Hollow-fiber membrane contactors, which can be combined with enzymatic resolution, have already emerged as a potential technology for enantiomeric resolution under continuous operation (see scheme; ORG denotes the organic phase). Furthermore, recently reported optically active polyelectrolyte multilayer (PEMU) membranes appear extremely promising for future applications in preparative chiral separations.

Presumed innocent, room-temperature ionic liquids are clean, often reusable, media for carrying out many synthetic, catalytic, separation, and analytical processes. However, they are not simply inert solvents, and a variety of decomposition pathways have been detected. In the structure of 1-n-butyl-3-methylimidazolium hexafluorophosphate shown, reactive bonds are marked with arrows (C grey, N blue, F green, P red).

Noncovalent interactions are treated as a form of hydrogen bonding to produce a new universal scale that can be used to estimate the free energies of interaction between any pair of neutral functional groups in any solvent. The important parameters are provided by the molecular electrostatic potential surface (the example depicted is that for carbon tetrachloride).

Stunning tricolored crystals with distinct regions of green, yellow, and orange luminescence (see picture) are deposited in solutions of potassium hydrogen phthalate that contain proflavin. The dye serves as a fluorescent probe of surface charge while identifying the polar crystallographic axis. Optical probes, common in biochemistry, can be used widely to study the specificity of noncovalent chemistry crystal growth from solution.

The hole story: using a new synthetic concept the title hexa-peri-hexabenzocoronenes (HBCs) were synthesized with high atom economy. The coaxial arrangement of the HBCs and arylamines allowed a “double-cable” hole transport (see picture), that is, transport through the central core (white) and the outer shell (green).

Making DNA work: A DNA nanomachine with a mechanism based on a DNA duplex–triplex transition (see figure) was constructed. The key component is a DNA triplex that contains C⁺GC triplets and is only stable under acidic conditions. The DNA machine uses H⁺ and OH⁻ ions as fuel and its only waste products are H₂O and NaCl.

A multipurpose flag: The inactivator 1 covalently labels the catalytic nucleophiles of retaining β-glycosidases to form species 2. The small azide group allows labeling of enzymes with sterically congested active sites. Staudinger ligation of 2 with phosphine–FLAG yields adduct 3, which can be used to detect and profile retaining β-glycosidase activities in complex mixtures.

New drug design possibilities are suggested by the results of a biological evaluation of the indole derivative 1 of pancratistatin, a known anticancer agent, in a panel of cancer cell lines. Enzymatic dihydroxylation was one of the key steps in the short, enantioselective synthesis of 1.

Virtual screening: Based on parameters which do not have to be measured, sets of attributes for solids are derived and used to predict whether a catalyst falls into one of five performance classes in propene oxidation, with a predictive power substantially exceeding the statistically expected values (see table (a confusion matrix): prediction rate indicates the correct assignment by the new method, ratio indicates the statistical expectation value).

Cyclopentenoid structures including compounds containing vinyl iodide, 1,3-diene, and heterocyclic moieties are obtained through the gold(I)-catalyzed 5-endo-dig addition of β-dicarbonyl compounds to unactivated alkynes under neutral conditions and at room temperature (RT). Both monocyclic and bicyclic cyclopentenes can be formed in excellent yields and with good diastereoselectivity (see scheme).

Measure for measure: Several measures indicate that carborane acids of the type H(CHB₁₁R₅X₆) (see scheme, green R, red X, gray H, pink B) for R=H, Cl and X=Cl, Br, I are the strongest pure Brønsted acids. Based on NMR and IR spectroscopy, H(CHB₁₁Cl₁₁) can lay claim to be the strongest isolable acid presently known.

That zinc in feeling: The complexes [(3,5-Me₂C₅H₃N)₂Zn(ESiMe₃)₂] (E=Se, 1; E=Te, 2) are prepared and found to be good reagents for the generation of ternary MM′E materials. From 2 (see structure; Te red, Zn blue, Si yellow, N green), the ternary ZnCdTe nanocluster [Zn_2.6Cd_7.4Te₄(TePh)₁₂(PnPr₃)₄] (3) is prepared. The optical properties of 3 are shown to be modulated relative to those of related binary CdTe cluster molecules.

New N-acyliminium ion methodology: 2-Halotryptophan esters serve as important synthetic building blocks for the stereocontrolled construction of spiro[pyrrolidine-3,3′-oxindoles] (see scheme). The cell-cycle inhibitor spirotryprostatin B is assembled in rapid fashion by using this methodology.

Chirality on the side suffices: The screw sense of 3₁₀- and α-helices formed by the oligopeptides 1, which have no α-carbon chiral centers, is controlled by the chiral centers in their side chains. These results imply that just the side chain chiral centers of isoleucine and threonine would affect the secondary structure of their oligopeptides.

Highly exothermic polymerization reactions of monomers have been carried out in ionic liquids (ILs) by employing an accelerating-rate calorimeter (ARC) to assess the role of the IL. The results indicate that the IL acts as an ideal heat sink in controlling the potential for the reactions to reach thermal runaway as well as contributing to a significant pressure reduction (see the acrylonitrile (AN) example depicted).

Methane, a building block for basic chemicals through its incorporation into alkanes: when a methane/propane mixture is passed over a tantalum hydride catalyst at 250 °C, propane is transformed into two ethane molecules through the incorporation of one methane unit. This reaction corresponds to a cross-metathesis of propane and methane (see scheme; Alk=alkyl).

η⁴-Vinylketene and/or metallacyclopentenone complexes can be considered key intermediates in the ruthenium- and rhodium-catalyzed ring-opening dimerization of cyclobutenones to give 2-pyranones as well as in the rhodium-catalyzed coupling reactions of cyclobutenones with 2-norbornene (see scheme).

A big plus for addition reactions: A catalytic amount of an azazirconacyclobutene is used in a novel carboamination reaction that involves net addition of an aldimine across a symmetrical alkyne to generate highly substituted α,β-unsaturated ketimine products (see scheme; Cp=C₅H₅).

Chloride coordination is the key: Dimethylzirconocene reacts with amides to form methylzirconium amide complexes. On heating, in the presence of a chloride source, these compounds are converted into N-acylimidozirconocene complexes that react intramolecularly to form the corresponding nitrile compounds (see scheme; Cp=C₅H₅). Mechanistic studies reveal that chloride coordination to zirconium is required for this transformation to occur.

Highly successful tin-free, radical-mediated alkylations of α,β-unsaturated carboxylic amides have been carried out. Alkyl iodides and bromides bearing α-electron-withdrawing groups undergo selective γ-additions to diene O,N-acetals (see scheme). This approach to γ-functionalization was further extended to the use of hetero groups, such as phenylsulfanyl and phenylsulfonyl species.

Green approach to inorganic nanostructures: CuCl nanoplatelets (see picture) were synthesized from mixtures of a Cu-containing ionic liquid crystal and 6-O-palmitoyl ascorbic acid. The particle size, thickness, and connectivity can be adjusted through varying the reaction temperature. The copper-containing precursor acts as both the template and the copper source. The ligand is not consumed in the precipitation and can be reused.

Nanoparticles functionalized with a trithiocarbonate ligand allow RAFT polymerization to be performed from their surface. Homopolymers, random copolymers, and block copolymers can be grown radially from trithiocarbonate-covered CdSe nanoparticles (see scheme). This technique gives excellent nanoparticle dispersion in a wide range of polymers, while maintaining the unique photophysical properties of the nanoparticles.

Considerable oxacarbenium ion character may be in the transition state of a highly β-selective mannosylation reaction that proceeds via an α-mannosyl triflate. An α-deuterium kinetic isotope effect of 1.2 was measured at −78 °C (≡1.1 at 25 °C). This information may be interpreted in terms of a stereoselective trapping of a transient contact ion pair or, alternatively, as representative of an “exploded” transition state (see scheme).

Domino effect: The skeleton of erythrina and B-homoerythrina alkaloids can be constructed in an efficient manner from readily available substrates (see Scheme) by a three-step domino reaction. These natural products constitute an interesting class of compounds because of their extensive biological activity.

Bright particles: The optical properties of luminescent nanocrystals (quantum dots, QDs) can be exploited only if they are have an appropriate surface derivatization. A straightforward method is presented to encapsulate single QDs with a homogeneous silica shell, while retaining their high luminescence (see picture).

A mechanism goes platinum: Hydrolytic deamination of cytosine is a major mutagenic event in DNA. Studies with a model system and DFT calculcations demonstrate that deamination is facilitated by coordination of the Pt^II center to the N3 atom (see scheme; C=cytosine, U=uracil).

Glowing marks: A new class of protein stains, the pyrylium dyes, undergo a strong color change (typically from blue to red, see picture) on covalently binding to proteins. While the free stains are almost nonfluorescent, the protein-conjugated forms are highly fluorescent. The dyes do not alter the charge of a protein, and thus do not change its electrophoretic properties. The stains also can be used in quantitative protein assays.

Acid-free Friedel–Crafts chemistry: A paradox? Nucleophilicity scales, based on reactions with benzhydrylium ions, show that many π systems are more nucleophilic than aqueous or alcoholic solutions that are generally employed as solvents for S_N1 reactions. Solvolytically generated carbocations can, therefore, be trapped by donor-substituted arenes and alkenes to form products of Friedel–Crafts-type reactions in neutral aqueous solutions (see scheme).

As part of a succinct synthesis, a new functionalization method leads to hitherto unknown polysilanols with an oligosilane backbone, a class of compounds with remarkable electronic properties. The trifluoroacetolysis of phenyl-substituted hydroxyoligosilanes yield trifluoroacetoxyoligosilanes almost quantitatively, and these can be converted into tri- and tetrasilanol, such as that shown, simply by hydrolysis.