The true ground state of 1 is a matter of debate, but for clarity and convenience the allene resonance form 1 a , is the most appropriate. The arguments for aromaticity made by Christl and Engels are shown to be incorrect.
X‐ray vision : Single‐crystal XRD experiments (see picture) reveal the excited‐state structure of the photomagnetic heterobimetallic title complex. The system shows a decrease in all the iron–ligand bond lengths, suggesting that photoexcitation involves a ligand‐to‐metal charge transfer or a change in the superexchange coupling between the metal centers.
Golden capillaries : A gold‐immobilized capillary column reactor allows oxidation of alcohols to carbonyl compounds using molecular oxygen. These capillary columns (see picture) can be used for at least four days without loss of activity.
Longer switching wavelengths and good photochemical yields and stabilities of the cis isomers in reducing aqueous environments are achieved by introducing 2,2′‐aminoalkyl substituents into 4,4′‐diamido‐substituted azobenzenes. The products are thus suitable for photocontrol of biomolecular structures in intracellular environments, such as switching between two peptide configurations (see picture).
Involuntary association : Anionic β‐galactosidase enzymes associate with positively charged Au nanoparticles to produce reduced‐charge conjugates, which assemble at oil–water interfaces to result in stable microcapsules (see picture). The microcapsules were formed quickly and showed high enzymatic activity, which makes them promising materials for biotechnology applications.
Taking the reins : The title transformation of thioamides and N‐diphenylphosphinoyl imines is described. By harnessing the power of cooperative catalysis between a soft Lewis acid and a hard Brønsted base, thioamide carbon pronucleophiles can furnish Mannich products (see scheme). Divergent transformation of the thioamide functionality highlights the utility of this methodology.
Round and round : Covalently bound spokes induce an efficient template‐directed cyclization towards a rigid molecular wheel (see figure) and afford dramatically increased shape‐persistence properties compared with non‐strutted macrocycles.
MOF on MOF: Core–shell porous coordination polymer (PCP) crystals are fabricated at the single‐crystal level by epitaxial growth in solution. Synchrotron X‐ray diffraction measurements unveiled the structural relationship between the shell crystal and the core crystal, where in‐plane rotational epitaxial growth compensates the difference in lattice constant.
Silica scaffolding : By employing functionalized mesoporous SBA‐15 silica, novel fluorescent cruciform‐silica hybrid materials are generated which preserve the desirable solution properties of cruciforms in the solid state for potential use in sensory schemes.
Positive discrimination : Chemo‐ and regioselective palladium‐catalyzed cycloetherification of allendiols, namely β,γ‐ and γ,δ‐allendiols, may occur by judicious choice of palladium‐catalyzed conditions owing to their potential ability to discriminate between both nucleophilic sites (see scheme).
Multistep in flow: The Seyferth–Gilbert reagent 1 has been applied in a flow system to rapidly synthesize terminal alkynes. The system has been further applied to synthesize triazole 3 from alcohol 2 in a three‐step oxidation/homologation/copper(I)‐catalyzed azide–alkyne cycloaddition sequence without isolation of intermediates (see scheme).
Lithium‐powered : A kinetic investigation into the asymmetric transfer hydrogenation of non‐activated aryl alkyl ketones, catalyzed by N‐Boc‐protected α‐amino acid hydroxyamide ruthenium–arene complexes, has revealed that the reactions proceed through an unprecedented bimetallic outer‐sphere mechanism. Under optimized conditions, these catalysts provide access to secondary alcohols in high yields and with excellent enantioselectivities (>99 % ee).
