Volume 7 Issue 11, November 2015

A vast number of possible isomers exist for each fullerene, yet few are observed experimentally. Neutral fullerenes typically minimize adjacent pentagons, but charged ones often tolerate them. Now, a simple model taking into account structural strain and π electronic aspects predicts the asymmetric relative stabilities of charged isomers.

Synthetic oligomers could potentially expand beyond the functions offered by proteins and nucleic acids. However, this requires precise methods for controlling their folding and self-assembly. Now, it is shown that two drastically different supramolecular architectures can be fabricated from closely related sequences using a single biomimetic scaffold.

A concise synthesis of the fungal natural product epicolactone suggests that this highly stereochemically complex yet racemic natural product may come from a cascade reaction between two polyhydroxylated arenes.

For many years, chemists have tried and failed to find efficient light-harvesting molecules based on Earth-abundant, environmentally friendly iron. Now, an iron complex has been developed with photoluminescent properties that are tuned to efficiently convert light to electrons.

C–H functionalization of organic compounds is an ideal yet challenging approach to organic synthesis. This Perspective covers the most recent developments concerning the palladium-catalysed norbornene-mediated C–H functionalization of arenes, including applications of these methodologies in natural products synthesis. Challenges as well as opportunities for future studies are also presented.

The self-assembly of short amphiphilic α-helicomimetic foldamers bearing proteinaceous side-chains can be controlled by manipulating the side-chain sequence. This enables the foldamers to be programmed to form either discrete helical bundles containing isolated cavities, or pH-responsive water-filled channels with controllable pore diameters.

Analysis of the structure of the highly complex yet racemic secondary metabolite epicolactone suggests that it may arise biosynthetically from a cascade similar to that which produces purpurogallin. This led to a synthesis of epicolactone in only eight steps using an intricate reaction cascade.

Using iron instead of the scarce ruthenium in light-harvesting complexes is challenging because iron complexes generally have short-lived excited states. Now an iron complex has been developed that has a long-lived excited state, which can lead to photo-induced electron injection into nanoporous TiO₂ with a yield of 92%.

Avoiding equal probability for clockwise and anticlockwise rotation is essential for the function of molecular motors, and both biological and synthetic systems take advantage of chirality to control the rotary direction. Now it has been shown, by integrating two rotor moieties in a symmetric meso motor design, that light-driven unidirectional rotary motion can be achieved in an achiral system.

Amphiphilic-peptide-driven opening of elastin-like protein molecules triggers the self-assembly of a multilayered membrane. This dynamic system can undergo morphogenesis into hierarchically ordered tubular structures that can be used to create complex scaffolds for tissue engineering.

Covalent organic frameworks (COFs) feature periodic layers and ordered pores that make them promising for applications in catalysis, but they typically suffer from poor stability. Now, adding methoxy groups to its pore walls has been shown to strengthen a COF's interlayer interactions, resulting in a stable, crystalline, porous material that can be further converted into chiral organocatalysts.

O-linked N-acetyl-glucosamine (O-GlcNAc) has been identified as an endogenous modification of α-synuclein; however, its effect on the properties of the protein is unclear. Now, recombinant protein and synthetic peptides have been combined to produce both unmodified and site-specifically O-GlcNAc-modified α-synuclein. The O-GlcNAc modification at threonine 72 was shown to inhibit the aggregation and associated toxicity of α-synuclein.

The rotational state of a molecule is not generally considered to play a role in how fast it reacts; however, when the temperature is low quantum effects become more important. Now, it is shown that at low temperatures rotationally excited H₂ molecules react with He faster than non-rotating ground-state molecules — a process mediated by stronger long-range attraction.

The stability of charged fullerenes is not as well understood as that of their neutral counterparts, with, for example, more frequent violations of the isolated-pentagon and pentagon-adjacency penalty rules. Now, a simple model based on the concepts of cage connectivity and frontier π orbitals predicts the relative stability of cationic and anionic fullerene isomers.

Cross-couplings between boronic acids and halides are a mainstay of synthetic organic chemistry but enantioselective ${\text{C}}_{s{p}^2}-{\text{C}}_{s{p}^3}$ couplings are rare, and simply retaining the stereochemistry of the starting material is problematic. Now, it is shown that racemic allylic halides can converted to single enantiomer products by a rhodium(I)-catalysed asymmetric allylic arylation using arylboronic acids

From sugar beets to TV screens, François-Xavier Coudert explores the history, applications and perils of the Scottish element, strontium