Comparison of the bond lengths for the lanthanide complexes of tripodal heptadentate ligands

The preparation and characterization of Ln(III) complexes (Ln = Sm, Yb) of tripodal heptadentate ligand trensal, tris[2-(saticylideneamino) ethyl]amine (H3L(1)) have been studied. The molecular structures of [LnL(1)] were determined by X-ray structural analysis; these are heptadentate complexes in which the metal ions are coordinated by the three oxygen atoms and the four nitrogen atoms. [LnL(1)] is a novel example because the coordination number is seven in the wide range of the series of [LnL(1)] (Ln = Y, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu). This has made it possible to compare the bond lengths for the lanthanide and yttrium complexes under the same coordination number. (C) 2003 Elsevier B.V. All rights reserved.