| Abstract
| - A number of silicon phthalocyanine bis-esters have been synthesized and characterized, with axialligands containing one or more tetrathiafulvalene groups. Variations in the substitution positionsaround a central aromatic “hinge” within the ligands lead to different molecular geometries, andthe fluorescence of the macrocyclic core is subsequently quenched to varying degrees by the electron-rich tetrathiafulvalene moiety, the magnitude of this effect being dependent upon both the relativeseparation of the two units and the flexibility of the linking group. Pc derivative 24, with a highlyflexible linker group, and pc derivative 28, with a dendritic axial ligand, have the intensity of themacrocycle emission reduced by 99% and 96%, respectively, relative to a similar silicon pc referencecompound lacking the TTF moieties. Molecular modeling studies of a series of such hybrids allowthe degree of this fluorescence quenching to be related to the intramolecular spacing. Additionally,the potential for rapid electrochemical switching of the phthalocyanine fluorescence by oxidationof the appended tetrathiafulvalene units is explored.
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