Nuevos materiales conmutables biestables Spin-Crossover para electrónica y espintrónica molecular
- Autores: Alejandro Orellana-Silla
- Directores de la Tesis: José Antonio Real (dir. tes.), Mª Carmen Muñoz Roca (codir. tes.)
- Lectura: En la Universitat de València ( España ) en 2026
- Idioma: inglés
- Número de páginas: 252
- Títulos paralelos:
- Novel bistable spin-crossover switchable materials for molecular electronics and spintronics
- Tribunal Calificador de la Tesis: Sacramento Ferrer Llúsar (presid.), José Sánchez Costa (secret.), Gábor Molnár (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Química
- Menciones:
- Internacional
- Calificación: Sobresaliente Cum Laude
- Materias:
- Enlaces
- Resumen
This Doctoral Thesis has been focused on the study of the spin transition phenomenon (SCO) in Fe(II) hexacoordinated complexes. In these complexes the Fe(II) has the propierty of reversibly changing its spin state between the high state (S = 2, HS) and low spin state (S = 0, LS) induced by external stimuli such as a change in temperature. More precisely, this thesis has been focused on the design, synthesis, and characterization of new Fe(II) 2D and 3D porous coordination polymers aiming at finding new host-guest relations able to induce SCO properties of interest for future applications. The SCO properties have been characterised by temperature dependent magnetic susceptibility and calorimetry measurements as well as X-ray diffraction studies combined with adsorption/desorption studies of selected guest molecules. In chapter 1, the theoretical foundation of the SCO phenomenon is briefly presented starting from basic ideas of the ligand field theory and potentian energy diagrams of the isolated SCO molecule. In chapter 2, the synthesis and characterization of a series of new clathrates derived from the SCO porous coordination polymer formulated {[Fe(tvp)2(NCS)2]@4(CH3CN·H2O)} is described. Immersion of crystals of this precursor compound, 1@4(CH3CN·H2O), in a series of liquid halobenzenes (PhXn) results in the complete substitution of 4(CH3CN·H2O) by halobenzene molecules obtaining in this way a series of new clathrates with general formula 1@2PhXn whose SCO properties are different from those of the original framework. In chapter 3, the synergy between SCO and the adsorption of guest molecules (G) in a new SCO porous coordination polymer of the Hofmann type has been undertaken. To do so, we have synthesized and characterized a new porous 2D framework with general formula {Fe(OHPym)2[M(CN)4]}·xG (1(OH)M·xG) being 5-OHPym = 5-hydroxipyrimidine, M = PdII, PtII, G = H2O, MeOH, EtOH and x = 0-1. To obtain relevant magneto-structural information, the results obtained have been compared with those of the isostructural system previously studied in our group, {Fe(NH2Pym)2[M(CN)4]}·xG (1(NH2)M) being 5-NH2Pym = 5-aminopyrimidine. In chapters 4 and 5 new Hofmann type 2D and 3D coordination polymers have been synthesized base in the combination between the bridging organic ligand 2,5-(dipyridine-4-yl)aniline (dpyan), FeII and the bridging inorganic ligands [MII(CN)4]2- (MII = Pd, Pt) and [AuI(CN)2]-. Both tetracyanometallates derivatives, formulated as {FeII(Hdpyan)2(μ2-[MII(CN)4])2}, are isomorphous and represent the first example of Hofmann type coordination polymers where the FeII centers are coordinated equatorially to four square-planar [MII(CN)4]2- groups that act as bis-monodentate bridging ligands, by two of the CN groups in trans positions, defining infinite {Fe(μ2-[MII(CN)4])2}n2n- layers. The combination of dpyan, FeII and the bridging anionic ligand [AuI(CN)2]- leads to different clathrates of the porous coordination polymer {FeII(dpyan)[AuI(CN)2]2}·xG [where G = MeOH, EtOH, (H2O:MeOH), NO2bz and 0 ≤ x ≤ 1]. The structure is constituted by a double interpenetration of two identical 3D frameworks that shows a different degree of distortion depending on the nature of G and x. Chapter 6 encompasses the conclusions of the overall work of this thesis.
