The synthesis, characterization, and catalytic performance of iridium(III) catalysts that bear an amide‐pendant cyclopentadienyl ligand ([Cp A IrI 2 ] 2 ) is reported. These [Cp A IrI 2 ] 2 catalysts were obtained from the complexation of a Cp A ligand precursor with [Ir(cod)OAc] 2 followed by oxidation. Double aromatic homologation reactions of benzamides with alkynes via fourfold C–H activation proceeded in good to high yield by using [Cp A IrI 2 ] 2 catalysts, demonstrating...
Mon Mar 30, 2020 17:01
A hafnium enzyme is better than none: The discrete hafnium metal‐oxo cluster [Hf18O10(OH)26(SO4)13⋅(H2O)33] (Hf18) acts as a nanozyme for the strictly selective hydrolysis of horse heart myoglobin (HHM) at Asp residues. Abstract The selective hydrolysis of proteins by non‐enzymatic catalysis is difficult to achieve, yet it is crucial for applications in biotechnology and proteomics. Herein, we report that discrete hafnium metal‐oxo cluster [Hf18O10(OH)26(SO4)13⋅(H2O)33] (Hf18), which is centred...
Mon Mar 30, 2020 16:27
The C‐O bond cleavage for activation of alcohols is synthetically useful and practically challenging. This work describes carbazate as a new type of electrochemically activated alkylating agent derived from ubiquitous alcohols for direct functionalization of heteroarenes under mild electrolytic conditions. The simple undivided cell at low oxidative potentials with carbon/platinum electrode set‐ups offers excellent substrate tolerance, affording a variety of primary, secondary and tertiary alkyl‐decorated...
Mon Mar 30, 2020 15:58
It’s of great significance to reveal the detailed mechanism of neighboring effects between monomers, as they could not only affect the intermediate bonding but also change the reaction pathway. This paper describes the electronic effect between neighboring Zn/Co monomers effectively promoting CO 2 electroreduction to CO. Zn and Co atoms coordinated on N doped carbon (ZnCoNC) shows a CO faradaic efficiency of 93.2% at ‐0.5 V vs. RHE during a 30‐hours test. Extended X‐ray absorption fine structure...
Mon Mar 30, 2020 15:55
Decarboxylative C–H functionalization reactions are highly attractive methods for forging carbon‐carbon bonds considering their inherent step‐ and atom‐economical features and the pervasiveness of carboxylic acids and C–H bonds. An ideal approach to achieve these dehydrogenative transformations is through hydrogen evolution without using any chemical oxidants. However, effective coupling of decarboxylative carbon‐carbon bond formation with proton reduction remains an unsolved challenge. Herein, we...
Mon Mar 30, 2020 15:00
The hydroxide‐exchange membrane fuel cell (HEMFC) is a promising energy conversion device. However, the development of HEMFC is hampered by the lack of platinum‐group‐metal‐free (PGM‐free) electrocatalysts for the hydrogen oxidation reaction (HOR). Here we report a Ni catalyst that exhibits the highest mass activity in HOR for a PGM‐free catalyst as well as excellent activity in the hydrogen evolution reaction (HER). This catalyst, Ni‐H 2 ‐2%, was optimized through pyrolysis of a Ni‐containing...
Mon Mar 30, 2020 13:33
Recent advances in scanning probe microscopy on surface enable not only direct observation of molecular structures but also local probe reactions, in which unstable short‐lived products have been synthesized and analyzed. Here, we demonstrate an endergonic reaction to synthesize a single Sondheimer‐Wong diyne from 6,13‐dibromopentaleno[1,2‐ b :4,5‐ b’ ]dinaphthalene by local probe chemistry on a ultra‐thin film of NaCl formed on a Cu(111) surface at 4.3 K. The structures of the precursor and...
Mon Mar 30, 2020 13:33
We report tandem alkyl‐arylations and phosphonyl‐arylations of vinyl ureas by way of a photocatalytic radical‐polar crossover mechanism. Addition of photoredox‐generated radicals to the alkene forms a new C–C or C–P bond and generates a product radical adjacent to the urea function. Reductive termination of the photocatalytic cycle generates an anion that undergoes a polar Truce‐Smiles rearrangement, forming a C–C bond. The reaction is successful with a range of α‐fluorinated alkyl sodium sulfinate...
Mon Mar 30, 2020 12:41
Thiolate/disulfide conversions are mediated by nickel complexes mimicking the key step in the catalytic cycle of methyl‐coenzyme M reductase. Cyclic voltammetry and EPR spectroscopic measurements reveal monoradical‐based reversible switching of NiII‐thiolate/NiII‐disulfide couples (see picture). Abstract According to the well‐accepted mechanism, methyl‐coenzyme M reductase (MCR) involves Ni‐mediated thiolate‐to‐disulfide conversion that sustains its catalytic cycle of methane formation in the...
Mon Mar 30, 2020 12:36
Play it, SAM: A sulfonium‐based homolytic substitution (SH) reaction was observed in the reaction of the radical S‐adenosyl‐l‐methionine (SAM) enzyme HemN. DFT calculations and model reactions showed that this type of chemistry is thermodynamically favorable and could be further explored in chemical synthesis. Abstract Sulfur‐based homolytic substitution (SH reaction) plays an important role in synthetic chemistry, yet whether such a reaction could occur on the positively charged sulfonium...
Mon Mar 30, 2020 12:36
Cell entry: A palladium(II)‐stapled bis(histidine) unit at the basic site of miniproteins leads to cell‐permeable derivatives that enable depropargylation reactions within the interior of living mammalian cells. Both the metal bridge and the peptide scaffolding are essential for the internalization, and for observing the intracellular transformations. Abstract The generation of catalytically active metalloproteins inside living mammalian cells is a major research challenge at the interface...
Mon Mar 30, 2020 12:36
Ancillary Ligation: The development of the first nickel‐catalyzed protocols for the cross‐coupling of sulfonamides with inexpensive and abundant (hetero)aryl chlorides and phenol derivatives is enabled by use of appropriate bisphosphine ligation. Abstract The development of Ni‐catalyzed C−N cross‐couplings of sulfonamides with (hetero)aryl chlorides is reported. These transformations, which were previously achievable only with Pd catalysis, are enabled by use of air‐stable (L)NiCl(o‐tol) pre‐catalysts...
Mon Mar 30, 2020 12:35
The pigment hypothesis and the interferences hypothesis suggested in the XIXth century in order to explain the colours of photochromatic images are discarded. The silver nanoparticles dispersions contained in the silver chloride matrix forming Becquerel images seem to be colour‐characteristic, indicating a plasmonic origin of the photochromatic images colours. Abstract The first colour photographs were created by a process introduced by Edmond Becquerel in 1848. The nature of these photochromatic...
Mon Mar 30, 2020 12:35
KRAS homo‐dimerization has been implicated in the activation of RAF kinases, however, the mechanism and structural basis remain elusive. We developed a system to study KRAS dimerization on nanodiscs using paramagnetic relaxation enhancement (PRE) NMR, and determined distinct structures of membrane‐anchored KRAS dimers in the active GTP‐ and inactive GDP‐loaded states. Both dimerize through an α4‐α5 interface, but the relative orientation of the protomers and their contacts differ substantially. Dimerization...
Sun Mar 29, 2020 18:24
Capture and release of peptides is often a critical operation in the pathway to discovering materials with novel functions. However, the best methods for efficient capture impede facile release. To overcome this challenge, we report secondary amino alcohol‐based linkers for release of peptides after capture. These amino alcohols are based on serine (seramox) or isoserine (isoseramox) and can be incorporated into peptides during solid‐phase peptide synthesis via reductive amination. Both linkers are...
Sun Mar 29, 2020 17:01
Perturbing the electronic structure of MoS2 basal plane via confining heteroatoms offers the opportunity to trigger in‐plane activity for hydrogen evolution reaction (HER). The key challenge consists in inducing the optimum HER activity by controlling the type and distribution of confined atoms. Herein, we report a distance synergy of MoS2‐confined single‐atom rhodium realizing an ultra‐high HER activity at the in‐plane S sites adjacent to the rhodium. By optimizing the distance between the confined...
Sun Mar 29, 2020 17:01
Through quantum‐chemical calculations, we investigate a family of metal−organic frameworks (MOFs) containing triazolate linkers, M 2 X 2 (BBTA) (M = metal, X = bridging anion, H 2 BBTA = 1 H ,5 H ‐benzo(1,2‐d:4,5‐d′)bistriazole), for their ability to form terminal metal‐oxo sites and subsequently activate the C−H bond of methane. By varying the metal and bridging anion in the framework, we show how to significantly tune the reactivity of this series of MOFs. The electronic structure of...
Sun Mar 29, 2020 17:01
As a compliment to several other publications that present Rolf Huisgen’s research achievements, the first part of this paper reveals the human side of this eminent chemist as he edges closer to his 100th birthday. From excerpts from many of his personal and professional writings, Huisgen’s personality and philosophies of life are revealed. Also revealed is Huisgen functioning as a historian of chemistry. The second part of this paper examines the scientometrics of Huisgen’s publication history. ...
Sat Mar 28, 2020 17:48
Intense research efforts in electrochemical energy storage are being devoted to multivalent ion technologies in order to meet the growing demands for high energy and low‐cost energy storage systems. However, the development of multivalent metal (such as Mg and Ca) based battery systems is hindered by lack of suitable cathode chemistries that show well reversible multi‐electron redox reactions. Cationic redox centers in the classical cathodes could only afford stepwise single electron transfer, which...
Fri Mar 27, 2020 21:18
The selective hydrogenation and hydrodeoxygenation of aromatic ketones is achieved using rhodium nanoparticles immobilized on an acid‐free triphenylphosphonium‐based supported ionic liquid phase (Rh@SILP(Ph 3 ‐P‐NTf 2 )). The flexible molecular approach used to assemble the individual catalyst components (SiO 2 , ionic liquid, nanoparticles) allows for the formation of a catalytic system possessing outstanding catalytic properties. In particular, an intimate contact between the nanoparticles...
Fri Mar 27, 2020 21:00
In the past decade, multiple catalytic C–H bond functionalization has been successfully applied in natural product synthesis as a strategy to reduce the number of steps, increase overall yield and employ more easily available starting materials. This minireview presents selected examples making use of multiple C–H bond functionalization in conceptually different ways. First, linear syntheses are discussed, wherein multiple C–H functionalization is employed either from simple (hetero)cyclic cores,...
Fri Mar 27, 2020 17:49
We report the synthesis, characterization, and spectroscopic investigations of a new responsive‐at‐metal cyclometalated platinum(II) complex. Through mild chemical oxidants and reductants, it was possible to obtain the same complex in three different oxidation states and each of these complexes was structurally characterized by single‐crystal X‐ray diffraction. We discovered that the platinum(II) complex displays strong solvatochromism in the solid‐state, which can be attributed to modulation of...
Fri Mar 27, 2020 17:40
The exponential proliferation of data during the Information Age has required the continuous exploration of novel storage paradigms, materials, and devices with increasing data density. As a step toward the ultimate limits in data density, the development of an electrically‐controllable, single‐molecule memristive element is reported. In this device, digital information is encoded through switching between two isomer states by applying a voltage signal to the molecular junction, and the information...
Fri Mar 27, 2020 17:39
Stiff‐stilbene, a sterically restricted fused ring analogue of stilbene, has been regularly used as a model compound in theoretical studies of stilbene photoisomerization. Lately, owing to its excellent photoswitching properties, it is increasingly being applied to reversibly control the properties and function of chemical as well as biological systems. Stiff stilbene photoswitches possess a number of advantageous properties including a high quantum yield for photoisomerization and a high thermal...
Fri Mar 27, 2020 17:39
Elucidating structural roles in photoinduced charge transfer is indispensable since nuclear rearrangements are simultaneously involved in the dynamics in most cases. However, it is hard to evaluate whether the structural changes occur or not by using conventional time‐resolved electronic spectroscopies. Here, we apply time‐resolved impulsive stimulated Raman spectroscopy to record the evolution of vibrational snapshots during charge separation dynamics of donor‐acceptor‐donor type quadrupolar perylene...
Fri Mar 27, 2020 16:19
Enantiopure molecules based on macrocyclic architecture are unique for applications in enantioselective host‐guest recognition, chiral sensing and asymmetric catalysis. Taking advantage of chiral transfer from the intrinsically planar chirality of pillar[5]arenes, we herein present an efficient and straightforward approach to achieve early examples of highly luminescent chiral systems ( P5NN and P5BN ). The optical resolution of their enantiomers has been carried out via preparative chiral HPLC,...
Fri Mar 27, 2020 14:48
Catalysis by chiral weakly‐coordinating anions (WCAs) remains underdeveloped due to the lack of a molecular design strategy for exploiting their characteristics, such as the non‐nucleophilic nature. Here, we report the development of a chiral borate ion comprising an O,N,N,O ‐tetradentate backbone, which ensures hitherto unattainable structural robustness. Upon pairing with a proton, the hydrogen borate acts as an effective catalyst for the asymmetric Prins‐type cyclization of vinyl ethers, providing...
Fri Mar 27, 2020 14:00
It is well known that symmetry plays a key role in chemical reactivity. Here we explore its’ role in vibrational strong coupling (VSC) for a charge transfer (CT) complexation reaction. By studying the trimethylated benzene – I 2 CT complex, we find first that VSC induces large changes in the equilibrium constant K of the CT complex, reflecting modifications in the ΔG° of the reaction. Furthermore, by tuning the microfluidic cavity modes to the different IR vibrations of the trimethylated benzene,...
Fri Mar 27, 2020 11:53
As part of efforts to enhance the applications of self‐assembled metallosupramolecular architectures (MSAs) there is considerable current interest in the development of lower symmetry heterometallic systems. Herein we report a strategy that enables the quantitative assembly of low symmetry heterobimetallic [PdPtL 4 ] 4+ cage C. We anticipated that the presence of two different metal ions (Pd(II) and Pt(II)) with differing labilities could enable the cage to be “opened” and “closed” selectively...
Fri Mar 27, 2020 11:53
Origins of OER: The metal geometry in cobalt phosphates was modulated from octahedral to tetrahedral by the simple removal of crystal water in Co3(PO4)2⋅8 H2O. The two materials form an ideal platform for the study the oxygen evolution reaction (OER) related to the metal coordination structure. Abstract The correlation between metal coordination and electrocatalytic water oxidation performance is elusive in many cobalt‐based materials. Herein, we designed an ideal Co phosphate‐based platform...
Fri Mar 27, 2020 11:05
Skeletal reorganization is a type of fascinating transformations owing to their intriguing mechanisms and utility in complex molecule synthesis. However, these reactions are limitedly known for most functional groups. Herein, we describe such an unusual process of oxetanes. In the presence of In(OTf)3 as catalyst, oxetane‐tethered anilines reacted unexpectedly to form 1,2‐dihydroquinolines. This process not only provides expedient access to dihydroquinolines, but also represents a new reaction of...
Fri Mar 27, 2020 10:49
Bulk=Hulk: Superbulky alkaline earth metal amide complexes were found to be extremely active catalysts for alkene hydrogenation, clearly extending the substrate scope. Even various arenes, including benzene, can be reduced under relatively mild conditions. Abstract Two series of bulky alkaline earth (Ae) metal amide complexes have been prepared: Ae[N(TRIP)2]2 (1‐Ae) and Ae[N(TRIP)(DIPP)]2 (2‐Ae) (Ae=Mg, Ca, Sr, Ba; TRIP=SiiPr3, DIPP=2,6‐diisopropylphenyl). While monomeric 1‐Ca was already known,...
Fri Mar 27, 2020 10:47
An abstract concept: A trigonal planar imido cobalt(III) complex, obtained from reaction of a quasi‐linear cobalt(I) complex with an organo azide, is capable of intermolecular H atom abstraction of C−H bonds. The resulting cobalt(II) amide itself can either deprotonate the substrate, facilitate an H atom abstraction or mediate a stepwise proton/electron transfer. As the latter regenerates the starting cobalt(I) complex, a first catalytic application is presented. Abstract The 3d‐metal mediated...
Fri Mar 27, 2020 10:46
Bridged Stilbenes: AIEgens Designed via a Simple Strategy to Control the Non‐radiative Decay Pathway
Bridged stilbene: Based on theoretical prediction of non‐radiative decay, a family of aggregation‐induced emission (AIE) luminogens is reported. Depending on the alkyl chain length, they exhibit different quantum yields. BPST[7] and DPB[7] with excellent AIE behavior are reported. Abstract To broaden the application of aggregation‐induced emission (AIE) luminogens (AIEgens), the design of novel small‐molecular dyes that exhibit high fluorescence quantum yield (Φfl) in the solid state is required....
Thu Mar 26, 2020 21:00
Red, Go! An effective protocol for the selective oxidation of amines into imines was unveiled by cooperative photocatalysis of Por‐sp2c‐COF and TEMPO illuminated by 623 nm red LEDs. Abstract 2D covalent organic frameworks (COFs) are receiving ongoing attention in semiconductor photocatalysis. Herein, we present a photocatalytic selective chemical transformation by combining sp2 carbon‐conjugated porphyrin‐based covalent organic framework (Por‐sp2c‐COF) photocatalysis with TEMPO catalysis illuminated...
Thu Mar 26, 2020 19:01
Twist and shout: Poly(phenylacetylene)s are helical polymers where the helical sense of the backbone and the pendant groups can differ. It is shown that a correct assignment of both helical senses can be done using Raman optical activity, which gives more structural insight than electronic circular dichroism alone. Abstract Poly(phenylacetylene)s are a family of helical polymers constituted by conjugated double bonds. Raman spectra of these polymers show a structural fingerprint of the polyene...
Thu Mar 26, 2020 18:59
Graphene synthesis in a flash: Despite more than 15 years of exploration, the efficient and low‐cost production of graphene, especially high‐quality graphene, remains a great challenge. Very recently, a breakthrough in the synthesis of graphene materials was reported by Tour et al. It realized a super‐fast synthesis of high‐quality graphene at low cost, showing a great potential for commercialization. Abstract Fast, mass, and low‐cost production of high‐quality graphene, which is alluring,...
Thu Mar 26, 2020 18:58
ZSM‐5 nanoboxes with low SARs: Rapid ageing of a sol gel synthesis mixture produces a parent zeolite with tetrahedral extra framework Al and a low silicon‐to‐aluminium ratio (SAR) value of ≈12, which is transformed to mesoporous ZSM‐5 nanoboxes with low SARs of ≈16 during post‐synthetic TPAOH treatment. The mesoporous ZSM‐5 nanoboxes shows comparatively enhanced mass transfer ability, catalytic cracking activity and longevity. Abstract ZSM‐5 zeolite nanoboxes with accessible meso‐micro‐pore...
Thu Mar 26, 2020 18:58
Take the structure‐guided route: Application of advanced gene mutagenesis methods and strategies ensure speed and reliability in laboratory evolution of selective enzymes as catalysts in organic chemistry and biotechnology. Recent developments in novel methodology from sequence‐based to structure‐guided methods are presented in this review. Abstract Directed evolution of stereo‐, regio‐, and chemoselective enzymes constitutes a unique way to generate biocatalysts for synthetically interesting...
Thu Mar 26, 2020 18:56
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