Die Merkmale zweier ikonischer Stoffklassen vereinen sich in der Struktur des hochkomplexen Diterpens Canataxpropellan und bilden eine beträchtliche Herausforderung, welche von Gaich und Mitarbeitern gemeistert wurde. Ihre wagemutige Strategie und der resultierende Nutzen für das Gebiet der Terpenchemie werden in diesem Highlight vorgestellt.

Tip of the volcano: Electrode materials are classically assessed by their location on a volcano curve, using the binding strength of a reaction intermediate (RI) as a descriptor. For a two-electron process, the apex of the volcano corresponds to thermoneutral binding of the reaction intermediate at zero overpotential. This Viewpoint addresses the definition of an optimum catalyst when kinetic effects and applied overpotential are factored in, illustrating a right shift of the volcano's top with increasing driving force.

Chirale NHC-Liganden sind in der enantioselektiven Übergangsmetallkatalyse allgegenwärtig, in der metallkatalysierten asymmetrischen C-H-Funktionalisierung ist ihre Verwendung aber noch in einem frühen Stadium. Dieser Kurzaufsatz beleuchtet die Entwicklungen und Fortschritte in diesem sich rasch entwickelnden Forschungsbereich.

Up and up: This Minireview summarizes recent developments in the switching of triplet–triplet-annihilation-based photon upconversion (TTA-UC) by various external stimuli. The stimuli-responsive TTA-UC systems are categorized into four types based on their switching mechanisms. TTA-UC has the potential to achieve biosensing and chemosensing with unprecedented sensitivity and selectivity.

Durch Kombination zweier energiearmer Photonen können thermodynamisch anspruchsvolle Reaktionen angetrieben werden. Das Zusammenspiel von empirischen Fortschritten und mechanistischen Einblicken aus der Spektroskopie machte Multiphotonen-Anregungsprozesse zugänglich für die präparative Photoredoxchemie. Ein Blick auf entwickelte Konzepte und Reaktionen identifiziert Herausforderungen, Sackgassen und zukünftige Möglichkeiten für diesen Forschungszweig.

Stack it up: A novel type of π-stacked polymer was synthesized via cyclo-copolymerization of an o-allenylaryl isocyanide. In the poly(quinolylene-2,3-methylene) bearing alanine derivatives as the side chain, the quinoline backbone forms a layered structure with π–π interactions stabilized by intramolecular hydrogen bonds. The structure was established based on spectroscopy and calculations, and confirmed by AFM measurements.

Breaking through: Tob and QSI (1) co-loaded squalenyl hydrogen sulfate nanoparticles (SqNPs) are shown to act on all stages of P. aeruginosa infections to eradicate bacterial infection [(a–c) and (e)] and penetrate biofilm, preventing its formation and recurrence (d).

A proof of concept is presented for the application of deep learning, an artificial intelligence technique, for high-quality, reliable, and very fast NMR spectra reconstruction from limited experimental data.

A reaction–diffusion process involving metal–organic framework (MOF) or metal–organic polyhedra (MOP) components as well as a crystal-growth modulator yields periodic bands containing microcrystals that have different shapes and also evolve in time into unusual (e.g., concave) shapes.

Zwei Übergangsmetallkomplexe mit Fluorid- und Cyanidoliganden, trans-[M^IVF₄(CN)₂]²⁻ (M=Re, Os), wurden durch siliziumvermittelte Fluoridabstraktion hergestellt. Hochfeld-EPR-Spektroskopie und Magnetisierungsdaten belegen eine erhöhte magnetische Anisotropie des Re^IV-Komplexes im Vergleich zum [ReF₆]²⁻-Vorläufer.

Chiral Allenes: 1,4-Addition of the migrating group and electrophile across an enyne-derived boronate complex occurs during the course of Pd-catalyzed conjunctive cross-coupling. This process generates chiral allenyl boronic esters with control of both axial and central chirality.

CO fragmentation: Mild visible-light-induced Pd-catalyzed intramolecular C−H arylation of amides is reported. The method features cleavage of C(sp²)−O bonds, leading to hybrid aryl Pd-radical intermediates. The following 1,5-hydrogen atom translocation, intramolecular cyclization, and rearomatization steps lead to valuable N-containing heterocyclic cores. Notably, this method provides access to products with readily enolizable functional groups that are incompatible with traditional Pd-catalyzed conditions. T=Tether.

A one-step high-pressure synthetic route is used to complex metal–inorganicframeworks built of transition metals(Hf, Os, and W) that are connected via polymeric nitrogen linkers. The pores are filled with ordered one-dimensional arrays of nitrogen molecules. Owing to the conjugated π-systems, these inorganic polymers are conductive materials.

Peripheral vision: A small-molecule fluorescent probe with aggregation-induced emission was developed for chromosome periphery imaging, which facilitates the segmentation of touching or overlapping chromosome clusters, identification of the centromere, and visualization of chromosome morphology. Its compatibility with FISH assays makes it a practical cytogenetic tool in assisting the precise location of a gene in designated chromosomes.

A chemical methodology finally addresses the undefeated challenge of modular and precision engineering of a Lys residue in a native protein. The remarkable control over selectivity provides the first-ever approach to target Lys beyond the protein-defined reactivity hotspot. This technology unfolds new gateways and renders analytically pure protein bioconjugates and homogeneous antibody-drug conjugates.

Ahead warp factor one: The force photogenerated by the phase-dependent transient elastic lattice deformation can actuate molecular crystals to move at a high speed.

Spillover of hydrogen species at Pt-TiO₂-Au interfaces has been investigated in situ using SERS with nanoscale spatial resolution through the precise fabrication of Au/TiO₂/Pt sandwich nanostructures. The fundamental mechanism of hydrogen spillover and its influence on selective hydrogenation are revealed.

Platinum is king! A responsive-at-metal Pt^II emitter undergoes controlled supramolecular and redox transformations. Pt^II selectively oxidizes into Pt^III or Pt^IV, thus diversifying the structural and photophysical properties of the system. Delicate modulation of Pt⋅⋅⋅Pt interactions by solvent molecules results in strong solvatochromism for the Pt^II complex.

Single-crystal nanowires (NWs) of the Al³⁺ dicarboxylate MIL-69(Al) MOF were synthesized by using graphene oxide nanoscrolls as structure-directing agents. The interplay between multimodal characterization techniques and molecular modeling unravels their mechanism of formation involving size-confinement and specific interactions.

Put it there! CYP505E3, a self-sufficient cytochrome P450 monooxygenase from the fungus Aspergillus terreus, catalyzes the regioselective in-chain hydroxylation of alkanes, fatty alcohols, and fatty acids at the ω-7 position. It can thus be used for the biocatalytic production of δ-dodecalactone from dodecanoic acid and1-dodecanol.

The charge of the light brigade: By a sequence of absorption and photo-induced electron-transfer processes electron-poor perylene bisimides (cp-BPI) are transformed into their electron-richdianions which upon another photoexcitation exhibit sufficient reductive power to drive hydrogen evolution at Pt/TiO₂ nanoparticles.

Brand-new combined harvesters: An organic–inorganic hybrid salt of phosphonium cations and Ni^II isothiocyanate ions was synthesized. It exhibits ferroelectric behavior and efficient mechanical energy harvesting and storage capabilities.

No cofactor needed! An uncommon cofactor-independent peroxygenase was engineered based on a promiscuous tautomerase that uses different hydroperoxides (t-BuOOH and H₂O₂) to achieve enantiocomplementary epoxidations of various α,β-unsaturated aldehydes, giving access to both enantiomers of the corresponding α,β-epoxy-aldehydes with high enantiopurity (up to 98 % ee).

Magnetic chain: A novel [Mo(CN)₇]⁴⁻ based single-chain magnet with a high relaxation barrier of 178(4) K is reported. The compound exhibits open magnetic hysteresis loops below 5.2 K, with a large coercive field of 1.5 T at 2 K. These exceptional properties are attributed to the strong anisotropic Mo^III–Mn^II exchange coupling.

PEO-b-PE block copolymers were formed by reversible addition–fragmentation chain transfer (RAFT) of ethylene. The ethylene polymerization-induced self-assembly (PISA) of the resulting block copolymers was achieved and morphologies including spheres, worms, and 2D platelets were obtained.

Silberpfeil: Eine durch Silber ausgelöste, heterogene, Pd-katalysierte oxidative Carbonylierung von Allenamiden ermöglicht den Aufbau von Pyrrolidonen und polycyclischen Verbindungen mit mehreren Stereozentren. Der Katalysator (Pd-AmP-CNC) kann mindestens 9-mal ohne Aktivitätsverlust verwendet werden. Das Ag-Salz entfernt Cl von Pd-AmP-CNC und erzeugt dabei hoch aktives Pd^II, was zu der hohen Effizienz führt.

Gold-catalyzed [4+3]-annulations of 2-(1-alkynyl)-2-alken-1-ones with anthranils to yield epoxybezoazepine products with excellent exo-diastereoselectivity (dr>25:1) are reported. More importantly, enantioselective versions of these [4+3]-cycloadditions have been developed with chiral gold catalysts under ambient conditions (DCM, 0 °C), with ee levels of 88.0–99.9 %, further highlighting their synthetic values.

The DNAzyme is in control: An RNA-cleaving DNAzyme (EC1) is used to control three DNA assembly reactions, resulting in an all-DNA system with the capability of ligand recognition, signal amplification, and signal reporting.

Topologically controlled ligands with a family of tetrahedral DNA frameworks (TDFs) were generated through the formation of 0-simplex to 3-simplex, and to simplicial complex. The multiple ligands are stoichiometrically and topologically arranged to allow the tuning of the binding strength between ligands and receptors as validated with cell sorting.

An NMR spectroscopy method has been developed to monitor site-specific phosphorylation at high pH and temperature, both of which are necessary for kinase activity but have previously prevented the thorough characterization of disordered proteins. This approach uses sensitivity-enhanced ¹³Cα-¹³CO experiments and is demonstrated using Mdm2, BRCA2, and Oct4. Using this approach, many more phosphorylation cases can now beinvestigated using NMR spectroscopy.

A nanopipette tip decorated with a Pt deposit is used as an open bipolar electrochemiluminescence device to achieve intracellular wireless electroanalysis. The porous structure of Pt deposit permits electrochemical transport of intracellular molecules into the nanopipette. Intracellular concentrations of H₂O₂ or glucose are measured in vivo as well as the intracellular sphingomyelinase activity.

Good things come in threes: An unprecedented dehydrogenative C−C cross-coupling with inexpensive bulk ethylene glycol and methanol has been developed by using a novel iridium catalyst bearing three N-heterocyclic carbenes (NHCs). This procedure represents a highly selective and atom-economic approach for the synthesis of lactic acid (TOF up to 3660 h⁻¹). TOF=turnover frequency; TON=turnover number.

Mapping the brain: In this work, an electrochemophysiological microarray was created for real-time mapping and simultaneous quantification of chemical signals for K⁺, Ca²⁺, Na⁺, and pH in the live brain of a freely moving rat, combined with recording the electrical signals using electrophysiology. This powerful tool could open a new vista in fundamental research on brains.

A fair COP: A covalent organic polymer is prepared by crosslinking the photosensitizer 4,4′,4′′,4′′′-(porphyrin-5,10,15,20-tetrayl)tetraaniline (TAPP) with 4,4′- (anthracene-9,10-diyl)dibenzoic acid (ADDA). Simultaneous generation of singlet oxygen by two mechanisms is achieved, which is promising in treating hypoxic tumors.

We built this CT: By studying the mesitylene–I₂ charge transfer (CT) complex, it is shown that vibrational strong coupling induces large changes in the equilibrium constant K_DA of the CT complex, which can be either enhanced or suppressed depending only on the symmetry of the vibration coupled to the vacuum electromagnetic field.

Send reinforcements: Binding affinities between foldamer-based receptors and anions are greatly reinforced by π-stacking within the receptors. The association constant increases by more than three orders of magnitude when N(CH₃)₂ is replaced with NO₂, despite both complexes forming five identical hydrogen bonds.

Electroactive MOFs: An electroactive metal–organic framework was designed as an electrochemiluminescence (ECL) emitter. It demonstrated a surface state mechanism in both co-reactant and annihilation ECL in aqueous medium. The self-enhanced cathodic ECL emission was realized via the accumulation of cation radicals.

The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu-catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of β-boryl ketones has been developed. A broad range of β-boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity.

It′s logical: A cellular AND gate ensures the specific uptake of a polymeric nanoassembly only when two proteins (alkaline phosphatase, ALP, and carbonic anhydrase, CA XI) are present on the cell surface. ALP removes a protecting group from the nanoassembly, exposing the ligand of CA XI, enabling uptake. These proteins can be present on the surface of the same cell (a unicellular AND gate) or on the surfaces of different cells (a bicellular AND gate).

Modified red blood cell membrane is used to fabricate a cell-like nanoparticle for safe and effective inhibition of phospholipase A2 (PLA2) based on a „lure and kill“ working mechanism. The resulting nanoparticle can attract the PLA2 enzyme and subsequently inhibit its bioactivity. As a result, the nanoparticle can effectively inhibit PLA2-induced hemolysis and protect animals from PLA2-induced lethality.

P-P-Pick up a proton: Inhibitor protonation inside human acid β-glucosidase or glucocerebrosidase (GCase), the enzyme involved in Gauchers disease, was directly observed using fluorescence. The results show that that derivatives of the inhibitors 1-deoxynojirimycin and isofagomine are protonated by GCase when bound, even if they are completely unprotonated outside the enzyme.

An Ir-catalyzed C(sp³)−H alkynylation of aliphatic ketones, aldehydes, and alcohols was achieved by using the corresponding oxime derivatives and a Ir^III catalyst. This general reaction is selective towards primary C(sp³)−H bonds and can be used for the late-stage C−H alkynylation of complex molecules.

Iridium(III) catalysts that bear an amide-pendant cyclopentadienyl ligand ([Cp^AIrI₂]₂) were synthesized and characterized. Double aromatic homologation reactions of benzamides with alkynes by fourfold C−H activation proceeded in good to high yields when these [Cp^AIrI₂]₂ catalysts were used, demonstrating their superior catalytic performance in this challenging transformation.

Two on the same path: On Rh surfaces, the electrochemical reductions of nitrogen and nitrate share the same reaction intermediate N₂H_x (0≤x≤2) in alkaline electrolytes. The intermediate was detected by both surface-enhanced infrared-absorption spectroscopy (SEIRAS) and differential electrochemical mass spectrometry (DEMS). Possible reaction pathways are also proposed.

HAT-trick: Flavin-dependent ‘ene'-reductases can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. The reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to a neutral benzylic radical in solution. Calculations reveal this radical to be „dynamically stable“ and therefore sufficiently long-lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer (HAT).

A polyaromatic cavity: The exclusive binding of a monounsaturated fatty acid from a mixture with the corresponding saturated substrate was demonstrated by an artificial polyaromatic receptor in water. Competitive binding experiments revealed higher binding affinity of the receptor for oligo- and polyunsaturated fatty acids (see picture). Within the receptor, the biosubstrates were stabilized against air, light, and heat owing to the polyaromatic shielding effect.

Combined harvester: Supramolecular co-assembly of lower-rim dodecyl-modified sulfonatocalix[4]arene (SC4AD) and naphthyl-1,8-diphenyl pyridinium derivative (NPS) gives a light-harvesting platform showing significant aggregation induced emission enhancement (AIEE). By using these near-infrared (NIR) emissive nanoparticles imaging in the Golgi apparatus is possible.

Getting rid of O₂ cylinders: Dry ambient air is utilized for a K-air (dry) battery, which sheds light on the reversible potassium superoxide electrochemistry. This motivates the development of high-efficiency superoxide battery technology and is an important step towards the direct use of air in metal–air batteries.

Single atoms of rhodium are confined in MoS₂, leading to an ultra-high HER activity. By optimizing the distance between the confined Rh atoms, a low overpotential of only 67 mV is achieved at a current density of 10 mA cm⁻², which surpasses the activity of most reported MoS₂-based catalysts in acidic solution.

Flexible Cyanide. Sperrige Kationen und schnelle Kristallisation ermöglichten die Isolierung und strukturelle Charakterisierung von den HCN-Cyanid-Aggregat-Vertretern [CN(HCN)₂)]⁻ und [CN(HCN)₃)]⁻ als Festkörper.

Ein komplexes Zusammenwirken: Eine umfangreiche Studie verbindet fortgeschrittene Spektroskopie und Theorie und zeigt das Auftreten elektronischer und sterischer Effekte bei reduzierten einzelnen Cu⁺/Cu²⁺ Dimeren in defektmanipulierten HKUST-1-SURMOFs zur Erzielung einer hohen katalytischen Aktivität für die Tieftemperatur-CO-Oxidation. Es wird ein neuer Reaktionsmechanismus mit einer ungeladenen O₂-Spezies als wichtigstem Zwischenprodukt vorgestellt.

Gib Acht! Alle acht Cyanid-Liganden der Octacyanometallate Mo(CN)₈⁴⁻ und W(CN)₈⁴⁻ werden unter supersauren Bedingungen protoniert, ohne dass Blausäure (HCN) gebildet wird. Stattdessen bilden sich homoleptische Komplexe von Mo⁴⁺ und W⁴⁺ mit acht Isoblausäure-Liganden, welche vollständig charakterisiert werden konnten.

Endlich mal was Positives. Ein Silyliumion ist schon alleine schwer handhabbar, aber was, wenn zwei dieser Superelektrophile in einem Molekül nah beieinander sind? In Abhängigkeit vom Abstand zwischen diesen Lewis-sauren Zentren wird eine solche, vormals kaum zu fassende zweizähnige Lewis-Säure greifbar, charakterisierbar und bei Raumtemperatur lagerfähig.

Electrochemical reduction of CO₂ to acetic acid is achieved with a molecular Mn^III-corrole complex. Electroreduction of Mn^III leads to the electroactive Mn^II species, which binds CO₂ and stabilizes the reduced intermediates to allow the reduction of CO₂ to acetic acid in a moderately acidic aqueous medium (pH 6) with a selectivity of 63 % and a turn over frequency of 8.25 h⁻¹, when immobilized on a carbon paper (CP) electrode.

Dropping into place: A droplet self-splitting strategy was developed to divide a droplet into microdroplets and deposit them in a well-defined array. Matter exchange between the generated microdroplets was fully prohibited in the self-splitting process, thus enabling simultaneous arrayed reactions (see picture) and the detection of multiple analytes using only one droplet of sample.

A dual function asymmetric catalysis by a chiral phosphoric acid catalyst that controls both enantioselective addition of an achiral α-vinyl allylboronate to aldehydes and pseudo-axial orientation of the α-vinyl group in the transition state is developed.

Combating MRSA: The kalimantacin antibiotics mimic the conformation of the natural fatty acyl substrate to inhibit the activity of the essential enoyl-ACP reductase enzyme FabI in Staphylococcus aureus. The findings of this study provide insights into the mode of action of this novel class of FabI inhibitors.

Cyclopropenium-based liquid crystals form lamellar or columnar mesophases, depending on the substitution of head group and the number of peripheral chains. The effective volume of headgroup versus hydrophobic part determines the mesophase type. These compounds bridge the gap between low molecular weight organocatalysts and polymeric electrolytes based on cyclopropenium.

Bridged stilbene: Based on theoretical prediction of non-radiative decay, a family of aggregation-induced emission (AIE) luminogens is reported. Depending on the alkyl chain length, they exhibit different quantum yields. BPST[7] and DPB[7] with excellent AIE behavior are reported.

Pd-Ni-Pt in the mix: A method for studying the intermixing process in a shaped nanoparticle was devised. It uses multilayered Pd-Ni-Pt core–shell nanocubes as precursors. Under mild conditions, the intermixing between Ni and Pt could be tuned by changing layer thickness and number, triggering intermixing while preserving nanoparticle shape.

Rare examples of low-oxidation-state molybdenum- and tungsten–oxo compounds (d³) have been prepared. They are found to possess long M−O bonds, owing to the oxo-radical character of their electronic structures. The stability of these compounds is strongly modulated via the steric bulk of the equatorial ligands, providing a design motif for controlling oxo-centered reactivity.

Real-time studies of the crystalline-to-vitreous conversion rate of a SiO₂ bilayer supported on Ru(0001) reveal an apparent activation energy of 4.2 eV for the process. DFT simulations suggest the formation of a Stone–Wales-type of defect as the starting point for the transformation.

Magnesium is selectively doped onto both tetrahedral (8a) and octahedral (16c) sites in Fd m LiNi_0.5Mn_1.5O₄. The Mg stabilizes the structure against structural deformation and suppresses unfavorable two-phase reactions during cycling process, thus contributing to an excellent extended-long-term electrochemical performance.

The good side: The preparation and spectroscopic identification of the complexes NNBe(η²-N₂) and (NN)₂Be(η²-N₂) and the energetically higher lying isomers Be(NN)₂ and Be(NN)₃ are reported. NNBe(η²-N₂) and (NN)₂Be(η²-N₂) are the first examples of covalently side-on bonded N₂ adducts of a main-group element. The analysis of the electronic structure using modern methods of quantum chemistry suggests that NNBe(η²-N₂) and (NN)₂Be(η²-N₂) should be classified as π complexes rather than metalladiazirines.

High-coercivity one-dimensional magnets: Novel cobalt(II)-nitronyl nitroxide radical chains featuring crystallographically determined alternating magnetic sublattices exhibit exceptional magnetic hardness and coercive fields up to 65 kOe.

A novel hydrovoltaic device for efficiently utilizing water flow in silicon nanowire arrays to generate constant electricity depending on natural water evaporation is demonstrated. Through changing ion concentration in water, as well as the length and surface charge of SiNWs, it was discovered that the mechanism of electricity generation is mainly ascribed to streaming potential.

A broadly applicable electrophotocatalytic method for the direct decarboxylative C−H alkylation and carbamoylation of heteroarenes has been developed. This method combines the advantages of photocatalysis and electrochemistry to enable the functionalization of a broad range of substrates and to allow the decarboxylative C−H functionalization reactions to proceed by H₂ evolution, obviating the need for oxidizing reagents and proton acceptors.

Iron-chelated semiconducting polycomplex nanoparticles (SPFeN) with the ability to induce ferroptosis and a near-infrared photothermal effect were developed for photoacoustic imaging-guided combination cancer therapy.

Generation of silyl radicals by photoinduced decarboxylation of silacarboxylic acids is described. The reaction proceeds smoothly in the presence of a commercially available photocatalyst with broad functional-group compatibility. This reaction could also be performed in the presence of water, enabling the use of D₂O as the deuteration reagent. Germyl radicals were similarly obtained.

Artificial Deprenylase: An oxoammonium cation has been identified as a unique chemical motif that targets prenylated i⁶A RNA and exhibits remarkable selectivity and efficiency in both live cells and plants. This demonstrates that small organic molecules as artificial enzyme mimics can be powerful tools to modulate RNA epigenetic modification for the precise control of biological events.

A catalyst with a high density of rare-earth single Er atoms supported on a carbon nitride nanotube (HD-Er₁/CN-NT) is synthesized by an atom-confinement and coordination strategy (ACC). Experimental results and DFT calculations reveal that the single Er atoms play a key role in the photocatalytic CO₂ reduction reaction in a pure-water system. The ACC strategy also extends to the synthesis of other rare-earth single-atom catalysts.

All in a spin: CO₂-responsive spin-state switching between high-spin (HS) and low-spin (LS) states at room temperature has been achieved in a monomeric cobalt(II) complex. It forms cavities generated by π–π stacking motifs and hydrogen-bond networks.