Volume 14 Issue 5, May 2022

In 2017 Professor Frances S. Ligler was inducted into the National Inventors Hall of Fame for her inventions in portable optical biosensors. Professor Ligler now talks to Nature Chemistry about the challenge of developing new sensor designs into reliable products, and some of the pitfalls to avoid in the development process.

Extending mass spectrometry measurements of biomolecules into the megadalton regime is challenging due to the limited resolving power of currently used mass analysers. Now, using single ion-charge detection Orbitrap mass spectrometry, a mass accuracy of 0.001% has been demonstrated for protein particles larger than 9 MDa.

Understanding how surface structure affects catalyst selectivity is limited by the ability to synthesize atomically precise active-site ensembles. Now, by using intermetallic Pd–Zn, a series of well-defined multinuclear Pd–metal–Pd catalytic sites have been generated and studied, providing insights into their selectivity for the semi-hydrogenation of acetylene.

The rational synthesis of organic nanotubes and their hierarchical architectures has remained challenging. Now, one-dimensional hollow covalent organic frameworks have been prepared that can further assemble into toroid-shaped materials.

Molecular photocatalysts for generating solar fuels such as hydrogen degrade over time, ceasing to function as intended. Now the mechanism by which a ruthenium–platinum-based hydrogen-evolving photocatalyst breaks down has been identified, leading to the development of a repair strategy that uses singlet oxygen to regenerate an inactivated bridging ligand.

Enzymes, either purified or as whole-cell biocatalysts, can be concatenated into catalytic cascades and used to produce pharmaceutically relevant molecules. This Review discusses the advantages and requirements of multistep enzyme cascades and also highlights how they can be harnessed to achieve highly sustainable and cost-efficient syntheses.

Molecular catalysts for artificial photosynthesis can break down during operation and stop working, whereas biological photosynthesis uses an enzymatic repair strategy to maintain function. Now, the degradation pathway of a hydrogen-evolving RuPt photocatalyst has been identified, enabling the development of an active repair strategy involving the use of ¹O₂ to reoxidize the deactivated bridging ligand.

A wide variety of covalent organic cages and two- and three-dimensional covalent organic frameworks have been obtained through dynamic covalent chemistry, yet the synthesis of their one-dimensional counterparts has remained challenging. Porous covalent organic nanotubes have now been prepared through reversible aldehyde–amine condensation and it has been shown that these can further assemble into toroidal architectures.

The mass precision and resolution in charge-detection mass spectrometry can be improved by correcting frequency drifts of single ions. Now, chasing these individual ions for seconds in an Orbitrap mass spectrometer has revealed the exceptional stability of ultra-high-mass ions, culminating in an effective resolution of greater than 100,000 at m/z = 35,000.

Advances in the design of heterogeneous catalysts are limited by our ability to synthesize atomically precise active-site ensembles. Now, the controlled synthesis of Pd–M–Pd catalytic sites (M = Zn, Pd, Cu, Ag and Au) has been demonstrated. Stoichiometric control identifies that Pd–Pd–Pd sites are active for ethylene hydrogenation, whereas Pd–Zn–Pd sites are not.

Information is physical, but the flow between information, energy and mechanics in chemical systems remains largely unexplored. Now, an autonomous molecular motor has been analysed with information thermodynamics, which relates information to other thermodynamic parameters. This treatment provides a general thermodynamic understanding of molecular motors, with practical implications for machine design.

Low-energy NO–He collisions have been studied and scattering resonances observed. By rotationally exciting NO before the collision, a controlled amount of angular momentum was added and its release in de-excitation collisions was monitored—additional quantum waves were imprinted in the angular distributions of the scattering products.

Influencing the products of a reaction through controlling the state of the reactants is a notable goal for chemists. It has now been shown that the reactivity of a pair of Fermi-coupled vibrational states of CH₃D(v₁-I and v₁-II) with a chlorine atom depends not only on the constituent basis modes, but also on the relative phase of the two modes in their wave-functions.

Although cobalt–carbene radicals have proved to be highly versatile intermediates for homogeneous catalysis, their spectroscopic detection and characterization have been limited. Now, by using hypervalent iodonium ylides, the formation and spectroscopic detection of a biscarbenoid N-enolate–carbene radical—which undergoes a complex catalytic pathway involving reversible N-enolate formation—has been demonstrated.

Combinatorial high-throughput methodologies can accelerate screening and discovery in biochemistry and biomedical sciences, but they often rely on large-scale analyses, making them time-consuming and expensive. Now, DNA-mediated fusion of single liposomes has been shown to enable the spatially resolved and parallel cargo delivery of subattolitre volumes in a stochastic order of succession.

A straightforward method for synthesizing optically active α-amino acids from abundant carboxylic acids has been developed. Based on a nitrene-mediated stereocontrolled 1,3-nitrogen shift, this approach provides access to a large variety of unnatural α-amino acids with aryl, allyl, propargyl and alkyl side chains and enables late-stage amination of carboxylic-acid-containing drugs.

Halogen-bonded co-crystals of a fluorinated azobenzene derivative and a volatile co-former can be cut, carved or engraved with micrometre-scale precision using low-power visible light. The proposed mechanism involves the local evaporation of the volatile component followed by recrystallization of the azobenzene co-former near the edge of the irradiation area.

Claire Murray ponders on the attraction benzene — a small, seemingly simple molecule — has long exerted on scientists, some of the insights gained through its exploration, and the varied applications found for this hexagonal ring and its derivatives.