Jean-Claude Bunzli - Self-Assembly of Helical Supramolecular Lanthanide Complexes

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      Publication Details (including relevant citation   information):

      Piguet,C., Bunzli,J.C.G., Bernardinelli,G., Hopfgartner,G.,   Williams,A.F. Journal of Alloys and Compounds  1995 225 (1-2) 324-330

      Abstract: The spontaneous strict self-assembly   of tailored oligo-multidentate ligands with d-transition metal   ions leads to the selective formation of polynuclear double- and   triple-helical supramolecular complexes. A significant   improvement of the selectivity of the processes can be achieved   by using segmental ligands which possess different binding units   connected by spacers favouring helical coordination and pure   heteropolynuclear helical complexes can be isolated under   thermodynamic control. The application of these principles to 4f   block ions requires the development of tridentate heterocyclic   ligands designed for the synthesis of triple-helical   self-assembled complexes containing lanthanides. The ligand 2,6   bis(1'-methyl-1H-benzimidazol-2'-yl)pyridine (L(4)) reacts with   Ln(3+) in acetonitrile to give the three successive complexes   [Ln(L(4))](3+), [Ln(L(4))(2)](3+) and [Ln(L(4))(3)](3+). The   three ligands in [Ln(L(4))(3)](3+) are wrapped around Eu(III) and   produce a pseudo-D-3 symmetrical structure considered as a   building block for triple-helical luminescent supramolecular   structures. The introduction of two tridentate binding units into   the oligomultidentate ligand L(6) leads to the formation of   dinuclear self-assembled triple-helical complexes   [Ln(2)(L(6))(3)](6+) which work as molecular light-converting   devices on the nanometric scale. The photophysical properties   together with the formation of analogous heterodinuclear and   homotrinuclear complexes are discussed

      Address (URL): WOS:A1995RR58500075