Stellated polyhedral assembly of a topologically complicated Pd4L4 ‘Solomon cube’

Abstract

Metallosupramolecular chemistry relies on self-assembly processes in which complicated species form through labile dative-covalent interactions. Two remarkable areas of this chemistry are the synthesis of topologically complicated threaded assemblies and of three-dimensional (3D) polyhedral assemblies. Very few polyhedral 3D metallosupramolecular assemblies show threaded motifs within them. Here we report an example of a new type of threaded 3D metallosupramolecular assembly built from four organic ligands and four palladium ions, a Pd(4)L(4) so-called 'Solomon's cube' in which interweaving and twisting of the ligands form both Solomon's links and figure-of-eight ring motifs. In the solid state, six of these Pd(4)L(4) tetramers assemble into a hollow spheroid that closely resembles a stellated truncated hexahedron.

Solvent‐Dependent Self‐Assembly Behaviour and Speciation Control of Pd6L8 Metallo‐supramolecular Cages

“…Metallo-supramolecular assemblies of ligand functionalised CTV-analogues include single-cage and double-cage catenating [M 3 L 2 ] capsule-like metallo-cryptophanes, [7] [M 4 L 4 ] and [M 6 L 4 ] tetrahedra, [8] [M 6 L 8 ] stella octangula assemblies, [9] and a self-entangled [M 4 L 4 ] cube. [10] The largest metallo-cages involving CTV-type ligands are the [Pd 6 L 8 ] 12+ stella octangula assemblies that occur with ligands that have 4-pyridyl groups appended, such as L1a, L1b and L2a (Scheme 1). [9] The crystal structure of the previously reported [Pd 6 (L1a) 8 ] 12+ stella octangula [9b] has six Pd II cations arranged in an octahedron with the eight L1a ligands taking up the octahedron's faces giving a 3 nm sized cage assembly, Scheme 1.…”

Lanthanide coordination polymers with pyridyl-N-oxide or carboxylate functionalised host ligands

“…The self-assembly of derivatised CTVs with metal cations is well established, and coordination polymers, [35][36][37] discrete metallo-cages, [38][39][40][41][42] and mechanically interlocked architectures [43][44][45] are known. However, the chemistry of mixed ligand systems is generally limited to the solution-phase, and we have recently demonstrated how the formation and manipulation of homo-and heteroleptic [Pd 6 L 8 ] 12+ octahedral cages can be controlled with high fidelity.…”

An infinite chainmail of M6L6 metallacycles featuring multiple Borromean links

“…34 This includes their use as components of coordination polymers and of discrete metallo-supramolecular cage-like assemblies, including the topologically complex assemblies of triply interlocking cage-catenane species 10,11 and a self-entangled Solomon's cube. 35 The cavitand (±)-tris(iso-nicotinoyl)cyclotriguaiacylene, L1, has been previously reported 36 Not only is the entanglement of metallacycles in complex 1 new, it is, to the best of our knowledge, the first chemical example of a chainmail crystalline network involving macrocycles. A chainmail requires chemically independent rings to be mechanically interlocked and can be characterized as a 0D (individual rings) to 2D (chainmail network) motif.…”