Synthesis, Characterization, and DNA-Binding and -Photocleavage Properties of Water-Soluble Lanthanide Porphyrinate Complexes

A series of cationic lanthanide porphyrinate complexes of the general formula [(Por)Ln(H2O)(3)](+) (Ln(3+) = Yb3+ and Er3+) were synthesized in moderate yields through the interaction of meso-pyridyl-substituted porphyrin free bases (H(2)Por) with [Ln{N(SiMe3)(2)}(3)]center dot x[LiCl(thf)(3)], and the corresponding neutral derivatives [(Por)Ln(L-OMe)] (L-OMe(-) =[(eta(5)-C5H5)Co{P(=O)(OMe)(2)}(3)](-)) were also prepared from [(Por)Ln(H2O)(3)](+) by the addition of the tripodal anion, L-OMe(-), an effective encapsulating agent for lanthanide ions. Furthermore, the water-soluble lanthanide(III) porphyrinate complexes-including [(cis-DMPyDPP)Yb(H2O)(3)]Cl-3 (cis-DMPyDPP = 5,10-bis(N-methylpyridinium-4'-y1)-15,20-di(phenyl)porphyrin), [(trans-DMPyDPP)Yb(H2O)(3)]Cl-3 (trans-DMPyDPP = 5,15-bis(N-methylpyridinium-4'-y1)-10,20-di(phenyl)porphyrin), [(TMPyP)Yb(L-OMe)]I-4, and [(TMPyP)Er(L-OMe)]I-4 (TMPyP = tetrakis(N-methylpyridinium-4-y1)porphyrin)-were obtained by methylation of the corresponding complexes with methyl iodide and unambiguously characterized. The binding interactions and photocleavage activities of the water-soluble lanthanide(III) porphyrinate complexes towards DNA were investigated by UV-visible, fluorescence, and near-infrared luminescence spectroscopy, as well as circular dichroism and gel electrophoresis.