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Recentment, la generació de radicals actius mitjançant metodologies fotocatalítiques amb llum visible ha permès la construcció d’una gran varietat d’enllaços CC. La inèrcia dels cloroalcans ha impedit el seu ús com a socis d'acoblament predominants tant en reaccions d'acoblament creuat convencionals com fotocatalítiques. De fet, s’han desenvolupat escassos exemples que utilitzin clorurs d’alquil inactivats com a fragments de síntesi, els quals presenten limitacions a l’hora d’aplicar-se de manera general. En aquesta direcció, aquesta tesi descriu el desenvolupament d’una nova família de complexos tetradentats de Co i Ni capaços d’activar diferents clorurs d’alquil. La disponibilitat, versatilitat i modelatge d’aquests lligands ens permet la modificació controlada de la primera esfera de coordinació del metall a partir del canvi de les propietats electròniques i estructurals del lligand. La col.lecció de divuit nous complexos de Co i Ni significa un nou escenari per al desenvolupament de metodologies sintètiques. Recientemente, la generación de radicales activos mediante metodologías fotocatalíticas con luz visible ha permitido la construcción de una gran variedad de enlaces CC. La inercia de los cloroalcanos ha impedido su uso como socios de ensamblaje predominantes tanto en reacciones de ensamblaje cruzado convencionales como fotocatalíticas. De hecho, se han desarrollado escasos ejemplos que utilicen cloruros de alquilo inactivados como fragmentos de síntesis, que presentan limitaciones a la hora de aplicarse de forma general. En esta dirección, esta tesis describe el desarrollo de una nueva familia de complejos tetradentados de Co i Ni capaces de activar diferentes cloruros de alquil. La disponibilidad, versatilidad y modelado de estos ligandos permite la modificación controlada de la primera esfera de coordinación del metal a partir del cambio de las propiedades electrónicas y estructurales del ligando. La colección de dieciocho nuevos complejos de Co i Ni significa un nuevo escenario para el desarrollo de metodologías sintéticas. Recent photocatalytic methods based on the visible-light-induced generation of reactive radicals have allowed the construction of a large variety of CC bonds. The inertness of chloroalkanes has precluded them as prevailing coupling partners in both conventional and photocatalytic cross-coupling reactions. In fact, few examples of using unactivated alkyl chlorides as building blocks have been developed, presenting limitations in their applicability for a general methodology. In this line, this thesis describes the development of a new familiy of tetradentate aminopyridine Co and Ni complexes able to activate different chloroalkanes. The ligand availability, modularity and versatility let us the tune the first coordination sphere of the metal by changing the electronic and structural features of the ligand. A collection of eighteen new Co and Ni complexes have been studied presenting a playground for synthetic methodology development.

The adsorption enthalpies, Ξ”Had, of a series of alkyl chlorides in acidic (H-FAU) zeolite have been investigated using density functional theory (DFT) and molecular mechanics methods. Two models were employed to simulate the zeolite cluster, each containing one BrΓΈnsted acid site. The first model, corresponding to the formula Al(OH)2(OHp)(SiOH2)11, forms a 12-membered ring (12T) constructed from 11 Si tetrahedral atoms and one Al atom in the windows of the twelve O atoms and has been fully optimized at the B3LYP/6-31+G(d,p) level of theory. The second model is represented by the more realistic cluster of 84 tetrahedral units (84T) and has been examined with the help of the ONIOM2 approach using the two layered schemes B3LYP/6-31+G(d,p):UFF and M06-2X/6-31+G(d,p):UFF in two series of calculations. The latter series using the newly developed M06-2X functional by Truhlar and coworkers (Zhao et al., J Chem Phys 123:161103, 2005; Zhao and Truhlar, Theor Chem Acc 120:215, 2008), is expected to make a more reliable and realistic estimation of the effect of the dispersion forces which are quite important in this type of systems. The calculated structural variations and adsorption enthalpies of the van der Waals 1:1 adsorption complex assumingly formed, are shown to exhibit an impressive dependence both on the size of the zeolite cluster model and on the theoretical method employed, particularly the M06-2X functional. Indeed, the M06-2X calculations bring out most clearly the important role and the significant contribution of the dispersion forces to the adsorption enthalpies of a series of the alkyl chlorides on acidic zeolite leading to Ξ”Had values higher by more than 30 % compared to the B3LYP results. Finally, the present calculations reconfirm the dependence of the interaction energy on the size and the branching of the alkyl radical. Reaction Kinetics, Mechanisms and Catalysis

The photosulfochlorination of n-tetradecane by sulfuryl chloride leads to a reaction mixture containing unreacted n-tetradecane, chloro n-tetradecanes and n-tetradecanesulfonyl chlorides. Direct and simultaneous GC analysis of the mixture of the sulfochlorinated and chlorinated isomers is followed by mass spectrometry identification of all the components either by electron impact (EI-MS) and by negative and positive chemical ionisation (NCI-MS and PCI-MS). With the goal of performing an accurate quantitative GC analysis, and as n-tetradecanesulfonyl chlorides prone to degrade partially into the corresponding chlorides, the former are converted to N,N-diethylsufonamides, more stable thermally, and then analysed by GC/EI-MS and GC/PCI-MS. The chloro n-tetradecanes, sulfonylchlorides and sulfonamides spectra present strong similarities. However, some differences between terminal and internal isomers are noticed and the peculiar behaviour of sulfonamides is emphasized.