Porphycenes have attracted attention for their ability to stabilize complexes with a wide range of metal cations. Coordination compounds of these macrocycles are endowed with of specific chemical, optical, electronic, spectroscopic and photochemical properties,1-8 such as, strong absoptions in the red region of the UV-vis spectrum. These characteristics have been used in the study of protein mimicry,9, 10 photodynamic therapy (PDT)11-16 and materials chemistry17, 18 The fusion of bipyrrolic entities with aromatic rings could led to a change in the photophysical properties of porphycenes, and could give rise to nonlinear optical (NLO) behavior.19 Taken in concert, these possibilities provides an incentive to study metal complexes of new porphycenes. With that goal in mind, presented here is the synthesis and the spectroscopic and voltamperometric analyses of four metollocene complexes of a relatively new annulated porphycenes, namely i-propyldinaphthoporphycene. Chapter 1 of this thesis provides a brief introduction into porphycenes and porphyrins as well as complexes prepared from these macrocycles. Because it relates more closely to the research described in this thesis, the emphasis will be on peripherally substituted and directly π-metallated porphyrin-like macrocycles. Annulated porphycenes and their metal complexes display geometric and optical features that differ from those of normal porphycenes. Chapter 2 details the coordination compounds of annulated porphycenes, as well as some of their optical and redox features. This chapter also summarizes the current synthesis of dinaphthoporphycenes, while detailing efforts by other authors to coordinate transition metals to dinaphthoporphycenes, which culminated in the preparation of the first nickel(II) complex known so far with this ligand. It was recently found that the electronic properties of porphycenes change from those of an electron donor to those of an electron acceptor when the RuCp* (Cp*: pentamethylcyclopentadienyl) fragment is coordinated to the “π-face” of the macrocycle. This finding, discovered using so-called etioporphycenes, motivated the author to explore the metal complexation chemistry of i-porpyldinaphthoporphycene. This led to the synthesis of four metalloporphycenes are described in Chapter 3. Here, the coordination of the [M(Cp*)]n+ (M = Ru, Ir and Rh) fragments to the π-electron framework was established by analytical, and structural means. Thus, this chapter provides of a description of the spectroscopic, structural and voltamperometric features of these complexes. / text

Anion binding has emerged as an important field of study due to the role that anionic species play in nature. As a consequence, considerable effort has been focused on the generation of anion receptors. These receptors have been designed to recognize anions through interactions, such as hydrogen bonding, donor-acceptor, and hydrophofic effects, in order to achieve higher sensitivity and selectivity. Another approach involves ion pair recognition, wherein the anions and cations are bound to the same system. Specifically, receptors bearing both hydrogen bonding donor and cation coordination sites have been of great interest as systems that lead to anion recognition and enhanced anion selectivities. Chapter 1 of this dissertation describes efforts to develop systems on the basis of modified Schiff-base calixpyrroles. This modification was achieved by incorporating a “strap” across the macrocycle to produce the so-called strapped Schiff-base calixpyrroles. The strap bearing amides are known to act as hydrogen bonding donors that can isolate the binding site from the medium. On the other hand, Schiff-base calixpyrroles have been widely studied as multidentate ligands for metal cation coordination. Therefore, the synthetic combination of these two moieties might provide a system wherein an ion pair complex is formed. Strapped Schiff-base calixpyrrole palladium complex were found to bind selectively cyanide anions. The effects of direct substitution on one meso position on the optical and photophysical properties of porphycenes was recently found to be dependent of the electronic properties of the substituten (e.g., electron donor or electron withdrawing group). However, the effects on the electronic and optical properties properties as a result of substitution through a conjugated spacer are as yet unknown. This led to the synthesis of four meso substituted etioporphycenes, which are described in Chapter 2. Here, the substitution through an ethenyl group was stablished by analytical and structural means. This chapter provides of a description of the spectroscopic, structural and voltamperometric features of these compounds. Experimental procedures and characterization data are reported in Chapter 3. / text

S'ha estudiat el desenvolupament de fotosensibilitzadors i la seva formulació en teràpia fotodinàmica. S'han caracteritzat les propietats fotofísiques dels fotosensibilitzadors porficènics. S'han proposat diferents estratègies tals com la introducció de grups carboxilat en la perifèria o ions de metalls pesants en el nucli, per millorar el disseny de nous fotosensibilitzadors basats en el macrocicle porficènic. Entre ells, el temocè (m-THPPo), el porficè anàleg a la temoporfina, mostra excel•lents propietats fotofísiques, fotoestabilitat i alta eficàcia fotodinàmica. A causa de la seva alta hidrofobicitat, s'ha desenvolupat una formulació liposomal per a l'administració in vitro i in vivo del temocè. m-THPPo/DPPC/DMPG (1:67.5:7.5 relació molar) té alta eficiència d'encapsulació mantenint les seves propietats tant fotofísiques com a biològiques. El temocè liposomal va exhibir l'eficàcia fotodinàmica in vitro més alta per molècula internalitzada, sent un sistema d'administració de fàrmacs eficaç per a una estratègia in vivo dirigida a les cèl•lules tumorals. El temocè encapsulat en micel•les de Cremophor EL va mostrar una mínima internalització cel•lular. Consistentment, la formulació micel•lar va mostrar millor la resposta in vivo quan s'utilitza en un règim vascular. Amb la finalitat de minimitzar la internalització del fotosensibilitzador en les cèl•lules normals, es van proposar liposomes decorats amb lligands folat. Aquesta estratègia resulta en una internalització dues vegades major dels liposomes dirigits al receptor folat respecte a la corresponent formulació no específica. Finalment, han estat explorats nous models cel•lulars in vitro per a l'optimització dels processos amb oxigen singlet. Els cultius cel•lulars en 3D reprodueixen l'heterogeneïtat d'oxigen i fotosensibilitzador que està present en els teixits reals, proporcionant informació molt útil per interpretar i predir el resultat de la teràpia fotodinàmica. També s'ha demostrat la capacitat de desactivació de l'oxigen singlet d'antioxidants en un model ex vivo de pell porcina. / Se ha estudiado el desarrollo de fotosensibilizadores y su formulación en terapia fotodinámica. Se han caracterizado las propiedades fotofísicas de los fotosensibilizadores porficénicos. Se han propuesto diferentes estrategias tales como la introducción de grupos carboxilato en la periferia o iones de metales pesados en el núcleo, para mejorar el diseño de nuevos fotosensibilizadores basados en el macrociclo porficénico. Entre ellos, el temoceno (m-THPPo), el porficeno análogo a la temoporfina, muestra excelentes propiedades fotofísicas, fotoestabilidad y alta eficacia fotodinámica. Debido a su alta hidrofobicidad, se ha desarrollado una formulación liposomal para la administración in vitro e in vivo del temoceno. m-THPPo/DPPC/DMPG (1:67.5:7.5 relación molar) tiene alta eficiencia de encapsulación manteniendo sus propiedades tanto fotofísicas como biológicas. El temoceno liposomal exhibió la eficacia fotodinámica in vitro más alta por molécula internalizada, siendo un sistema de administración de fármacos eficaz para una estrategia in vivo dirigida a las células tumorales. El temoceno encapsulado en micelas de Cremophor EL mostró una mínima internalización celular. Consistentemente, la formulación micelar mostró mejor la respuesta in vivo cuando se utiliza en un régimen vascular. Con el fin de minimizar la internalización del fotosensibilizador en las células normales, se propusieron liposomas decorados con ligandos folato. Esta estrategia resulta en una internalización dos veces mayor de los liposomas dirigidos al receptor folato respecto a la correspondiente formulación no específica. Por último, han sido explorados nuevos modelos celulares in vitro para la optimización de los procesos con oxígeno singlete. Los cultivos celulares en 3D reproducen la heterogeneidad de oxígeno y fotosensibilizador que está presente en los tejidos reales, proporcionando información muy útil para interpretar y predecir el resultado de la terapia fotodinámica. También se ha demostrado la capacidad de desactivación del oxígeno singlete de antioxidantes en un modelo ex vivo de piel porcina. / The photosensitizer and formulation development in photodynamic therapy have been studied. They have been characterized the photophysical properties of new porphycene-based photosensitizers. Different strategies such as the introduction of carboxylate groups in the periphery or heavy metal ions in the core have been proposed for improving the design of novel photosensitizers based on the porphycene macrocycle. Among them, temocene (m-THPPo), the porphycene analogue to temoporfin, shows excellent photophysical properties, superior photostability and high photodynamic efficiency. Owing to its high hydrophobicity, a liposomal formulation has been developed for in vitro and in vivo administration of temocene. m-THPPo/DPPC/DMPG (1:67.5:7.5 molar ratio) yielded high encapsulation efficiency maintaining its photophysical and biological properties. Liposomal temocene exhibited the highest in vitro killing efficacy per uptaken molecule and they were an efficient drug delivery system for in vivo tumor cell targeting strategy. Temocene encapsulated in Cremophor EL micelles showed minimal cell internalization. Consistently, micellar formulation showed the best in vivo response when used in a vascular regime. In order to minimize the internalization of the photosensitizer in normal cells, liposomes decorated with folic acid ligands were proposed. This strategy leads to a 2-fold higher uptake of folate-targeted liposomes than the corresponding non-targeted formulation. Finally, new in vitro cellular models for a better optimization of singlet oxygen-involved processes were explored. 3D cellular cultures reproduced the oxygen and photosensitizer heterogeneity found in real tissues, providing useful information to interpret and predict the photodynamic therapy outcome. The singlet oxygen quenching ability of antioxidants in ex vivo porcine skin model has also been demonstrated.