Chains, Necklaces and Weaving Chain-link Grids from Self-Assembly Reactions

Assembly of two ditopic units, a phenanthroline substituted by 4-ethynyl pyridines at the 2-and 9-positions and a dimetallic paddlewheel, gives a linear chain polymer rather than a closed cyclic species, which would appear equally possible. The chain may be decorated by binding a copper-containing macrocycle around the phenanthroline units to form a polypseudorotaxane. When two phenanthroline ligands are assembled in a first step around copper(I), the paddlewheel acceptor can link them in a second step to form a two-dimensional interwoven grid that resembles the form of a chain-link fence. Each copper(I) centre in this structure is chiral, and the crystal shows complete homochirality, implying selection during the assembly process. Lassemblage de deux unites ditopiques, une phenantroline substituee sur les positions 2 et 9 par la 4-ethynyl pyridine et un paddlewheel dimetallique, donne une chaine polymerique lineaire plutot quune espece cyclique fermee qui serait egalement possible. La chaine peut etre decoree en liant un macrocycle contenant du Cu-I autour des unites phenantroline pour former un polypseudorotaxane. Si lors dune premiere etape, deux ligands phenantroline sont assemble autour de Cu-I, laccepteur paddlewheel peut les lier au cours dune deuxieme etape pour former un maillage entrelace bidimensionnel rappelant une cloture grillagee. Chaque centre cuivre(I) dans la structure est chiral et le cristal est strictement homochiral. Ceci implique une selection au cours du processus dassemblage.