determined that the most energetic lone pair could determine whether it is tridentate or linear coordinating ligand. Potential linkers between the 2,6-di(pyrazol-1-yl)-pyridine scaffold and a tether group are assessed. Iron(II) complexes of the simpler analogue compounds show varying magnetic behaviours, including the highest symmetry breaking associated to SCO ever reported (Chapter 6). Successful deposition of novel iron(II) complexes of 2,6-di(pyrazol-1-yl)- pyridine based tethered ligands on gold or metal-oxides was developed at the ICMol (Valencia). However the integrity of SCO at the surface was not proved by the current techniques (Chapter 7). The account of all experimental details for the compounds and analytical techniques which are the subject of discussion in this work are described in the last chapter, 8.
Supervisor: Halcrow, Malcolm A. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available