Volume 11 Issue 1, January 2019

Let’s flip over the periodic table to peek at its dark side.

At its inception, the periodic table sorted elements by weight, so it may be surprising that the heaviest natural element on Earth remains controversial, or at best, nebulous. In the strange, perhaps-unfinished search for this weightiest nucleus, the only definitive conclusion is that it lies somewhere beyond uranium.

The periodic table as we know it now seems complete, its current 118 elements nicely fitting in the seven familiar rows. How many more can be synthesized — and how will the table expand to accommodate them? The search for ever-heavier elements is pointing towards new periods, though perhaps not as neatly ordered as the first seven.

Scientists and non-scientists alike have long been dreaming of elements with mighty properties. Perhaps the fictional materials they have conjured up are not as far from reality as it may at first seem.

The structural features and catalytic performances of catalyst particles have now been correlated using a fluorescence microscopy approach, by tracking nanoprobes as well as fluorescent reaction products. Such mapping enables exploration of structure–function relationships, which is essential for the design of better catalysts.

One goal of synthetic biologists is to develop artificial systems to help study biological processes. Now, cell communication and differentiation have been demonstrated using spatiotemporal patterns created in artificial multicellular compartments.

Gold nanomaterials are attractive for a variety of applications, including in medicine, but need to be made stable enough to operate in biological systems. Now, gold nanorods have been stabilized for photothermal therapy by sequential surface anchoring, using a bidendate PEG-based ligand that features a thiolate moiety and an Au–NHC moiety.

The accessibility of materials’ porous domains is typically explored through bulk, and often non-visual, measurements. Now, an integrated fluorescence microscopy approach has established a direct visual relationship between pore architecture (which depends on pore sizes and interconnectivity), molecular transport, and in turn catalytic performance in industrial-grade catalyst particles.

Synthetic gene circuits encapsulated in lipid membrane compartments are often employed as artificial cell mimics, but these lack the complex behaviour of biological tissues. Now, spatial information based on chemical gradients has been used to engineer non-trivial dynamics such as signal propagation and differentiation in an artificial multicellular system.

Establishing a fundamental understanding of the electronic structure of actinides remains a challenging task for both experiment and theory. Now, it is shown that for the uranium dimer, relativity and electron correlation affects not only the nature of the electronic ground state, but also lowers the bond multiplicity in comparison to previous studies.

Catalytic activation of non-polar unstrained C−C bonds remains challenging. Now, the C(aryl)−C(aryl) bonds in 2,2′-biphenols can be cleaved using phosphinites as a recyclable directing group through a rhodium-based spirocyclic intermediate. In particular, the biaryl linkage found in softwood lignin could be cleaved using this method.

Synthetic receptors can be used to help understand biological systems, but rarely compete in terms of affinity or selectivity. Now, a glucose-binding compound has been prepared that, despite its symmetry and simplicity, can match all but the strongest glucose-binding proteins. The high binding affinity and outstanding selectivity of this receptor may translate into biomedical applications.

N-heterocyclic carbenes (NHCs) are valuable surface anchors, but their use has remained limited to either spherical or planar nanomaterials. Now, they have been grafted onto gold nanorods through a bidentate ligand featuring a thiolate and a NHC–gold complex. The resulting nanorods are robust towards a wide range of harsh conditions and show promise for photothermal therapy.

The use of Li or Na as electrodes in Li-Na alloy–O₂ batteries creates formidable challenges for both safety and stability because of their oxidative corrosion and the growth of dendrites and cracks on their surface. Now, an aprotic bimetal Li-Na alloy–O₂ battery with high cycling stability has been developed using a Li-Na eutectic alloy anode and an electrolyte additive.

Limitations associated with the primary amination of aryl C–H bonds include the poor control of regioselectivity with electron-rich substrates and the challenging nature of the reaction in the case of electron-deficient arenes. Now, site-directed C–C bond primary amination of simple alkylarenes and benzyl alcohols provides a route for the direct and efficient preparation of anilines.

The preparation of conjugates between proteins and small molecules is often challenging and requires several synthetic steps to functionalize each component for conjugation. Now, a conjugation methodology that leverages an electrophilic Se–S bond of selenocysteine to create bioconjugates between polypeptides and complex small molecules has been described.

Heteromultivalency, which involves the simultaneous interactions of more than one type of ligand with more than one type of receptor, is common in biological systems but challenging to engineer artificially. Now, a heteromultivalent platform prepared by co-assembling cyclodextrin and calixarene amphiphiles has shown self-adaptive peptide binding with high affinity. The platform was used to sequester amyloid β-peptides, reducing amyloid cytotoxicity.

Yuri Oganessian relates the story of the formation and decay of a doubly odd moscovium nucleus.