News & Views in 2015

Mass production at the nanoscale requires molecular machines that can control, with high fidelity, the spatial orientation of other reactive species. The demonstration of a synthetic system in which a molecular robotic arm can be used to manipulate the position of a chemical cargo is a significant step towards achieving this goal.

Supramolecular processes are attractive for the generation of functional materials, but managing multiple, competing self-assembly pathways has remained challenging. Now, the self-assembly of a platinum compound into three different aggregates has been elucidated, visualized in real time, and controlled.

Fullerene-based dendritic structures coated with 120 sugars can be made in high yields in a relatively short sequence of reactions. The mannosylated compound is shown to inhibit Ebola infection in cells more efficiently than monofullerene-based glycoclusters.

γ-Butyrolactone is a biomass-derived cyclic ester that is commonly thought to be non-polymerizable. Now, exploiting the thermodynamics of polymer formation and careful control of the reaction conditions has made this possible leading to high-molecular-weight products and control of polymer topology.

The catalytic activity of a rotaxane incorporating a gold(I) centre can be switched on by the addition of a guest ion that can bind inside the macrocyclic cavity of the system. The nature of the guest can also influence the selectivity of the catalyst, reminiscent of allosteric modulation in enzymes.

The quantitative self-assembly of mechanically interlocked molecules in water, instead of organic solvents, opens up the possibility of such systems being used in a biological context where their functions can be interfaced with biomolecular systems.

Catalytic methods are among the most valuable tools for sustainable synthesis. Domino catalysis enables multiple reactions to be combined so that synthetic efficiency may begin to approach that of nature, but significant challenges remain before this promising approach can fulfil the needs of pharmaceutical and materials chemistry.

Vision is initiated by photoisomerization of 11-cis retinal in the visual pigment rhodopsin — a fast and efficient process. Spectroscopic studies now demonstrate that the transition from the reactant photoexcited-state to the ground-state photoproduct, which mediates this important reaction, occurs on a sub-50-fs timescale and is vibrationally coherent.

Racemic or enantiomerically pure alcohols can be converted with high yield into enantiopure chiral amines in a one-pot redox-neutral cascade process by the clever combination of an alcohol dehydrogenase and an appropriate amine dehydrogenase.

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.

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 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.

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.

Spin-triplet excitations commonly migrate through direct electron exchange between neighbouring molecules. Now, experiments show that back-and-forth interconversion between spin-triplet and spin-singlet states can significantly speed up triplet migration in organic crystals.

A patterned, spatially resolved gel has now been devised. The two-component gel is formed by sequential assembly of two independent networks of fibres, and the subsequent selective removal of one network by irradiation.

A method for directly probing binding interactions in free solution, without the need for chemical tagging, offers exciting opportunities for non-perturbative analyses of biomolecules in their native state.

Nanocrystals with precisely defined structures offer promise as components of advanced materials yet they are challenging to create. Now, a nanocrystal made up of seven cadmium and twelve chloride ions has been synthesized via a biotemplating approach that uses a de novo designed protein.

Preparation and structural characterization of the catalytic intermediates of two similar thiolate-ligated haem proteins (cytochrome P450 Compound-I and chloroperoxidase Compound-I) has explained the structural basis for the difference in their reactivity.