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.