title: Synthesis of multi-1,10-phenanthroline ligands with 1,3-phenylene linkers and their lithium complexes.
abstract: The synthesis of two multisite ligands containing four and five 1,10-phenanthroline (phen) chelates in line, respectively, is presented. The connectors are 1,3-phenylene linkers. The two ligands were prepared following multistep procedures, the two key reactions being the Suzuki coupling reaction between aromatic nuclei and the nucleophilic addition of aryllithium derivatives onto a phen fragment. The coordination chemistry of both ligands with Li+ ions was very clean and selective, whereas their reaction with copper(I) led to intractable mixtures of insoluble complexes. The tetraphen and the pentaphen compounds afforded almost quantitatively the four- and five-lithium double-stranded helical complexes, respectively. The helical systems are probably highly wound, as indicated by NMR measurements. The pronounced strain of the 5-Li+ complex is reflected by the easy loss of a lithium cation, as shown by electrospray mass spectrometry.
authors.affiliation: Laboratoire de Chimie Organo-Minérale, UMR 7513 du CNRS, Institut Le Bel, Université Louis Pasteur, 4 rue Blaise Pascal, 67000 Strasbourg Cedex, France.
authors.forename: Christiane
authors.initials: C
authors.lastname: Dietrich-Buchecker
authors.forename: Benoît
authors.initials: B
authors.lastname: Colasson
authors.forename: Damien
authors.initials: D
authors.lastname: Jouvenot
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Sauvage