One in seven: A Li₄H₄ unit that is coordinated with three bis(amino)alane units takes the form of a cube; the compound was isolated in molecular form and characterized by X-ray analysis (see molecular structure; pink Li, blue N, gray Al, white H, yellow Si). During the reaction of this molecule with an equimolar amount of water only one of the seven H atoms reacts to give the hydrolysis product Li₄H₃(OH)[HAl{N(SiMe₃)}₂]₃.

The Lewis acid TiCl₄ allows the intermolecular hydroamination of vinylarenes (see scheme). Some of the hydroamination products undergo rearrangements to give ortho-alkylated compounds. The catalyst tolerates a range of functional groups (R′=CF₃, Cl, CN, F, Br) and provides the products in good yields. This method was also applied to the synthesis of a tetrahydroisoquinoline derivative.

Green light for alkene metathesis: A strong σ-donor ligand L favors the active conformation (green in the scheme) of the carbene ligand in the ruthenium complex and thus leads to high catalytic activity of the second-generation Grubbs catalysts.

Going straight: Thermolysis of the germylidyne complexes trans-[Cl(depe)₂MGe(η¹-Cp*)] (M=Mo, W; depe=Et₂PCH₂CH₂PEt₂, Cp*=C₅Me₅) leads upon cleavage of the GeCp* bond to 1, the first compounds in which a Ge₂ unit is trapped between two transition-metal centers by triple bonds. Quantum chemical analyses suggest a weak conjugation of the M−Ge triple bonds in the linear chain MGeGeM.

A spoonful of sugar …︁ A carbohydrate-based fully synthetic vaccine 1, composed of a tumor-associated Tn antigen, a peptide T epitope, and a lipopeptide (see structure), shows potential as a candidate against cancer. Incorporation of the glycolipopeptide into liposomes gave a formulation that was able to elicit a T cell dependent antibody response in mice.

Pro and anti: Recognition of chloride ion and through-membrane H⁺/Cl⁻ ion transport (“symport”) could account for the biological effects (anticancer activity) of prodigiosin, as inferred from model studies involving pyrrole-based anion receptors designed to mimic the key features of this naturally occurring pigment (see picture).

Expanding our synthetic tool repertoire: The DMP-mediated oxidation of a range of amide substrates has been demonstrated, affording the corresponding imides and N-acyl vinylogous carbamates and ureas. Likewise, an array of benzylic and related amines have also been successfully converted into their nitrile counterparts (see scheme; DMP=Dess–Martin periodinane).

Space program: A general template technique has been developed that enables various Au/Pt nanostructures, such as macroporous 3D films and nanostructures constructed from hollow spheres, to be prepared on silicon wafers and glass substrates (see SEM image). These ordered metallic nanostructures with hierarchical porosity could be useful in industrial applications, including catalytic nanoreactors, sensors, porous electrodes, and fuel cells.

Helpful neighbors: [Pd{2-(OH)C₆H₄}I(tmeda)] reacts at room temperature with excess RCN (R=Me, C₆F₅, CH₂CH) and TlOTf (1 equiv) to give [Pd{1-O-2-[C(R)NH]C₆H₄-κ²-O,N}(tmeda)]OTf (see scheme). The proximal OH group plays a crucial role in this first example of the insertion of a nitrile into a late-transition-metal–carbon bond. Tf=trifluoromethanesulfonyl, tmeda=N,N,N′,N′- tetramethylethylenediamine.

Selective nucleation of aragonite can be achieved at ambient conditions in water by using block copolymer microgels at a very low concentration (0.1 ppm). One polymer template particle is sufficient to control the nucleation of a ring of aragonite single crystals, which propagate into a sheaf structure (see SEM image). Each aragonite crystal is protected by an outer amorphous layer that results in prolonged stability of the aragonite.

On-again, off-again personality: Superhydrophobic conducting polypyrrole (PPy) films are synthesized through a facile electrochemical process. The PPy films exhibit an extended porous structure with both coarse- and fine-scale roughness (see image). By controlling the electrical potential, PPy films can be switched between the oxidized state and the neutral state, resulting in reversibly switchable superhydrophobic and superhydrophilic properties.

A mosaic pattern: Single virus particle nanoarrays can be made through the positioning and orientation of viral particles on nanotemplate surfaces generated by dip-pen nanolithography. Viral immobilization was characterized with antibody–virus recognition and infrared spectroscopy (an example array of particles is shown in the AFM image).

Heterobimetallic sulfides of composition [LAl(μ-S)₂MCp₂] (M=Ti, Zr) react smoothly with two equivalents of water by ring opening and chalcogen exchange to form the heterobimetallic oxide–hydroxide–hydrogensulfides [LAl(OH)(μ-O)MCp₂(SH)] (Ti derivative shown). The presence of the hydrolysis intermediate [LAl(SH)(μ-O)MCp₂(SH)] in the reaction mixture confirms the proposed pathway.

Deprotonative metalation of ferrocene by a lithium zincate reagent was carried out to form the neutral zinc complex [(Fc)₂Zn(tmeda)] and the anionic zincate [Li(thf)₄][(Fc)₃Zn] (see scheme; tmp=2,2,6,6-tetramethylpiperidine, TMEDA=N,N,N′,N′-tetramethylethylenediamine). A 1:1:1 mixture of TMEDA, Li(tmp), and nBu₂Zn is used to readily prepare the lithium zincate reagent [LinBu₂Zn(tmp)(tmeda)] in situ.

Screw top: Photoelectron spectroscopy of doubly charged [FeCp′₂] (1) and singly charged [Cp′FeCp′H] (2; Cp′=η⁵-C₅H₄CO₂⁻) shows that strong intramolecular coulomb repulsion keeps 1 in the trans form, with the two CO₂⁻ groups on the Cp′ ligands oriented opposite to each other, whereas 2 assumes the cis form owing to formation of a strong intramolecular H bond. Fe blue, O red, C gray.

From linear to dendritic: Glycine is part of the predominant sequence in collagen proteins, and aspartate is similar to the repeating unit of poly(benzyl glutamate)s (PBG)s. Collagen and PBGs are linear peptides that self-organize into fibers and form liquid-crystalline phases and gel solvents. How would a molecule self-assemble if it was built by arranging Gly-Asp units in a dendritic way (see picture)? A dendron as both gelator and liquid crystal?

Aminic or iminic: Two tautomeric forms of oxidized guanosine have been produced by chemical radiation methods—by direct oxidation of guanosine or from the protonation of the 8-bromoguanosine electron adduct—and identified. The tautomerization from the iminic to the aminic arrangement has an activation energy of 23.0 kJ mol⁻¹ and occurs through a complex transition state (see scheme).

When normal is a surprise: Studies of a ligand-substitution reaction of a Pt^II complex (see picture; apa: 2,6-bis(aminomethyl)pyridine) in water, methanol, and the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide reveal that the ionic liquid behaves “normally”, that is, as any other solvent. In the ionic liquid, changes in the polarity of the transition state only play a minor role.

A clever way to clavolonine: The total synthesis of the lycopodium alkaloid clavolonine (2) from a linear precursor 1 that contains the complete 16-carbon-atom chain is reported (see scheme). Intramolecular and transannular cascade reaction sequences are explored from both linear and macrocyclic precursors. A variety of polycyclic structures are rapidly constructed from simple acyclic precursors.

Natural product inspired asymmetric catalysis resulted from an effort directed toward colombiasin A and related complex targets. The discovery of highly selective quinone Diels–Alder reactions catalyzed by the new, monomeric [(Schiff base)Cr^III] complex 1 was a requisite step in the synthetic endeavor (see scheme; TES=triethylsilyl, DBU=1,8-diazabicyclo[5.4.0]undec-7-ene).

A made-to-order asymmetric catalytic reaction was applied in the key quinone Diels–Alder step of the total syntheses of the title compounds (see scheme for the synthesis of colombiasin A). The reaction was highly regio- and diastereoselective.

Bimetallic nanotubes: Uniform arrays of metal nanotubes were prepared by the electrodeposition of a thin metallic film on the pore walls of anodic aluminum oxide membranes decorated with metallic nanoparticles. Multisegmented nanotubes with a bimetallic stacking configuration along the nanotube axis can be fabricated (see picture). The technique is applicable to a wide variety of conducting and semiconducting materials.

A pair to fret about: Biotinylated phosphor nanoparticles that emit upconversion luminescence have been taken with biotinylated Au nanoparticles, which act as energy acceptors, and the pair has been applied to the determination of trace amounts of avidin based on fluorescence resonant energy transfer (FRET; see picture).

Good to high conversions (70–100 %) into optically active tri- or tetracyclic nitrogen-containing compounds 1 based on 1,2-dihydroisoquinolines and 1,2-dihydrophthalazines proceed with high diastereoselectivity (d.r.≥15:1) and good to excellent enantioselectivity (85–96 % ee) in the presence of a chiral amine.

In rare form: Although the structure of the body-centered cubic (bcu) net is commonly found in textbooks, its eight-connected topology is extremely rare in metal–organic frameworks owing to severe geometric requirements. The first example of a highly porous, neutral bcu-type framework (see picture) assembled from a unique eight-connected tricopper cluster and a 5-(4-pyridyl)tetrazolate ligand as linker is reported.

The heavy-atom effect cannot explain the difference in the third-order nonlinear optical properties of the clusters [Ag₁₀(dcapp)₄](OH)₂⋅12 H₂O (1, see structure), [Zn₄O(dcapp)₃]⋅6 H₂O (2), and [Hg₂(dcapp)₂] (3) (H₂dcapp=2,6-dicarboxamido-2-pyridylpyridine). Quantum chemical calculations show that the NLO properties of 1 are controlled both by the metal and the ligand, while those of 2 and 3 are controlled by the ligand only.

Tiles go down the tube: A novel method for the preparation of DNA tubes by using the DNA tile system with the assistance of a four-way-branched DNA–porphyrin connector is described (see schematic representation). The detailed DNA tube structures were characterized by atomic force microscopy.

A light switch: The mechanism of transmission of the photoinduced torsional strain along a cyclic peptide, incorporating a biomimetic photochemical switch, is resolved by quantum mechanics/molecular mechanics and molecular dynamics simulations. The excited-state cis→trans motion of the switch does not affect the conformation of the peptide which only begins to change after decay to the ground state at a conical intersection (CI; see scheme).