Synthesis and properties of novel phthalocvanines and related N-containing macrocycles.

Abstract

Phthalocyanines and other closely related compounds are an important class of macrocycles with many commercial applications. They display interesting optoelectronic and coordination properties, which has resulted in their utilisation in a wide range of fields including optical data storage, electrochromic and optical limiting devices, photosensitizers and medicinal therapeutic agents, and multistage-redox-dependent fluorophores. The synthesis, optoelectronic and surface-assembly properties of several new axially disubstituted silicon phthalocyanines are detailed in this work. Axial ligands include phenyl, terphenyl, thienyl and pyrenyl derivatives. Their absorption and emission spectra are reported and fluorescence lifetimes and quantum yields are correlated with the ligand structures. The optoelectronic properties of a novel free-base phthalocyanine bearing peripherally attached fluorene substituents are also described. Several of these silicon-phthalocyanines were used to assemble thin films on electrode surfaces, and techniques such as scanning Kelvin nanoprobe microscopy and atomic force microscopy, as well as chronoamperometric measurements were used to probe these surfaces. A number of free-base porphyrins bearing a variety of aryl substituents at the meso-positions are also described. The conversion of some of these free-base porphyrins to metalloporphynns is detailed, and a thorough examination of the fluorescence properties of all synthesised porphyrins is also presented. Pyrazinoporphyrazines are a closely-related analogue of phthalocyanines, and several new examples of these systems have been synthesised. As with both the phthalocyanines and porphyrins, their fluorescence properties have been investigated in detail.