Synthesis of cobalt cluster-based supramolecular triple-stranded helicates

Abstract

A cobalt cluster-based triple-stranded helicate, Co8(PDA)6(PTA)3(DMF)3(H2O)3 () (PDA = 2,6-pyridinedicarboxylate, PTA = benzene-1,3-dicarboxylate, DMF = dimethylformamide) was successfully synthesized and fully characterized. Complex can be used as a supramolecular building block in constructing a higher-order helix-of-helix structure, [Co8(PDA)6(PTA)3(DMF)2(H2O)4-0.51(Co(OHn)2)] (n = 1 or 2) ().

A Cobalt Supramolecular Triple-Stranded Helicate-based Discrete Molecular Cage

“…S13). It should be noted that the left-handed conformation is topologically similar to that reported previously35, whereas the right-handed conformation shows a structure similar to that of a basic supramolecular module of 1 . Variable-temperature (4–300 K) magnetic measurement of complex 2 is conducted under an applied field of 500 Oe (Supplementary Fig.…”

“…Each Co-TSH, comprising two tetranuclear Co clusters linked together by three tbu -PTA ligands (Supplementary Fig. S2), is geometrically similar to that reported previously35. Each Co-TSH forms coordination bonds with two Co5 atoms through its unoccupied carboxylate oxygen atoms (Supplementary Fig.…”

“…For example, molecular structures with large confined cavities created by the coordination-driven assembly of simple organic compounds and metals as the nodes have been reported121314151617. The rational design of single molecular structures using multi-nuclear metal clusters (these were described as “secondary building blocks” in the previous reports)181920212223 and various di- or multicarboxylate organic ligands has also been achieved242526272829303132333435. Despite the structural distinction, their preparative paradigms are commonly confined by the use of simple coordination modes involving the assemblies of metal ions and ligands (“primary” assembly)12131415161736 or multinuclear metal clusters and multifunctional ligands (“secondary” assembly)181920212223242526272829303132333435 (Fig.…”

“…A cobalt supramolecular triple-stranded helicate (Co-TSH)-based discrete high-order molecular cage is successfully synthesized. PDA ligand is chosen due to its considerable importance in the formation of tetranuclear cobalt cluster as a primary assembly (PDA = 2,6-pyridinedicarboxylate)35. Two tetranuclear clusters with tbu -PTA generate a Co-TSH as a conceptual secondary assembly ( tbu -PTA = 5-tert-butyl isophthalate).…”

Metal‐Ion Tuning in Triple‐Stranded Helicate‐Based Metallosupramolecules

“…For structural analysis of the related structures, multilevel coordination‐driven assembly has been proposed to systematically classify their structural hierarchy . Deliberate variation of PTA derivatives has also been attempted; however, supramolecules with similar helical geometry are always obtained, suggesting that the helical structure could be the key point in drawing the assembly of these heteroleptic supramolecules. These experimental observations are one of the essential motivations to further examine the generation of such heteroleptic helicates by varying the transition‐metal ions.…”