Articles in 2022

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.

Rhodopsin activation is driven by an ultrafast double-bond isomerization, but questions remain about the origin of its sensitivity. Now, quantum–classical simulations show that, 15 fs after light absorption, a degeneracy between the reactive excited state and a neighbouring state causes the splitting of the rhodopsin population into subpopulations, which propagate with different velocities, leading to distinct contributions to the quantum efficiency.

Carbonic anhydrase enzymatically catalyses CO₂ hydration, and its effect on enzymatic and heterogeneous CO₂ reduction has now been studied. Through the co-immobilization of carbonic anhydrase, it has been shown that faster CO₂ hydration kinetics are beneficial for enzymatic catalysis (using formate dehydrogenase) but detrimental for heterogeneous catalysts, such as gold.

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.

Stereochemically defined trisubstituted alkenyl fluorides are important compounds for drug discovery, agrochemical development and materials science, but their preparation is challenging. Now, a practical and widely applicable catalytic strategy enables access to a large assortment of olefins bearing a fluoro-chloro terminus. Subsequent cross-coupling generates the corresponding trisubstituted alkenyl fluorides.

Controlling the crystallographic registry of layered materials through interlayer twist angles has introduced a distinctive degree of freedom for tuning their electronic behaviour. Now, the interfacial electrochemical kinetics of solution-phase redox complexes at twisted bilayer graphene electrodes have been modulated by the angle-dependent tuning of moiré-derived flat bands.

Phase-separated compartments have long been proposed as precursors to cellular life. Now, it has been shown that RNA–peptide protocells are more robust when formed using shorter (rather than longer) peptides, and that peptide sequence determines the functional materials properties of these compartments.

Generating strategies that use modern synthetic methods to access privileged chemical space is a central goal of total synthesis. Now, a strategy that is orthogonal to classic approaches, coupled with C–H functionalization methods, leads to the shortest synthesis of the sesquiterpenoid longiborneol and divergent syntheses of oxygenated longiborneol congeners.

Reliable intracellular delivery of antibodies is one of the grand challenges in biomedical research, with the potential to address unmet clinical needs or to enable basic research. Now, it has been shown that tricyclic peptide complexes can transport functional antibodies into the cytoplasm and nucleus of cells to specifically target intracellular proteins.

Polyoxometalate clusters have been assembled into two-dimensional ‘clusterphene’ layers that are held together by coordination to lanthanide ions and electrostatic interactions with quaternary ammonium cations. The resulting materials resemble graphene sheets on account of their uniform hexagonal pores and are shown to catalyse epoxidation reactions due to their in-plane electron delocalization.

Neptunium was the first actinide to be artificially synthesized, yet its chemistry has remained relatively unexplored. Most neptunium chemistry involves the neptunyl di(oxo) motif, and transuranic compounds with only one metal–ligand multiple bond are generally rare. Now, a stable complex of neptunium in the +5 oxidation state has been isolated that features a single terminal Np–O multiple bond.

Nanometre-sized polyaromatic hydrocarbons (nanographenes) have been largely explored as single-layer systems. Now a C₆₄ nanographene comprising a planar core decorated with four terphenyl–imide moieties at its periphery has been shown to assemble with coronene to form bi- and trilayer host–guest complexes in solution, as well as tetra-, hexa- and multilayer stacks in the crystalline state.

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.

Coacervate microdroplets formed from pH- and redox-responsive peptides and self-assembled by liquid–liquid phase separation have been shown to quickly recruit macromolecular therapeutics—such as peptides, large proteins and mRNAs—and directly enter the cytosol of cells via a non-endocytic pathway. The subsequent release of therapeutic cargo is mediated by endogenic glutathione.

It’s unclear how protometabolic reactions emerged and evolved into extant metabolic pathways such as the tricarboxylic acid cycle. Now, it has been shown that cyanide acts as a mild and efficient reducing agent, mediating abiotic transformations of tricarboxylic acid intermediates and derivatives.

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.

The hydrohalogenation of alkenes generally forms branched alkyl halides. Now, a palladium-catalysed method has been developed for the remote hydrohalogenation of internal and terminal alkenes, enabling the efficient synthesis of linear alkyl halides. The method uses an engineered Pyox ligand with a hydroxy group, which is essential for accelerating the oxidative halogenation.

Borophene, a two-dimensional boron sheet, can adopt a variety of polymorphic structures that are predicted to possess interesting and potentially useful electronic properties. Micrometre-scale single-crystal borophene domains have now been grown on a square-lattice Cu(100) surface. The resulting boron sheets feature a rectangular unit cell, intrinsic stripe modulations and an unusual electron band structure.

Decoupling the processes of light harvesting and catalytic hydrogen evolution could be a potentially important step in storing solar energy. This has now been achieved with a single molecular unit: a light-harvesting ruthenium complex–polyoxometalate dyad that absorbs light, separates and stores charge and then generates hydrogen on demand following the addition of a proton donor.

Sulfonyl fluorides typically react with nucleophiles exclusively at sulfur, leading to the substitution of fluoride, as is the case in SuFEx reactions. Now, an alternative defluorosulfonylative reaction has been developed, coupling 3-aryloxetane sulfonyl fluorides with amines to generate amino-oxetanes. The mild conditions and high functional group tolerance enable the preparation of oxetane analogues of benzamide drugs via oxetane carbocation intermediates.