Insights About the Mechanism of the Formation of Supramolecular pi -Stacked Rectangles Based on Cu super(I) Bimetallic Complexes Bearing a Bridging Phosphane Ligand

• Published in: European journal of inorganic chemistry Vol. 2014; no. 10; pp. 1788 - 1796
• Main Authors: Nohra, Brigitte, Reau, Regis, Lescop, Christophe
• Format: Journal Article
• Language: English
• Published: 01-04-2014
• Subjects: Assemblies; Bimetals; Clips; Derivatives; Ligands; NMR spectroscopy; Rectangles; Self assembly
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201301209

The variation in the ratio of the reactants in the supramolecular self-assembly reaction of the bimetallic Cu super(I) "U-shaped" molecular clip 1 with the 1,4-dicyanobenzene 3 and the 1,8-anthracene-9,10-carbonitrile 4 "short" ditopic ligand have allowed the observation of new "open" supramolecular assemblies 7 and 8, respectively, in addition to the previously characterized pi -stacked supramolecular rectangles 5 and 6, respectively. These new derivatives have been characterized by their solid-state structure obtained by X-ray diffraction on single crystals and by NMR spectroscopy in the case of derivative 7. Depending on the extent of the pi system included in the core of the homoditopic linker, different behaviors are observed. In the case of derivative 7 based on the "phenyl" linker 3, a 1:1 1/3 ratio affords the open derivative in a good yield, whereas a 1:0.5 1/4 ratio allows the isolation of derivative 8 in very low yield. These results allow for a tentative analysis of the mechanism that occurs along with the supramolecular self-assembly processes to afford pi -stacked supramolecular rectangles. Variation of the ratio of the reactants in the reaction of a Cu super(I) dimer acting as a "U-shaped" molecular clip with selected homoditopic pi -conjugated linkers allows the observation of "open" tetrametallic supramolecular assemblies together with pi -stacked metallocyclophanes. This will help us understand the mechanism of such self-assembly reactions.