Influence of Carbohydrate Biological Vectors on the Two-Photon Resonance of Porphyrin Oligomers

We propose a spectroscopic study of pi-conjugated porphyrin dimers and a triphenylamine centered trimer bearing monoethyleneglycol-peracetylated a-mannose targeting moieties, which were synthesized for application to two-photon absorption photodynamic therapy (2PA-PDT). The collected spectroscopic data are explained through comparison with previous results obtained on similar nonvectorized analogues. It appears that the different shifts and variations in linear and nonlinear absorption and emission bands are mainly due to an increased twist between the tetrapyrrolic units. The 2PA properties of the triphenylamine-centered trimer have been studied, and two fluorescence emission bands are observed that seem to originate from two different 2PA excitation pathways. These results have important implication for the design of new vectorized photosensitizers for 2PA-PDT.