Articles in 2017

A range of mechanisms have evolved for communicating information across cell membranes, but designing synthetic analogues is far from trivial. A collection of articles in this issue discuss different methods of passing chemical information across lipid bilayers using artificial systems.

Tin has been ubiquitous throughout the course of human history, from Bronze Age tools to lithium-ion battery components, yet Michael A. Tarselli warns it should not be deemed pedestrian. Its tendency to linger in human tissues presents a dangerous side that steers researchers towards greener chemistries.

Tenure is vitally important when it comes to the creation and promotion of knowledge — and Bruce Gibb explains why.

Life has evolved elaborate means of communicating essential chemical information across cell membranes. Inspired by biology, two new artificial mechanisms have now been developed that use synthetic messenger molecules to relay chemical signals into or across lipid membranes.

The assembly–disassembly–organization–reassembly (ADOR) process has recently enabled the synthesis of unusual — and sometimes previously inaccessible — inorganic materials. Further insight into its complex mechanism has now been gained that explains the unexpected formation and structure of such a zeolite.

Cross coupling under transition-metal-free conditions is an attractive and economic alternative to traditional transition-metal-catalysed methods. Metal-free coupling of azaallyls has now been demonstrated with vinyl bromide electrophiles, delivering allylic amines in excellent yields. Moreover, mechanistic evidence supports dual reaction pathways triggered by azaallyl anions and radicals.

Polypropionates can be grown — one carbon atom at a time — using the iterative homologation of boronic esters. This assembly line strategy was enabled through the use of enantioenriched lithiated α-chlorosilanes as masked carbinol units. Polypropionates were obtained in a fully stereocontrolled manner, including the stereochemically challenging anti–anti isomers.

Berkelium is the only transplutonium element predicted to be able to exhibit both +III and +IV oxidation states in solution. Bk(IV) has now been stabilized through chelation with a siderophore derivative. The resulting neutral coordination compound was characterized and compared with the negatively charged species obtained by chelation of neighbouring trivalent actinides.

An interconverting system of three distinct stereoisomers of a cuboctahedral Co^II-based cage is able to regulate the binding affinities of large anionic guests. Through cooperative templation with fullerene guests, the cage converts into a desymmetrized cage that in turn exhibits positive cooperativity in binding of an icosahedral anion; this interaction is anti-cooperative in the fullerene-free parent.

Using chiral modifiers on the surfaces of heterogeneous catalysts is a potentially fruitful route to practical stereoselective chemistry. Now, a study of the dynamics of prochiral adsorbates on modified surfaces has shown that they can rapidly interconvert between adsorption states of different prochirality.

A chiral molecule on a metal surface can set up a prochiral molecule for an enantioselective reaction step by forming a hydrogen-bonded complex that imposes a specific adsorption geometry. Time-lapsed scanning tunnelling microscopy and density functional theory studies reveal that such complexes can sometimes switch between states of opposing prochirality.

The self-propagation of misfolded conformations of tau occurs in neurodegenerative diseases, including Alzheimer's disease. The microtubule-binding region, tau_244-372, reproduces much of the aggregation behaviour of tau in cells and animal models. Now, it has been shown that a 31-residue peptide from tau's R3 domain forms a cross-β conformation that efficiently seeds aggregation of tau_244-372 in cells.

Dissociative reactions in the solid state are prone to sample damage. Now, improved sample handling and measurement conditions enable the study of the dissociative reaction of a model triatomic system in the solid state on ultrafast timescales, revealing the significant impact of lattice coordination on the reaction pathway.

Abiotic hydrogel polymer nanoparticles with affinity for a key vascular endothelial growth factor (VEGF₁₆₅) have now been developed. This high-protein affinity was engineered by carefully controlling the amount and the substitution pattern of sulfated N-acetylglucosamines and the inclusion of a hydrophobic group in the monomer.

The manner in which carboxylates bind to the surface of nanoparticles has been an important question in materials science. Now, multinuclear magnetic resonance experiments — alongside DFT calculations, XPS and TEM measurements — have elucidated the three-dimensional ligand structures of gold nanoparticles capped with various ratios of carboxylate-containing ligands, and enabled the determination of the most probable binding modes.

Alasdair Skelton and Brett F. Thornton examine the twisting path through the several discoveries of ytterbium, from the eighteenth century to the present.

There are many unanswered questions regarding how the biomolecules and biomechanical processes that define life came to be. A collection of Articles in this issue show how intermediates in RNA synthesis might have formed and how the initiation and evolution of RNA replication might have occurred.

A unique transformation for the site-selective cleavage of one C–C single bond and two C–H bonds in sequence has now been developed. This enables a simple carbon skeleton to be reorganized into a significantly more complex form with remarkable efficiency.

Biomimetic molecules that can be easily tailored offer numerous opportunities. Now, boron-based clusters have been shown to be excellent biomimetics. The ease with which the cluster surfaces can be modified stands to change how chemists might go about preparing materials for imaging, drug delivery and other applications.

Tyrosine sulfation strongly enhances the inhibition of thrombin by the tick-derived anticoagulants madanin-1 and chimadanin. Protein chemical synthesis and structural studies have revealed a mode of inhibition that is unprecedented among cysteine-free anticoagulant proteins. This inhibition occurs through the recognition of the highly basic exosite II of thrombin.