Porphyrin-containing glycodendrimers

Two dendrimers, incorporating tetrasubstituted porphyrin units as their cores and, in one case, four perbenzoylated and, in the other case, twelve peracetylated beta-D-glucopyranosyl residues at their peripheries, have been synthesized in yields of 39 and 16%, respectively. The deprotection of these dendrimers was achieved quantitatively under Zemplen conditions. The protected and deprotected dendrimers were characterized by liquid secondary-ion or matrix-assisted laser desorption ionization time-of-flight mass spectrometry and by a combination of one- and two-dimensional H-1 and C-13 NMR spectroscopy. All the glycodendrimers were also characterized by absorption and emission spectroscopy, and lifetime measurements. The most relevant result is that both protected and deprotected dendrimers show two fluorescence lifetime values that are different from the porphyrin model compounds. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).