A monumental achievement for coordination chemistry that also re-addresses the role of molybdenum in the nitrogenase FeMo cofactor is the discovery of the catalytic reduction of dinitrogen at a well-defined molybdenum complex by protons and electrons (see picture).

The degeneracy of the genetic code—the fact that 61 codons in mRNA direct only 20 different amino acid monomers in ribosomal polypeptide synthesis—provides the necessary ambiguity for reassigning codons for the sequence-specific incorporation of artificial amino acids. Genetic engineering of specific tRNA and aminoacyl-tRNA ligase is a tool for the insertion of nonstandard amino acids in ribosomal polypeptide elongation.

Fascinating structures are displayed by many allenic natural products. Among these stimulating synthetic targets is the grasshopper ketone 1, which was isolated from the defense secretion of the large flightless grasshopper Romalea microptera (see picture). Allenes are being applied more and more frequently as enzyme inhibitors, cytotoxic, or antiviral agents.

Full Metal Jacket: Simple stirring of a five component mixture at room temperature is sufficient to assemble a wide range of octahedrally coordinated [2]metallorotaxanes under thermodynamic control (see picture).

A negative response: Anion formation induces translocation of the macrocycle in a molecular shuttle (see picture). Shuttling only occurs in polar solvents and is unaffected by the nature of the countercation or the presence of other anions.

A step-by-step strategy for the assembly of “millipede” artificial enzymes involves attachment of two separate molecular strands to a flexible polymeric backbone. One strand contains a substrate receptor site designed around a transition state mimic, whilst the other carries a catalytically active group (see picture).

A rich harvest: A visible-light-harvesting system has been created utilizing an organogel medium (see picture; the inset shows different gel mixtures). Mixing four different perylene derivatives in the gel phase sets up an energy gradient in the gel fibrils. The well-defined nanofibers harvest a wide range of light energy in the visible region (i.e., sunlight) to the energy sink in a stepwise manner.

The importance of tolerance: A Cobalt complex with bis(imino)pyridine ligand promotes the alternating copolymerization of ethylene with 2-aryl-1-methylenecyclopropanes to give polymers with regulated C₄ repeating units that have a three-membered ring (see scheme). The polymerization is tolerant of functional groups on the three-membered ring such as methoxy and chloro groups.

A radical step: The addition of radicals to amino acrylates and subsequent H-atom transfer in the presence of chiral Lewis acid activators provides β²-amino acids in high yields and enantiomeric purity (see scheme; Ln*=chiral ligands, Fmoc=9-fluorenylmethoxycarbonyl).

Right to the core: Gold(III)-catalyzed cycloisomerization of o-alkynylbenzaldehydes to 2-benzopyrylium salts and subsequent in situ oxidation have been employed to prepare the core structure of azaphilone natural products, such as the sphingosine kinase inhibitor S-15183 (see scheme, DCE=1,2-dichloroethane, TFA=trifluoroacetic acid)), and several unnatural azaphilones.

By manipulating the crystallization conditions of C-methyl recorcinarene, a motif of self-assembled helical nanotubes held together by extensive π⋅⋅⋅π interactions is obtained. The tube, depicted (red=O, white=H, gray=C), has an exo-functionalized hydrophilic outer surface capable of complex formation with cationic or neutral guests and a hydrophobic interior potentially suitable for the transportation of small hydrophobic molecules.

Ink flowing from a pen: Direct-write dip-pen nanolithography of His-tagged proteins (ubiquitin and thioredoxin) has been used to generate biologically active protein nanoarrays with feature sizes as small as 80 nm on nickel oxide surfaces without the need for an applied electric field. The protein molecules in this system seem to diffuse from the Ni-coated atomic force microscopy (AFM) tips to the Ni-coated substrate (see diagram).

Prochiral ditriflates can act as substrates in asymmetric Suzuki couplings by using an enantioselective desymmetrization strategy. The products are obtained with selectivities up to 86 % ee and contain a quaternary carbon center and a synthetically useful vinyl triflate functionality (see scheme).

Platinum drops in and eats out: Platinum nanoparticles penetrate from the surface of the zeolite into its bulk, creating hexagonal mesopores of about the same width as the platinum particles (see micrograph). It is as if the platinum particles tunnel into the crystal. The mesopores are formed along particular directions in the zeolite crystal, and their walls consisted of specific zeolite crystal faces.

Dip, wash, and analyze: Molecules can be attached to tailored porous silicon wafers by using Diels–Alder reactions and efficiently detached and detected in the laser pulse of a MALDI mass spectrometer in a positionally encoded manner (see scheme).

A water-soluble poly(dimethylsiloxane-b-ferrocenylsilane) diblock copolymer containing a hydrophilic cationic polyferrocene block, which is formed in a self-assembly process, yields redox-active vesicles with a diameter of approximately 85 nm (see figure) in which the organometallic block is located on both the outside and the inside of the formed aggregates.

Not a creature from the ocean depths, but the product of synthetic chemistry aided by self-assembly is shown in the photomicrograph. The densely packed, hollow spheres with highly blistered surfaces offer the possibility of a useful encapsulation system which is simple, cheap, and endowed with a particularly high capture volume.

A new mechanism for reducing oxidative stress: Di(3-hydroxypropyl) selenide has exceptionally high glutathione peroxidase-like catalytic activity in the reduction of tert-butyl hydroperoxide with benzyl thiol. The catalytic cycle proceeds via a novel spirodioxaselenanonane, which was isolated and characterized spectroscopically, as well as by X-ray crystallography.

The complete carbon skeleton of welwitindolinone A isonitrile has been prepared by using a [2+2] cycloaddition to establish the bicyclo[4.2.0]octane core and a SmI₂-mediated intramolecular reductive cyclization between an enone and an aryl isocyanate to stereoselectively install the spiro-oxindole (see scheme; DBU=1,8-diazabicyclo[5.4.0]undec-7-ene).

Three to four contiguous stereogenic centers are formed in the title reaction (see scheme). The optically active cyclohexanones are formed as single diastereomers with excellent enantioselectivities (up to 99 % ee) and can be transformed into synthetically useful building blocks.

CH activation of imidazolium salts by coordinatively unsaturated low-valent Ni and Pd complexes occurs under mild conditions. Surprisingly stable hydrido–metal–N-heterocyclic carbene complexes were isolated (see scheme), which demonstrates the ease with which imidazolium-based ionic liquids may react with transition-metal complexes during catalysis.

An intriguing catch: Gutingimycin (1) from the marine streptomycete isolate B8652 is a conjugate of guanine and trioxacarcin A, as extensive NMR measurements and a crystal structure analysis show. The natural product is formed most likely by the selective attack of trioxacarcin A on the bacterial DNA, which results in strand breakage and may explain the high cytotoxicity of the latter.

. ‥and yet so different. Non-heme iron complexes catalyze the stereoselective oxidation of CH and CC bonds. Isomeric Fe^III-η¹-hydroperoxo and Fe^III-η²-peroxo complexes (see picture), important intermediates in these reactions, were studied by EPR, resonance Raman, and UV/Vis spectroscopies.

Impressing models: A novel polymer catalyst shows even higher catalytic activity for the hydrolysis of carbonates than catalytic antibodies prepared for the same purpose. The catalyst was prepared by molecular imprinting with a stable transition state analogue and the introduction of an amidinium function and a Zn²⁺ ion in the active site in a defined orientation (see picture).

Beneath the surface lies the answer: Metallosupramolecular cations are deposited in an ordered manner on a copper surface, which had previously been covered with chloride ions. The anion layer acts as a second-order template, whose interactions with the cation determine the adsorption process (see scheme).

Four isomers with the formula H₃PSi (1–4) were detected directly by matrix isolation spectroscopy. The n-adduct 1 is formed upon cocondensation of silicon atoms and phosphane. Subsequent irradiation leads to 2, 3, and 4. The structures were elucidated by comparing experimental and calculated IR spectra.

Tuned to the right network: Chiral, heterometallic coordination polymers can be prepared readily by using the chiral (2S,3S)-1,2,3,4-butanetetramine, a labile, divalent transition-metal cation such as Cu²⁺, and an oligonuclear, rhenium–chalcogenide–cyano cluster as starting materials (see picture).

Pent-up potential: A novel type of metallocalixarenes for molecular recognition processes is synthesized. The self-assembling platinum(II) macrocycles are built from cisplatin analogues with tertiary amine ligands and the nucleobases uracil or thymine (see picture red O, blue N, orange Pt). The pentanuclear complex cations exhibit an asymmetric structure and bind anions by supramolecular interactions.