Change is good: Significant product and process innovation is taking place in the chemical industry. This Essay emphasizes how these changes are driven by global societal megatrends concerning the environment, health, and energy.

HOF the shelf: Hydrogen-bonded organic frameworks (HOFs) are described systematically based on hydrogen-bonding patterns (supramolecular synthons) and molecular structures (tectons). HOFs can show thermal and chemical durability, a large surface area, and permanent porosity.

Illuminating OCF₃ and OCF₂H: Tri- and difluoromethyl ethers are privileged moieties in the realm of medicinal chemistry and are found in marketed pharmaceuticals and agrichemicals. The recent advances in visible-light photocatalytic synthesis of these moieties will likely render their introduction routine as a part of drug design and drug discovery processes.

The soft side of robots: This Review gives an overview of current advances in materials with intrinsic softness as well as soft machines, robots, and haptic interfaces. The focus lies on two specific topics: bio-inspired design and additive manufacturing.

Magic bullet: The field of antibody–drug conjugates (ADCs) is emerging as one of the frontiers in biomedical research, particularly in the area of cancer treatment. Covering oncological applications, and after a brief history of the emergence of the field of ADCs triggered more than a century ago by Paul Ehrlich's “magic bullet” concept, this Review primarily focuses on chemical synthesis aspects of the field.

The correlation of Co₃O₄ catalysts having different crystallographic surfaces with reducibility and the formation energy of oxygen vacancies is described. Distinct product selectivity of CO₂ hydrogenation is observed. The key step (CH₃−O* bond breaking), which affects C₁ product distribution, was identified by in situ DRIFTS and DFT, suggesting that oxygen vacancies can promote the CH₃−O* bond breaking.

Tetra- and penta-anions containing less than a hundred atoms with −4 and −5 charge states that are stable in the gas phase are proposed. A universal model is established to explain their large stability and predict new ones.

Multiple dehydration cycles were used to produce depsipeptide mixtures. Periodic disruption of the system equilibrium alters the product distribution and increases the catalytic activity of the products. These findings could shed light on how early biological systems may select for specific subsets of polymers.

Hydrating chiral arenes: The structures of singly and doubly hydrated [4]helicene were captured in the gas phase using high-resolution microwave spectroscopy. A trend in the preferred docking site is observed and interpreted in terms of the hierarchy of intermolecular interactions.

Ground to satisfaction: Ball milling can be used to synthesize a wide variety of supported catalysts with nanometer-sized particles of the active phase. In this way liquid-phase processing can be avoided in the synthesis of one of the most important classes of solid catalysts.

Three enamine hole-transporting materials (HTMs) based on Tröger's base scaffold were synthesized. These compounds are obtained in a three-step facile synthesis from commercially available materials without the need of expensive catalysts, inert conditions or time-consuming purification steps.

Sialyl-globo-series glycans, including DSGb5 and sialylglobosides, have been prepared using both a one-pot multiple enzyme synthesis method and chemoenzymatic synthesis. The resulting glycans were screened for binding to sialic-acid-binding, immunoglobulin-type lectin-7 (siglet-7) using a glycan-microarray-based binding assay.

Time to split: N₂ cleavage in a one-electron oxidation reaction of trans-[Mo(depe)₂(N₂)₂], a simple molybdenum complex supported by bidentate phosphine ligands, is studied. The one-electron chemical and electrochemical oxidation reaction of Mo⁰ to Mo^I produces a Mo^IV terminal nitride complex via formation of Mo^II−N=N−Mo^II structures, which undergo cleavage of the bridging N₂ molecule.

Tunnel vision: The hydroalkoxylation of a molecular species adsorbed on a Ag(111) surface has been shown by scanning tunneling microscopy complemented by X-ray electron spectroscopy and density functional theory to proceed at temperatures as low as 150 K. The proton-tunneling-mediated pathway was theoretically disentangled and confirmed experimentally through the kinetic isotope effect.

Two paths: Cross-conjugated paths within a quinoidal pro-diradicaloid tetrathiophene serve to lower the singlet–triplet gap and increase the stability of the molecule. The cross-conjugation lies along both the inter-dicyano and inter-dione acceptor paths.

Common thread: A two-dimensional poly-pseudo-rotaxane is reported wherein the guest molecule (C8) serves to thread the pillar[5]arene (L) units as well as crosslink one-dimensional coordinative polymeric arrays. The combination of L and C8 with silver(I) ion affords the first example of a two-dimensional poly-pseudo-rotaxane.

TADF, Tada! By using a tri-spiral donor, the thermally activated delayed fluorescence (TADF) emitter TspiroS-TRZ can achieve a 90 % horizontal orientation dipole ratio and greatly alleviate aggregation-caused emission quenching (ACQ). The emitter demonstrates state-of-the-art external quantum efficiencies (EQEs) of 33.3, 20.0, and 22.8 % in purely organic doped, nondoped sky-blue, and white TADF-OLEDs, respectively. HTAU=hole transporting adjusting unit, OLED=organic light-emitting diode.

Hot iron: Magnetic heating of Fe_2.2C@Ru nanoparticles in solution gives rise to high local temperatures which make it possible to perform the selective hydrodeoxygenation of acetophenone derivatives and platform molecules such as furfural (see figure) and hydroxymethylfurfural under mild conditions (3 bar H₂). These reactions are otherwise carried out with standard heterogeneous catalysts at high H₂ pressures and temperatures.

Cocrystals comprising trans-1,2-diphenylethylene (TSB) and 1,2,4,5-tetracyanobenzene (TCNB) display thermally activated delayed fluorescence (TADF). The intermolecular charge transfer nature in cocrystals contributes to a small singlet–triplet energy gap and, together with crystalline state in cocrystals, is responsible for the TADF.

Reaching for the sky: The heavy atom Ge in a σ–π conjugated polymer host provided a high E_T level for efficient host–guest energy transfer, low orientation polarizability leading to bluer emission from the guest, and enhanced spin–orbit coupling to promote reverse intersystem crossing and the harvesting of triplet excitons for light emission. The observed sky-blue TADF electroluminescence had a record external quantum efficiency of 24.1 %.

Cutting the Gordian knot: Collision-induced dissociation and travelling-wave ion-mobility mass spectrometry together provide a fast screening method to identify the topology of molecular Hopf and Solomon links, a [3]catenate, and a trefoil knot, even when they coexist in quickly equilibrating dynamic combinatorial libraries.

A whole lot of electrons and holes: A highly efficient Z-scheme photocatalyst was constructed from 1D CdS and 2D CoS₂. Experimental and theoretical evidence suggests that the transition layer at the interface enables electrons to be transferred from CdS to CoS₂, thus resulting in more photogenerated electrons and holes participating in the surface photocatalytic reaction.

The magic of bulky ligands: In contrast to the 15-atom bipyramidal core in [Au_23−xAg_x(SR)₁₆], the structure of [Au_23−xAg_x(S-Adm)₁₅] comprises an Au_13−xAg_x icosahedral core, three Au₃(SR)₄ units, and one AgS₃ staple motif. Benefitting from Ag doping, [Au_23−xAg_x(S-Adm)₁₅] exhibits drastically improved photocatalytic activity for the degradation of rhodamine B and phenol under visible-light irradiation compared to Au₂₃ nanoclusters.

Double action: A cucurbit[7]uril host can promote and inhibit two reactions simultaneously, leading to the diversion of the normal reaction course with the reversal of chemoselectivity. These findings may give insight into the action of enzyme mimics and other chemical networks.

Side-chain immiscibility allows full control over the formation of a highly stable, discrete anti-cooperative assembly that is in competition with the formation of cooperative supramolecular polymers, which may open up new strategies for pathway control in self-assembly.

A roll of the dice: A universal approach to prepare shape-tunable 3D crystals of several metal nitride clusterfullerenes (NCFs), including cubes and dice, which can be readily switched by changing the volume ratio of good (mesitylene) and poor (isopropanol) solvents, is reported. The dice-shaped crystals exhibit anomalously enhanced photoluminescence (PL) relative to that of the cubes.

A palladium catalyst loading as low as 0.5 mol % enables the cross-coupling of α-bromo carboxamides and aryl boronic acids, generating a series of chiral α-aryl carboxamides in good yields and excellent enantioselectivities. The development of a chiral P,P=O ligand was critical in suppressing the formation of biaryl side products.

mRNAs were bundled, through hybridization with RNA-oligonucleotide linkers, to form nano-assemblies (R-NAs), resulting in enhanced stability towards RNase and preserved translational activity. R-NAs could be delivered into mouse brain, without the use of a transfection reagent. This strategy could improve the efficiency of mRNA-based therapeutics.

Electrode plating: Strong lithiophilicity and fast lithium-ion migration at elevated temperature facilitate the formation of large and sparse Li nuclei, thus contributing to a compact and smooth Li deposition layer on anodes. Thus dendrite-free Li metal anodes with excellent electrochemical performances were achieved for metal-based batteries.

Alterations: Metal-free linear conjugated polymer (LCP) catalysts were developed using N-, S-, or Se-heterocycles with well-defined molecular structures. The LCPs possess good solubility, strong dipole interactions, and tunable local atoms, which can alter the spin density and charge distributions of the conjugated structures, leading to tunable active sites and good oxygen reduction reaction (ORR) activity.

Will behave well if treated well: A simple chemical modification strategy was designed for the preparation of a polymer–alloy hybrid layer on lithium metal for dendrite-free anodes. Treated lithium anodes exhibited outstanding cycling performance in Li–S and Li–LiFePO₄ full cells and retained good electrochemical performance after exposure to humid air (see picture).

BN/CC isosterism: Doubly BO- and BN-doped perylenes have been prepared, which further expand the chemical space of a ubiquitous building block for organic electronic materials. The key cyclization step proceeds via a quantitative Wacker-type addition reaction of BO−H or BN−H bonds to adjacent alkynyl moieties.

A chemical proteomic platform that integrates gel filtration with activity-based protein profiling (ABPP) provides a method to assess small-molecule electrophiles for reversible versus irreversible interactions with cysteine residues in native biological systems, revealing the broad potential for reversible covalency as a strategy for chemical-probe discovery.

Stability: A new rigid coplanar poly(p-phenylene vinylene) (PPV) derivative, LPPV-1, is synthesized with a rigid planar backbone and low-lying LUMO, which lead to reduced conformational disorder and high n-type doping efficiency. The conductivity of LPPV-1 is up to 1.1 S cm⁻¹, and the power factor is only 2 % after a 7 day exposure to air. This work represents an effective strategy towards high-performance and potentially air-stable n-type polymer thermoelectrics.

The first direct C−SP(=O)(OR′)(OR′′) coupling of diverse and chiral phosphorothioate salts with aryl iodides, enabled by an air- and moisture-stable Pd^I dimer is demonstrated. The mechanistic and computational data suggest distinct dinuclear Pd^I catalysis to be operative, which allows for operationally simple couplings with broad scope and full retention of stereochemistry.

Strong noncovalent interaction: While halogen bonding has been widely recognized in many fields of chemistry, a benchmark spectroscopic measurement of its strength is still absent. Here, the strength of a poster child halogen bond between Br⁻ and CCl₃Br using anion photoelectron spectroscopy is reported.

Nanoparticles coated with bacterial outer membranes (denoted “OM-NPs”) are reported as an anti-adhesion nanomedicine that competes with source bacteria for binding sites and therefore inhibits bacterial adhesion to the host cells. Specifically, OM-NPs prepared with Helicobacter pylori outer membrane were demonstrated to inhibit bacterial binding to the gastric epithelial cells and stomach tissues.

Due for a promotion: Catalytic site preference can be manipulated for the rational design of advanced catalysts. In Ru-based electrocatalysts for the hydrogen evolution reaction, RuSi is identified as a Pt-like electrocatalyst, due to the promotion of the Ru top sites, which are efficient but subordinate in the Ru(0001) catalyst surface.

Near-infrared-active quantum dots (QDs) have been designed to generate therapeutic superoxide radicals within pathogens. The combination of activation using a deep-tissue-penetrating light source, and selective mechanism of action, produces an effective treatment. These heavy-metal-free InP QDs successfully eliminate a multidrug-resistant critical pathogen, while leaving human cells unharmed in vitro.

The integration of planar and distorted structures with long alkyl side chains to obtain molecules with high emission efficiency both in solution and the solid state is demonstrated. Efficient intracellular bioimaging using the molecules with different concentrations demonstrates the possibility of applying the highly emissive systems.

Go native: Pd^II-catalyzed C(sp³)−H olefination of native amide substrates was developed. To utilize the extremely weak carbonyl coordination ability of amides, an electron-deficient pyridinesulfonic acid ligand was designed. Structurally diverse amide substrates, including lactams, underwent olefination without the undesired cyclization. Olefination products were further diversified through synthetic transformations on the alkenyl moiety.

A new brick: The oxygen center in the phosphaketenes E-P=C=O can be readily replaced by nitrogen to give alkali salts of phosphanyl cyanophosphides [E-PCN]⁻, which are further converted into E₂(PCN). These compounds can be used as synthons for the dianion [PCN]²⁻, which is a building block for PCNB heteroallenes and PCN-containing metal complexes.

In step: The straightforward transformation of 5-hydroxymethyl furfural (HMF) into a polymer is reported here for the first time. This unprecedented step-growth copolymerization of HMF and dihydrosilanes proceeds by a coordination mechanism to afford linear poly(silyl ether)s in the presence of B(C₆F₅)₃ and a heteroscorpionate zinc hydride complex.

1,2,3,4: A unique intermolecular denitrogenative annulation of 1,2,3,4-tetrazoles and alkynes was discovered by employing a catalytic amount of Fe(TPP)Cl and Zn dust. This reaction precludes the traditional click reaction between organic azides and alkynes.

The first example of an enantioselective denitrogenative cyclization of benzotriazoles with allenes and N-allenamides is enabled using Pd/PC-Phos catalysis, and provides rapid access to optically active 3-methyleneindolines in good yields with high ee values. The method features a general substrate scope, high regioselectivity, and mild reaction conditions. Tf=trifluoromethanesulfonyl.

A little help from my azobenzenes: Photosensitive azobenzenes are used to regulate RAFT polymerization. With light switched alternatively off or on, azobenzenes of certain concentration result in RAFT polymerizations proceeding smoothly or being quenched.

CatalySED! An organocatalytic role for a benzimidazolium salt in radical chemistry is reported. A highly reducing intermediate (−1.86 V vs. SCE) is produced simply by treatment with NaBH₄ and then using air as initiator. This is the first time that an organic super electron donor has been used catalytically, which introduces a novel catalytic approach for the upconversion of reducing power.

Bondage partners: The first examples of compounds containing beryllium–aluminum bonds are prepared by additions of beryllium–halide bonds, in simple beryllium dihalide adducts, across the metal center of an aluminum(I) heterocycle (see picture, Dip=2,6-diisopropylphenyl). Computational studies reveal the covalent Be-Al bonds to be weakly polarized, and high in s-character.

A concise synthetic route to chiral aldehyde catalysts with Pd-catalyzed atroposelective C−H naphthylation as a key reaction is reported. These chiral aldehyde catalysts were successfully employed as ligands in the asymmetric activation of glycine esters enabling a higher level of asymmetric induction and reaction activity. A wide range of enantioenriched biaryls were prepared in synthetically useful yields with excellent enantioselectivities (up to >99 % ee).

Revealing tracks: GFP-targeting nanobodies were conjugated to single-walled carbon nanotubes (SWCNT), which show nonbleaching fluorescence in the near-infrared regime. The SWCNT–nanobody conjugates were then used for targeted sensing of dopamine and in vivo deep-tissue immunolabeling, as well as for tracking a motor protein in embryos of Drosophila melanogaster.

An activity-based, photo-crosslinking fluorescent probe is used to map the sub-mitochondrial distribution of mammalian nitroreductases. This probe is activated sequentially by nitroreductases and light to give a photo-crosslinked adduct of active enzymes. This probe can be combined with a mitochondria-specific marker for two-color, three-dimensional, single-molecule fluorescence microscopy.

Highly enantioselective catalytic protonation of bis-silyl ketene acetals delivers α-branched carboxylic acids, including nonsteroidal anti-inflammatory arylpropionic acids such as Ibuprofen, in high enantiomeric purity and high yields. The process can be incorporated in an overall deracemization of α-branched carboxylic acids, involving a double deprotonation and silylation followed by the catalytic asymmetric protonation.

Inversion: Two C−C bonds are formed between three conjugate acceptors by N-heterocyclic carbene (NHC) catalyzed polarity inversion of α,β-unsaturated ketones and esters. Inter- and intramolecular (5+1) annulations are possible, exploiting an unusual vinyl dianion synthon strategy. The reaction provides access to mono- and bicyclic cyclohexanones. Mechanistic studies and derivatizations are also reported. EWG=electron-withdrawing group.

In lithium–sulfur batteries, oxygen vacancies are usually considered beneficial in the catalytic conversion of polysulfides. The conversion of polysulfides is now shown to be hindered by oxygen vacancies on ultrathin niobic acid. The inferior performance induced by the oxygen vacancy was attributed to the decreased electric conductivity and the weakened adsorption of polysulfides on the catalyst surface.

A power conversion efficiency of 21.38 % with negligible hysteresis is obtained for planar-type perovskite solar cells. NH₄Cl-induced coagulated SnO₂ colloids were studied as the electron transport layer (ETL), and the ETL/perovskite interface is modified with a well-matched energy band alignment and suppressed defects.

A new arrow in the quiver: A highly chemo- and enantioselective hydrogenation of α-formyl enamides has been developed for the synthesis of chiral α-amido aldehydes in high yields (98–99 %), with excellent chemo- and enantioselectivities (up to >99.9 % ee), and with high substrate/catalyst ratios (up to 20000 S/C). Computations give a clear description of the R/S pathways of the catalytic cycle.

A promiscuous C-glycosyltransferase, TcCGT1, is highlighted. TcCGT1 represents the first flavone 8-C-glycosyltransferase that exhibits robust substrate promiscuity towards different types of flavonoids. The crystal structure of TcCGT1, the first crystal structure of a plant CGT, is shown. This work provides a basis for protein engineering to design efficient glycosylation biocatalysts for drug discovery.

Rb₃YSi₂O₇:Eu is used for phosphor-converted LEDs in solid-state lighting. It exhibits impressive properties, including an unprecedented blue-light-excited red emission in the oxide system. The results can initiate more exploration on how site-selective occupation design enables the discovery of blue-light-excited Eu²⁺-doped red-emitting oxide-based phosphors for white LEDs.

Ternary monodisperse CoPtAu nanoparticles are shown to be an efficient electro-oxidation catalyst to cleave the C−C bond of ethanol. It favors a complete oxidation to CO₂.

Novel pyrroloindoline alkaloids: Eight rare natural products were identified and their biosynthetic pathways were elucidated by heterologous expression of two gene clusters. Cytochrome P450s as key enzymes catalyze the regio- and stereospecific transfer of a guaninyl moiety to C3 of the indole ring in cyclo-l-Trp-l-Phe (Tyr). Non-enzymatic epimerization via keto–enol tautomerism further increases structural diversity.