Dissymmetrical U-Shaped π-Stacked Supramolecular Assemblies by Using a Dinuclear CuI Clip with Organophosphorus Ligands and Monotopic Fully π-Conjugated Ligands

Reactions between the U-shaped binuclear Cu-I complex A that bears short metal-metal distances and the cyano-capped monotopic -conjugated ligands 1-5 that carry gradually bulkier polyaromatic terminal fragments lead to the formation of -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 -conjugated systems present large (6, 7, and 9) or medium (8 and 10) intramolecular overlap, thus revealing - interactions. These assemblies self-organize into head-to-tail -stacked dimers that in turn self-assemble to afford infinite columnar stacks. The nature, extent, and complexity of the intermolecular contacts within the head-to-tail -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 - 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 -stacked columns based on dissymmetrical and functional -conjugated systems.