Biomimetic Self-Assembly of Co^II-Seamed Hexameric Metal–Organic Nanocapsules

Abstract

A Co II 18 L 6 hexameric metal−organic nanocapsule (MONC) has been prepared and characterized using biomimetic self-assembly as the synthetic methodology. Akin to the biological behavior of zinc-finger proteins' release, uptake, and electrophilic substitution of Zn 2+ ions, the assembly of this novel MONC has been accomplished by employing three sequential processes: assembly of the framework, metal ion insertion, and metal exchange, resulting in the formation of the Co II 18 L 6 hexameric MONC. In this work, inspired by the biological behavior of metalloproteins, rational control of multiple complex supramolecular self-assembly has been achieved.

Supramolecular Coordination Complexes as Optical Biosensors

“…The counteranion chosen to balance the charge of cationic SCCs can play a large role in the formation of aggregate species and can therefore be influential in determining the optical properties of the assembly. Stang and co-workers have also reported tetraphenylethylene (TPE)-based drum-shaped metallacycles (3,4) and investigated the influence of the counter-anion on the photophysical properties of their assemblies (aggregation-induced-emission) ( Figure 2 (b)). [19] The molar absorption coefficients (ɛ), fluorescence emission intensities, and quantum yield (Φ F ) values in CH 2 Cl 2 follow the order PF 6 À > OTf À > NO 3 À .…”

“…The advantages of using SCCs in biological applications include: (1) the ease of fine tuning the dimensions of complexes; (2) the potential to select metal ions with specific size, coordination geometries, oxidation state and versatility for biological applications; (3) the ease of incorporating essential functional groups into the SCC scaffold through modular pre‐ or post‐self‐assembly modifications, and; (4) the guest binding potential of the internal cavities of SCCs. The selective guest‐binding capacity of SCCs derives from their well‐defined internal cavities and drives interest into their application for analyte discrimination and sensing [1b,3] . In particular, the development of SCCs with a fluorescence signature provides a route towards an optical readout upon guest capture.…”

Controlled hierarchical self-assembly of networked coordination nanocapsulesviathe use of molecular chaperones

“…26 We only recently achieved the assembly of Co II hexameric MONCs by using a route inspired by zinc-nger proteins (ZNFs). 33 In that case the Zn II ion was used to direct assembly of hexameric MONCs that were spontaneously transmetallated with Co II ions to afford the target assembly. Such results indicate that new MONCs with redox-active functionality may (as can be the case with biological systems) require additional templates or chaperones to control their assembly into the correct state.…”

Actinide Separation Inspired by Self-Assembled Metal–Polyphenolic Nanocages

“…The cone-shaped PgCn, which is the tetramer of the natural phenolic mimic pyrogallol (PG) with variable length sidechain groups (Figure 1c), has been demonstrated as a versatile precursor for construction of metal-organic nanocapsules. [24][25][26][27][28][29][30][31][32][33][34] Based on coordination assemblies of PgCn (n = 3, 5 or 9) with actinides ions, we have achieved high-performance uranyl capture via uranyl-PgCn nanocages (Figure 1d) assembled in situ in monophasic or biphasic solvent systems. This type of extraction as nanoscale species is unprecedented for actinide ions and it leads to a novel paradigm for hybrid nanocluster-based actinide sequestration, which may be considered as "nanoextraction".…”