Double the fun: The future of cross-coupling chemistry lies in the development of cleaner synthetic methods for carbon–carbon bond formation. A recent advancement in the field of nickel-catalyzed C(sp²)–C(sp³) cross-couplings (see scheme) via two CH activations represents a major step forward.

Growing bigger: A versatile approach toward the construction of nanosize π-conjugated macrocycles by Vernier templation has been demonstrated. The use of linear tetranuclear Zn^II porprhyrin complexes and a suitable and readily available six-site template leads to formation and isolation of a giant, monodisperse macrocycle in a limited amount of synthetic steps, marking Vernier complex formation a powerful and new tool for the creation of superstructures (see picture).

Pince me: N-heterocyclic nitrenium cations have been framed into pincer motifs to explore their unprecedented ligand behavior to transition metals. This work fills a long-standing gap in the series of main-group N-heterocyclic carbene(NHC)-type ligands (see picture). Reasonable π-acceptor and weak σ-donor properties of these new ligands are expected to play a pivotal role in many organometallic reactions and in catalysis in the near future.

Since the moment Dan Shechtman discovered a material with an ordered but aperiodic (“quasiperiodic”) structure, which was believed to be impossible at the time, he began a long battle to convince his colleagues that his data were real. His efforts were finally rewarded with a Nobel Prize. The picture shows the projected electron density distribution function of decagonal Al-Co-Ni with Penrose tiling as an example of a quasicrystal.

Save your samples! The original compound [Co(en)₂(NO₂)₂]Br prepared by Alfred Werner's student Edith Humphrey around 1900 did not crystallize as a conglomerate, but rather formed twinned crystals of both enantiomorphs. These findings, together with similar results for further samples from the Werner laboratory, provide new insight to the claim that Werner could have proved his coordination theory ten years earlier.

A new option: Classical carbonylation reactions employ organohalides as electrophiles to produce carbonyl compounds. Now a series of carbonylative derivatives can also efficiently synthesized by oxidative carbonylation reactions that have an enriched substrate scope and milder reaction conditions. This Minireview summarizes newly developed oxidative carbonylation reactions employing either RM or RH as the nucleophiles.

From nature with love! Biological relevance is the key argument in the search for small molecules that enable the chemical-biological analysis of biological systems or modulation of disease states. Biology-oriented synthesis (BIOS) uses this criterion to chart and navigate vast chemical structure space and to identify biologically relevant scaffold structures as guides for the synthesis of compound libraries (see picture).

Come together! A combined real- and reciprocal-space total scattering approach was realized by applying Debye and radial distribution functions to nanocrystalline and amorphous fractions within the same experimental pattern. The method allows for the quantitative description of microstructural features induced by the amorphous–crystalline interplay in silica–titania nanocomposites (see picture).

Two in one: Two pseudorotaxanes can be combined to form a twin-axial hetero[7]rotaxane (see picture) by using the copper-catalyzed alkyne–azide “click” reaction. The synthetic route, in which twin-axial and single-axial rotaxanes are formed, combines self-assembly and the formation of covalent bonds to ensure the correct positioning of the two types of rings in the final product.

Two are better than one: A mixed-solvent method for liquid exfoliation of MoS₂, WS₂, and BN nanosheets is presented. Although ethanol and water are both poor solvents for this process, ethanol/water mixtures of appropriate composition, which can be predicted on the basis of Hansen solubility parameters, result in efficient exfoliation (see schematic) to give highly stable suspensions.

“Cohort-ry” in motion: The chemistry following CoC bond homolysis in coenzyme B₁₂-dependent ethanolamine ammonia lyase is known to favor dissociation, but what of the protein contribution? Experiments reveal the radical pair reaction dynamics to be coupled to the ps–ns protein dynamics in B₁₂ photolysis. This raises the possibility of a subtle, dynamic contribution to homolysis, which acts in cohort with electrostatics and H-abstraction from the substrate.

CC coupling of 1,7-dibromoperylene bisimide with sterically hindered 2,6-di-tert-butylphenol by a carbon nucleophilic substitution reaction in the absence of transition-metal catalysts gave novel halochromic perylene bisimides (see picture). The corresponding phenolate ions of these compounds exhibit unprecedented NIR spectroscopic properties including strong absorption with maxima at around 1200 nm.

Wire self-assembly: Short oligo(phenylene ethynylene) modules (black structures, see picture) are assembled by attached DNA strands, which also direct the formation of 1,3-diyne linkages between the modules by the Cu-mediated Glaser–Eglinton reaction to selectively form dimer, trimer, and tetramer conjugated wires of up to 8 nm in length.

Split peas: Nanopeapods consisting of highly ordered, wavy NiO nanopods embedded with equally spaced Pt nanopeas were fabricated by the oxidation of multisegmented Ni/Pt nanowires at low temperatures. The Ni/Pt interface is an efficient platform for enhancing the outward diffusion of Ni during oxidation and for manipulating the nucleation of vacancies in Ni, which intrinsically behaves in an uncontrolled manner.

Gaining recognition: The structure of a previously unrecognized antiparallel dimer of rat islet amyloid polypeptide bound to anionic membrane nanodiscs was examined by using a combination of single-pair FRET and Rosetta model refinement. Models of the dimer showed a likely interface for lipid binding and suggest key interactions may also occur in the human isoform, thereby providing possible insights into fibril formation in type II diabetes.

Taking control: Selective catalysts for olefin dihydroxylation have been generated by the combination of apo-streptavidin and OsO₄. Site-directed mutagenesis allows improvement of enantioselectivity and even inversion of enantiopreference in certain cases. Notably allyl phenyl sulfide and cis-β-methylstyrene were converted with unprecedented enantiomeric excess.

The first example of solution-based deposition of strongly nonlinear optical inorganic thin films at low temperatures of 125–250 °C is presented. The obtained glassy and crystalline films of highly nonlinear APSe₆ compounds (A=K, Rb; χ⁽²⁾≈150 pm V⁻¹) exhibit strong, inherent second harmonic and difference frequency generation (SHG and DFG) in the visible and near-IR spectral region at room temperature without the need of poling (see picture).

An antiadhesive nanofilm has been designed and prepared in one step in water onto commercial poly(dimethylsiloxane) (PDMS) by mimicking the external region of cell membranes. The resulting biomimetic surfaces are effective in suppressing protein adsorption as well as bacterial and mammalian cell adhesion.

Turn off the light: A white-light source is used to control the propulsion of catalytic microengines powered by the local decomposition of hydrogen peroxide into oxygen and water. The influence of the wavelength of the light and intensity on the fuel conditions provides a remote control over the power of the self-propelled microengines (see picture).

Thermochromic nitroxide: A nitroxide radical (AZADO) exhibits thermochromism with a structural change from a dimer at low temperature (4 °C) to paired monomers with large antiferromagnetic interaction at high temperature (35 °C). An hysteresis loop is observed in the magnetic data of this compound, revealing it to exhibit a first-order phase transition with room-temperature magnetic bistability.

A new twist: A multi-probe and multi-frequency approach is shown for dissecting the folding dynamics of individual protein structural elements. In response to a temperature jump the 3₁₀-helix (blue in the picture) of the miniprotein Trp-cage unfolds before the global unfolding of the protein, whereas the formation of the cage structure depends on the folding of the α-helix (red).

Flexibility provides selectivity: The selective adsorption of CO₂ from mixtures with N₂, CH₄, and N₂O in a dynamic porous coordination polymer (see monomer structure) was evaluated by ATR-FTIR spectroscopy, GC, and SANS. All three techniques indicate highly selective adsorption of CO₂ from CO₂/CH₄ and CO₂/N₂ mixtures at 30 °C, with no selectivity observed for the CO₂/N₂O system.

Two kinds of imaging: A fluorescent sensor membrane is presented that responds to pH and to pO₂ at different emission wavelengths. The fluorescence intensities can be imaged with a digital camera using the red-green-blue (RGB) data storage option.

A quantum leap: By means of quantum mechanics/molecular mechanics metadynamics simulations, a front-face S_Ni-type reaction for glycosyl transfer with retention of the anomeric configuration is shown to be feasible. A short-lived oxocarbenium-like species (see picture; O red, P gold, N blue, C black) is identified and provides the complete itinerary of this long sought after molecular mechanism.

Happy marriage: For the first time, a fused TCNQ–TTF–TCNQ triad has been synthesized and structurally characterized. Strong bending is observed in both the TTF bridge and the benzo-TCNQ moieties, which prevents good packing for intermolecular charge transfer. The Vis/NIR and VT-EPR studies of the mixed-valence derivative of the triad indicate that the electrons are moving from one acceptor moiety to the other through the donor TTF bridge.

A polymer-embedded dendritic, bodipy-based panchromatic absorber with a built-in energy gradient concentrates incident solar radiation at a terminal chromophore, resulting in a monochromatized emission directed to the sides of the polymer waveguide (see picture). This particular design minimizes self-absorption losses from the peripheral antenna units with an impressive S factor of 10 000.

NO going back makes possible facile Friedel–Crafts benzylations with moderate reaction temperatures, simple reaction workups, and improved substrate scope for the formation of synthetically important diarylmethanes (see scheme). Upon complexation with BF₃⋅OEt₂, hydroxamates serve as reversible leaving groups that stabilize highly reactive carbocations. Even deactivated arenes and electron-deficient benzylhydroxamates react cleanly under these conditions.

Three become one: The cationic rhodium(I) complex [Rh(cod)₂]BF₄ catalyzes the [2+2+1] cross-cyclotrimerization of silylacetylenes and two alkynyl esters, leading to substituted silylfulvenes (see scheme; cod=1,5-cyclooctadiene). The reductive complexation of the silylfulvene product with RhCl₃ in EtOH furnished the corresponding dinuclear electron-deficient cyclopentadienyl rhodium(III) complex.

Positive thinking: A cationic rhodium(I)/H₈-binap complex catalyzes the chemo-, regio-, and stereoselective completely intermolecular [2+2+2] cross-trimerization of two aryl ethynyl ethers with both electron-deficient and electron-rich carbonyl compounds (see scheme; cod=1,5-cyclooctadiene). This reaction proceeded at room temperature to give aryloxy-substituted dienyl esters in good yields.

Flexible friend: The N-(2-pyridyl)sulfonyl group acts as a removable directing group in the Pd^II-catalyzed aryl CH ortho alkenylation of N-alkyl aniline, benzylamine, and phenethylamine derivatives with electron-poor alkenes. The products were obtained in high yields (70–90 %) and with complete regiocontrol. The mild reductive N-sulfonyl removal enables the construction of a variety of nitrogen heterocycles. EWG=electron-withdrawing group.

Partial to particular particles: The morphology of the polymer particles can be controlled in ethylene/CO copolymerization by pressurizing catalyst-containing 1-octanol droplets dispersed in water. The palladium catalyst should be harnessed with lipophilic long alkyl chains. Polymer particles of 0.5–1.0 mm size (see micrographs) with bulk densities of 0.2–0.3 g mL⁻¹ are produced without reactor fouling.

Proton relay: A side-on Ru–O₂ complex with pendent amines in the ligand backbone has been synthesized to model proton delivery in O₂ reduction (see scheme and structure; red O, purple Ru, blue N, yellow P). Protonation occurs at the amine near the O₂ ligand, forming a hydrogen bond between the ammonium ion and the O₂ ligand, leading to a small increase in OO bond length.

On the move: The title compounds 1, which are unique heterocyclic systems containing a PB bond, have been synthesized by the reduction of 1-diarylboryl-8-dichlorophosphinonaphthalene derivatives (see scheme). Both experimental and theoretical results for 1 revealed an effective interaction between the phosphorus atom, boron atom, and naphthyl moiety. Furthermore, 1 exhibits orange fluorescence in solution.

With a coat for activity: A highly active enzyme was prepared by coating Burkholderia cepacia lipase with an ionic surfactant for use in dynamic kinetic resolution (DKR). Important features of this enzyme include: the fastest DKR of 1-phenylethanol, the highly enantioselective DKR of a wide range of secondary alcohols (RCH(OH)Ar), and the switching of lipase enantioselectivity in DKR depending on the shape of the aliphatic chain (R).

Construction by shining light! A [2+2] cycloaddition reaction in a 2D coordination polymer accompanied by single-crystal-to-single-crystal structural transformation to a 3D structure highlights the retrosynthesis of a 3D structure from a 2D layer compound (see scheme, Zn red, 4-styrylpyridine blue/turquoise).

Vapor-sized: In a plasma-based route to multimetallic nanoparticles (NPs), vapor mixtures of organometallic compounds are dissociated in an atmospheric-pressure microplasma (see picture). The size and composition of the particles is controlled by the relative vapor concentrations of the precursors.

A viable nitrogen source for the aminohydroxylation reaction of terminal alkenes: By adding a N-O based reoxidant onto an amino acid acyl carbon atom, compounds were obtained that facilitated catalytic turnover and also promoted the conjugation of an amino acid with an alkene. High levels of regioselectivity were observed, as well as good stereoselectivity induced by catalytic amounts of a chiral ligand.

A new path to chiral alcohols: Asymmetric reduction of ketones was achieved utilizing a chiral Brønsted acid as precatalyst for the first time. Using catecholborane as the reducing agent, a highly enantioselective formation of chiral secondary alcohols was found with a broad substrate scope. Mechanistic studies indicate that phosphoryl catechol borate derived from the reaction of the Brønsted acid with catecholborane produced the active catalyst (see scheme).

O/NH⋅⋅⋅π hydrogen bonds: Water–benzene and ammonia–benzene complexes are stabilized by the Lewis acid B(C₆F₅)₃ and provide rare structural (X-ray) and infrared spectroscopic data for water–benzene and ammonia–benzene complexes in the solid state (see picture). The infrared spectra of the complexes showed that the OH and NH stretching frequencies decrease significantly on benzene complexation.

A hybrid electrocatalyst for the oxygen reduction reaction (ORR), consisting of Co_1−xS nanoparticles directly nucleated and grown on sheets of reduced graphene oxide (RGO; see SEM image), was prepared by a mild solution-phase reaction followed by an annealing step. The Co_1−xS–RGO hybrid has the highest catalytic performance of all cobalt chalcogenide based ORR catalysts, as revealed inter alia by measurements with a rotating-disk electrode (see picture; RHE = reversible hydrogen electrode).

The incredible bulk: A highly C-center-selective alkynylation of nonactivated alkyl halides with the corresponding Grignard reagents is achieved by using the iron-phosphine complex 1. Primary and secondary alkyl iodides, bromides, and chlorides take part in the reaction to give the substituted alkynes in good to excellent yields. Sequential cyclization/cross-coupling reactions are also demonstrated.

Going with the flow: Patterning of various inorganic materials was achieved by phase separation between the nanomaterials and a polymer melt as well as concentrating the nanomaterials in defined areas by a polymer melt flow. This technique generated micro- and nanostructured patterns of metals and semiconductors (see picture).

Highly functionalized cyclopentenones have been prepared stereospecifically through a chemoselective copper(II)-mediated Nazarov/Wagner–Meerwein rearrangement sequence. After the initial 4π electrocyclization, this reaction involves two sequential [1,2]-migrations depending upon both migratory ability and steric bulk of the substituents at C1 and C5 (see scheme). The proposed mechanism of the reaction is supported by DFT studies.

An open and closed case: The photochromic bisthienylethene BTTE based on benzobisthiadiazole exhibits excellent photochromic performance in both solution and single crystals (see picture). BTTE shows excellent thermal stability, which is comparable to the widely known five-membered hexafluorocyclopentene-based counterpart.

Twisted organization: Pyrolysis of nanocrystalline cellulose (NCC)/silica composite films leads to mesoporous carbon materials with long-range chiral organization (see picture). The NCC acts as a template and the resulting mesoporous carbon has a high specific surface area (>1400 m² g⁻¹) and accurately replicates the left-handed helical structure of the chiral nematic NCC films.

Sulfur, so good: Crystallization of phosphorus polysulfides catena-P₂S₇ is enhanced by catalytic amounts of anhydrous FeCl₃ (see scheme, P blue, S yellow). The formation of polysulfide bridges is observed which is typical for vulcanization reactions.

The Clp proteolytic machinery has important functions in many bacteria such as L. monocytogenes. Some organisms encode for two uncharacterized ClpP isoforms. Vibralactone was used to study the activity and assembly of ClpP1 and ClpP2 subunits in a hetero-oligomeric complex. Electron microscopic images reveal that the tetradecameric assembly is made up of two stacked homoheptameric ClpP1 and ClpP2 rings.

Nonsymmetric motion: Solid-state NMR measurements of dipolar coupling tensors provide insight into protein dynamics. The hitherto ignored asymmetry of the dipolar coupling tensor contains valuable information about motional asymmetry, which was used in the first direct site-resolved measurement of such tensors. Important motions such as rotamer jumps can now be directly detected in the solid state.