No metal needed: Boron does the job! The activation of the inert dinitrogen molecule has fascinated chemists for ages. In a ground-breaking study Braunschweig and co-workers have now demonstrated that N₂ activation can be achieved with the aid of the p-block element boron—a reactivity previously restricted to transition metals.

SABRE-rattling: Signal amplification by reversible exchange (SABRE) is a hyperpolarization technique that dramatically enhances magnetic resonance signals. This Minireview tracks its development since its discovery in 2009 and offers an outlook on its potential use for both analytic sciences and disease diagnosis.

Polymers with pores: Porous polyelectrolytes are increasingly being used for environmental, energy, biomedical, and catalysis applications. This Review focuses on how the synergy of pores and charge brings about new functionalities and opportunities.

A twist of graphene: An inherently chiral bilayer nanographene with a helicene linker has been synthesized as the racemate and the M isomer with 93 % ee. This first member of a new family of twisted double-layer polyaromatic hydrocarbons is characterized, and its electrochemical and photophysical properties explored.

The in vitro biosynthesis of an oxyvinylglycine is reported for l-2-amino-4-methoxy-trans-3-butenoic acid (AMB). AMB is synthesized from glutamate as an alanyl-AMB dipeptide. Crafting the AMB vinyl ether requires a cascade of modifications, including a cryptic hydroxylation and a likely 2,3-dehydration.

Safe and secure: A hydrogel based on a luminescent Tb^III–carboxymethyl cellulose complex was developed for the selective detection, protection, and storage of fingerprint information. The imaging information could be quenched with ClO⁻ ions and recovered by the addition of SCN⁻, thus leading to reversible on/off switching of the luminescence signal for fingerprint information encryption and decryption.

Lending support: The effect of surface hydroxyl groups, on supported vanadium catalysts, on the activity of propane dehydrogenation is studied. Although surface OH groups slightly suppress its dehydrogenation activity, the catalyst stability is increased. DFT calculations confirm that the existence of OH groups block the exposed V³⁺, on which there is a strong tendency to form coke.

Guided by the light: Photoswitchable chemically induced dimerization (psCID), a chemo-optogenetic approach for controlling cellular function in a rapid and reversible manner, is presented. Using psCID, the degree of dimerization and dedimerization could be fine-tuned by applying different doses of illumination and the localization of proteins and positioning of organelles in living cells was controlled with high spatial and temporal precision.

The more the merrier: Biomolecules on live cells play essential roles in determining how cells recognize the environment. The surface of live cells can be functionalized to display polyvalent biomolecular structures for enhanced molecular recognition compared to monovalent functionalization.

How many electrons? Decaheme cytochromes function as electron conduits for extracellular electron transport in Shewanella oneidensis MR-1. Calculations suggest that redox potentials of the hemes depend on the number of electrons flowing through the system, and that different regimes are operational at different environments or conditions (in vivo, or when the cytochrome is isolated in solution or bound to the electrodes).

Crystal clear: High-resolution crystal structures were obtained for ternary complexes of the prenyltransferase AmbP1 with geranyl cis-indolyl vinyl isonitrile and geranyl S-thiodiphosphate. Comparison of the structures obtained in the presence and absence of Mg²⁺ provides mechanistic insight into Mg²⁺-dependent allosteric control of regiospecificity in prenyltransferases.

A lamellar membrane with regular, straight, and robust 2 nm interlayer channels are fabricated using double-layered Ti₃C₂T_x MXenes as rigid building blocks via a direct self-stacking. Such channels permit precise molecular rejection, and unparalleled permeation spanning from water to organics, which make them superior in comparison to those formed by flexible GO sheets.

A facile strategy to form 3D porous Cu@Cu₂O aerogel networks by self-assembling Cu@Cu₂O nanoparticles for constructing catalytic interfaces as electrocatalysts and mimicking peroxidases is reported. The 3D Cu@Cu₂O aerogel networks exhibit excellent electrocatalysis ability toward glucose oxidation and peroxidase-like catalytic activity to the oxidation of a variety of substrates, including dopamine, in the presence of H₂O₂.

Free-standing air cathodes based on 3D hierarchically porous carbon membranes with continuous macroporous channels were prepared by a dual-template method. The macropores are demonstrated to play an important role in the electrochemical performance of the air cathodes in Li-O₂ batteries.

Feeding indoles: Thaxtomins are phytotoxins with potent bioactivity and a novel mode of action. The thaxtomin NRPS from S. scabies, along with genes encoding tryptophan synthase (TrpS), from Salmonella typhimurium, were assembled in a S. albus heterologous host. Feeding indole analogues to this host allowed the biosynthesis of a series of thaxtomin derivatives in a single fermentation from commercially available indole starting materials.

Three birds with one stone: A template protection–sacrifice method was developed to encapsulate metastable metal/metal oxide nanoparticles such as Cu₂O into metal–organic frameworks. SiO₂ serves as a sacrificial template for forming the yolk–shell structure, as a protective shell for Cu₂O nanocubes, and as a space holder in the porous composite.

Bottle rockets: A carbonaceous nanobottle (CNB) motor was described for near infrared (NIR) light-driven jet propulsion. This NIR light-powered CNB motor exhibits fuel-free propulsion and control of the swimming velocity by external light and has great potential for future biomedical applications.

The exchange dynamics of supramolecular polymers based on benzene-1,3,5-tricarboxamide (BTA) can be regulated by copolymerizing molecules with dendronized (dBTA) and linear (nBTA) ethylene glycol-based water-soluble side chains. Whereas nBTAs form long nanofibers in water, dBTAs do not polymerize. The copolymerization of the two BTAs results in more stable long nanofibers.

Generous to a fault: Structural defects in photocatalytic polymeric carbon nitrides are correlated with photocatalyzed hydrogen evolution. An increased number of terminal N−H bonds (▪(blue)) and reduced hydrogen bonding is associated with high performance, whereas polymer containing fewer terminal N−H bonds (•) solicits lower performance.

Opposite sides: Alkyne hydrostannation catalysts are traditionally effective at providing 1,1-vinylstannanes (α-products), with the selective delivery of E-configured 1,2-vinylstannanes ((E)-β-products) being much more challenging. Reported here is a molybdenum/isocyanide-based catalyst that overcomes this difficulty with high regioselectivity.

The more the merrier: Described is the direct synthesis of aryl bis(trifluoromethyl)carbinols from aryl bromides and fluorosulfates with a stoichiometric amount of carbon monoxide and two equivalents of trifluoromethyltrimethylsilane. The method exhibits good yields, broad scope, and good functional-group tolerance, and is suitable for carbon-isotope labeling.

Evolution for synthetic efficiency: Target-driven evolution optimizes enzymes for synthetically desired transformations under conditions that challenge and surpass known limitations of enzyme performance. A biocatalyst that was engineered for stereoselective, dynamic kinetic reduction in a high-pH environment has enabled an efficient synthesis of vibegron, a potent β₃-adrenergic agonist for the treatment of overactive bladder syndrome.

How the FMN riboswitch aptamer recognizes anionic FMN in the presence of molecular crowding agent without Mg²⁺ ion, which mimics conditions in pathogenic bacterial cells, was investigated. Structural, kinetic, and thermodynamic analyses under crowding conditions reveal that FMN binding occurs through an induced fit mechanism. This is in contrast to the known conformational selection mechanism that occurs in the presence of Mg²⁺.

Think thin: Ultrathin chiral metal–organic framework (CMOF) nanosheets of only few layers in thickness are prepared for the first time by a biomimetic strategy. Benefiting from the much larger number of exposed chiral sites, ultrathin CMOF nanosheets exhibit far superior enantioselectivity in chiral separation than their bulk counterparts.

Stimuli-responsive protein fluids: A type of bio-based fluid exhibiting shear-induced phase transitions has been generated by electrostatic complexation of supercharged polypeptides with aromatic surfactants. This sensitive, fast, and persistent self-ordering behavior was exploited for water flow detection and capturing of fingerprint information by easily recordable birefringence.

Fast and efficient CO₂ reduction: A facile strategy of catholyte-free electrocatalytic CO₂ reduction (CF-CO₂R) for formate production is proposed to avoid a solubility limitation in an aqueous electrolyte. The CF-CO₂R method provides an increased CO₂ transfer rate to the electrocatalyst and showed a significantly high formate concentration at a high current density with a high Faradaic efficiency for formate production at a low cell voltage.

Not just a happy medium: A vinylogous Pictet–Spengler cyclization has been developed for the generation of indole-annulated medium-sized rings. The method enables the synthesis of tetrahydroazocinoindoles with a fully substituted carbon center, a structural motif that is prevalent in biologically active alkaloids. The strategy has been applied to the total synthesis of (±)-lundurine A (see scheme).

ENabled: Utilizing ethylenediamine (EN) as a substitute for metal cations leads to a universal pH regulation strategy for DNA self-assembly. The approach not only provides a general, sequence-independent, pH-responsive platform for dynamic DNA nanotechnology, but also endows DNA self-assembly with the benefits from a metal-ion-free environment.

Going strong: Catalytic addition reactions of very weakly acidic nonactivated alkylarenes such as toluene and its derivatives were developed by using a strongly basic mixed catalyst system under mild reaction conditions. Addition reactions with imines and alkenes proceeded smoothly under proton-transfer conditions to afford the desired products in good to high yields. An asymmetric addition reaction of an alkylarene was also found to be possible.

Green fingers: Valuable polyester monomers and plasticizers, 1,4-cyclohexanedimethanol (CHDM), 1,4-cyclohexanedicarboxylic acid (CHDA), and 1,2-cyclohexanedicarboxylates, are produced by a two-step route using formaldehyde, crotonaldehyde, and acrylate (or fumarate) as the feedstocks.

CO₂ inside the hydride: The terminal zinc hydride complex [Tntm]ZnH, based on the electron-deficient tris(6-tert-butyl-3-thiopyridazinyl)methanide ligand, is an excellent catalyst for the hydrosilylation of CO₂ at room temperature, forming exclusively the respective silyl formate. This fast reaction is attributed to the electron-deficient properties of the [Tntm] ligand in combination with its flexible coordination.

Activator-free carboxylation reactions of benzyl and aryl halides with simple formic acid are reported. Key to success was the use of a palladium bisphosphine complex, which both catalyzes the decomposition of formic acid and activates the C−X bond of the substrate.

Gentle as an ox: A broad range of alkynes underwent gold-catalyzed stereoselective thioallylation with high efficiency (low catalyst loading, high yields). The gold(I) catalyst acts as both a π-acid for alkyne activation and a redox catalyst for Au^I/III coupling, while the sulfonium cation generated in situ functions as a mild oxidant (see scheme).

Ligand design: An iron-catalyzed cross-coupling between arylmagnesium bromides and difluoroalkyl bromides, with modified N,N,N′,N′-tetramethyl-ethane-1,2-diamine (TMEDA) as a ligand, is described. The combination of iron(II) salts with L enables the difluoroalkylations with a wide range of difluoroalkyl bromides, thus providing general and cost-efficient access to difluoroalkylated arenes that are of great interest in the life sciences.

The light FFFantastic: An unprecedented application of trifluoromethanesulfonic anhydride as a radical trifluoromethylation reagent was developed by merging photoredox catalysis and pyridine activation. The synthetic utility of this method is exemplified by the C−H trifluoromethylation of (hetero)arenes and trifluoromethyltriflation of alkynes.

Communications skills: The photophysical and redox properties of the complex of two [10]cycloparaphenylenes ([10]CPPs) with bis(azafullerene) (C₅₉N)₂ support an electronic interaction between the components. This supramolecular organic fullerene assembly demonstrates C₆₀-like ground-state properties and metallofullerene-like excited-state properties opening new avenues for organic materials.

Good as gold: A gold-catalyzed π-extension of anthranils with o-ethynylbiaryls as reagents was developed that provides a novel, short, and flexible approach to diverse N-doped polycyclic aromatic hydrocarbons (PAHs). The mechanism is proposed to involve a nucleophilic addition/ring opening/regiospecific C−H annulation/protodeauration sequence terminated by a Friedel–Crafts-type cyclization.

Iron-forged rings: An iron-catalyzed ring-closing metathesis of aliphatic ethers generates substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates.