Synthesis of Ditopic Porphyrins and Lanthanide Complexes on their Basis: Luminescent Features

Abstract

It is known that lanthanide-porphyrins have some advantages in comparison with free-base porphyrins as potential agents in medical practice due to their unique luminescent and magnetic features.[1,2] But their application is confined by two important aspects, such as relatively low chemical stability in comparison with many other metal-porphyrins and negligible value of IR-luminescence quantum yield. In this connection the creation of new stable lanthanide-porphyrins on the basis of porphyrins modified with strong chelating agents has an important role. These objects should exclude the disadvantages of lanthanide-porphyrins. One of the basic priorities in the creation of such compounds is their simultaneous use as the contrast agents in magnetic resonance investigation (MRI) and as the agents in photodynamic therapy (PDT).[3] The modification of porphyrin by the second coordinating ligand, in particular, by aminopolycarbonic acid (e.g. EDTA ethylenediaminetetraacetic acid or DTPA diethylenetriaminepentaacetic acid) can be considered as an effective method. But there are only few works which are devoted to such compounds and they don’t describe the luminescent properties of lanthanides in them.[3-7] Therefore study of 4f-luminescence in these compounds is actual. In this work the study of the influence of the structure of monoand homobinuclear lanthanide complexes on their spectral-luminescent properties is carried out. The compounds have been obtained on the basis of ATPP (mono-p-aminotetraphenylporphyrin) modified by EDTA and DTPA.