Heteroleptic Triple-Stranded Metallosupramolecules with Hydrophobic Inner Voids

The systematic combination of well-defined coordination spheres and multiple types of ligands (heteroleptic) can lead to the generation of hierarchical metallosupramolecules with a high level of complexity and functionality. In particular, a specific multilevel coordination-driven assembly through the initiate generation of multinuclear clusters can form unique heteroleptic multiple-stranded supramolecular complexes. Herein, we report novel triple-stranded nickel-based supramolecules constructed from two different ditopic ligands ([1,1':3',1''-terphenyl]-4,4''-dicarboxylate (TP) and 2,6-pyridinedicarboxylate (PDA)) and a nickel precursor. The solid-state structures of the as-synthesized supramolecules revealed that three PDA ligands are employed to fabricate a tetranuclear ({Ni₄}) cluster, and two {Ni₄} clusters are assembled to form the final triple-stranded metallosupramolecules by three TP ligands. The bridging TP ligands also provide large inner voids with highly hydrophobic environments. Structural investigation of the generated complexes provided a deeper understanding of the aspects driving the formation of heteroleptic supramolecules, which is crucial for the design of multiple-strands with desired morphologies and functionalities.

Recent advances in heteroleptic multiple-stranded metallosupramolecules

Well-ordered combination of defined coordination spheres and multiple types of ligands (heteroleptic) in a given structure can expand the structural complexity and functional diversity of the resulting metallosupramolecules. Such heteroleptic metallosupramolecular architectures are expected to afford advanced utility in a variety of applications. In this concise review article, recent advances in the development of multi-nuclear-cluster-based heteroleptic multiple-stranded (HLMS) metallosupramolecules are summarized and demonstrated. To construct HLMS metallosupramolecules, one type of multitopic ligands can be employed for building up multiple strands, while another type of ligands can be utilized to construct multi-nuclear clusters. Most HLMS metallosupramolecules adopt helical geometries and have high molecular symmetry, which can be key factors for the structural completion. HLMS metallosupramolecules can be used as basic building blocks for the fabrication of higher-order polymeric or discrete assembly architectures with well-defined geometries.

Coordinative helix–helix association of heteroleptic metallosupramolecular helicates

Coordinative helix–helix association of racemic metallosupramolecular helicates is controllably synthesized and fully characterized.