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A paper-based colorimetric sensor system (PBCSS) was developed to detect the amount of bis(pinacolato)diboron (B2Pin2) and applied as a high-throughput screening protocol in Ir-catalyzed C−H borylation. First, 96 ligands were screened for the borylation of benzene, and then 12 of them were selected and tested for five substrates. These reaction mixtures were spotted in the PBCSS, showing a blue-violet color. The value of the gray scale of each reaction was obtained from these colored spots and converted to the extent of conversion of B2Pin2. The extents of conversion of B2Pin2 obtained from the PBCSS showed good correlation with those obtained from gas chromatography analysis. In addition, the modified conversion using blank data showed good correlation with the yield of products. [ABSTRACT FROM AUTHOR]

In this paper, Pd‐catalyzed [4+2] decarboxylative cycloaddition of 4‐vinylbenzodioxinones with barbiturate‐derived alkenes has been developed, leading to various spirobarbiturate−chromane derivatives in high yields with excellent diastereo‐ and enantioselectivities. The scale‐up reaction and further derivation of the product were demonstrated. A plausible reaction mechanism was also proposed. [ABSTRACT FROM AUTHOR]

Biohybrid catalysts that operate in aqueous media are intriguing for systems chemistry. In this paper, we investigate whether control over the self‐assembly of biohybrid catalysts can tune their properties. As a model, we use the catalytic activity of functional hybrid molecules consisting of a catalytic H‐dPro‐Pro‐Glu tripeptide, derivatized with fatty acid and nucleobase moieties. This combination of simple biological components merged the catalytic properties of the peptide with the self‐assembly of the lipid, and the structural ordering of the nucleobases. The biomolecule hybrids self‐assemble in aqueous media into fibrillar assemblies and catalyze the reaction between butanal and nitrostyrene. The interactions between the nucleobases enhanced the order of the supramolecular structures and affected their catalytic activity and stereoselectivity. The results point to the significant control and ordering that nucleobases can provide in the self‐assembly of biologically inspired supramolecular catalysts. [ABSTRACT FROM AUTHOR]

Transition metal radical‐type carbene transfer catalysis is a sustainable and atom‐efficient method to generate C−C bonds, especially to produce fine chemicals and pharmaceuticals. A significant amount of research has therefore been devoted to applying this methodology, which resulted in innovative routes toward otherwise synthetically challenging products and a detailed mechanistic understanding of the catalytic systems. Furthermore, combined experimental and theoretical efforts elucidated the reactivity of carbene radical complexes and their off‐cycle pathways. The latter can imply the formation of N‐enolate and bridging carbenes, and undesired hydrogen atom transfer by the carbene radical species from the reaction medium which can lead to catalyst deactivation. In this concept paper, we demonstrate that understanding off‐cycle and deactivation pathways not only affords solutions to circumvent them, but can also uncover novel reactivity for new applications. In particular, considering off‐cycle species involved in metalloradical catalysis can stimulate further development of radical‐type carbene transfer reactions. [ABSTRACT FROM AUTHOR]

The phosphanoxy‐substituted phosphaalkene bearing the P=C−O−P skeleton can be prepared from diphosphene Mes*P=PMes* (Mes*=2,4,6‐tBu3C6H2), and their use for catalysis is of interest. In this paper, complexation of the phosphanoxy‐substituted phosphaalkenes with gold are investigated, and the catalytic activity of the mono‐ and bis(chlorogold) complexes are subsequently evaluated. Reaction of the P=C−O−P compound with (tht)AuCl (tht=tetrahydrothiophene) showed dominant coordination on the sp3 phosphorus, and complete coordination on the sp2 phosphorus required removal of tetrahydrothiophene. Atoms In Molecules (AIM) analysis based on the X‐ray structure of the mono(chlorogold) complex indicated a pseudo coordinating interaction between the gold center and the P=C unit. The bis(chlorogold) complexes displayed conformational isomerism, and catalyzed the cycloisomerization/alkoxycyclization of 1,6‐enyne and for hydration of terminal alkyne without activation treatment. Even the mono(chlorogold) complexes catalyzed the alkoxycyclization reactions without a silver co‐catalyst, indicating that the alcohols were effective in activating the AuCl unit. [ABSTRACT FROM AUTHOR]

All studies on oxygen‐evolution reaction by Mn oxides in the presence of cerium(IV) ammonium nitrate (CAN) have been so far carried out by synthesizing Mn oxides in the first step. And then, followed by the investigation of the Mn oxides in the presence of oxidants for oxygen‐evolution reaction (OER). This paper presents a case study of a new and promising strategy for in situ catalyst synthesis by the adding MnII to either CAN or KMnO4/CAN solution, resulting in the formation of Mn‐based catalysts for OER. The catalysts were characterized by scanning electron microscopy, energy‐dispersive spectroscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray absorption spectroscopy, and X‐ray photoelectron spectroscopy. Both compounds contained nano‐sized particles that catalyzed OER in the presence of CAN. The turnover frequencies for both catalysts were 0.02 (mmolO2 /molMn⋅s). [ABSTRACT FROM AUTHOR]

Colloidal quantum dot (QD) photocatalysts have the electrochemical and optical properties to be highly effective for a range of redox reactions. QDs are proven photo‐redox catalysts for a variety of reactions in organic solvents but are less prominent for aqueous reactions. Aqueous QD photocatalysts require hydrophilic ligand shells that provide long‐term colloidal stability but are not so tight‐binding as to prevent catalytic substrates from accessing the QD surface. Common thiolate ligands, which also poison many co‐catalysts and undergo photo‐oxidative desorption, are therefore often not an option. This paper describes a framework for the design of water‐solubilizing ligands that are in dynamic exchange on and off the QD surface, but still provide long‐term colloidal stability to CdS QDs. The binding affinity and inter‐ligand electrostatic interactions of a bifunctional ligand, aminoethyl phosphonic acid (AEP), are tuned with the pH of the dispersion. The key to colloidal stability is electrostatic stabilization of the monolayer. This work demonstrates a means of mimicking the stabilizing power of a thiolate‐bound ligand with a zwitterionic tail group, but without the thiolate binding group. [ABSTRACT FROM AUTHOR]

The article abstracts of various research papers that were recently been published in sister journals of the "Chemistry: A European Journal," including papers on synthesis of lactones, biosynthesis of lactic acid and homogeneous catalysis.

Abstract: Ionic porous organic polymers have attracted much attention due to their broad applications in catalysis, energy storage/conversion, proton conduction, etc. In this paper, an ionic porous organic polymer, CMP‐PM‐Me, was synthesized through post‐synthetic modification of a pyrimidine‐based conjugated microporous polymer, CMP‐PM, which was constructed by the palladium catalyzed Sonogashira reaction of 1,3,5‐triethynylbenzen and 2,5‐dibromopyrimidine. These two polymers are porous with Brunauer–Emmett–Teller surface areas of 416 and 241 m2 g−1 for CMP‐PM and CMP‐PM‐Me, respectively. Due to the cationic framework, CMP‐PM‐Me exhibits a much faster and more efficient adsorption performance to anionic dyes such as Congo red (CR) and methyl orange (MO) than that of CMP‐PM with a neutral framework. The uptakes for CR are 400.0 mg g−1 for CMP‐PM‐Me and 344.8 mg g−1 for CMP‐PM, respectively. Furthermore, CMP‐PM‐Me could quickly and drastically separate anionic dyes from the binary mixed solution of anionic and nonanionic dyes within a short time. This work not only enriches the family of ionic organic porous polymers and widens their synthetic utility, but also demonstrates their applications in the adsorption and separation of anionic dyes in water. [ABSTRACT FROM AUTHOR]

In the last decade, numerous studies of graphene doping by various metal and nonmetal elements have been done in order to obtain tailored properties, such as non-zero band gap, electrocatalytic activity, or controlled optical properties. From nonmetal elements, boron and nitrogen were the most studied dopants. Recently, it has been shown that in some cases the enhanced electrocatalytic activity of graphene and its derivatives can be attributed to metal impurities rather than to nonmetal elements. In this paper, we investigated the electrocatalytical properties of B/N codoped graphene with respect to the content of metallic impurities introduced by the synthesis procedures. For this purpose, a permanganate (Hummers) and a chlorate (Hofmann) route were used for the preparation of the starting graphene oxides (GO). The GO used for the synthesis of B/N codoped graphene had significantly difference compositions of oxygen functionalities as well as metallic impurities introduced by the different synthetic procedures. We performed a detailed structural and chemical analysis of the doped graphene samples to correlate their electrocatalytic activity with the concentration of incorporated boron and nitrogen as well as metallic impurities. [ABSTRACT FROM AUTHOR]

Controlling the shape of the conducting polymer-noble metal composites is a key factor in determining their properties and applications. In this paper, we demonstrate a novel strategy to fabricate Au-polypyrrole (PPy) composites with unusual morphology using poly(4-vinylpyridine) (P4VP) brush grafted on graphene oxide (GO) as a reaction chamber. When the GO/P4VP brush bearing AuCl4− ions is exposed to pyrrole vapor or directly immersed into pyrrole solution, novel Au−PPy nanotubules and flower-like Au mesoparticles-PPy composites are formed on the surface of GO/P4VP brush, respectively. The application of the as-prepared GO/P4VP/Au−PPy composites in catalysis and surface-enhanced Raman scattering (SERS) are investigated. The relevant results exhibit that the GO/P4VP/Au−PPy nanotubules can act as an efficient catalyst for reduction of 4-nitrophenol, and the GO/P4VP/flower-like Au mesoparticles-PPy composites can be used as a sensor platform for the detection of organic molecules by SERS. [ABSTRACT FROM AUTHOR]

Fuel cells, water electrolyzers, and metal-air batteries are important energy systems that have started to play some roles in our renewable energy landscapes. However, despite much research works carried out on them, they have not yet found large-scale applications, mainly due to the unavailability of sustainable catalysts that can catalyze the reactions employed in them. Currently, noble metal-based materials are the ones that are commonly used as catalysts in most commercial fuel cells, electrolyzers, and metal-air batteries. Hence, there has been considerable research efforts worldwide to find alternative noble metal-free and metal-free catalysts composed of inexpensive, earth-abundant elements for use in the catalytic reactions employed in these energy systems. In this concept paper, a brief introduction on catalysis in renewable energy systems, followed by the recent efforts to develop sustainable, heteroatom-doped carbon and non-noble metal-based electrocatalysts, the challenges to unravel their structure-catalytic activity relationships, and the authors' perspectives on these topics and materials, are discussed. [ABSTRACT FROM AUTHOR]

Lignosulfonate (LS) is an organic waste generated as a byproduct of the cooking process in sulfite pulping in the manufacture of paper. In this paper, LS was used as an anionic supporting material for immobilizing cationic species, which can then be used as heterogeneous catalysts in some organic transformations. With this strategy, three lignin-supported catalysts were prepared including 1) lignin-SO3Sc(OTf)2, 2) lignin-SO3Cu(OTf), and 3) lignin-IL@NH2 (IL=ionic liquid). These solid materials were then examined in many organic transformations. It was finally found that, compared with its homogeneous counterpart as well as some other solid catalysts that are prepared by using different supports with the same metal or catalytically active species, the lignin-supported catalysts showed better performance in these reactions not only in terms of activity but also with regard to recyclability. [ABSTRACT FROM AUTHOR]

Metal nitrenoids and metal carbenoids exhibit similar reactivity for insertion into a C−H bond and a C=C double bond. These reactions have attracted the attention of organic chemists due to their unusual bond-forming ability, but the reactivity difference between these chemical species has not been studied. In this paper, we examined the reactivity difference using the corresponding Rh nitrenoid and Rh carbenoid precursors. The Rh nitrenoid inserted into an intramolecular C( sp 3)−H bond adjacent to an amide nitrogen, affording functionalized spiroaminals that are ubiquitous in natural products, while the Rh carbenoid inserted into an amide C−N bond. The totally different reactivity was rationalized by the relatively low energy barrier for the C−H insertion reaction of the Rh nitrenoid. Computational analysis suggests that the origin of the discrepancy is the electrophilicity of the coordinating atoms to the Rh complex. [ABSTRACT FROM AUTHOR]

In view of their intensive use as ligands in many reactions catalyzed by transition-metal complexes, modulation of the bonding properties of N-heterocyclic carbenes (NHCs) on a rational basis is highly desirable, which should enable optimization of current applications or even promote new functions. In this paper, we provide a quantitative analysis of the chemical bond between a metal fragment AuCl and a series of 29 different NHCs in [(NHC)AuCl] complexes. NHCs electronic properties are modified through: i) variation of the groups attached to the NHC nitrogen atoms or backbone; ii) change of unsaturation/size of the NHC ring; iii) inclusion of paracyclophane moieties; or iv) heteroatom substitution on the NHC ring. For evaluating the donation and back-donation components of the Dewar-Chatt-Duncanson (DCD) model in the NHC−AuCl bond, we apply the charge-displacement (CD) analysis within the NOCV (natural orbitals for chemical valence) framework, a methodology that avoids the constraint of using symmetrized structures. We show that modulation of the NHC bonding properties requires substantial modification of their structure, such as, for instance, insertion of two ketone groups into the NHC backbone (which enhances the π back-donation bond component and introduces an effective electronic communication within the NHC ring) or replacement of a nitrogen atom in the ring with an sp3 or sp2 carbon atom (which increases and decreases the π back-donation bond component, respectively). We extend our investigation by quantitatively comparing the NHC electronic structures for a subset of 13 NHCs in [(NHC)PPh] adducts, the 31P NMR chemical shift values of which are experimentally available. The latter have been considered as a suitable tool for measuring the NHCs π acceptor properties [Bertrand et al., Angew. Chem. Int. Ed. 2013, 52, 2939-2943]. We show that information obtained using the metal fragment can be transferred to the PPh moiety and vice versa. However, the 31P NMR chemical shift values only qualitatively correlate with the π acceptor properties of the NHCs, with the stronger π acidic carbenes as the most outliners. [ABSTRACT FROM AUTHOR]

In this paper, a facile strategy is reported for the preparation of well-dispersed Pt nanoparticles in ordered mesoporous silica (Pt@OMS) by using a hybrid mesoporous phenolic resin-silica nanocomposite as the parent material. The phenolic resin polymer is proposed herein to be the key in preventing the aggregation of Pt nanoparticles during their formation process and making contributions both to enhance the surface area and enlarge the pore size of the support. The Pt@OMS proves to be a highly active and stable catalyst for both gas-phase oxidation of CO and liquid-phase hydrogenation of 4-nitrophenol. This work might open new avenues for the preparation of noble metal nanoparticles in mesoporous silica with unique structures for catalytic applications. [ABSTRACT FROM AUTHOR]

The family of polyoxometalate (POM) intercalated layered double hydroxide (LDH) composite materials has shown great promise for the design of functional materials with numerous applications. It is known that intercalation of the classical Keggin polyoxometalate (POM) of [PW12O40]3− (PW12) into layered double hydroxides (LDHs) is very unlikely to take place by conventional ion exchange methods due to spatial and geometrical restrictions. In this paper, such an intercalated compound of Mg0.73Al0.22(OH)2 [PW12O40]0.04⋅0.98 H2O (Mg3Al-PW12) has been successfully obtained by applying a spontaneous flocculation method. The Mg3Al-PW12 has been fully characterized by using a wide range of methods (XRD, SEM, TEM, XPS, EDX, XPS, FT-IR, NMR, BET). XRD patterns of Mg3Al-PW12 exhibit no impurity phase usually observed next to the (003) diffraction peak. Subsequent application of the Mg3Al-PW12 as catalyst in Knoevenagel condensation reactions of various aldehydes and ketones with Z-CH2-Z′ type substrates (ethyl cyanoacetate and malononitrile) at 60 °C in mixed solvents ( V2-propanol: Vwater=2:1) demonstrated highly efficient catalytic activity. The synergistic effect between the acidic and basic sites of the Mg3Al-PW12 composite proved to be crucial for the efficiency of the condensation reactions. Additionally, the Mg3Al-PW12-catalyzed Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate demonstrated the highest turnover number (TON) of 47 980 reported so far for this reaction. [ABSTRACT FROM AUTHOR]

This paper reports on the development of an efficient synthesis of enantiopure phospha[6]helicenes through a [2+2+2] alkyne cyclotrimerization reaction. The corresponding gold complexes proved to be highly efficient both in terms of catalytic activity and enantioselectivity in [2+2] and [4+2] cycloaddition reactions. Furthermore, in the presence of an external nucleophile, such as water or alcohols, the tandem cyclization/addition reactions take place in high yields and excellent diastereo- and enantioselectivities. [ABSTRACT FROM AUTHOR]

This paper describes the development of a palladium-catalyzed decarboxylative inter- and intramolecular condensation reaction of isoxazol-5(4 H)-ones with carbonyl compounds in the presence of PPh3, giving various 2-azabuta-1,3-dienes or pyrroles in moderate to high yields. [ABSTRACT FROM AUTHOR]

This paper describes a new route for the synthesis of 1′-homo- N-nucleoside derivatives by means of either methyltrioxorhenium (MTO) or supported MTO catalysts, with H2O2 as the primary oxidant. Under these selective conditions, the oxyfunctionalization of the heterocyclic ring and the N heteroatom oxidation were operative processes, regardless of the type of substrate used, that is, purine or pyrimidine derivatives. In addition, the oxidation of 1′-homo- N-thionucleosides, showed the occurrence of site-specific oxidative nucleophilic substitutions of the heterocyclic ring. The MTO/H2O2 system showed, in general, high reactivity under both homogeneous and heterogeneous conditions, affording the final products with high conversion values of substrates and from medium to high yields. Many of the novel 1′-homo- N-nucleoside analogues were active against the influenza A virus, without any cytotoxic effects, retaining their activity in both protected and unprotected forms. [ABSTRACT FROM AUTHOR]

Highly reduced, anionic cobalt complexes supported by bis(iminoacenaphthene) diimine (BIAN) ligands catalyze the dehydrogenation of amine boranes. Using the same catalysts, transfer hydrogenations of olefins, imines, and N‐heteroarenes with ammonia borane as a dihydrogen surrogate have been developed. Challenging trisubstituted olefins can be reduced under an external H2 pressure with ammonia borane as an activator. The cover image shows a transfer hydrogenation reaction of quinoline, an ammonia borane molecule, and the molecular structure of a precatalyst complex, where 1,5‐cyclooctadiene serves as a placeholder for vacant coordination sites. The silhouette of the beautiful city of Regensburg, Germany, where most of this work was performed, is displayed in the background. More information can be found in the Full Paper by R. Wolf, A. Jacobi von Wagelin et al. on page 238. [ABSTRACT FROM AUTHOR]

Knowledge about the active conformation of an asymmetric catalyst is highly valuable in order to understand its stereo‐inductive power, but spectroscopic access to these structures is often limited. This work showcases the application of vibrational CD spectroscopy to reveal the binding geometries of hydrogen‐bonding adducts of Takemoto's catalyst with five carboxylic acids. It was found that popular dispersion corrected DFT functionals to yield wrong structures for some of the adducts and that the characteristic VCD spectral signatures of the hydrogen‐bonded complexes are particularly helpful in identifying and correcting the wrongly predicted geometries. More information can be found in the Full Paper by C. Merten and N. M. Kreienborg on page 17948. [ABSTRACT FROM AUTHOR]

Is S2N2 aromatic? According to off‐nucleus shielding calculations reported here, S2N2 is the first example of an inorganic ring showing substantial changes in aromaticity upon transition from the aromatic ground state to either the strongly antiaromatic and unstable first singlet excited, or the antiaromatic lowest triplet electronic states. More information can be found in the Full Paper by P. B. Karadakov et al. on page 16803. [ABSTRACT FROM AUTHOR]

The importance and functional relevance of S⋅⋅⋅Sn tetrel‐bonding interactions in the activation of peroxisome proliferator‐activated receptors (PPARs) by organotin molecules was evidenced using a combined theoretical and Protein Data Bank analysis. In the figure, three hummingbirds carrying sulfur atoms establish tetrel‐bonding interactions with the organotin molecules that hang from the tree trunk. These molecules are anchored to the protein through the establishment of covalent S−Sn bonds. More information can be found in the Full Paper by A. Bauzá et al. on page 16576. [ABSTRACT FROM AUTHOR]

The cover picture highlights eight of the papers published in this themed issue, specially put together for the 17th International Symposium on Silicon Chemistry. In the top row from left to right: R. West et al. (p. 9184 ff.), P. Jutzi (p. 9192 ff.), and S. E. Denmark et al. (p. 9268 ff.). In the middle row: left C. Limberg and D. Pinkert (p. 9166 ff.) and right H. ‐ J. Freund et al. (p. 9176 ff.). In the bottom row from left to right: Y. Kaneko et al. (p. 9394 ff.), A. Filippou et al. (p. 9280 ff.), and G. H. Robinson et al. (p. 9208 ff.). The range of papers reflects how silicon chemistry can provide a platform for synergistic solutions through novel method developments of synthetic and analytical tools and the interconnection of different disciplines in molecular and materials chemistry. [ABSTRACT FROM AUTHOR]

The application of computational methods to predict mutations that can enhance the catalytic power of enzymes can be of great importance, since it allows a more rational and directed way to mutate the enzymes, which can save time and resources compared to producing mutations at random. We present computational methods to predict mutations that enhance the catalytic rate of DszD, an enzyme that intervenes in the 4S pathway together with DszA, DszB and DszC. This has potential as a cheaper and greener alternative for biodesulfurization of crude oil. More information can be found in the Full Paper by Ramos et al. on page 17231 ff. [ABSTRACT FROM AUTHOR]

The nuclear magnetic resonance (NMR) detectability of several TB‐relevant agents have been significantly improved through the use of the parahydrogen‐based hyperpolarization protocol signal amplification by reversible exchange (SABRE) in conjunction with the 2H‐labelling of key sites within their molecular structures and the 2H‐labelling of the magnetization‐transfer catalyst. The T1 relaxation times and polarization levels of these agents are quantified under test conditions to produce a protocol to identify structurally optimized motifs for future detection in MRI. For more information see the Full Paper by S. B. Duckett et al. on page 16990 ff. [ABSTRACT FROM AUTHOR]

Guanosine‐rich DNA sequences can fold into quadruplex structures which are not only biologically relevant, but also promising for applications in aqueous homogenous catalysis. Here, an asymmetric Michael addition is catalyzed by covalently modified G‐quadruplexes in combination with copper ions. Using systematic chemical variation and various spectrometric techniques, the key parameters that govern rate acceleration and stereoselectivity were identified. More information can be found in the Full Paper by A. Jäschke et al. on page 12162 ff. [ABSTRACT FROM AUTHOR]

δ ‐ Lactones withanti ‐ Baeyer – Villiger regiochemistry are formed by aerobic, cerium ‐ catalyzed umpolung reactions. A mechanistic proposal involving an oxycarbenium ion intermediate is supported by kinetics of the reaction (Hammett plot). Furthermore, a conformational analysis obtained by DFT calculations explains the anti ‐ Baeyer – Villiger regiochemistry of the rearrangement reaction by a primary stereoelectronic effect. More information can be found in the Full Paper by J. Christoffers, et al. on page 7245. [ABSTRACT FROM AUTHOR]

Mono‐protected l‐amino acid (l‐MPAA)‐accelerated iridium(III)‐catalyzed halogenation of (hetero)anilides at room temperature provides a general route to halogenation (Cl, Br, I) of (hetero)arenes through C(sp2)−H activation. The synthetic utility of the method was demonstrated through the synthesis of a quinolone derivative. More information can be found in the Full Paper by I. A. Nicholls and S. Kathiravan on page 7031. [ABSTRACT FROM AUTHOR]

The influence of peripheral groups present at the macrocycle (c‐, d‐, meso‐positions) of vitamin B12 derivatives on catalytic activity in the C−H activation of olefins is described. These catalysts are shown to halo the engraved bell. To justify the obtained yields, DFT calculations were performed, examining the relationship between the electron density on the cobalt ion and the yield. We discovered that the experimental points mapped out the bell‐shaped Gaussian distribution. More information can be found in the Full Paper by K. ó Proinsias, D. Gryko et al. on page 7024. [ABSTRACT FROM AUTHOR]

Coordination Complexes Transition‐metal binuclear complexes with tetradentate ligands are very useful in applications for catalytic reactions and molecular magnetic materials. Two azido‐bridged Ni(II) complex shows strong ferromagnetic coupling via the bridged end‐on azido ligands, while two ethoxo‐bridged Fe(III) complex exhibits antiferromagnetic interaction via the bridged ethoxo groups. Remarkably, the Ni(II) binuclear complex shows excellent catalytic activities for the epoxidation of aliphatic, aromatic, and terminal olefins, in which it is the first example as an efficient Ni(II) catalyst for the terminal olefin epoxidation. More information can be found in the Full Paper by K. S. Min et al. on page 3023 ff. [ABSTRACT FROM AUTHOR]

Cyclic peptides are a class of compounds with high therapeutic potential. They possess very promising bioactivities, such as antitumor and antiviral (including anti ‐ HIV) activity. However, effective production of these compounds by synthetic approaches have not been achieved to date, which motivates the study of biological methods of macrocyclization of peptides. A quantum mechanics/molecular mechanics (QM/MM) study was used to unveil the atomistic portrait and energy profile of the catalytic mechanism of PatG macrocyclase (PatGmac), which is synthesized by an obligate symbiont of a sea sponge (Lissoclinum patella). PatGmac can cyclize a variety of peptides requiring only a recognition signal sequence (AYDG). This enzyme may thus hold the key to producing high ‐ interest cyclic peptides with therapeutic and biotechnological applications on large scale and attract further attention to the immense potential of the underwater world. More information can be found in the Full Paper by M. J. Ramos et al. on page 13089 ff. [ABSTRACT FROM AUTHOR]

Iridium stands at the center of a vortex of electrons that are transferred to and from the surrounding reaction components in this radical aminocarbonylation method. The combination of visible ‐ light irradiation and low ‐ pressure ex situ carbon monoxide generation makes this an attractive and operationally simple approach for preparing β ‐ hydride ‐ containing alkyl amides. Additional cover art acknowledgements: Bobo Skillinghaug and Johan Sjöstedt. More information can be found in the Full Paper by L. R. Odell et al. on page 9155 ff. [ABSTRACT FROM AUTHOR]

Nanoparticle Agglomeration Reversible agglomeration of uncapped nanoparticles is revealed. Bismuth oxide nanoparticles deagglomerate in nanoparticle impact voltammetry. Electrolytically induced deagglomeration within the electrode diffusion field is confirmed through imaging of the near exclusive deposition of monomeric nanoparticle deposits. For more details, see the Full Paper by R. G. Compton et al. on page 7408 ff. [ABSTRACT FROM AUTHOR]

A cerium complex with a dianionic pentadentate ligand acted as a catalyst for aerobic oxidation of arylmethanols, in which a dinuclear cerium(IV) side‐on peroxo complex was the key intermediate. The corresponding trivalent complex was able to activate dioxygen, and the oxidation proceeded catalytically under atmospheric pressure with inexpensive and environmentally friendly dioxygen as the primary oxidant. More information can be found in the Full Paper by K. Mashima, H. Tsurugi et al. on page 4008 ff. [ABSTRACT FROM AUTHOR]

Biocatalysis γ‐Butyrobetaine hydroxylase (BBOX) contains an aromatic cage for the recognition of the positively charged trimethylammonium group of its γ‐butyrobetaine (γBB) substrate. Enyzme binding and kinetic analyses on substrate analogues with P and As substituting for N in the trimethylammonium group show that the analogues are good BBOX substrates, which follow the efficiency trend N+>P+>As+, but an uncharged carbon analogue of γBB is not a good BBOX substrate, thus highlighting the importance of energetically favorable cation–π interactions in productive substrate recognition. For more information, see the Full Paper from J. Mecinović et al. on page 1270 ff. [ABSTRACT FROM AUTHOR]

Polyheterohalogenated naphthalenes are synthesized by using a copper ‐ catalyzed regioselective benzannulation of chloro ‐ , bromo ‐ , and iodoalkynes. This modular approach based on readily available haloalkynes and benzaldehydes provides independent control of halide substitution at six of the seven naphthalene positions of 2 ‐ arylnaphthalenes. Insight into the reaction mechanism and the origin of the regioselectivity is described by W. R. Dichtel et al. in their Full Paper on page 18122 ff. [ABSTRACT FROM AUTHOR]

A catalytic vortex producing quinones was realized by a (μ ‐ η2:η2) ‐ peroxo dicopper(II) core resembling the active centre of tyrosinase. This biomimetic species is stabilised by a new bis(pyrazolyl)imidazolylmethane ligand. Kinetic experiments show that this peroxide species mediates phenole hydroxylation with almost biological speed. This enhancement was achieved by exchanging a pyridinyl donor against the imidazolyl donor. For more details, see the Full Paper by S. Herres ‐ Pawlis and co ‐ workers on page 17639 ff. [ABSTRACT FROM AUTHOR]

The assembly of selectively substituted fluorenes and fluorenols is achieved by a Rh ‐ catalyzed cyclotrimerization of substituted 1 ‐ propynyl ‐ 2 ‐ ethynylbenzenes with terminal and internal alkynes. The formed fluorenols could be easily converted into the corresponding substituted 9,9′ ‐ spirobifluorenes, which are candidates for optoeletronics. The spirobifluorene structure resembles dougong—a structural element of interlocking wooden brackets, which is nicely exemplified by the ceiling of the Hall of Supreme Harmony in the Forbidden City. For more details see the Full Paper by M. Kotora and co ‐ workers on page 13577 ff. [ABSTRACT FROM AUTHOR]

A key mechanistic finding in the pyrimidine ‐ directed Ru ‐ catalysed CH arylation of indoles is that the catalyst loses its cymene ligand. This is described in detail in the Full Paper by L. T. Pilarski and co ‐ workers on page 5380 ff. The picture illustrates this by way of a ruthenium “magician” standing on a pyrimidine directing group and breaking the indole CH bond by casting a spell with his wand. With his other hand, the magician is raising a hat in the shape of the cymene ligand. An aryl boronic acid, floating nearby, represents one of the other reagents used in the reaction. [ABSTRACT FROM AUTHOR]

Oligonucleotides In their Full Paper on page 3596 ff., J. E. Šponer et al. report on the results of molecular dynamics (MD) simulations used to investigate whether tetraloop ‐ like overhang geometries might give rise to ribozyme ‐ like activity in short Watson – Crick complementary oligoG/oligoC sequences. Their results demonstrate that the studied tetraloop ‐ like overhang geometries are able to stabilize the 2′ ‐ and 3′ ‐ OH groups of the acceptor ribose in the vicinity of the phosphate of the donor strand for several tens to hundreds of nanoseconds, which is entirely sufficient for the required transphosphorylation reactions to proceed. [ABSTRACT FROM AUTHOR]

In the final step of fermentation, which is catalysed by yeast alcohol dehydrogenases, hydride ion is transferred from NADPH to acetaldehyde bound and activated by the active ‐ site zinc ion; the ethanol for fine beverages results. Inspired by this biological chemistry, in their Full Paper on page 2821 ff., S. Colbran et al. report an artificial catalyst for the transfer hydrogenation of imines. Experiments backed by theoretical calculations suggest the mechanism of the new catalyses parallels that of the natural system. [ABSTRACT FROM AUTHOR]

Polyoxometalate ligands play a key role in facilitating a ruthenium catalyst access to a high ‐ valent reactive state in aerobic oxidation in water. In their Full Paper on page 10932 ff., C. Bo, M. Bonchio et al. show that the reaction involves novel ruthenium – peroxo and oxene intermediates embedded within a totally inorganic POM environment. This breakthrough perspective is one the central themes of the European COST action entitled Polyoxometalate Chemistry for Molecular Nanoscience (PoCheMoN). The cover art is inspired by the popular fantasy game (Pokémon). [ABSTRACT FROM AUTHOR]

An inorganic–organic hybrid surfactant with a hexavanadate cluster as the polar head group underwent stepwise assembly into micelles and finally, a 1D nanobelt structure with the cooperation of hydrophobic, electrostatic, and hydrogen‐bonding interactions; these last interactions are directional and lead to the anisotropic assemblies. The nanobelts are highly efficient heterogeneous catalysts for the oxidation of organic sulfides because most of the hexavanadates are exposed to the surface, showing its potential application in the petroleum industry and in environmentally benign chemistry. For more details see the Full Paper by T. Li, Y. Wei, T. Liu et al. on page 9589 ff. [ABSTRACT FROM AUTHOR]