With an iron hand: Iron is one of the very few metals that have been successfully used as highly effective base-metal catalysts in practical, kilogram-scale industrial cross-couplings. The Minireview provides an introduction to the fundamental aspects of practical iron catalysis, highlights areas for improvement, and identifies new fields to be explored.

Materials birth: Over the last decade, there has been considerable progress in the synthesis of functional inorganic materials by using the low-temperature molecular precursor approach. This Minireview presents recent advances where this approach has enabled a facile access to high-performance catalysts for water-splitting.

Spin doctoring: Considerable progress has been made in the past decade in the area of parahydrogen-based hyperpolarization techniques for biomedical applications. This Review provides a selective overview of these developments, covering the areas of spin physics, catalysis, instrumentation, preparation of the contrast agent, and applications.

Bicyclic enzymes: An approach that enables cyclization through the installation of modular crosslinks into native proteins composed entirely of proteinogenic amino acids is reported. Three surface-exposed cysteine residues are introduced, which are then reacted with a triselectrophile to generate a bicyclic enzyme with strongly increased stability towards thermal and chemical denaturation.

I heal: A zinc–iodine flow battery was prepared using highly soluble KI and ZnBr₂ as the redox reactants to avoid the precipitation of the catholyte and anolyte. Employing a low-cost porous polyolefin membrane can effectively eliminate the accumulation of zinc dendrites and the membrane can even heal itself after micro-short-circuiting as a result of overcharging.

Driving out contaminants: Hydrophobic reduced graphene oxides (rGOs) are introduced into agarose hydrogel beads to effectively remove various organic compounds from water through adsorption driven by the hydrophobic attraction. The removal efficiency of organic compounds noticeably depends on their solubility in water and considerably increases with salinity in aqueous media.

Leading light: An upconversion-based substrate was designed and constructed for photocontrolled multidirectional differentiation of mesenchymal stem cells (MSCs). The detachment of 4-(hydroxymethyl)-3-nitrobenzoic acid modified poly(ethylene glycol) moieties on the substrate can be adjusted by near-infrared (NIR) irradiation, which dynamically changes cell–matrix interactions and induces adipogenic or osteogenic differentiation of the MSCs.

It's under control: Post-translational modification is a common mechanism to control protein conformation and regulate function. This principle was expanded to control the formation of supramolecular assemblies by altering the conformational bias of self-assembling peptides through dephosphorylation.

A photoinduced catalytic asymmetric Giese-type reaction was developed that provides practical access to enantioenriched β-substituted γ-aminobutyric acid analogues, particularly previously inaccessible ones with fluorinated quaternary stereocenters.

Multiple functionalized graphene nanosheets accumulate in mitochondria after cellular uptake, disrupting mitochondrial function upon laser irradiation and resulting in more of the released Doxorubicin (DOX) being delivered into the nucleus. These multiple functionalized graphene sheets could overcome multidrug resistance and achieve effective synergistic tumor therapy. hPG=hyperbranched polyglycerol.

No Payne, no gain: A domino [3+2] cycloaddition/Payne-type rearrangement allows the synthesis of elusive heterocycles from carbon dioxide and epoxy alcohols. This attractive, metal-free, and operationally simple approach affords a wide range of highly substituted cyclic carbonates. The mechanistic manifold resembles that of the Payne rearrangement of epoxy alcohols, as shown by various control experiments.

Mechano-Click polymerization: Mechanochemical polymerization using piezochemically driven copper catalyzed azide–alkyne “Click” reaction has been shown here. Ultrasonic activation of piezoelectric nanoparticles was used to generate a Cu^I catalyst to promote click polymerization and polymer crosslinking. Sonochemical polymerization will provide us with the tools to design polymeric materials that grow or become stronger with mechanical activation.

High pressure is used to modify the optical and electrical properties of zero-dimensional halide perovskite. The pressure response of Cs₃Bi₂I₉ is significant under pressure along with phenomenal photoluminescence (PL) enhancement, band-gap narrowing, and metallization, promoting its photovoltaic applications by better materials-by-design.

Sensing on film: A facile strategy for fabricating a CNT-embedded isoporous film is introduced. A chemiresistive sensor based on the functional film was developed for efficient detection of humidity and volatile organic compounds.

Stepping out of line: Site-specific mutagenesis and kinetic analysis of the versatile rhizoxin polyketide synthase (PKS) branching module identified critical conserved residues and showed that the ketosynthase (KS) domain promotes both Michael addition and lactonization. Moreover, the branching module tolerates substrates with varying acyl chain lengths to form various medium-sized lactones (see scheme).

Synergistic properties: A defect-free core–shell molecular cocrystal was constructed. It combines good CO₂ adsorption capacity in the core with high CO₂/CH₄ selectivity from the surrounding shell, and tunable surface hydrophobicity.

Triple whammy: Triply fused porphyrin-nanographene conjugates (1 and 2) have been synthesized by the Scholl reaction using tailor-made porphyrin based precursors. The conjugates show broad and intense near-infrared absorption. The self-assembled bilayer of 2 was observed at the trichlorobenzene/highly oriented pyrolytic graphite (HOPG) interface.

Light and electricity: The photo-electrochemical C−H bond activation of cyclohexane to produce cyclohexanol and cyclohexanone (KA oil) with high partial oxidation selectivity (99 %) was achieved in air at room temperature and at atmospheric pressure. The production rate of KA oil was accelerated by applying a bias. The incident photon to current efficiencies at 365 and 420 nm were 57 % and 24 %, respectively.

Well healed: A new type of supramolecular polymer with water-enhanced healing was prepared from a self-assembled oligomer network with multivalent hydrogen bonds assisted crystallization and multiphase separation. Reversible dissociation/association of the multivalent hydrogen bonds in the presence of water provides the mechanism of water-enhanced healing.

The water oxidation rate is enhanced by two orders of magnitude by preorganising Ru(bda)(PySO₃TBA)₂ catalysts to nanospheres, effectively eliminating diffusion limitations for the O−O coupling step at very low overall catalyst concentration. This preorganization strategy also provides new ways to study the reaction mechanism by varying the local catalyst concentration, while leaving the overall concentrations the same.

Silver core: Two Ag₆@Ti₁₆-oxo nanoclusters with atomic core–shell structures show optical limiting effects towards 532 nm laser. The differences between the two clusters lie in the orientation of the Ag₆ cluster inside the semiconductive Ti−O shell. This orientation influences the optical properties of the nanoclusters.

Shell seekers: Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) was used to probe the electronic structures and reveal the catalytic mechanisms on Pd/Pt-overlayer-coated Au single crystals. This work opens up a novel way to detect the electronic structures of heterogeneous metal interfaces and understand catalytic mechanisms at the molecular level.

One stop shop: Isolated cobalt single-atom sites stabilized on an ordered porous nitrogen-doped carbon matrix are highly efficient catalysts for acceptorless dehydrogenation of N-heterocycles to release H₂, and the reverse transfer hydrogenation (or hydrogenation) of N-heterocycles with a hydrogen source to store H₂.

A CuO nanowire array was synthesized by a simple thermal oxidation method. A low-cost, high-stability AC inorganic powder electroluminescent device was achieved by taking advantage of the heterogeneous junction structure of the CuO nanowire array/Zn₂GeO₄:Mn phosphor powder.

[Ag₄₆S₇(SPhMe₂)₂₄]NO₃, a thiolated silver nanocluster, was synthesized and structurally resolved by X-ray analysis. Interstitial sulfur was found in the lattice void of Ag₄₆ without lattice distortion or expansion; the classic theory of interstitial metal solid solutions might thus be not applicable at the quantum scale. Unprecedented chemical bonds and asymmetrically coordinated μ₄-S were found and might be related to the interstitial sulfur.

Rapid performance: The first fully automated continuous-flow platform for fluorescence quenching studies and Stern–Volmer analysis is described. Equipped with user-friendly software, the platform offers to any user the possibility to rapidly perform (<1 hour) these insightful analyses, thus accelerating reaction discovery. Compared to batch methods, an increase in the accuracy and reproducibility of the measured data was observed.

Highway to L: A new method of preparing nanosized zeolite L crystals from silicates composed of highly interdispersed potassium ions reveals that a uniform distribution of inorganic structure-directing agents can alter the pathway of zeolite crystallization and dramatically reduce synthesis time.

Interface geometry: Variations in the activity of Au/Fe₂O₃ catalysts for the CO oxidation, when increasing the size of the gold particles in the range of 2–5 nm, is intimately associated with the geometrical structure of the interfacial perimeter Au atoms. In smaller gold particles, the perimeter gold atoms have a low-coordinated environment and thus show a much higher intrinsic activity.

In U go: Supramolecular nanocapsule 1⋅(BArF)₈ is able to sequentially and selectively entrap the endohedral metallofullerenes U₂@C₈₀ and Sc₂CU@C₈₀, simply by soaking crystals of 1⋅(BArF)₈ in a toluene solution of arc-produced soot. The endohedral metallofullerenes are easily released, giving highly pure fractions of U₂@C₈₀ and Sc₂CU@C₈₀ in one step.

Guiding light: Through a bottom-up process, 2D halogen-bonded DPEpe-F₄DIB cocrystals were fabricated that act as an asymmetric optical waveguide with the optical-loss coefficients of R_Backward=0.0346 dB μm⁻¹ and R_Forward=0.0894 dB μm⁻¹ along the [010] crystal direction. This is further demonstrated in a microscale optical logic gate with multiple input/out channels.

A powerful tool for the generation of complex molecules is the copper catalyzed multi-functionalization of unsaturated carbon-carbon bonds. A regiodivergent process that allows a switch between 1,4- and 4,1-borocupration of 1,3-dienes upon a simple change in ligand is described.

Supra-bowls: A π-bowl is ready to experience the outside world as it peers into the window of potential that could exist with its immobilization inside the scaffold. Corannulene integration resulted in the first examples of purely organic crystalline porous materials with tunable electronic profiles and four-orders-of-magnitude conductivity enhancement in comparison with the parent framework.

Strong enhancement of the multi-resonance effect in thermally activated delayed fluorescence species by a peripheral carbazole unit substitution was applied for a material with a photoluminescent quantum yield of up to 97.48 %. The maximum luminance exceeded 16 000 cd m⁻² and the highest external quantum efficiency was up to 32.1 %.

Three in one shot: Functionalized tribenzotriquinacenes (TBTQs), in particular those with C₃ symmetry, are useful molecular building blocks. Electrophilic aromatic substitution of the parent TBTQ produces predominantly the C₁ isomer (3:1 statistical C₁/C₃ ratio); however, the C₃ isomer was obtained as the main product (C₃/C₁ 2.6:1) by the triple borylation of TBTQ and shown to be a versatile precursor to other C₃-symmetric TBTQs (see scheme).

Movers and shakers: The mechanism of molecular movement in elastically flexible crystals of bis(acetylacetonato)copper(II) upon bending and temperature variation have been investigated and compared. Marked differences in molecular movement are observed.

Fully inorganic, perovskite-derived zero-dimensional Cs₄SnBr₆ exhibits room-temperature broad-band photoluminescence from self-trapped excitons, centered at 540 nm with a quantum yield of 15±5 % (298 K; near 100 % at 200 K), and a large Stokes shift of ca.1.2 eV. A compositional series, Cs_4−xA_xSn(Br_1−yI_y)₆ (A=Rb, K; x≤1, y≤1), was obtained wherein the emission peak ranges from 500 nm to 620 nm.

Captive, but free: An encapsulation system based on the hepatitis B virus capsid is described, in which an engineered high-affinity interaction between cargo and capsid proteins can be modulated by Ca²⁺. Cargo proteins are loaded into capsids in the presence of Ca²⁺, while ligand removal triggers unbinding inside the container.

Complement the synthetic toolkit: A form-independent activation of zinc, concomitant generation of organozinc species, and engagement in a Negishi cross-coupling reaction via mechanochemical methods is reported. The reported method exhibits a broad substrate scope for both C(sp³)–C(sp²) and C(sp²)–C(sp²) couplings.

In the nick of time: Ultrafast oxidation kinetics of nickel nanoparticles was revealed by millisecond in situ electron diffraction at ambient pressure in a transmission electron microscope.

Hydrogel growing from a surface: A pH-responsive dendritic benzene-1,3,5-tricarboxamide peptide conjugate self-assembles into 1D supramolecular polymers at pH<5.6. The system was kinetically and mechanistically studied and modeled, and hydrogels were grown from solid–liquid interfaces driven by proton diffusion.

A soft touch: A versatile, direct, metal-catalyzed reductive functionalization reaction of secondary amides, to give functionalized amines and heterocycles, was developed. A broad substrate scope for both the amide and nucleophile was observed. Viable nucleophiles include reactive and soft C nucleophiles as well as a P nucleophile. The reaction exhibits good chemoselectivity and tolerates several sensitive functional groups (FGs).

Finding a needle in a haystack: Novel selective substrates for high-throughput screening allowed the identification of rare, unconventional glycosidases from metagenomic DNA amongst a myriad of similar enzymes. Traditional substrates face a high back ground activity from these similar enzymes, which can mask the desired hits and/or lead to false positive hits.

Shifty hydride: An unprecedented gold(I)-catalyzed tandem cycloisomerization of 1,5-enynes, initiated by 1,6-hydride transfer, was explored for the ready assembly of tricyclic skeletons. The reaction proceeds with the formation of two new carbon–carbon bonds and three rings by a single chemical operation in a stereospecific manner.

Shifting gears: Disclosed herein is efficient access to widely invoked cationic Cp*Co^III cobaltacycles, in C−H activation, by combining the stabilizing effect of MeCN with the presence of HFIP as an accelerating additive. This perfluorinated alcohol also exhibits a positive impact on mechanistically divergent alkyne hydroarylation and oxidative annulation processes under catalytic conditions.

The direct enantioselective synthesis of chiral azaheteroaryl ethylamines from vinyl-substituted N-heterocycles and anilines is reported. A chiral phosphoric acid catalyst promotes dearomatizing aza-Michael addition to generate a prochiral exocyclic aryl enamine, which undergoes asymmetric protonation upon rearomatization, giving the products in high selectivity.

A self-digitization dielectrophoretic (SD-DEP) chip was designed by employing the traditional DEP and insulator DEP to create the local electric field for single-cell manipulation and downstream nucleic acid analysis. The multistep procedures of cell manipulation, lysis, and chemical analysis were performed in the integrated microdevice, consuming minimal reagents, minimizing contamination, and increasing assay sensitivity.

A size-reducible nanodrug with an enhanced photodynamic effect is constructed by self-assembly of a multifunctional indocyanine dye. Owing to the aggregation-enhanced photodynamic effect of the dye, the nanodrug exhibits a distinct singlet oxygen quantum yield. The generated singlet oxygen self-triggers the size reduction of the nanodrug, which facilitates deep tumor penetration of the nanodrug and accelerates chemodrug CPT release.

In a flash: Rapid (0.1 s) and mild (20 °C) synthesis of N-carboxy anhydrides (NCAs) using basic-to-acidic flash switching and subsequent flash dilution was demonstrated. This process enabled the synthesis of acid-labile NCAs, which are impossible to access using conventional batch conditions. The developed process requires simple phase separations and recrystallization to yield pure NCAs. This microflow approach could pave the way to on-demand, on-site NCA synthesis.

One giant leap: Reported here is the single-step construction of an anti-configured deoxypropionate motif by syndiospecific propylene oligomerization. This strategy was applied to the single-step preparation of rel-(2R,4S,6R,8S)-2,4,6,8-tetramethylundecan-1-ol, the racemic mixture of the synthetic fragment of the cuticular hydrocarbons isolated from the cane beetle Antitrogus parvulus.

Captured! An electronically neutral 2-arylsilacyclobutane generates a nucleophilic carbanion at room temperature through cleavage of the benzylic C−Si bond when simply dissolved in a polar aprotic solvents such as N,N-dimethylformamide (DMF). The nucleophilic species is capable of capturing carbon dioxide to furnish a silalactone. The carboxylation reaction is unique in that no additional activating agents are required.

Spontaneous phospholipid vesicle generation and extension in a dipeptide/phospholipid system is demonstrated. Dissolution of the dipeptide crystal provides both the driving force and phospholipid constituents for vesicle generation and extension.

A Zn-ProPhenol catalyzed asymmetric Mannich reaction between butenolides and polyfluorinated alkynyl ketimines generates vinylogous products featuring two contiguous tetrasubstituted stereogenic centers. This is the first successful use of ketimines in the ProPhenol Mannich process, and the reaction can be performed on large scale with reduced catalyst loading.

Iron clad: An alkoxyl radical guided strategy for site-selective functionalization of unactivated methylene and methine C−H bonds, enabled by an Fe^II-catalyzed redox process, is described. The mild, expeditious, and modular protocol allows efficient remote aliphatic fluorination, chlorination, amination, and alkynylation of structurally and electronically varied primary, secondary, and tertiary hydroperoxides with excellent functional-group tolerance.

What a relief: The carbon–carbon bond activation of [n]cycloparaphenylenes ([n]CPPs) by a transition-metal complex is herein reported. The Pt⁰ complex Pt(PPh₃)₄ regioselectively cleaves two C−C σ bonds of [5]CPP and [6]CPP to give cyclic dinuclear platinum complexes in high yields. Theoretical calculations reveal that the relief of ring strain drives the reaction. The cyclic complex was further transformed into a cyclic diketone by a CO insertion reaction.

Synthesis of uncommon bifunctional allylic derivatives bearing a silane and an alcohol within the same allylic system is reported. The method relies on the use of hydrosilanes and adequately functionalized cyclopropenes, which deliver the allyl fragment via regioselective generation of a Rh^II vinyl carbene intermediate. The method shows a remarkably broad scope, including an intramolecular version for the synthesis of cyclic siloxanes or extension to allylic amines.

A pinch of salt: A metal-free N-arylation of primary and secondary amines with diaryliodonium salts has been developed. The methodology is unprecedented for metal-free reactions in terms of amine scope and the ability to transfer both electron-withdrawing and electron-donating aryl groups, and it tolerates steric bulk well.

The marine natural products keramamide A and L were synthesized for the first time by a convergent and flexible route. The installation of the substituted tryptophan moieties was accomplished at the very end of the synthesis on the cyclic peptides, and thus enabled the synthesis of both natural products from one common precursor.

Cobalt-catalyzed alkenylations: A range of functionalized aryl and alkenyl zinc pivalates underwent cobalt-catalyzed alkenylations with alkenyl acetates in good yields under remarkably mild reaction conditions at 23 °C. The efficient catalytic system tolerated various functional groups and enabled excellent stereoselectivities (Z/E<1:99).

Boron with torque! A chiral variant of tris(pentafluorophenyl)borane [B(C₆F₅)₃] promotes Lewis acid catalyzed Nazarov cyclizations of activated precursors with high enantiomeric excesses. The diastereoselectivity is also good, usually favoring the cis isomer in synthetically useful ratios. B(C₆F₅)₃ catalyzes the ring closure of the same set of substrates in racemic fashion.

Stressed out: A new mechanophore, ferrocene, was embedded in polyurethane and poly(methyl acrylate). When these polymers are subjected to mechanical stress in solution (sonication), the chains break at the ferrocene units and iron ions are released into solution. The controlled release of iron ions from ferrocene is of interest for analytical and medical applications as well as for the catalysis of organic reactions.

A jack of all trades: The new structure type M₅B₁₂O₂₅(OH) is formed under extreme conditions of around 12 GPa and 1450 °C with either In³⁺ or Ga³⁺ as the metal ion M. It not only features an interesting structure with cuboctahedral BO₄-tetrahedra cages and distorted metal-atom-centered octahedra, but shows also luminescence when doped with Eu³⁺ and unexpected high photocatalytic activity for hydrogen production when irradiated with UV light (when M=In).

The boron rarity: boron(II) cations are rare and their chemistry largely unknown. Starting from a diborane with two easily exchangeable triflate substituents several new boron(II) cations are readily synthesized. For the first time the combined Lewis acidic and electron-donor properties of boron(II) cations could be used for the reduction of organic molecules

Adding value through electrocatalysis: The electrocatalytic oxidation of the biorefinery product 5-(hydroxymethyl)furfural (HMF) to the prospective platform chemical 2,5-furandicarboxylic acid (FDCA) over nickel boride (Ni_xB) modified nickel foam in an electrochemical flow reactor proceeds with a very high FDCA yield of 98.5 % at a faradaic efficiency of 100 %. Ni_xB appears to be a very promising catalyst for electrochemical HMF oxidation.

Reading the fine print: Patterned monolayers of N-heterocyclic carbenes (NHCs) on gold surfaces were obtained by microcontact printing of NHC–CO₂ adducts and NHC(H)[HCO₃] salts. The protocol enables facile access to versatile NHC-modified gold surfaces with highly stable patterns, enhanced conductivity, and the option for further modification.