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Angewandte Chemie
International Edition
Michelle Livings
3 October 2010
Covalent Layer-by-Layer Assembly and Solvent Memory
of Multilayer Films from Homobifunctional
Poly(dimethylsiloxane)
16 August 2010, Volume 49, Issue 35, pp 6116-6119
A simple procedure was used for the covalent layer-by-layer assembly of
homobifunctional H2N-poly(dimethoxysilane)-NH2 on SiO2 surfaces that
leads to robust layer-by-layer films of optical quality (see picture; photo on
left) despite the use of non-purified commercial starting materials. The films
show a solvent memory for swelling and de-swelling when immersed in the
corresponding solvent for each polymer.
Bioinspired Self-Healing Superhydrophobic Coating
16 August 2010, Volume 49, Issue 35, pp 6129-6133
Self-healing superhydrophobic coatings are fabricated by preserving healing
agents of reacted fluoroalkylsilane in layered polymeric coatings that are
porous and rigidly flexible. When the top layer of fluoroalkyl chains
decomposes or the coatings are scratched, the healing agents migrate to
the surface to restore the superhydrophobicity of the coatings (see picture).
Reduction of a Metal-Organic Framework by an Organometallic
Complex: Magnetic Properties and Structure of the Inclusion
Compound [(η5-C5H5)2Co]0.5@MIL-47(V)
16 August 2010, Volume 49, Issue 35, pp 6212-6215
The stoichiometric reduction of the
MIL-47(V) framework (see picture;
green VO6 octahedra) was
performed using cobaltocene as an
organometallic reducing agent. The
formation of a mixed-valence
compound with a V3+/V4+ ratio of
1:1 was confirmed by magnetic
susceptibility measurements.
Incorporation of cobaltocene into
the MIL-47(V) framework can be
reversed upon treatment with
water.
BioMOFs: Metal-Organic Frameworks for Biological and
Medical Applications
23 August 2010, Volume 49, Issue 36, pp 6260-6266
A tremendous number of drugs have been developed but not applied further
owing to poor bioavailability. To solve this problem, stable nontoxic metal–
organic frameworks have been developed as drug-delivery vehicles and
even as bioactive species in their own right.
High Performance Langmuir-Blodgett Monolayer
Transistors with High Responsivity
23 August 2010, Volume 49, Issue 36, pp 6319-6323
Molecular field-effect transistors
with bulk-like carrier mobility
(as high as 0.04 cm2 V−1 s−1),
high on/off current ratios (over
106), and high responsivity are
formed by the integration of
Langmuir–Blodgett techniques
with sophisticated
micro/nanofabrication. The
transistors are formed from
self-assembled uniform
monolayers of copper
phthalocyanine (CuPc)
semiconductors and singlelayer graphene as planar
contacts.
Regulation of a Real-Time Self-Healing Process in
Organogel Tissues by Molecular Adhesives
23 August 2010, Volume 49, Issue 36, pp 6338-6342
The thixotropic processes that occur in a naphthalenediimide-based
organogel can be imaged in real time by TEM and AFM (see picture).
The self-assembled 1D fibers disintegrate under mechanical stress
and undergo a self-healing process during a resting time to
reconstitute the 1D fibers.
Innovative Inorganic-Organic Nanohybrid Materials:
Coupling Quantum Dots to Carbon Nanotubes
23 August 2010, Volume 49, Issue 36, pp 6425-6429
Covalent bonds (peptide
condensation) and
noncovalent interactions (π–π
stacking) have been employed
en route toward versatile
donor–acceptor inorganic–
organic nanohybrids, QDpyrene/SWNT. A chargetransfer event within the
hybrid transforms the excitonic
state of the quantum dot into a
charge-transfer state that has
a lifetime of several
nanoseconds.
Towards Understanding the Catalytic Reforming of
Biomass in Supercritical Water
23 August 2010, Volume 49, Issue 36, pp 6434-6437
The function of a working
ruthenium catalyst during the
reforming of ethanol in
supercritical water was
studied in situ using X-ray
absorption spectroscopy (see
picture). The reforming of
ethanol over a supported
ruthenium catalyst in sub- and
supercritical water is
suggested to proceed by the
same mechanism as steam
reforming at low pressures.
Supramolecular Control of Stiffness and Strength in
Lightweight High-Performance Nacre-Mimetic Paper
with Fire-Shielding Properties
23 August 2010, Volume 49, Issue 36, pp6448-6453
Hard/soft core/shell colloidal building
blocks allow large-scale self-assembly
to form nacre-mimetic paper. The
strength and stiffness of this material
can be tailored by supramolecular ionic
bonds. These lightweight biomimetic
materials show excellent and tunable
mechanical properties and heat and
fire-shielding capabilities.
A Graphene Oxide-Organic Dye Ionic Complex with
DNA-Sensing and Optical-Limiting Properties
3 September 2010, Volume 49, Issue 37, pp 6549-6553
A charge-transfer complex between
graphene oxide (GO) and pyrene
dye PNPB has been synthesized by
a simple ion-exchange process. Its
highly specific interactions with
DNA compared to other
biomolecules (see scheme) allows
selective and rapid detection of
DNA in biological mixtures. It also
exhibits broadband optical limiting.
Water-Soluble Supramolecular Polymerization Driven by Multiple
Host-Stabilized Charge-Transfer Interactions
3 September 2010, Volume 49, Issue 37, pp 6576-6579
A supramolecular polymer with a high degree of polymerization has
been constructed on the basis of multiple host-stabilized charge-transfer
interactions (see picture; DADV is a dianthracenyl bis(bipyridinium
bromide), CB[8]=cucurbit[8]uril). Through interactions between
supramolecular polymer chains, a reversible gel can also be obtained.
One-Step Conversion of Aromatic Hydrocarbon Bay
Regions into Unsubstituted Benzene Rings: A Reagent
for the Low-Temperature, Metal-Free Growth of SingleChirality Carbon Nanotubes
3 September 2010, Volume 49, Issue 37, pp 6626-6628
The controlled chemical synthesis of
uniform, single-walled carbon
nanotubes from short hydrocarbon
templates, such as aromatic belts
and geodesic nanotube end-caps, by
a Diels–Alder
cycloaddition/rearomatization
strategy requires a potent “masked
acetylene” capable of transforming
hydrocarbon bay regions into new
unsubstituted benzene rings in a
single operation. Nitroethylene has
been found to effect such
benzannulations (see scheme).
Ionic Liquids as Versatile Precursors for Functionalized Porous Carbon and
Carbon-Oxide Composite Materials by Confined Carbonization
3 September 2010, Volume 49, Issue 37, pp 6664-6668
Thermolysis of an ionic liquid (IL) gives no char residue, whereas heating
the same IL trapped within an oxide framework affords high carbonization
yields (see picture). This confinement method allows incorporation of
heteroatoms from the parent IL in the final products, for the development
of functionalized porous carbon and carbon–oxide composite materials.