Single molecule reactivity, self-assembly, and self-directed growth can be used to generate patterns on the nanometer scale. For example, molecular building blocks can be organized on substrate surfaces (see picture). New approaches that take advantage of single-molecule reactivity and self-organization, as well as stabilization of structures on substrate surfaces, are introduced.

Neutral alkyl-substituted spirobiphenalenyl radicals (see formula) were recently reported that exhibit bistability as a consequence of temperature-dependent hysteretic switching. The high- and low-temperature forms display significant differences in their electrical, optical, and magnetic properties.

Success squared! The French mathematician Jacques Hadamard (1865–1963; pictured) significantly improved the analysis of complex signals by introducing a decomposition based on square waves. A review is presented of the application of the Hadamard transform to time-of-flight mass spectrometry. The primary benefit of this technique is the gain in signal-to-noise ratio associated with signal multiplexing.

Seven total syntheses of the title compound 1 have already been reported. In this Review, the authors discuss the fascinating strategies (e.g. see scheme) employed in the various assemblies of the key fragments, including the quaternary center C20, the oxindole moiety, and the bicyclooctane residue.

Microchip innovation: A thin-film microchip system has been developed for microelectrospray Fourier-transform ion-cyclotron resonance mass spectrometry. Application perspectives include the analysis of combinatorial libraries and high-performance proteomics (as shown for the peptide fragment of the phosphorylation domain (512–538) of human neurofibrillary tau protein; the seven phosphorylation sites are indicated in red).

A self-organized dynamic growth process (“morphosynthesis”) involving mineral formation at a membrane-type surface leads to discrete inorganic shells of star-shape morphology (see picture). CTAB=cetyltrimethylammonium bromide.

Distances between paramagnetic transition-metal ions in compounds can be studied by using the pulsed electron–electron double-resonance method. Hereby, the relative orientation (red arrow) of the metal centers (Cu^II, blue sphere), as well as the principal axes of the g tensor (green arrows) relative to the ligands play an important role (schematic representation: dimer of the copper protein azurin).

Combined strength: Only the combination of aluminate complexes with their neutral Lewis acids allows the controlled regioregular ring-opening polymerization of industrially important propylene oxide. The chain propagation proceeds at both aluminium centers according to a novel mechanism (see scheme).

Although a poly(propylene oxide) (PPO) chain was previously thought to be impenetrable to α-cyclodextrin, the middle poly(ethylene oxide) (PEO) block of PPO-PEO-PPO triblock copolymers can be selectively recognized and included by α-cyclodextrin to form polypseudorotaxanes (see schematic representation), even though it is flanked by two PPO blocks.

Bendy tubes: Lipid nanotubes can be aligned by a novel and simple method, whereby a fine line of a single nanotube is drawn freely by microinjecting the aqueous dispersion onto a glass plate. This technique is simple and highly adaptable; even words can be written (see picture)! The tubes can be bent and their Young's modulus measured by manipulation with optical tweezers.

One- and two-dimensional coordination polymers (see picture) in which the bridging ligands are coated with crown ethers (red) can be prepared by metal–ligand self-assembly. These metal-based polyrotaxanes contain channels and cavities that are lined with mechanically linked molecular components. This structural design has significant potential for tuning the physical properties of internal cavities and the production of materials that contain functional molecular entities that may be addressable or controllable.

Twisted figure-of-eight structures are found for the perfluorinated meso-aryl-substituted expanded porphyrins synthesized from 3,4-difluoropyrrole and pentafluorobenzaldehyde under modified Rothemund–Lindsey conditions. The crystal structure of the [26]hexaphyrin (see picture) consists of two almost planar tripyrrolic subunits which are tilted by approximately 60° in which a distinct alternation in the bond lengths of the π-electronic system is evident.

Most chemical syntheses of thiazolines use serine residues, whereas nature employs cysteine residues. In a biomimetic approach, [(Ph₃P⁺)₂O](OTf⁻)₂ was used to promote triphenylmethyl (Tr) deprotection and dehydrocyclization of simple cysteine N-amides to give thiazolines in excellent chemical and optical yields (see scheme). This mild method was extended to the synthesis of, for example, thiazolines from cysteine-containing dipeptides in high yield and without significant loss of chirality at the C2-exomethine carbon atom. TF=trifluoromethanesulfonyl, Cbz=benzyloxycarbonyl

Hydrogen bonds to metal complexes located within the active sites of proteins have been implicated in the regulation of function. Incorporation of these noncovalent interactions into a synthetic system with bridging oxo ligands is reported. Unprecedented thermal stability of a complex with a {Co^III(μ-O)₂Co^III} core is observed (see picture), in which intramolecular hydrogen bonds to the oxo ligands are present.

Independent of substrate and solvent, the CC bond-forming reaction of organosilicon reagents with α,β-unsaturated carbonyl compounds can be catalyzed by an iridium complex to give exclusively the Mizoroki–Heck-type addition/elimination product (see scheme). This result sharply contrasts the analogous reaction with a rhodium catalyst under similar conditions in which the 1,4-addition product is obtained preferentially. cod=cycloocta-1,5-diene.

A vanadium-substituted polyoxomolybdate ion ([PV₂Mo₁₀O₄₀]⁵⁻, top right) can activate nitrous oxide to promote the highly selective catalytic oxidation of primary and secondary alcohols to aldehydes and ketones, and the oxidation of various alkylaromatic substrates (see scheme).

The epimerization of a single axial hydroxy group in a carbohydrate can affect carbohydrate–carbohydrate interactions significantly. Glycolipid micelles and glycolipid-containing Langmuir monolayers (see picture) were used to model these key interactions on the molecular level. (GM₃ is the ganglioside sialosyl-lactosylceramide found on the surface of melanoma cells.)

The copper-catalyzed cycloisomerization of thioalkynyl ketones 1 a and thioalkynyl imines 1 b allows the efficient synthesis of 3-thio-substituted furans 3 a and pyrroles 3 b, an important class of heterocyclic unit previously inaccessible by standard cycloisomerization techniques. A plausible mechanism for this unusual cascade involves a 1,2-migration of the thio group in the intermediate keto- and iminoallenyl sulfides 2. DMA=N,N-dimethylacetamide.

A new set of wheels: Substituting a chromium ion in [Cr₈F₈(O₂CCMe₃)₁₆] with one of a number of alternative transition metals has yielded an unprecedented family of heterometallic wheel complexes (see picture), supported at their centers by secondary ammonium ions. Both 3d (Mn, Fe, Co, Ni) and 4d (Cd) metals have been employed to produce such structures, the magnetic and spectroscopic properties of which are discussed.

The stereoelectronic properties of the PR₂(2,6-Me₂C₆H₃) (R=Ph, Cy) ligand can be used to stabilize an unprecedented class of 14-electron platinum(II) complexes. The X-ray analysis of the cyclometalated cyclohexyl derivative reveals an agostic interaction between the Pt center and an o-methyl moiety (see picture). The fast and reversible formation of three-coordinate platinum–hydrido complexes occurs by reaction with H₂, and is achieved through the cleavage of a platinum–carbon bond.

The electronic nature of iron porphyrin complexes and iodobenzene derivatives markedly influences the formation of iodosylbenzene–iron(III) porphyrin intermediates 2, which are generated in the reaction of oxoiron(IV) porphyrin cation radicals 1 and iodobenzene. Epoxidation of olefins by 2 affords high yields of epoxide products.

The use of Wilkinson's catalyst with diisopropylphosphinite ligands acting as cocatalysts allows the catalytic orthoarylation of phenols [Eq. (1)], a process that relies on a CH activation of a phenol that has been incorporated into the cocatalyst by transesterification.

η⁶-Bonding characteristics are exhibited by stable germabenzene complexes that are stabilized with the extremely bulky 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl ligand. The ring system coordinates to transition-metal centers (M=Cr, Mo; see picture) to give the first evidence of the aromatic character in germabenzene complexes, from the standpoint of their chemical reactivity.

A radical idea: A diversity-oriented synthesis of α-amino acid derivatives is realized by the silyltelluride-mediated radical coupling of imines and isonitriles followed by various transformations of the carbon–tellurium bond of the coupling products (see scheme). The α-amino radical generated from the imine and the silyltelluride is the key intermediate in the coupling reaction.