Versatile strategies of multicomponent coupling reactions to synthesize variously substituted pyrroles 1 are summarized. These heterocycles are important targets as molecules in their own right, for their pharmacological properties, as well as intermediates for more elaborate syntheses.

The close race between Zintl ions and fullerides has gone into the second round, initialized by the synthesis of the soluble endohedral cluster [Pt@Pb₁₂]²⁻ (see picture, left). The structural characterization of an anion with almost ideal icosahedral symmetry illustrates that many heteroatomic clusters observed in the gas phase can, indeed, be regarded as endohedral clusters.

Out of the kitchen into the laboratory: Direct heating by microwave irradiation (see picture) in many cases enables synthesis to be carried out in a fraction of the time required with conventional heating techniques. The use of microwave heating in organic synthesis is growing rapidly and the advantages not only include faster reaction times, but also higher product yields, cleaner reactions, better controllability, and reproducibility.

Prefabricated construction techniques: A solvothermal route involving iron(III) trimeric secondary building units has been developed. Two new open-framework iron (III) dicarboxylates have been characterized from X-ray powder diffraction studies. Their 3D structures are built up from trimers of iron polyhedra related through dicarboxylates, thus creating cationic frameworks with 1D pore systems filled with solvent molecules and anions (see example).

Structure prediction of hybrid organic–inorganic frameworks is now computationally possible. The employed method embraces the concept of hybrid framework through the automated assembly of predefined organic and inorganic building units in 3D space. Crystal structures of hybrid candidates are predicted (space group, cell parameters, atomic positions; see picture), together with an estimate of their lattice energies.

A perfect combination: The association of a chromium(III) trimeric building unit and 1,3,5-benzenetricarboxylate led to the powdered solid MIL-100. Simulations provided a crystal structure solution, which matched the experimental powder XRD pattern. This unique simulation/diffraction combination allowed the structure determination of a giant-pore solid with a zeotype architecture, built up from hybrid supertetrahedra (see picture).

Fine-tuning the N-donor ability of a bidentate aminopyridyl ligand facilitated the selective synthesis of complexes 1 (no methyl substituent) and 2 (with a methyl substituent) which possess valence tautomeric nickel(II) semiquinonato and nickel(III) catecholato frameworks, respectively.

Small world: Metallic nanomagnets (MNMs) dispersed in spherical colloids can be prepared by the aerosol evaporation of an aqueous sol containing mineralized ferritin and a colloidal matrix precursor (see picture). Essential to the success of the method is the template effect provided by ferritin.

Robust porous frameworks are formed by the dipeptides L-Ala-L-Val (see structure) and L-Val-L-Ala that have a high capacity and selectivity for gas sorption. The dipeptides assemble through hydrogen bonds as a 6₁ helix to form channels with average diameters of 5.13 and 4.90 Å, respectively.

The data fit, but the structures are different. Two methods for the interpretation of NMR data of a β-hexapeptide are compared. While the simulated annealing procedure suggests the formation of a (P)-2₈-helix, unrestrained molecular dynamics simulations indicate that the NMR data can also be described by a much broader ensemble of conformations, in which (P)-2.5₁₂-helical structures are prominent (see diagram).

Illuminating phase changes: Absorption of X-ray photons induces reversible internal charge-transfer processes in the mixed-valence Mn/Fe cyanide Rb_0.7Mn^II_1.15[Fe^III(CN)₆]⋅2 H₂O over a broad temperature range. Both continuous and abrupt phase transformations can be triggered (see scheme; HS=high spin, LS=low spin) and because the X-rays simultaneously probe the structural properties of the material, the resulting phase diagram can be elucidated in detail.

¹²⁹Xe NMR spectroscopy meets protein engineering: NMR spectroscopy with laser-polarized ¹²⁹Xe can be used to report protein conformations only if a protein has a conformationally sensitive xenon-binding cavity. However, many proteins lack such reporter sites. A straightforward design process is used to engineer a xenon-binding cavity into the ribose-binding protein (see picture) that allows the ¹²⁹Xe NMR spectroscopic report of protein conformation and ligand binding.

Targeting micelles: Cyclic pentapeptide cRGDfK (red triangles), which targets integrin α_vβ₃, was conjugated to the outer shell of doxorubicin-loaded (red hexagons) polymeric micelles by using a post-micelle modification method. The modified micelles significantly enhanced their internalization (up to 30-fold) by receptor-mediated endocytosis in tumor endothelial cells overexpressing the α_vβ₃ receptor.

Filled doughnuts: Molybdenum crown cluster MC accommodates up to three molecules of aminophenyl-substituted metalloporphyrins through hydrogen-bonding interactions, to form discrete inorganic–organic nanocomposite materials (see picture; blue polyhedra=MC, space-filling model=metalloporphyrin). Ultrahigh-vacuum scanning tunneling microscopy, in conjunction with scanning tunneling spectroscopy, at 80 K confirms the formation of the inclusion complex.

The combinatorial approach: A library of fluorescent styryl dyes (320 compounds) was prepared by solid-phase chemistry. The dyes were screened for their detection of amyloid aggregates, which are associated with diseases such as Alzheimer's, and two of the 320 compounds screened, 2C40 and 2E10, showed promise as brain-imaging agents (see microscopy image).

A brighter future for siloles. Luminescent silole chromophores with the highest quantum efficiencies reported for a fully substituted monomeric silole are generated by altering the steric properties of the substituent groups. Treatment of 1,1-dimethylsiloles with Bu₄NF (TBAF) in THF rapidly gives stereospecific desilylation at room temperature (see scheme). Intense solid-state photoluminescence is observed in thin films of the silole fluorophores.

Axes of power: Jahn–Teller isomerism (that is, Jahn–Teller distortion along different axes) accounts for the presence of both faster and slower relaxing magnetization dynamics of the title compound (see core structure; blue Mn, red O, gray C), which is a single-molecule magnet (SMM). The new compound is a structural variant of the [Mn₁₂] family of SMMs and is prepared by a reductive aggregation of [MnO₄]⁻ in a mixture of MeOH/PhCO₂H.

Modification of tetrathiafulvalene with an imidazolyl substituent as a hydrogen-bond donor allows the generation of a hydrogen-bonded 2:1 charge-transfer complex with chloranil. This complex forms a three-dimensional network with columnar stacking of each component and multiple S⋅⋅⋅S interactions (see picture). This strongly hydrogen-bonded purely organic conducting material is the first to display metallic behavior.

Get turned on: Fluorescent photochromic organic nanoparticles (FPONs) of 1 (see picture) show a strongly enhanced fluorescence emission with increasing concentration and bistable photochromism. High-contrast on/off fluorescence switching has been successfully implemented in size-tuned FPONs of 1 and also in a photo-rewritable polymer film highly loaded with 1.

Supramolecular polymerization of dendritic zinc porphyrins with two carboxylic acid functionalities leads to the formation of J-aggregates through multipoint π-stacking interactions. Spin-coating of the J-aggregate solutions gives optically active films, whose sense of chirality can be selected by the spinning direction (see picture). The chiroptical memory is thermally stable up to the melting temperatures of the spin-coated films.

Rapid screening: For optimizing the weight fraction of enzyme in enzyme electrodes, the scanning electrochemical microscopy (SECM) screening method described gives results (see picture) in good agreement with those obtained by the traditional rotating-disk-electrode method but in one tenth of the time and with a reduction in the amount of polymer and enzyme required by a factor of 100 000.

α,α-Disubstituted β-lactones can be obtained by the cycloaddition of the corresponding ketenes with aldehydes (see scheme). For the first time, a chiral PPY derivative, 1, serves as an efficient catalyst for the asymmetric synthesis of β-lactones (PPY=4-pyrrolidin-1-ylpyridine). To date, this is the only catalyst that is effective for enantioselective cycloadditions of disubstituted ketenes with aldehydes.

The chemical reduction of H[AuCl₄] with ortho-phenylenediamine in aqueous media at room temperature and ambient pressure allows the synthesis of Au nanoplates with lengths of several micrometers (see SEM image). The as-prepared nanoplates are single crystals with a preferential growth direction along the Au (111) plane and mainly hexagonal in shape.

Taking up the semiconducting baton: Organic field-effect transistors fabricated with a new class of extremely electron-deficient cyanated perylene diimides are air-stable and exhibit n-type mobilities as high as 0.64 cm² V⁻¹ s⁻¹ (see scheme). Devices can be fabricated from vapor-deposited and solution-cast films as well as top- and bottom-contact electrode configurations.

Deprotonation of the trifluoroacyl hydride complex 1 with tert-butyllithium leads to difluoroketene adduct 2. Coordination of the difluoroketene to iridium through the CC bond is confirmed by X-ray diffraction (see scheme). This complex is the first isolated and characterized dihaloketene complex and provides the only structural data for difluoroketene.

Magnetic hollow Fe₃O₄–polymer hybrid nanospheres (see figure) were prepared by adding Fe₃O₄ nanoparticles to an aqueous solution of polymer–monomer pairs composed of a cationic polymer (chitosan) and an anionic monomer (acrylic acid), followed by polymerization of acrylic acid and selective crosslinking of chitosan at the end of the polymerization.

Substituents on both the nucleoside arylsulfonate as well as the aryl amine component have a significant impact on their coupling to form 2,6-diaminopurine-2′-deoxyribonucleosides (see scheme). A systematic study of ligands for the Pd catalysts in amination and CC cross-coupling reactions gives insight into the structural elements that lead to effective catalysis.

Competing reactions, not consecutive processes, are the oxidation of styrene to styrene epoxide and the formation of phenylacetaldehyde (PADH). In situ NMR and EPR spectroscopic analysis of styrene oxidation on TS-1 zeolite (see picture) demonstrated that Brønsted acid sites provide the active centers needed to transform an intermediate hemiacetal species into PADH.

A question of identity: A palladium complex featuring a carbenic S,C,S-based pincer ligand is reported (see scheme). DFT calculations show that, unlike classical carbene complexes, coordination occurs through donation from a d orbital at the metal into the empty n_p orbital of the carbene fragment, with the n_σ orbital essentially acting as a nonbonding orbital. The complex is shown to have nucleophilic character.