title: Dissymmetrical U-shaped π-stacked supramolecular assemblies by using a dinuclear Cu(I) clip with organophosphorus ligands and monotopic fully π-conjugated ligands.
abstract: Reactions between the U-shaped binuclear Cu(I) complex A that bears short metal-metal distances and the cyano-capped monotopic π-conjugated ligands 1-5 that carry gradually bulkier polyaromatic terminal fragments lead to the formation of π-stacked supramolecular assemblies 6-10, respectively, in yields of 50-80 %. These derivatives have been characterized by multinuclear NMR spectroscopic analysis and X-ray diffraction studies. Their solid-state structures show the selective formation of U-shaped supramolecular assemblies in which two monotopic π-conjugated systems present large (6, 7, and 9) or medium (8 and 10) intramolecular π overlap, thus revealing π-π interactions. These assemblies self-organize into head-to-tail π-stacked dimers that in turn self-assemble to afford infinite columnar π stacks. The nature, extent, and complexity of the intermolecular contacts within the head-to-tail π-stacked dimer depend on the nature of the terminal polyaromatic fragment carried by the cyano-capped monotopic ligand, but it does not alter the result of the self-assembling process. These results demonstrate that the dinuclear molecular clip A that bears short metal-metal distances allows selective supramolecular assembly processes driven by the formation of intra- and intermolecular short π-π interactions in the resulting self-assembled structures; thus, demonstrating that their shape is not only dictated by the symmetry of the building blocks. This approach opens perspectives toward the formation of extended π-stacked columns based on dissymmetrical and functional π-conjugated systems.
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France), Fax: (+33) 2-23-23-69-39.
authors.forename: Mehdi
authors.initials: M
authors.lastname: El Sayed Moussa
authors.forename: Kevin
authors.initials: K
authors.lastname: Guillois
authors.forename: Wenting
authors.initials: W
authors.lastname: Shen
authors.forename: Régis
authors.initials: R
authors.lastname: Réau
authors.forename: Jeanne
authors.initials: J
authors.lastname: Crassous
authors.forename: Christophe
authors.initials: C
authors.lastname: Lescop
keywords: P ligands; conjugation; noncovalent interactions; polycycles; self-assembly