Porphyrinoid-Fullerene Dyads decorated with Hydroxy Acetate Tethers for Immobilization on Metal Oxide Surfaces

Abstract

Porphyrinoids are macrocyclic molecules, of which porphyrins and phthalocyanines are examples of. Porphyrins share the same basic pyrrolic ring structure, as hemin and chlorophyll, where the four pyrroles are joined by methine bridges. They are all found in nature, whereas phthalocyanines and porphyrazines are purely synthetic compounds. The difference between porphyrazines and porphyrins is the aza-bridges that connect the pyrroles.

The literature review explains the history of research of porphyrins and phthalocyanines in detail. Several synthetic methods are described for both chromophores. The high-yield condensation method for synthesizing porphyrins, developed by Lindsey et al., is reported. Lindsey method is a two step-one flask synthesis, where an aldehyde and pyrrole upon acid catalysis are tetramerizing into a porphyrinogen molecule, which is further oxidized into porphyrin. This method is suitable for mixed condensations, where the two different aldehydes A and B are first mixed in statistical proportions, e.g. 3 and 1, with pyrrole in a dry solvent, followed by the second step - oxidation of the porphyrinogen into porphyrin. For phthalocyanines the general synthetic steps are first described briefly, followed by a closer look on the synthetic steps of preparing unsymmetrical phthalocyanines, e.g. AB3, with three different methods; statistical condensation, synthesis via subphthalocyanine and solid-phase method.

The Results and Discussion part of this Thesis shows extensive experimental work for preparation of both porphyrin- and phthalocyanine chromophores with hydroxyacetate tethers. Porphyrin synthesis required seven intermediate steps and products. Preparing the linkers for the phthalocyanine were attempted with two different pathways; one-step and three-step method. The final products and all the intermediate products were characterized by NMR and mass spectra.