Sequential synthesis of rigid multi-bipyridine ligands bearing diethynyl/phenyl solubilizing fragments

Reliable and practical synthetic routes for the construction of multitopic bipyridine ligands are presented. The first series contains the chelating f ragments connected via an ethynyl function and the second series is built f rom an alternation of ethynyl/phenyl/bipyridine modules. The synthetic prot ocol is based on sequential Pd-promoted cross-coupling reactions between se lected bis-bpy or ethynyl/phenyl/bpy intermediates of increasing size. The ligands bearing functionalized 1,4-diethynyl-2,5-di(dodecyloxy)benzene subu nits are soluble in chlorinated solvents. (C) 2000 Elsevier Science Ltd. Al l rights reserved.