Symmetric and Asymmetric Coupling of Pyridylpyrimidine for the Synthesis of Polynucleating Ligands

A convenient synthetic approach to build up new polynucleating ligands is presented. Symmetric and asymmetric pyridylpyrimidine dimers are produced by radical anion coupling and nucleophilic addition, respectively. A diruthenium complex of the asymmetric ligand was synthesised and characterised by cyclic voltammetry, luminescence and 99Ru NMR spectroscopy. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)