Self-assembly of supramolecular boxes

Self-Assembly of Discrete Cyclic Nanostructures Mediated by Transition Metals

“…Mass spectrometry and singlecrystal X-ray studies allowed the unambiguous elucidation of its structure. 34 Interestingly, a topologically similar assembly was also obtained by Hannon and co-workers, using octahedral group IIb metals such as cadmium. Reaction of the same ligand with cadmium(II) acetate furnished a structure similar to 4 in which the cadmium cation occupies a pseudooctahedral environment, additionally coordinated by a bidentate acetate ligand and a methanol solvent molecule.…”

Effect of Ligand Spacer on Metallosupramolecular Architectures: From a Dinuclear Copper(II) Double Helicate to a Tetranuclear Copper(II) Complex

“…[5] Derivatives of beta-diketonates, [37] dipyrromethenes, [38][39][40] iminopyrroles, [41] and pyridyl Schiff bases [24,[42][43][44][45][46] have been used as organic ligands for the synthesis of dinuclear clusters and clusters of higher nuclearity. [47,48] In contrast, very few Schiff-base-type iminophenol ligands have been reported for this purpose.…”

Spacer Control of Directionality in Supramolecular Helicates Using an Inexpensive Approach

“…If a nonsymmetrical ligand is used for helicate formation, the issue of controlling the relative orientations (or directions) of the ligands within the helical superstructure arises. This issue is important because selectively orienting substituents on the outside of a helix is desirable in order to control the assembly of helicates into larger supramolecular arrays (we have previously used this principle to control the aggregation of supramolecular boxes [2] ) or to relay the chiral information inherent in the helix to an extra-helical site.Constable et al have shown that by careful positioning of bulky substituents on the back of a ligand, double helices of an exclusive head-to-head or head-to-tail ligand orientation can be assembled.[6] However, such interactions seem to represent a relatively small energy term and may be relieved by a flattening of the helical pitch resulting in a mix of head-tohead and head-to-tail helices in solution, for all but the most bulky substituents.[6] An alternative approach is to use different donor sets to control the assembly: Piguet et al [7] and Albrecht and Fröhlich [8] have used ligands containing two different binding units to form directional triple helices.We reasoned that an alternative approach might be to introduce asymmetry into a spacer placed between the metalbinding domains. Since this introduces the asymmetry directly within the helical array rather than at the periphery, it seems likely to provide a greater energetic stabilization for one orientation over the other.…”

“…If a nonsymmetrical ligand is used for helicate formation, the issue of controlling the relative orientations (or directions) of the ligands within the helical superstructure arises. This issue is important because selectively orienting substituents on the outside of a helix is desirable in order to control the assembly of helicates into larger supramolecular arrays (we have previously used this principle to control the aggregation of supramolecular boxes [2] ) or to relay the chiral information inherent in the helix to an extra-helical site.Constable et al have shown that by careful positioning of bulky substituents on the back of a ligand, double helices of an exclusive head-to-head or head-to-tail ligand orientation can be assembled. [6] However, such interactions seem to represent a relatively small energy term and may be relieved by a flattening of the helical pitch resulting in a mix of head-tohead and head-to-tail helices in solution, for all but the most bulky substituents.…”