Germanium(IV) phthalocyanine-porphyrin based hetero trimers: synthesis, spectroscopy and photochemistry

Abstract

The known oxophilicity of Germanium(IV) ion of Germanium(IV) phthalocyanine and porphyrins have been exploited to synthesize functionally active, "axial-bonding" -type hetero oligomers. These hetero trimers have been fully characterized by elemental analysis, FAB-MS, UV-visible, proton nuclear magnetic resonance (1D and 1 H -1 H COSY) and fluorescence spectroscopies, as well as differential pulse voltammetric method. Comparison of their spectroscopic and electrochemical data with those of the corresponding individual constituents reveals that there is no apparent π–π interactions in these "vertically" linked hetero oligomers. The fluorescence quantum yields were found to be lower of these hetero oligomers in comparison with those of the monomeric chromophores. Electronic energy transfer and photoinduced electron transfer from axial porphyrins to central metalloid phthalocyanine and photoinduced electron transfer from singlet state of axial porphyrins to central metalloid phthalocyanine is detected in these hetero oligomers.