What's the matter? The laboratory Raman spectra for carbonic acid (H2CO3), both for the β‐polymorph and its amorphous state, are required to detect carbonic acid on the surface of the pole caps of Mars in 2009, when the Mars Microbeam Raman Spectrometer lands on the planet. The picture shows a martian crater with ice of unknown composition, possibly containing carbonic acid (image adapted from DLR, with permission from ESA, DLR, and FU Berlin –‐G. Neukum).
How low can you go? An FeII4 square was prepared by self‐assembly and exhibits both thermally induced and photoinduced spin crossover from a system with four high‐spin (HS) centers to one with two high‐spin and two low‐spin (LS) centers. The spin‐crossover sites are located on the same side of the square, and the spin transition and magnetic interactions (see picture) are synergistically coupled.
A variety of tertiary silanes , even those with functional substituents, undergo an unprecedented iron‐catalyzed dehydrogenative coupling (see scheme) in a convenient approach to disilanes, including unsymmetrical disilanes and polymers with Si? Si bonds in the backbone. Consideration of the catalytic reaction pathway revealed the intermediacy of a hydrido(disilyl)iron(IV) complex.
Unstable? We're able! 1,n‐Glycols serve as synthetic equivalents to unstable dialdehydes in two‐directional carbonyl allylation from the alcohol oxidation level under iridium‐catalyzed transfer hydrogenation conditions. Iterative asymmetric allylation employing 1,3‐propanediol enables the rapid assembly of protected 1,3‐polyol substructures with exceptional levels of stereocontrol.
The fungus Rhizopus microsporus …? ; shown in the micrograph on the cover picture, harbors the endosymbiotic bacteria Burkholderia rhizoxinica that produces the antimitotic polyketide macrolide rhizoxin (see structure). In their Communication on page 5001 ff. , C. Hertweck and co‐workers show that the enzyme rhizoxin polyketide synthase is uniquely capable of introducing a β branch (highlighted by the magnifying glass) by a Michael‐type addition of a malonyl unit to an acryloyl intermediate.
Discriminating by color : A 2D colorimetric indicator array has been designed by a crystal engineering approach (N???H? O hydrogen bonding and charge‐transfer complexation) involving solid‐state co‐grinding for the visual discrimination of positional isomers of dihydroxynaphthalene. Factors governing the close packing of π planes, and hence color of the complex, were determined by single‐crystal X‐ray analysis, allowing fine tuning by crystal engineering.
It's in the bond : The cleavage of C? H bonds by two related oxoiron(IV) complexes shows a range of kinetic isotope effect (KIE) values that exhibit an unusual dependence on the C? H bond strength. Large nonclassical KIEs are observed for bond strengths below 93 kcal mol?1, while semiclassical values are found above this value (see graph, DHA=9,10‐dihydroanthracene). This nonintuitive behavior can be rationalized by invoking a two‐state reactivity model.
Tea time! Gold nanoparticles (GNPs) could be readily prepared by a general strategy involving the reduction of aqueous HAuCl4 in the presence of traditional Chinese medicines (TCMs). Spheroidal and triangular gold nanoparticles were observed depending on the TCM used. The strategy exemplified the universal application of plant bioresources for the synthesis of GNPs and catalytic purposes.
The Lewis acid B(C6F5)3 in combination with hydrosilanes exhibits remarkable activity in the oligomerization of sulfone‐ and phosphonate‐based monomers. This process opens new routes to high‐tech silicone‐based materials, i.e., thermoplastic elastomers and heat‐resistant polysiloxanes.
Always on the move : Molecular dynamics of perylene cores in columnar structures influences the processability and self‐healing of these materials. A combination of X‐ray scattering and advanced solid‐state NMR methods show that these systems have restricted angular mobility of the cores even in the frozen phase, and a cooperative spiral type of motion in the liquid crystalline phase (see picture).
Bridging or pendant? Palladium and rhodium complexes deriving from an ambiphilic phosphine–borane ligand are shown to adopt a bridging P→M? Cl→B coordination mode in the solid state. DFT calculations provide more insight into the Cl→B interaction and suggest the possible interconversion of the bridging and B‐pendant forms in solution.
