Volume 10 Issue 6, June 2018

As the most abundant class of biomolecules on Earth, carbohydrates are implicated in a multitude of biological functions. Now, a simple chemical transformation has enabled the direct and selective installation of carbohydrates onto a diverse range of small molecules and peptides.

The beauty and activity of enzymes inspire chemists to tailor new and better non-biological catalysts. Now, a study reveals that the active sites within heterogeneous catalysts actively cooperate in a fashion phenomenologically similar to, but mechanistically distinct, from enzymes.

A manganese phthalocyanine has been shown to catalyse intermolecular C–H amination reactions—proceeding through an electrophilic metallonitrene intermediate—with high levels of reactivity and site selectivity. Demonstrating good tolerance for tertiary amine, pyridine and benzimidazole moieties, nitrogen functionality can be selectively installed at electron-rich, sterically exposed benzylic sites in bioactive molecules.

The vibrational relaxation of molecules adsorbed at metal surfaces is considered to be relatively fast and thus examples of vibrationally induced chemistry at surfaces are rare. The adsorption and subsequent desorption of long-lived vibrationally excited CO molecules from a gold surface have now been observed, suggesting that vibrational promotion of surface chemistry might be more prevalent than currently thought.

An effective antiviral against the common cold could prevent exacerbations in asthma and chronic obstructive pulmonary disease, but the diversity and adaptability of the virus makes it a highly challenging target. Now, picomolar inhibitors of a human lipid transferase have been developed. Targeting this human lipid transferase could provide an effective and broad-spectrum approach to block viral replication in the host.

Nanocatalysts can undergo various dynamic phenomena that affect their activity, such as restructuring and spillover. Now, using spatially and temporally resolved imaging of individual catalytic reactions, cooperative communication between different sites within single palladium- and gold-based nanocatalysts, and between different nanocatalysts, has been observed during three distinct catalytic reactions.

Isolable compounds displaying new fundamental forms of conformational isomerism were last discovered in 1914 (atropisomerism) and 1961 (hindered pyramidal inversion). Now, a new form—referred to as akamptisomerism—has been described through four resolved stereoisomers of a transoid (BF)O(BF)-quinoxalinoporphyrin compound. The stereodescriptors parvo and amplo, necessary for their classification, have also been introduced.

Controlled motion in mechanically interlocked molecules, such as a macrocycle moving back and forth along the axle of a rotaxane, forms the basis of complex functions in molecular machinery. Now, ring-through-ring shuttling has been achieved using two macrocycles that switch position between two anchoring sites, which involves the smaller ring passing through the larger one.

I-motif DNA structures are thought to form in cytosine-rich regions of the genome and to have regulatory functions; however, in vivo evidence for the existence of such structures has so far remained elusive. Now an engineered antibody that is selective for i-motif structures has been developed and used to detect i-motifs in the nuclei of human cells.

The phase in which a crystal exists can have a direct influence over its properties; however, it is usually difficult to control during synthesis. Now it has been shown that micrometre-sized metallic 1T′-MoS₂- and 1T′-MoSe₂-layered crystals can be prepared in high phase purity on a large scale, and that they display promising electrocatalytic activity towards the hydrogen evolution reaction.

Glycosylation is an attractive strategy to functionalize natural products and peptides for biomedical use, but non-enzymatic approaches usually require organic solvent and protecting groups. Now, an aqueous phenolic O-glycosylation reaction that uses glycosyl fluoride donors and a calcium salt has been developed for a wide range of substrates, including complex unprotected peptides.

Our understanding of reaction dynamics has developed as more accurate measurements of product state-resolved angular distributions have become available. Now, fast forward-scattering oscillations in the product angular distribution of the benchmark chemical reaction H + HD → H₂ + D have been observed and are in excellent agreement with quantum-mechanical dynamics calculations.

Biological systems are made up of complex networks that can respond to stimuli and function across relatively long distances in molecular terms. Now, it has been shown that a local disruption (the isomerization of just a single azobenzene unit) at the interface of supramolecular glassy polymersomes can immediately spread through over 500 bonds, significantly changing membrane permeability and enabling controllable release of guest molecules.

Calcium-ion batteries are potentially attractive alternatives to lithium-ion batteries, but remain largely unexplored because of low performance. A reversible calcium alloying/de-alloying reaction with the tin anode has now been coupled with the intercalation/de-intercalation of hexafluorophosphate in the graphite cathode to enable a calcium-ion battery that operates stably at room temperature.

Cholesterol embedded in lipid membranes strongly promotes the aggregation of Aβ42 that is associated with Alzheimer's disease. Now, a kinetic analysis has shown that the mechanism of action responsible for this effect involves the introduction of a heterogeneous nucleation pathway that enhances the primary nucleation rate of Aβ42 aggregation by up to 20-fold.

Scientists take nomenclature seriously, but tritium was named in a casual aside. Brett F. Thornton and Shawn C. Burdette discuss the heavy, radioactive hydrogen isotope that is available for purchase online.