Jean-Claude Bunzli - Non-cytotoxic, bifunctional Eu-III and Tb-III luminescent macrocyclic complexes for luminescence resonant energy-transfer experiments

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      Ferrand,A.C., Imbert,D., Chauvin,A.S., Vandevyver,C.D.B.,   Bunzli,J.C.G. Chemistry-A European Journal  2007 13 (31) 8678-8687

      Abstract: A new macrocyclic ligand, L-3, has   been synthesised, based on the cyclen framework grafted with   three phenacyl light-harvesting groups and a C-5-alkyl chain   bearing a carboxylic acid function as a potential linker for   biological material. Acidity constants are determined by   spectrophotometric titrations, as well as conditional stability   constants for the resulting 1:1 complexes with trivalent   lanthanide ions. ne complexes have stabilities comparable to   1,4,7,10-tetrakis(carbamoyl-methyl)-1,4,7,10-tetraazacyclododecane   (dtma) complexes, with pLn approximate to 12-13. Photophysical   properties of the ligand and of the EuL3 and TbL3 complexes have   been determined for both microcrystalline samples and solutions   in water and acetonitrile. They point to the metal ion being   present in an environment with axial symmetry derived from the C,   point group. The hydration number determined for TbL3 decreases   with increasing pH value and becomes fractional at pH 7.5, which   points to an equilibrium between two differently solvated species   and probably to the participation of the deprotonated carboxylic   acid chain in the complexation. The quantum yields in water (1.9%   for Eu-III, 3.4 % for Tb-III) are smaller than those for   complexes with the symmetrically substituted parent macrocycle,   but efficient luminescence resonant energy transfer (LRET) was   observed when Cy5 dye was added to the solutions. Finally, the   influence of the TbL3 Complex on cell viability is tested on both   malignant (5D10 mouse hybridoma, Jurkat human T leukaemia, MCF-7   human breast carcinoma) and non-malignant (Hacat human   keratinocyte) cell lines. Cell viability after 24 h incubation at   37 degrees C with 500 mu m TbL3 was > 90 % for all cell lines,   except Jurkat (>70%). All of these properties make LnL(3)   complexes interesting potential probes for bioanalyses

      Address (URL): WOS:000250733600004