Supramolecular Chirality in Coordination Chemistry

Coordination-Driven Face-Directed Self-Assembly of Trigonal Prisms. Face-Based Conformational Chirality

“…31 We consider first the chirality of the isolated star connectors 1a -1d, and then, the chirality of the assembled prisms.…”

“…30 Optically active three-dimensional cages with vertex metal atoms carrying achiral ligands in a chiral octahedral arrangement have been explored by Raymond and coworkers. 7,31,32 We now introduce the concept of face-based cage chirality, which has a different origin, as it is defined by the cage faces and not vertices or edges. Star connectors used to define cage faces are frequently propeller-shaped, with all arms attached to the central moiety twisted in the same sense.…”

Stereochemical Communication within Tetrahedral Capsules

“…In the area of metal-mediated self-assembly, a deeper understanding of the principles governing how chirality is relayed within assembled frameworks will aid the rational design of stable enantiopure ensembles. Metalorganic capsules 21,22 with chirotopic 23 cavities 24,25 have already found application in stereoselective guest recognition and sensing 2628 and as asymmetric reaction vessels. 29,30 Full stereocontrol of large assemblies, however, remains elusive, hindering efforts to mimic the stereoselective processes that occur in enzymatic binding pockets.…”

“…One of the most general strategies 21,22 for the preparation of metalorganic capsules combines rigid chelating organic ligands and metals with welldefined coordination spheres, so that the overall geometry is controlled by the symmetries and connectivity between the ligands and the metal employed. 21,25 Usually, the vertices of these structures are tris-chelate metal complexes with pseudooctahedral coordination geometry and threefold symmetry. This arrangement results in inherently chiral structures assembled from achiral subunits, where the helical chirality (¦ or ª) arises from the arrangement of the three chelating ligands around the metal center ( Figure 1).…”

“…This arrangement results in inherently chiral structures assembled from achiral subunits, where the helical chirality (¦ or ª) arises from the arrangement of the three chelating ligands around the metal center ( Figure 1). 25 Research in our laboratory employs subcomponent selfassembly 31 for the construction of increasingly complex 2D and 3D metallosupramolecular architectures. 3236 This process involves the assembly of simple building blocks by the formation of dynamic coordinative (N ¼ M) and covalent (N=C) 37 bonds during a single overall process (Figure 1).…”