2 research outputs found
Free-Standing Monolayer Two-Dimensional Supramolecular Organic Framework with Good Internal Order
Utilizing dynamic self-assembly and
self-sorting to obtain large-area,
molecularly precise monolayered structures represents a promising
approach toward two-dimensional supramolecular organic frameworks
(2D SOF) or 2D supramolecular polymers. So far, related approaches
suffer from small domain sizes, fragility and weak long-range internal
order. Here we report on the self-assembly of a host–guest
enhanced donor–acceptor interaction, consisting of a tris(methoxynaphthyl)-substituted
truxene spacer, and a naphthalene diimide substituted with <i>N</i>-methyl viologenyl moieties as donor and acceptor monomers,
respectively, in combination with cucurbit[8]uril as host monomer
toward monolayers of an unprecedented 2D SOF. Featuring orthogonal
solubility, the participating molecules self-assemble at a liquid–liquid
interface, yielding exceptionally large-area, insoluble films, which
were analyzed by transmission electron microscopy, atomic force microscopy
and optical microscopy to be monolayers with a thickness of 1.8 nm,
homogeneously covering areas up to 0.25 cm<sup>2</sup>, and featuring
the ability to be free-standing over holes of 10 μm<sup>2</sup>. Characterization with ultraviolet–visible absorption spectroscopy,
solid-state nuclear magnetic resonance spectroscopy, infrared spectroscopy,
and grazing incidence wide-angle X-ray scattering allowed for confirmation
of a successful complexation of all three monomers toward an internal
long-range order and gave indications to an expected hexagonal superstructure.
Our results extend the existing variety of two-dimensional soft nanomaterials
by a versatile supramolecular approach, whereas the possibility of
varying the functional monomers is supposed to open adaptability to
different applications like membranes, sensors, molecular sieves,
and optoelectronics
Persulfurated Coronene: A New Generation of “Sulflower”
We report the first
synthesis of a persulfurated polycyclic aromatic
hydrocarbon (PAH) as a next-generation “sulflower.”
In this novel PAH, disulfide units establish an all-sulfur periphery
around a coronene core. The structure, electronic properties, and
redox behavior were investigated by microscopic, spectroscopic and
electrochemical methods and supported by density functional theory.
The sulfur-rich character of persulfurated coronene renders it a promising
cathode material for lithium–sulfur batteries, displaying a
high capacity of 520 mAh g<sup>–1</sup> after 120 cycles at
0.6 C with a high-capacity retention of 90%