The synthesis and reactivity of novel perfluorinated phthalonitriles and phthalocyanines

In this project we have designed bioinspired catalysts modeled after the reactivity of the heme-metalloprotein Cytochrome P₄₅₀, an enzyme that performs oxidations of hydrocarbons. Our synthetic targets are a novel class of molecules, three-dimensional perfluorinated phthalocyanines. The three-dimensionality is the result of placing bulky substituents, perfluoroisopropyl groups, on the peripheral rings of the phthalocyanines. These models contain no carbon hydrogen bonds, only non-oxidizable carbon fluorines bonds; hence the robustness of these molecules viewed as molecular reactors. First we prepared non-planar perfluorinated phthalonitriles as the ligand precursors. From 19F NMR studies we were able to determine their conformation in solution as being identical to their conformation in solid-state.; The bulky substituents create a fluorine-lined cavity around the metal center while hindering the formation of oxo-bridged dinuclear complexes and minimizing self-aggregation in solution. Activation of oxygen was studied along two lines.; Diamagnetic phthalocyanines may be used for “photodynamic therapy” (PDT), a process in which a light activated sensitizer produces singlet oxygen to cause destruction of tumor cells. Perfluorinated zinc phthalocyanine was synthesized and studied as potential PDT sensitizer. Unlike planar zinc phthalocyanines, our three-dimensional zinc complex does not aggregate, exhibits a long triplet-state lifetime, and produces effectively singlet oxygen, as demonstrated by the photoproduction of L-tryptophan hydroperoxide and the curing of breast tumors in mice.; A three-dimensional perfluorinated cobalt (II) phthalocyanine performs the direct formation of ylidic carbon-phosphorous bonds, a process in which two hydrogen atoms are eliminated as water. This reaction, which occurs at ambient conditions and uses air as the oxidizing agent, eliminates the need for halogenated intermediates. Furthermore, based upon this chemistry, we demonstrate a catalytic cycle illustrating a strategy for transforming a stoichiometric process into a catalytic, environmentally benign, one.