Youzhi

Packaged and delivered: Water‐soluble molecular capsules consisting of V‐shaped amphiphiles were designed for the uptake of polycyclic aromatic hydrocarbons (PAHs). The PAHs were released from the molecular containers in 0.1 m H₂SO₄ at an electrochemical interface, thus enabling the facile preparation of 2D PAH adlayers on an Au surface with controlled nanostructure formation (see picture).

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are excellent building blocks for the creation of two‐dimensional (2D) nanosheets. However, large PAHs tend to exhibit poor or no solubility in organic solvents and water. To overcome this issue, we employed water‐soluble micellar capsules consisting of V‐shaped amphiphilic molecules. Characteristic electrochemical behavior was observed in 0.1 m H₂SO₄ in the presence of the water‐soluble capsules containing PAHs, such as ovalene, circobiphenyl, and dicoronylene. Furthermore, under these conditions, PAHs were released from the capsules, resulting in the formation of a 2D adlayer of PAHs at the electrochemical interface. Finally, using electrochemical scanning tunneling microscopy, we demonstrate that our molecular containers based on water‐soluble molecular capsules allow the facile preparation of 2D PAH adlayers in addition to structurally controlling nanostructure formation on Au surfaces.

Concyclic CH-π arrays for single-axis rotations of a bowl in a tube

Concyclic CH-π arrays for single-axis rotations of a bowl in a tube, Published online: 17 September 2018; doi:10.1038/s41467-018-06270-6

The weak and directional CH-π hydrogen bond has rarely been exploited in the design of supramolecular complexes and molecular machinery. Here, the authors construct a bowl-in-tube complex stabilized solely by concyclic CH-π hydrogen bonds, and show that the guest exhibits single-axis rotational motion despite tight association with the host.

Solvatochromic covalent organic frameworks

Solvatochromic covalent organic frameworks, Published online: 18 September 2018; doi:10.1038/s41467-018-06161-w

Covalent organic frameworks (COFs) find increasing application as sensor material, but fast switching solvatochromism was not realized. Here the authors demonstrate that combination of electron-rich and -deficient building blocks leads to COFs which fast and reversibly change of their electronic structure depending on the surrounding atmosphere.

Angewandte Chemie International Edition, EarlyView.

Angewandte Chemie International Edition, EarlyView.

Notwithstanding the many synthetic protocols for producing mechanically interlocked molecules (MIMs)—whose unique structural features raise the prospect of their potential use in areas as diverse as molecular electronics and artificial molecular machines—mechanically interlocked structures containing multiple components, which repel each other, remain undocumented for the most part. Herein, we report the efficient syntheses of a 12+ charged [3]catenane and a 24+ charged radial [5]catenane, which consist of three and five mechanically interlocked polycationic rings, respectively, despite their mutual Coulombic repulsion.

Angewandte Chemie International Edition, Volume 0, Issue ja, -Not available-.

Angewandte Chemie International Edition, EarlyView.

Angewandte Chemie International Edition, EarlyView.

Polymerization of monomers into periodic two-dimensional networks provides structurally precise, layered macromolecular sheets that exhibit desirable mechanical, optoelectronic, and molecular transport properties. Two-dimensional covalent organic frameworks (2D COFs) offer broad monomer scope but are generally isolated as powders comprising aggregated nanometer-scale crystallites. We found that 2D COF formation could be controlled using a two-step procedure in which monomers are added slowly to preformed nanoparticle seeds. The resulting 2D COFs are isolated as single-crystalline, micrometer-sized particles. Transient absorption spectroscopy of the dispersed COF nanoparticles revealed improvement in signal quality by two to three orders of magnitude relative to polycrystalline powder samples, and suggests exciton diffusion over longer length scales than those obtained through previous approaches. These findings should enable a broad exploration of synthetic 2D polymer structures and properties.