Anionic Templates Drive Conversion between a Zn^II₉L₆ Tricapped Trigonal Prism and Zn^II₆L₄ Pseudo-Octahedra

Abstract

This work introduces the use of 8-aminoquinoline subcomponents to generate complex three-dimensional structures. Together with a tris(formylpyridine), 8-aminoquinoline condensed around Zn II templates to produce a tris(tridentate) ligand. This ligand is incorporated into either a tricapped trigonal prismatic Zn II 9 L 6 structure or a pair of pseudo-octahedral Zn II 6 L 4 diastereomers, with S 4 and D 2 symmetries. Introduction of a methyl group onto the aminoquinoline modulated the coordination sphere of Zn II , which favored the Zn II 9 L 6 structure and disfavored the Zn II 6 L 4 assembly. The tricapped trigonal prismatic Zn II 9 L 6 architecture converted into a single Zn II 6 L 4 cage diastereomer following the addition of a dianionic 4,4′dinitrostilbene-2,2′-disulfonate guest. Four of these guests clustered tightly at the four windows of the Zn II 6 L 4 cage, held in place through electrostatic interactions and hydrogen bonding, stabilize a single diastereomeric configuration with S 4 symmetry.

Cavity-Shape-Dependent Divergent Chemical Reaction inside Aqueous Pd6L4 Cages

“…1 crystallized in the monoclinic space group C 2/ c with an octahedral structure. Unlike previously reported octahedral cages, due to the unsymmetrical nature of the ligand L1 , it did not have a T d -symmetry. The cage was devoid of any symmetry elements other than a C 2 -principal axis.…”

“…The available volume of the cavity was calculated using the MoloVol software . The cavity volume was found to be 593.8 Å 3 (Figure d), which was in the range of that obtained for other octahedral cages …”

Guest-Induced Reversible Transformation between an Azulene-Based Pd2L4 Lantern-Shaped Cage and a Pd4L8 Tetrahedron

“…Here we introduce a new system capable of undergoing a fully reversible guest-triggered transformation from a [Pd 2 L 4 ] lantern-shaped coordination cage to a larger [Pd 4 L 8 ] distorted tetrahedron. The quantitative and rapid reversibility of this system contrasts with previous reports on cage transformations, where reversibility was, for example, not explored or resulted in an unfavorable equilibrium state …”

“…30 Here we introduce a new system capable of undergoing a fully reversible guest-triggered transformation from a [Pd 2 L 4 ] lantern-shaped coordination cage to a larger [Pd 4 L 8 ] distorted tetrahedron. The quantitative and rapid reversibility of this system contrasts with previous reports on cage transformations, where reversibility was, for example, not explored 31 or resulted in an unfavorable equilibrium state. 32 In addition, the trigger for the reverse transformation in our case is a second, different [Pd 2 L 4 ] cage capable of narcissistically self-sorting and being able to "steal" the guest from the first cage.…”

A truncated triangular prism constructed by using imidazole–terpyridine building blocks

“…Ligands with at least three coordination orientations should be designed for this purpose, as reported by Newkome et al 23–25 Utilizing terpyridinyl ligands, a series of Archimedean solid-shaped cages has been reported such as octahedron, 26 cuboctahedron, 27 and icosidodecahedron. 28 Among the topological shapes of cages, the truncated triangular prism cage in Faleis’ polyhedron, which shows a D 3h symmetry, 29,30 is rarely reported.…”