Freeze frame: The Nobel Prize in Chemistry 2017 was jointly awarded to Jacques Dubochet, Joachim Frank, and Richard Henderson for “developing cryo‐electron microscopy (cryo‐EM) for the high‐resolution structure determination of biomolecules in solution”. This Highlight describes how the field of cryo‐EM developed from the first transmission electron microscope in 1931 to the sophisticated technique of today.

Light‐emitting compounds for bioimaging: In the last decade, chemists have significantly expanded the toolbox of imaging agents by preparing new bio‐ and chemiluminescence compounds. These developments include synthetic analogues of luciferin, caged luciferin‐based bioluminogenic probes, and the recently emerging highly bright chemiluminescence dioxetane probes.

Being selective: The selective oxidation of methane to methanol in high yield is currently elusive, but when accomplished it could redefine the petrochemical industry. This Review illustrates the homogeneous and heterogeneous catalytic routes for this process and discerns the most promising approaches with the potential to conquer the challenge.

According to the principle of valence isoelectronicity, the first formal phosphorus analogue of the well‐known 1,2,3‐triazolylidenes (mesoionic carbenes) has been prepared and structurally characterized. The highly delocalized π‐system in the aromatic heterocycle is similar to the electronic situation established for related abnormal carbenes. First results on the coordination chemistry of this compound are presented.

The Brønsted acidity of the H‐silane HSi(SiCl₃)₃ is extremely high, namely more than 43 orders of magnitude higher than that of HSiMe₃ and even slightly higher than that of HCl in MeCN. Its deprotonation with an N‐heterocyclic carbene provides the conjugate base Si(SiCl₃)₃⁻, a weakly coordinating anion.

Superacidic SO: The unprecedented non‐rigid complex C₆(CH₃)₆SO²⁺ (AsF₆⁻)₂ was isolated from the reaction of hexamethylbenzene with SO₂, anhydrous HF, and AsF₅. The energetic barrier for the migration of the SO moiety over the benzene ring was calculated to be close to zero.

From tissues to organs: Electrochemical soft‐probe bioimaging of thick tissues and organs was developed to create highly resolved maps of the biodistributions of injected nano drug carriers, skin cancer biomarkers, and redox‐active proteins. The application of the new “spider probe” which brushes gently over the tissues increases data acquisition rates. The electrochemically obtained images are free from optical interferences.

The molecular details of the hydrogen turnover by [FeFe]‐hydrolases in nature are not yet fully understood. FTIR spectro‐electrochemical studies on [FeFe]‐hydrogenases now prove there is a proton‐coupled electron transfer in the reduction of the catalytic [4Fe‐4S] cluster.

In the red: A red‐light‐emitting pyrotechnic composition of high color purity that does not contain any strontium‐ or halogen‐based materials is disclosed. The formulation features a lithium‐based nitrogen‐rich material that serves as both an oxidizer and colorant in the formulation, and it may be of interest to both the military and civilian pyrotechnics communities.

A wafer‐thin sensor: The preparation of a crystalline, highly‐oriented, and thickness‐controlled thin film with an electronically conductive MOF is reported. Chemiresistive sensors based on these thin films show a high response, excellent selectivity, fast response speed, and good long‐term stability towards NH₃ gas at room temperature.

VE/CKA, the ideal couple: The radical copolymerization between cyclic ketene acetal (CKA) monomers and vinyl ether (VE) derivatives led to a new and easy way to prepare homogeneously functionalized aliphatic polyesters (left to right in picture: nanoparticles, bioelastomers, antibacterial surfaces).

Unnatural Selection: The spontaneously reactive SpyTag/SpyCatcher pair was previously developed by engineering an adhesin protein from S. pyogenes. Phage library selection enabled evolution of the peptide and protein partners for accelerated isopeptide bond formation with high specificity. The resulting SpyCatcher002 was fused to the protein intimin on the bacterial outer membrane, thereby allowing fluorescent imaging of intimin dynamics during cell division.

From planar to curved surfaces: The way that the geometrical curvature of the surface influences the global van der Waals interactions between thiol molecules is visualized by means of electrochemical measurements and molecular dynamic calculations.

OmpT substrate optimization: Substrate specificity of a bacterial outer‐membrane protease OmpT is determined through use of peptide arrays and SAMDI‐MS, a label‐free high‐throughput mass‐spectrometry‐based assay. By screening hundreds of peptide substrates, it is possible to identify an optimal peptide sequence that dramatically improves the catalytic efficiency of the protease. Prod=product, Subst=substrate.

Avoid long delays: A novel molecular design for thermally activated delayed fluorescence (TADF) emitters based on a donor–σ–acceptor motif led to short TADF decay lifetimes of less than 400 ns. Since shorter delayed lifetimes in TADF emitters are highly beneficial for device performance, this design strategy is expected to provide an effective approach to advanced TADF materials.

Kinetically trapped structures, including lamellae, dumbbells, and nanotubes, are directly prepared by aqueous dispersion RAFT polymerization of a cyclodextrin/styrene complex. Introducing host–guest interactions enables the dispersion polymerization of water‐immiscible monomers for nanoparticle synthesis and morphology control.

The crystal structure of the calcium‐dependent antibiotic (CDA) laspartomycin C bound to its bacterial target undecaprenyl phosphate (C₅₅‐P) is presented. This is the first structure of a CDA bound to both calcium and its target. Unlike any clinically used antibiotic, laspartomycin C kills bacteria by binding C₅₅‐P and effectively blocks peptidoglycan biosynthesis. This structure provides a clear explanation for this interaction.

A mild, efficient, and selective method for C(sp³)−H bond activation and amidation that employs thioamides as the directing group, with aryl‐, heteroaryl‐, and alkyl‐substituted dioxazolones under Co^IIICp* catalytic conditions, is described.

Lay it on the line: A linear molecularly imprinted polymer prepared against a signalling peptide of the pathogen Streptococcus pneumoniae can block quorum sensing and abrogate virulence. These results indicate that this approach has the potential to be used for the development of effective anti‐infective agents against pathogenic Gram‐positive bacteria.

Biofilm formation by pathogenic bacteria is typical of chronic infections, and lectins often play key roles in establishing biofilms. The drug‐resistant pathogen Pseudomonas aeruginosa employs lectins LecA and LecB as virulence factors and biofilm building blocks. A covalent lectin inhibitor specific to a carbohydrate binding site is described and its application in LecA‐specific in vitro imaging of biofilms formed by P. aeruginosa presented.

Playing drops and marbles: Small magnets are used to precisely drive the motion of floating drops and liquid marbles, made of water, oil or nonmagnetic fluids, and without the use of magnetosensitive particles for the first time. Digital microfluidic operations, such as transport along complex trajectories and programmed drop fusion, are demonstrated.

Big wheel turning: The exchange‐coupling constants of the largest Cr^III−Ln^III wheel was exactly predicted and experimentally confirmed using a pulsed high‐field magnetization technique, which leads to a large ground spin state (S_T=16) for the Gd analogue and a tunnelling‐free single‐molecule magnet behaviour for the Dy analogue.

Supracontrolled: The kinetics of supramolecular polymerization with a rigid host and a flexible guest monomer can be controlled through the introduction of a pH‐responsive competitive guest (green rod; blue pathway). This polymerization system can be kinetically trapped by tuning pH at different stages, and supramolecular polymers with different molecular weights can be obtained. Red pathway: uncontrolled.

Is bronze better than gold? Alloys of Cu‐Zn‐Sn are found to be effective for mediating the reduction of CO₂ to CO and formate.

CdS in the shell: The growth of a submonolayer CdS shell (see picture: yellow) on PbS quantum dots (QDs, gray spheres) suppresses charge transfer (red arrow: hole transfer) and enhances the efficiency of triplet energy transfer (blue arrow) from PbS QDs to surface‐anchored tetracene from 60 % to 72 %. This explains the increase in the NIR to visible photon upconversion quantum yield from 3.5 % to 5.0 %.

N₂ the breach… Diphenyldiazomethane reacts with HB(C₆F₅)₂ and B(C₆F₅)₃ to afford 1,1‐hydroboration and adduct formation, respectively. The adduct Ph₂CN₂B(C₆F₅)₃ liberates N₂ and the diphenylcarbene–borane adduct. Computational studies suggest that N₂ capture is thermodynamically favourable, despite the exothermicity of carbene–borane adduct formation.

Call me Al=Al: The observation experimentally by photoelectron spectroscopy of an Al=Al double bond has been achieved. Double‐bond formation involved the transmutation of Al atoms into Si atoms by electron donation in the LiAl₂H₄⁻ cluster, and it was backed up by ab initio studies.

Unchained: Amine‐substituted dicyanomethyl radicals have been known to form σ‐dimers. However, a dicyanomethyl radical with the julolidine skeleton (JD^.) does not form the σ‐dimer and was successfully isolated as a stable radical in spite of the absence of bulky protecting groups. This radical is in equilibrium with its π‐dimer in toluene solution.

Photo finish: A mild versatile method for the generation of highly unstable diazo compounds through photolysis of oxadiazolines and subsequent coupling with boronic acids is described. Simple changes in the workup conditions allow the divergent generation of protodeboronated and oxidized products, along with boronic pinacol esters, with excellent functional‐group tolerance.

More power for electric vehicles: A lithium‐ion battery based on a Li₂V₂(PO₄)₃ cathode and a prelithiated hard carbon (HC) anode is fabricated through a simple prelithiation strategy. The battery shows supercapacitor‐like high power, long cycle life and much improved low‐temperature performance.

Near‐IR fluorophore scaffold: A unique class of rhodol‐based NIR dyes with large Stokes shifts, high fluorescence quantum yields, excellent photostability, and optically tunable groups were developed. They are expected to be useful fluorophore scaffolds in the development of new NIR probes for bioimaging.

More efficient on their own: Atomically dispersed cobalt catalysts with excellent recyclability were developed for the dehydrogenation of formic acid (see picture). By tuning the metal/ligand ratio of the catalyst precursor, the structure of the heterogeneous material could be changed from nanoparticles to highly dispersed metal centers. Experimental results show the presence of CoN_x species as the active sites.

The cat for the HAT: The metal‐free visible‐light‐driven hydrosilylation of electron‐deficient alkenes was accomplished through the synergistic combination of an organophotoredox catalyst and a highly electrophilic hydrogen atom transfer (HAT) catalyst while the hydrosilylation of electron‐rich alkenes was achieved by combining the photocatalyst with a polarity‐reversal catalyst.

CEST bon: The NMR properties of lanthanide ion complexes formed with DOTA‐tetraamide ligands with four pendant primary amine groups were examined by relaxometry and chemical exchange saturation transfer (CEST). The CEST signal of the Eu^III complexes increased dramatically at low pH while the r₂ relaxivity of the Dy^III complexes increased dramatically at higher pH values.

Without a trace: Tertiary stereogenic centers are installed by a traceless asymmetric reductive allylboration catalyzed by chiral biphenols. The reaction proceeds via a transient enantioenriched allyic diazene species which breaks down through a sigmatropic rearrangement to generate 1,4‐dienes, bearing either aryl‐ or alkyl‐substituted tertiary stereocenters, with high enantio‐ and diastereoselectivities.

G, that's hot: The activity and heat‐resistant properties of tetramolecular G‐quadruplex/hemin DNAzymes can be improved by adenines for application as a catalyst at high temperature. The catalytic activities of the DNAzymes were investigated (up to 95 °C; up to 18 h at 75 °C) with the standard peroxidase‐mimicking oxidation of 2,2′‐azino‐bis(3‐ethylbenzothiozoline‐6‐sulfonic acid) (ABTS) by H₂O₂.

Super boron: The TEMPO radical reduces triplet dioxygen to the superoxide state in the presence of the strong boron Lewis acid B(C₆F₅)₃. The sensitive radical anion species was isolated and characterized by methods including X‐ray crystal structure analysis and EPR spectroscopy.

Rather select: A rhodium(II)‐catalyzed reaction of newly prepared 4‐acyl‐1‐sulfonyl‐1,2,3‐triazoles with benzene, and its derivatives, is investigated. Acceptor/acceptor carbenoids generated from 4‐acyltriazoles undergo selective insertion at aromatic C(sp²)−H bonds in the presence of benzylic C(sp³)−H bonds to produce N‐sulfonylenaminones. esp=α,α,α′,α′‐tetramethyl‐1,3‐benzene‐dipropionate.

Hydrides in a pinch: A barium hydride complex [(Tp^Ad,iPr)Ba(μ‐H)]₂ was obtained by the hydrogenolysis of (Tp^Ad,iPr)Ba[CH(SiMe₃)₂](THF). The steric demand of the super bulky hydrotris(3‐adamantyl‐5‐isopropyl‐pyrazolyl)borate ligand (Tp^Ad,iPr) is sufficient to stabilize the dimer. Reactions with diyne and CO indicate a rich chemistry for this complex.

A barium hydride cluster was prepared by reaction of Ba[N(SiMe₃)₂]₂ with PhSiH₃ in toluene. Despite lack of additional Lewis bases, Ba₇H₇[N(SiMe₃)₂]₇ is remarkably soluble in aromatic solvents. The cluster is retained in solution, and no coalescence of hydride signals is observed by NMR spectroscopy even at 95 °C. The benzene‐solubilized cluster is strongly reducing and reacts at room temperature with isolated alkenes, including ethylene.

The use of chiral diazaphospholenes as catalysts for asymmetric synthesis is reported. A conveniently synthesized diazaphospholene catalyzes the asymmetric reduction of imines, with pinacolborane, to secondary amines with low catalyst loadings at ambient temperature (see example).

Revival of the poly(ortho ester)s: A facile catalytic method is reported for production of poly(ortho ester)s (POEs) from air‐ and moisture‐stable vinyl acetal precursors. The mild and efficient method is versatile with respect to monomer incorporation, and it allows access to novel materials and side‐chain functionalization of a sensitive, degradable polymer backbone.

Stay safe: The reaction of thiocarbonyl fluoride, generated from difluorocarbene, with various amines proceeded smoothly under mild conditions to give thiocarbamoyl fluorides, isothiocyanates, and difluoromethylthiolated heterocycles. Thiocarbonyl fluoride is generated in situ and no special safety precautions are needed.

Scholarly pursuits: Total syntheses of the monoterpenoid indole alkaloids (±)‐alstoscholarisine B and C, which were originally isolated from the leaves of Alstonia scholaris, were accomplished from readily available starting materials. A key step is Michael addition of the enolate derived from an indole‐2‐acetic ester to an α,β‐unsaturated N‐sulfonyllactam.