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Herein is reported the catalytic, visible light-promoted, decarboxylative halogenation (bromination, chlorination, and iodination) of aliphatic carboxylic acids. This operationally-simple reaction tolerates a range of functional groups, proceeds at room temperature, and is redox neutral. By employing an iridium photocatalyst in concert with a halogen atom source, the use of stoichiometric metals such as silver, mercury, thallium, and lead can be circumvented. This reaction grants access to valuable synthetic building blocks from the large pool of cheap, readily available carboxylic acids.

An unprecedented and challenging radical-radical cross-coupling of α-aminoalkyl radicals with monofluoroalkenyl radicals derived from gem-difluoroalkenes was achieved. This first example of tandem C(sp(3) )-H and C(sp(2) )-F bond functionalization through visible-light photoredox catalysis offers a facile and flexible access to privileged tetrasubstituted monofluoroalkenes under very mild reaction conditions. The striking features of this redox-neutral method in terms of scope, functional-group tolerance, and regioselectivity are illustrated by the late-stage fluoroalkenylation of complex molecular architectures such as bioactive (+)-diltiazem, rosiglitazone, dihydroartemisinin, oleanic acid, and androsterone derivatives, which represent important new α-amino C-H monofluoroalkenylations.

Multiple-bonded iron-oxo and -nitrido species have been identified or proposed as key intermediates in a range of important chemical transformations. The reported model complexes feature various coordination geometries and distinct electronic structures, and therefore exhibit diverse reactivity. The present contribution highlights the synergy from both experimental and theoretical standpoints to elucidate their different bonding situations and delineate their common mechanistic features in hydrogen-atom abstraction processes. Our analysis reveals that a radical centered on the abstracting atom E (E=O, N), which is generated via homolysis of covalent Fe−E bonds upon approaching the transition state, is an intrinsic C−H cleaving agent. The iron-oxo species is predicted to be more reactive than its nitride congener, in general, because the O−H bond formed in the H-atom transfer process is often stronger than the corresponding N−H bond.

This Review covers design strategies, synthetic challenges, host-guest chemistry, and functional properties of interlocked supramolecular cages. Some dynamic covalent organic structures are discussed, as are selected examples of interpenetration in metal-organic frameworks, but the main focus is on discrete coordination architectures, that is, metal-mediated dimers. Factors leading to interpenetration, such as geometry, flexibility and chemical makeup of the ligands, coordination environment, solvent effects, and selection of suitable counter anions and guest molecules, are discussed. In particular, banana-shaped bis-pyridyl ligands together with square-planar metal cations have proven to be suitable building blocks for the construction of interpenetrated double-cages obeying the formula [M4 L8 ]. The peculiar topology of these double-cages results in a linear arrangement of three mechanically coupled pockets. This allows for the implementation of interesting guest encapsulation effects such as allosteric binding and template-controlled selectivity. In stimuli-responsive systems, anionic triggers can toggle the binding of neutral guests or even induce complete structural conversions. The increasing structural and functional complexity in this class of self-assembled hosts promises the construction of intelligent receptors, novel catalytic systems, and functional materials.

A selective, practical and general incorporation of fluoroalkyl groups into organic frameworks is of great interest for synthesis. Herein we report the first metal-free, initiator-free, and general photochemical perfluoroalkylation of a variety of N,N-dialkylhydrazones at room temperature in the absence of any external photocatalyst. It constitutes an important advance in perfluoroalkyl radical addition to CN π bonds for the synthesis of hydrazones instead of amines. Affordable and easily available perfluoroalkyl iodides serve as effective precursors. The excellent regio-, stereo- and chemoselectivity as well as the broad substrate scope make this a very promising synthetic tool.

N-heterocyclic carbene (NHC)-metal complexes have become known as efficient catalysts for numerous transition metal catalyzed processes. An important application of many NHC-metal complexes is in the field of asymmetric catalysis, and this is achieved through the introduction of chiral information on the NHC ligands. Among the asymmetric transformations catalyzed by NHC-metal complexes is asymmetric hydrogenation, which is an attractive process for the synthesis of optically active compounds due to its high atom economy. However, to date, few chiral NHC-metal catalysts have been reported to be highly stereoselective for asymmetric hydrogenation. Over the past few years our group has made some significant breakthroughs within the field of asymmetric hydrogenation using chiral NHC catalysts. We have reported the NHC-Ru catalyzed asymmetric hydrogenation of a wide range of heterocyclic compounds with high regio- and enantioselectivity. The field of chiral NHC-metal complex catalyzed asymmetric hydrogenation ...

The Hg-rich amalgams La11,7Hg44,03 (I), Nd11Hg44.5 (II), and Sm11Hg44.5 (III) are prepared by dissolving the lanthanoid metals in a Hg surplus (evacuated glass ampoule, 300 °C, 12 h) followed by removal of excess Hg via distillation.

Rapid progress has been made in the last five years towards resolution of the structure of nature's water splitting catalyst - a Mn4O5Ca cofactor embedded in Photosystem II - especially in the field of X-ray crystallography. In addition, recent magnetic resonance data have allowed the structure of the cofactor to be accessed in its last metastable intermediate state, prior to O-O bond formation. This activated form of the catalyst is geometrically similar to that seen by X-ray crystallography, which represents the resting state of the cofactor, but requires the coordination of an additional water molecule to the cofactor, rendering all Mn ions six coordinate. Importantly, it locates two water derived, Mn bound oxygen ligands in close proximity. It is these two oxygen ligands that likely form the product O2 molecule, as proposed earlier by quantum chemical modeling. Current views on the molecular level events that facilitate catalyst activation, that is, catalyst/substrate deprotonation, Mn oxidation and water molecule insertion are briefly described.

As possible electrolyte materials for all-solid-state Na-ion batteries (NIBs), scandium-substituted Na3Zr2(SiO4)2(PO4) in the structure of NASICONs (Na superionic conductors) has received hardly any attention so far, although among all the trivalent cations, Sc3+ might be the most suitable substitution ion for Na3Zr2(SiO4)2(PO4) because the ionic radius of Sc3+ (74.5 pm) is the closest to that of Zr4+ (72.0 pm). In this study, a solution-assisted solid-state reaction (SASSR) method is described, and a series of scandium-substituted Na3Zr2(SiO4)2(PO4) with the formula of Na3+xScxZr2-x(SiO4)2(PO4) (NSZSPx, 0 ≤ x ≤ 0.6) have been prepared. This synthesis route can be applied for powder preparation on a large scale and at low cost. With increasing degrees of scandium substitution, the total conductivity of the samples also increases. An optimum total Na-ion conductivity of 4.0 × 10–3 S cm–1 at 25 °C is achieved by Na3.4Sc0.4Zr1.6(SiO4)2(PO4) (NSZSP0.4), which is the best value of all reported polycrystalline ...

This review summarizes the progress in organo- f- element chemistry during the year 2015. The year 2015 witnessed a slight increase of contributions in the fields of organolanthanide and organoactinide chemistry over 2014 ( ca. 10% more). A continuing trend for many years which continued into 2015 was the investigation of highly reactive lanthanide alkyl complexes supported by non-cyclopentadienyl ligands ( e.g. amidinates, β -diketiminates etc. ). Many of these complexes found useful applications in homogeneous catalysis. Trinuclear rare-earth metal methylidene (CH 2 2− ) complexes are an emerging class of compounds that serve as methylidene transfer agents for the methylenation of carbonyl compounds. The range of rare-earth metal alkyl complexes bearing different types of carbene ligands have also been further expanded. Several new lanthanide phosphido and phosphinidene complexes have been stabilized by specially designed N,N ′-chelating ligands. The range of fully characterized lanthanide(II) compounds of the type [K(2.2.2-cryptand)][Cp′ 3 Ln] (Cp′ = C 5 H 4 SiMe 3 ) has again been significantly expanded so that the +2 ions are now available for yttrium and all the lanthanides (except promethium, which was not studied due to its high radioactivity). The first well-defined lutetacyclopentadienes have been synthesized and their reactivity has been studied. The synthesis, structure, and reactivity of the extremely reactive yttrium metallocene ethyl complex Cp* 2 Y(CH 2 CH 3 ), including activation of methane, have been reported. Significant progress has also been made in the field of endohedral metallofullerenes. Notably, encapsulation of a large La 2 C 2 cluster inside D 5 (450) C 100 induced a 5% axial compression of the cage, as compared with the structure of La 2 @D 5 (450) C 100 . The number of well-characterized heterometallic organolanthanide complexes has also witnessed a remarkable growth. An impressive number of interesting contributions have been published in the field of organolanthanide catalysis, with an emphasis on Ln-catalyzed olefin and diene polymerization. Approximately 20% of the papers published in 2015 were in the area of organoactinide chemistry. Notable results include the synthesis and characterization of homoleptic uranium(IV) tetrabenzyl complexes and a simple mono(imido) thorium complex and the first bis(imido) thorium complex, K[Th( NDipp))(NR 2 ) 3 ] and K 2 [Th( NDipp) 2 )(NR 2 ) 2 ] (Dipp = 2,6-diisopropylphenyl, R = SiMe 3 ). The reactivity of the unusual base-free imido complex [ η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 Th N( p -tolyl) has also been studied. A highly remarkable achievement in 2015 was the synthesis of crystalline molecular complexes of the [{C 5 H 3 (SiMe 3 ) 2 } 3 Th] − anion containing thorium in the formal +2 oxidation state. Various unusual transformations have been achieved using the Cp* 2 Th platform. For example, a unique thorium phosphinidene complex obtained from the reaction of Cp* 2 Th(CH 3 ) 2 with H 2 P(2,4,6- i Pr 3 C 6 H 2 ) has been prepared and structurally characterized. Other remarkable results include the preparation of novel actinide metallacyclocumulenes and metallacyclopentadienes. The synthesis of [3]thoro- and [3]uranocenophanes, the first structurally authenticated ansa -bridged actinocenes, has also been reported. Finally, significant progress has been made in the field of organoactinide catalysis.

The design, development and application of an efficient procedure for the concise synthesis of the 1,3-syn- and anti-tetrahydropyrimidine cores of manzacidins are reported. The intramolecular allylic substitution reaction of a readily available joint urea-type substrate enables the facile preparation of both diastereomers in high yields. The practical application of this approach is demonstrated in the efficient and modular preparation of the authentic heterocyclic cores of manzacidins, structurally unique bromopyrrole alkaloids of marine origin. Additional features of this route include the stereoselective generation of the central amine core with an appending quaternary center by an asymmetric addition of a Grignard reagent to a chiral tert-butanesulfinyl ketimine following an optimized Ellman protocol and a cross-metathesis of a challenging homoallylic urea substrate, which proceeds in good yields in the presence of an organic phosphoric acid.

Diels–Alder cycloaddition reactions of 1,3,5-hexatriynes with tetraphenylcyclopentadienone have been performed, and mainly gave 1,2-diethynyl-3,4,5,6-tetraphenylbenzene derivatives as products. The Diels–Alder reactions were optimized under conventional heating and microwave irradiation conditions, and showed good selectivity towards the central carbon–carbon triple bond of the triyne. Empirical evidence suggests that the selectivity of the reaction is governed predominantly by the steric demands of the end-groups of the triyne. Several of the Diels–Alder products could be further elaborated by a sequence of desilylation and oxidative homocoupling to provide dimeric products. The homocoupling reaction was optimized by Pd catalysis. The X-ray crystallographic analysis of two derivatives is reported.

A comparative study on the catalytic activity of different group 9 [Cp*M(III)] complexes in the formal [4 + 2] cycloaddition of arenes with rarely explored free imines and dioxazolones for the construction of multisubstituted quinazolines is reported herein. This investigation revealed that the cobalt catalyst is uniquely suited to this transformation due to its strong Lewis acidity and high sensitivity to steric hindrance.

In the last decade, many nanomachines with controlled molecular motions have been studied, mainly on metallic surfaces, which are easy to obtain very clean, and are stable over months. However, the studies of mechanical properties of nanomachines are mainly performed at very low temperatures, usually between 5 and 80 K, which prevents any kind of applications. In this Minireview, we will present our strategy to operate at higher temperatures, in particular through the use of semiconducting silicon surfaces. We also review our best achievements in the field through some examples of rotating molecular machines that have been designed, synthesized, and studied in our groups. On metallic surfaces, the nanovehicles are molecules with two or four triptycenes as wheels and the molecular motor is built around a ruthenium organometallic center with a piano-stool geometry and peripheric ferrocenyl groups. On semiconducting silicon surfaces, vehicles are also made from triptycene fragments and the rotor is a pentaphenylbenzene molecule.

The authors thank the European Union (Marie Curie ITN SusPhos, Grant Agreement No. 317404) for financial support.

Highly selective tandem nucleophilic addition/cross-coupling reactions of alkynes have been developed using visible-light-promoted dual gold/photoredox catalysis. The simultaneous oxidation of Au(I) and coordination of the coupling partner by photo-generated aryl radicals, and the use of catalytically inactive gold precatalysts allows for high levels of selectivity for the cross-coupled products without competing hydrofunctionalization or homocoupling. As demonstrated in representative arylative Meyer-Schuster and hydration reactions, this work expands the scope of dual gold/photoredox catalysis to the largest class of substrates for gold catalysts and benefits from the mild and environmentally attractive nature of visible-light activation.

Stromata (fruiting bodies) from the xylariaceous fungus Annulohypoxylon truncatum collected in Texas were analyzed for novel secondary metabolites. Two asterriquinone-type pigments named truncaquinones A ( 1 ) and B ( 2 ) were obtained by preparative HPLC in addition to the known truncatone. Their structures were elucidated by HRESIMS and NMR data. 4 J correlations were crucial to assign a methoxy signal in 1 ; these were observed in HMBC spectra with extended long range evolution delay (Δ) times. The pigments exhibited cytotoxic effects besides weak activity against Gram positive bacteria.

Described herein is a new and straightforward decarboxylative di- and trifluoromethylthiolation of alkyl carboxylic acids promoted by visible light. This approach enables the synthesis of biologically relevant alkyl SCF2H and SCF3 compounds from cheap and abundant carboxylic acids. The method is operationally simple, using irradiation from household light sources, and its mild reaction conditions make it tolerant of a range of functional groups. The strategy employs electrophilic phthalimide-derived di- and trifluoromethylthiolation reagents and exploits the ability of the imidyl radical to carry a radical chain.

Azobenzenes are versatile photoswitches that can be cycled between their trans- and cis-configuration with light. The wavelengths required for this isomerization are substantially shifted from the UV to the visible range through tetra-ortho-chlorination. These halogenated azobenzenes display unique photoswitching characteristics, but their syntheses remain limited and inefficient. A new general method for the synthesis of tetra-ortho-chloro azobenzenes has been developed, which relies on direct palladium(II)-catalyzed C-H activation of pre-existing standard azobenzenes. This late-stage functionalization has a broad substrate scope and can be used to create a variety of useful building blocks for the construction of more elaborate redshifted photopharmaceuticals. This method is used to prepare red-AzCA-4, a photoswitchable vanilloid that enables optical control of the cation channel TRPV1 with visible light.

Although a large number of pharmaceutical therapies are available to treat cardiovascular diseases like heart failure, in many medical conditions treatment is still not optimal and, therefore, the need for innovative, safe and efficacious drugs is still very high in this indication. Biomarkers are an important tool in the preclinical and clinical drug development process; they allow patient selection for clinical studies as well as therapy monitoring during studies. Biomarker concepts in cardiovascular indications differ very much from those in oncology and are very diverse. The present article gives an overview of the pathomechanisms of heart failure and describes the socioeconomic impact of the disease and the biomarker strategies being applied in the development of new heart failure drugs. The focus lies on protein biomarkers that can be measured in the blood and on functional biomarkers that can be derived from implanted and wearable medical devices.

Reaction of chromonyl Meldrum’s acid and N-substituted 2-aminobenzamides was studied in the presence of acidic and basic catalysts. The use of methanesulfonic acid as a catalyst in this reaction led to the synthesis of chromonyl quinazolinones through employing Meldrum’s acid as a carbon leaving group. However, in the presence of basic catalyst, this reaction gave functionalized 2-pyridones.

The design of new and better heterogeneous catalysts needed to accommodate the growing demand for energy from renewable sources is an important challenge for coming generations. Most surface catalyzed processes involve a large number of complex reaction networks and the energetics ultimately defines the turn-over-frequency and the selectivity of the process. In order not to get lost in the large quantities of data, simplification schemes that still contain the key elements of the reaction are required. Adsorption and transition state scaling relations constitutes such a scheme that not only maps the reaction relevant information in terms of few parameters but also provides an efficient way of screening for new materials in a continuous multi-dimensional energy space. As with all relations they impose certain restrictions on what can be achieved and in this paper, I show why these limitations exist and how we can change the behavior through an energy-resolved approach that still maintains the screening capabilities needed in computational catalysis.

Herein, we report a new visible-light-promoted strategy to access radical trifluoromethylthiolation reactions by combining halide and photoredox catalysis. This approach allows for the synthesis of vinyl-SCF3 compounds of relevance in pharmaceutical chemistry directly from alkenes under mild conditions with irradiation from household light sources. Furthermore, alkyl-SCF3-containing cyclic ketone and oxindole derivatives can be accessed by radical-polar crossover semi-pinacol and cyclization processes. Inexpensive halide salts play a crucial role in activating the trifluoromethylthiolating reagent towards photoredox catalysis and aid the formation of the SCF3 radical.

On the basis of many literature measurements, a critical overview is given on essential noncovalent interactions in synthetic supramolecular complexes, accompanied by analyses with selected proteins. The methods, which can be applied to derive binding increments for single noncovalent interactions, start with the evaluation of consistency and additivity with a sufficiently large number of different host–guest complexes by applying linear free energy relations. Other strategies involve the use of double mutant cycles, of molecular balances, of dynamic combinatorial libraries, and of crystal structures. Promises and limitations of these strategies are discussed. Most of the analyses stem from solution studies, but a few also from gas phase. The empirically derived interactions are then presented on the basis of selected complexes with respect to ion pairing, hydrogen bonding, electrostatic contributions, halogen bonding, π–π-stacking, dispersive forces, cation−π and anion−π interactions, and contributions f...

Difluorotris(pentafluoroethyl)phosphorane, (C 2 F 5 ) 3 PF 2 , was found to be an active catalyst for the Michael addition reaction of 1,3-β-diketones or β-ketoesters (Michael donors) and linear or cyclic unsaturated ketones (Michael acceptors). The reaction proceeds under mild conditions with low catalyst loading and results in the formation of the Michael addition products in moderate to high yields. The developed protocol does not require the use of a base for the in situ generation of a carbanion (Michael donor).

This report describes Bronsted acid catalyzed de novo synthesis of silyldienol ethers bearing tetrasubstituted double bonds via an intermediacy of 2-silyloxypentadienyl cations. The reactivity of these novel cationic intermediates could be modulated and harnessed toward direct nucleophilic additions regioselectively at the γ-position to produce highly functionalized silyldienol ethers with tunable control of the resulting double bond geometry.

A redox-neutral cobalt(III)-catalyzed synthetic approach for the direct synthesis of unprotected indoles showcasing an N-N bond cleavage is reported. The herein newly introduced Boc-protected hydrazines establish a beneficial addition to the limited portfolio of oxidizing directing groups for cobalt(III) catalysis. Moreover, the developed catalytic methodology tolerates a good variety of functional groups.

The first gold-catalyzed photoredox C(sp(2) )-H difluoroalkylation and perfluoroalkylation of hydrazones with readily available RF -Br reagents is reported. The resulting gem-difluoromethylated and perfluoroalkylated hydrazones are highly functionalized, versatile molecules. A mild reduction of the coupling products can efficiently produce gem-difluoromethylated β-amino phosphonic acids and β-amino acid derivatives. In mechanistic studies, a difluoroalkyl radical intermediate was detected by an EPR spin-trapping experiment, indicating that a gold-catalyzed radical pathway is operating.

In this novel approach, a Ru(II)-NHC catalyst is used to chemoselectively hydrogenate thiazepinone derivatives in good to high yields and with excellent enantioselectivities.

An efficient single-step conversion of (R)-BINAM to highly enantiopure (R)-NOBIN is developed.

Thermal condensation of 2,3-diamino-1,4-(bistriisopropylsilylethynyl)benzene, -naphthalene,-anthracene, and -benzothiadiazole substrates with 1,2-naphthalenedione forms bent benzophenazine-type heteroarenes in a one-step reaction in good to excellent yields. The targets are investigated by UV/Vis spectroscopy, cyclic voltammetry, and single-crystal X-ray crystallography. The packing of the targets in the solid state follows either a herringbone or a brick wall motif. In the case of 8,13-bis(triisopropylsilylethynyl)dibenzo[a,i]phenazine, polymorphs with either packing result.

For the first time, a broad range of indoles and pyrroles are trichloromethylthiolated using a bench-stable N-trichloromethylthiosaccharin as reagent.

The gold-catalyzed CH annulation of anthranil derivatives with alkynes offers a facile, flexible, and atom-economical one-step route to unprotected 7-acylindoles. An intermediate α-imino gold carbene, generated by an intermolecular reaction, promotes ortho-aryl CH functionalization to afford the target products. The transformation proceeds with a broad range of substrates under mild conditions. Moreover, the obtained functionalized indole products represent a versatile platform for the construction of diverse indolyl frameworks.