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Dimer derivative of Zn and Mn Porfirin: Synthesis, caracterization and energy transfer studies

Porphyrins have revealed that factors as the energy transfer distance, molecular geometry and the difference of electronic potential, are important in a well defined electronic transfer. Porphyrin- containing donor-acceptor systems have been usefully employed to test various theoretical descriptions of electron transfer. The objective of this paper consists on the synthesis, purification and characterization by UV/Vis spectroscopy, ¹H and 19F NMR, luminescence and lifetime of new molecular models, allowing the investigation of energy transfer parameters. This study was accomplished using the dimer Zn,Mn(TPPF4)2pip and its monomers ZnTPPF4pipH and MnF5TPP. The dimer characterization, Zn,Mn(TPPF4)2pip, was difficult due to the presence of Mn3+. The strong overlap between dpi orbitals of manganese and the porphyrin pi system increases the interaction manganese-porphyrin in changing the UV/Vis electronic spectrum and distorting the ¹H and 19F NMR signals of dimer. The presence of Mn3+ shifts the reduction potential of E1/2 of the porphyrin ring to more negatives values, what results in more difficult reductions, disabling the transfer of energy from Zincporphyrin to Manganeseporphyrin.

Energy transfer; dimer complex and NMR


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