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Synthesis of molecular containers capable of incorporating multiple fullerenes remains challenging. Reported here is that room‐temperature mixing of metal ions with W‐shaped bispyridine ligands featuring polyaromatic panels results in the quantitative formation of a peanut‐shaped M2L4 capsule. The capsule reversibly converts into two molecules of an ML2 double tube in response to changes in the solvent. Notably, the capsule allows the incorporation of two fullerene molecules into the connected two spherical cavities at room temperature. The close proximity yet non‐contact of the encapsulated C60 molecules, with a separation of 6.4 Å, was revealed by X‐ray crystallographic analysis. The resultant, unusual fullerene dimer undergoes sequential reduction within the capsule to generate (C60.−)2, C60.−⋅C602−, and (C602−)2 species. Furthermore, temperature‐controlled stepwise incorporation of two C60 molecules into the capsule is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: The effect of molecular interactions between the components on the self‐assembly process of Pd2L4 structures was investigated by a 1H NMR‐based quantitative approach (QASAP: quantitative analysis of self‐assembly process). Although the self‐assembly of the Pd2L4 cage without interactions between the bent ligands took place, mainly producing small intermediates, the self‐assembly of the Pd2L4 capsule composed of bent ligands with anthracene panels tends to produce large intermediates containing more components than the capsule. This is ascribed to steric interactions between the panels. [ABSTRACT FROM AUTHOR]

For the development of novel nanospace with unique electrostatic character, we prepared new capsular and tubular nanostructures by the quantitative assembly of metal ions and bent bisacridinium ligands. The capsule and tube have closed spherical and open cylindrical cavities, respectively, with diameters of around 1 nm surrounded by cationic polyaromatic panels. Thanks to the facile synthetic protocol (three steps), another polycationic capsule with an elliptical nanocavity was also prepared by using an elongated ligand. In spite of the absence of pendant hydrophilic groups, the spherical polyaromatic capsule shows sufficient water solubility due to the polycationic shell. Moreover, the highly cationic cavity (12+) can selectively encapsulate anionic organic compounds in water. [ABSTRACT FROM AUTHOR]

Preparation of molecular nanostructures with polyradical frameworks remains a significant challenge because of the limited synthetic accessibility which is entirely different from that of neutral and ionic ones. Herein we report the quantitative formation of a new M2L4 molecular capsule from metal ions and dihydrophenazine-based ligands. The capsule has a spherical nanocavity (ca. 1 nm in diameter) enclosed by eight redox-active, dihydrophenazine panels. Electrochemical oxidation of the capsule leads to the generation of multiple radical cations on the shell framework. Moreover, a stable tetra(radical cation) capsule can be reversibly obtained by chemical as well as electrochemical oxidation. [ABSTRACT FROM AUTHOR]

Anisotropic expansion of a spherical M2L4 coordination capsule through the elongation of the ligand led to a new M2L'4 capsule. The expanded capsule provides an elliptical cavity encircled by polyaromatic frameworks with large openings and thereby can encapsulate elliptical fullerene C70 and monofunctionalized fullerene C60 in high yields. In addition, selective formation of a new M2L2L'2 capsule occurs by mixing the original M2L4 and expanded M2L'4 capsules in a 1:1 ratio upon addition of C60 or monofunctionalized C60 as a template molecule. [ABSTRACT FROM AUTHOR]

An M2L4 coordination capsule or an M2L2 coordination tube was selectively formed by the combination of HgII hinges and bent bispyridine ligands. The two structures reversibly interconvert at room temperature in response to modulation of the metal-to-ligand ratio and exhibit different host-guest interaction behavior. The capsule alone encapsulates large spherical molecules, fullerenes C60 and C70, and the bound guests are released upon capsule-to-tube transformation by the simple addition of metal ions. [ABSTRACT FROM AUTHOR]

A bowl-shaped organic host was prepared by linking two anthracene-embedded bispyridine ligands with two methylene spacers. The water-soluble host has a hemispherical hydrophobic cavity (∼1 nm in diameter) with two cationic methylenebispyridinyl (Lewis acidic) moieties and shows the selective recognition and encapsulation of aromatic guest molecules containing carbonyl groups in water. [ABSTRACT FROM AUTHOR]

M2L4molecular capsules self-assembled from M(ii) ions (where M = Zn, Ni, and Pd) and bent bidentate ligands constructed from anthracene fluorophores. The Ni(ii) and Zn(ii) capsules exhibited weak to strong blue emission unlike traditional Pd(ii) cages and capsules. [ABSTRACT FROM AUTHOR]

A new M2L4 molecular capsule with an aromatic shell was prepared using two Pd(II) ions and four bisanthracene ligands. The self-assembled capsule possesses a cavity with a diameter of ~1 nm that can encapsulate medium-sized spherical and planar molecules as well as a very large molecule (C60) in quantitative yields. The encapsulated guests are fully segregated and shielded from the external environment by the large anthracene panels. [ABSTRACT FROM AUTHOR]