The polyolefin industry is dominated by gas‐phase and slurry‐phase polymerization techniques using heterogeneous catalysts. In contrast, the polyolefin academic research is extensively focused on homogeneous systems, especially for the field of late‐transition‐metal catalysts. The heterogenization of homogeneous catalysts represents a general strategy to provide "drop‐in" catalyst solutions for existing industrial polyolefin synthetic strategies. In this paper, we report an alternative, potentially...
Sun May 17, 2020 20:11
Reactions of difluoro iodotoluene with NH‐sulfoximines provide new hypervalent iodine(III) reagents, which photocatalytically transfer a fluoro and a sulfoximidoyl group onto styrenes with high regioselectivity. The substrate scope is broad with respect to both sulfoximines and olefins. Following an operationally simple protocol, a large library of fluorine‐containing N‐functionalized sulfoximines can be accessed. Results from mechanistic investigations revealed the importance of radical intermediates.
Sat May 16, 2020 22:53
We report a facile and efficient two‐step synthetic route for p‐substituted tris(2‐pyridylmethyl)amine (TPMA) ligands to form Cu complexes with the highest activity in Atom Transfer Radical Polymerization (ATRP) to‐date. The synthetic procedure followed a divergent approach, where the p‐Cl substituents in tris(4‐chloro‐2‐pyridylmethyl)amine (TPMA3Cl) were replaced in one‐step and high yield by electron‐donating cyclic amines (pyrrolidine (TPMAPYR), piperidine (TPMAPIP), and morpholine (TPMAMOR))...
Sat May 16, 2020 19:56
The in vivo optical detection of cellular senescence has been accomplished by using mesoporous silica nanoparticles loaded with the NIR‐FDA approved Nile Blue ( NB ) dye and capped with a galactohexasaccharide ( S3 ). Emission at 672 nm of NB is highly quenched inside S3 , yet a remarkable emission enhancement is observed upon cap hydrolysis in the presence of β‐galactosidase. The efficacy of the probe to optically detect cellular senescence is tested in vitro in melanoma SK‐Mel‐103 and...
Sat May 16, 2020 19:55
Here we report the development of an 18F‐labeled, activity‐based small molecule probe targeting the cancer‐associated serine hydrolase NCEH1. We undertook a focused medicinal chemistry campaign to simultaneously preserve potent and specific NCEH1 labeling in live cells and animals, while permitting facile 18F radionuclide incorporation required for PET imaging. The resulting molecule, [18F]JW199, labels active NCEH1 in live cells at nM concentrations and greater than 1,000‐fold selectivity relative...
Sat May 16, 2020 18:54
Seeds of construction: Through experimental studies and computer simulations, a seeded‐assembly strategy was developed to control the crucial nucleation and assembly pathway in DNA brick assembly by accelerating the assembly kinetics, lowering the free‐energy barrier to nucleation and increasing the optimal temperatures for isothermal assembly. Abstract Recently, the DNA brick strategy has provided a highly modular and scalable approach for the construction of complex structures, which can...
Fri May 15, 2020 22:00
Phosphorus‐modified all‐silica zeolites exhibit activity and selectivity in certain Brønsted acid catalyzed reactions for biomass conversion. In an effort to achieve similar performance with catalysts having well‐defined sites, we report the incorporation of Brønsted acidity to metal‐organic frameworks with the UiO‐66 topology, achieved by attaching phosphonic acid to the 1,4‐benzenedicarboxylate ligand and using it to form UiO‐66‐PO 3 H 2 by post‐synthesis modification. Characterization reveals...
Fri May 15, 2020 20:55
To offset the environmental impact of platinum group element (PGE) mining, recycling techniques are being thoroughly explored. Porous organic polymers (POPs) have shown significant promise, due to their selectivity and ability to withstand harsh conditions. A series of pyridine‐based POP nanotraps, POP‐Py, POP‐pNH2‐Py, and POP‐oNH2‐Py, have been rationally designed and systematically explored for the capture of palladium, one of the most utilized PGEs. All the POP nanotraps demonstrated record uptakes...
Fri May 15, 2020 20:26
We report the synthesis, x‐ray crystal structure, and molecular recognition properties of pillar[n]arene derivative P[6]AS which we refer to as Pillar[6]MaxQ along with analogues P[5]AS and P[7]AS toward guests 1 – 18 . The ultratight binding affinity of P[5]AS and P[6]AS toward quaternary (di)ammonium ions renders them prime candidates for in vitro and in vivo non‐covalent bioconjugation for imaging and delivery applications and as in vivo sequestration agents.
Fri May 15, 2020 19:25
Cyclin‐dependent kinase 2 (CDK2) is a potential therapeutic target for the treatment of cancer. Development of CDK2 inhibitors has been extremely challenging as its ATP‐binding site shares high similarity with CDK1, a related kinase whose inhibition causes toxic effects. Here, we report the development of TMX‐2172, a heterobifunctional CDK2 degrader with degradation selectivity for CDK2 and CDK5 over not only CDK1, but transcriptional CDKs (CDK7 and CDK9) and cell cycle CDKs (CDK4 and CDK6) as well....
Fri May 15, 2020 16:57
2,3,3‐Trisubstituted indolenine constitutes an integral part of many biologically important monoterpene indole alkaloids. We report herein an unprecedented access to this skeleton by a TiCl 3 ‐mediated reductive cyclization of tetrasubstituted alkenes bearing a 2‐nitrophenyl substituent. The proof of concept is demonstrated firstly by accomplishing a concise total synthesis of (+)‐1,2‐dehydroaspidospermidine featuring a late stage application of this key transformation. A sequence of reduction...
Fri May 15, 2020 16:55
Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C 5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd‐promoted ZnO‐ZrO 2 catalyst. The sequence of reaction steps involved in the C 5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in‐situ generation of the acetone intermediate and the cross‐aldol condensation between the...
Fri May 15, 2020 16:54
The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa‐aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff ‐base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed‐phase HPLC enables the isolation of the all‐ trans isomer of the Fe(II) terpyridine complex 1 , which is fully characterized....
Fri May 15, 2020 16:53
Polymeric carbon nitride materials have been successfully used in numerous light‐to‐energy conversion applications ranging from photocatalysis to optoelectronics. For a new application and modelling, we first refined the crystal structure of potassium poly(heptazine imide) (K‐PHI) – a benchmark carbon nitride material in photocatalysis – by means of X‐ray powder diffraction and transmission electron microscopy. Using the crystal structure of K‐PHI, periodic DFT calculations were performed to calculate...
Fri May 15, 2020 13:54
Taking the shortcut: Examples of tunneling by second‐row atoms are increasing and the limits are being expanded. This Minireview summarizes recent examples of heavy‐atom tunneling, highlights unique approaches for its detection, and describes computational efforts toward its prediction. Common features of these reactions and future challenges are discussed. Abstract In the past few years, numerous investigations have been reported on the role of heavy‐atom tunneling in the area of pericyclic...
Fri May 15, 2020 12:24
Carbon quantum dots (CDs) have inspired vast interests due to their prominent photoluminescence (PL) performances and promising applications in optoelectronic, biomedical and sensing fields. Notably, the development of effective approaches for large‐scale CDs production may greatly promote the further advancement of their practical applications. In this review, the newly emerging methods for the large‐scale production of CDs are summarized, such as microwave, ultrasonic, plasma, magnetic hyperthermia...
Fri May 15, 2020 12:37
Rechargeable Li metal anode coupling with high‐voltage cathodes is a promising tendency for high‐energy‐density batteries exceeding 300 Wh kg‐1. However, achieving long lifespan under realistic conditions remains a “Gordian knot” for practical‐used cells because of the low Li reversibility and electrolyte exhaustion. Here, we report an advancing dual‐additives electrolyte containing unique solvation structure of tris(pentafluorophenyl)borane additives and lithium nitrate (LiNO3) in carbonate‐based...
Fri May 15, 2020 11:57
Enantioselective carboaminations of olefins constitute an attractive strategy for a rapid increase in molecular complexity from readily available starting materials. We report an intermolecular asymmetric carboamination of acrylates using rhodium(III)‐catalyzed alkenyl C‐H activations of N‐enoxysuccinimides to generate the nitrogen and carbon portion for the transfer. A rhodium complex equipped with a tailored bulky tri‐substituted chiral Cpx ligand ensures carboamination chemoselectivity as well...
Fri May 15, 2020 11:57
Gut sensing: The indigenous metabolic status of mouse gut microbiota is quantified by flow cytometry using the signal from fluorescent d‐amino acid‐based in vivo labeling as the indicator of bacterial metabolic activities, and signals from fluorescence in situ hybridization to indicate their taxonomic identification. Abstract Herein, we propose a metabolic d‐amino acid‐based labeling and in situ hybridization‐facilitated (MeDabLISH) strategy for the quantitative analysis of the indigenous metabolic...
Thu May 14, 2020 22:49
The first synthetic access to N‐trifluoromethyl hydrazines, indoles and their derivatives is described. These compounds proved to be remarkably robust, being compatible with acids, bases, and a wide range of synthetic manipulations. Abstract Reported herein is the first efficient strategy to synthesize a broad range of unsymmetrical N‐CF3 hydrazines, which served as platform to unlock numerous currently inaccessible derivatives, such as tri‐ and tetra‐substituted N‐CF3 hydrazines, hydrazones,...
Thu May 14, 2020 22:47
The importance of the whole picture: Aggregation‐induced emission (AIE) research demonstrates that many properties and functions that are absent in molecular species can be found in molecular aggregates. AIE research thus emphasizes the significance of aggregate science in addition to molecular science for materials development. Abstract Aggregation‐induced emission (AIE) describes a photophysical phenomenon in which molecular aggregates exhibit stronger emission than the single molecules....
Thu May 14, 2020 22:46
Synthesis of All‐Carbon Disubstituted Bicyclo[1.1.1]pentanes by Iron‐Catalyzed Kumada Cross‐Coupling
1,3‐C‐disubstituted bicyclo[1.1.1]pentanes (BCPs) are accessed from 1‐iodo‐BCPs by direct iron‐catalyzed cross‐coupling with aryl and heteroaryl Grignard reagents. This represents the first general use of iodo‐BCPs as cross‐coupling electrophiles, and the first Kumada coupling of tertiary iodides in general. Benefiting from short reaction times, mild conditions, and broad scope, it enables the synthesis of a wide range of BCPs including drug analogues. Abstract 1,3‐Disubstituted bicyclo[1.1.1]pentanes...
Thu May 14, 2020 22:44
A giant globular 102 Ag atom nanocluster has been isolated by a templating approach. The nanocluster features an unprecedented sodalite‐type silver orthophosphate cluster (SOC) stabilized in a rare 60‐Ag rhombicosidodecahedron. This is a reminder of the key role of the SOC as a molecular analogue of the important Ag3PO4 semiconducting material. Abstract The synthesis and structure of a giant 102‐silver‐atom nanocluster (NC) 1 is presented. X‐ray structural analysis reveals that 1 features a...
Thu May 14, 2020 22:42
In‐situ evolution of electrocatalysts is of paramount importance in defining catalytic reactions. In their Research Article (DOI: https://doi.org/10.1002/anie.20200313610.1002/anie.202003136), J.‐Q. Huang and co‐workers reveal the electrochemical phase evolution of metal‐based pre‐catalysts in working Li–S batteries that enables stable operation of high‐rate and electrolyte‐starved Li–S batteries. The general concept of electrochemically induced sulfurization is verified by thermodynamic energetics...
Thu May 14, 2020 22:41
Alkaptonuria (AKU) is a rare genetic disease that leads to cartilage pigmentation and degradation, a symptom first reported by Rudolf Virchow of Charité Hospital in Berlin in 1866. Using DNP‐enhanced solid‐state NMR and EPR spectroscopy, W. Y. Chow, J. A. Gallagher, H. Oschkinat, and co‐workers (DOI: https://doi.org/10.1002/anie.20200061810.1002/anie.202000618) indicate a role for semiquinone radicals in the chemistry of the pigmentation process, and propose that transient glycyl radicals underlie...
Thu May 14, 2020 22:41
Ion arrangements in a conductive metal–organic framework (MOF) electrode are examined with in operando neutron scattering, as reported by L. He et al. in their Research Article (DOI: https://doi.org/10.1002/anie.20191620110.1002/anie.201916201). The non‐destructive method provides direct and accurate information on the multi‐length scale morphology of the dry MOF, the pore accessibility upon soaking with solvent and electrolyte, and the changes in species confined within the micropores under operating...
Thu May 14, 2020 22:40
Operando resonance Raman (RR) spectroscopy was used by Z. Mao, B. Zhao, Y. M. Jung, and co‐workers (DOI: https://doi.org/10.1002/anie.20191582410.1002/anie.201915824) for noninvasive and nondestructive microscopic investigations of dynamic interface evolutions in dye‐sensitized solar cells (DSCs) under operando conditions. The creation of new species was observed and interactions between charge separation pathways and molecular vibrations were studied. The operando RR spectroscopy can also be used...
Thu May 14, 2020 22:40
Temperature‐mediated water capture and release in composite materials including a metal–organic framework (MIL‐101(Cr)) and a thermo‐responsive polymer (poly(N‐isopropylacrylamide, PNIPAM) is demonstrated by G. Maurin, D. Zhao, and co‐workers in their Research Article (DOI: https://doi.org/10.1002/anie.20200238410.1002/anie.202002384). PNIPAM is introduced into the cavity of MIL‐101(Cr) by in‐situ polymerization of the loaded monomer. The resultant composites show very high water uptake and can release...
Thu May 14, 2020 22:40
Alkaptonuria is a rare disease that leads to striking pigmentation and mechanical failure of cartilage tissue. DNP‐enhanced solid‐state NMR enabled us to observe disruption of interstrand hydrogen bonding in collagen proteins from alkaptonuria patient tissue. A mechanism involving transient glycyl radicals is proposed as basis of the degradation and pigmentation of cartilage tissue in alkaptonuria. Abstract Alkaptonuria (AKU) is a rare disease characterized by high levels of homogentisic acid...
Thu May 14, 2020 22:40
Selenium is an essential trace element named after the Greek goddess of the moon, Selene. In their Research Article (DOI: https://doi.org/10.1002/anie.20200359510.1002/anie.202003595), W. Hou, G. Yang, R. A. Lerner et al. introduce benzoselenazolone as a new selenide reagent for on‐DNA C−H selenylation under rhodium(III) catalysis. This work expands the chemical space of DNA‐encoded libraries to selenium‐containing molecules (SeDELs) and lays the foundation for the development of selenium‐containing...
Thu May 14, 2020 22:40
Soft x‐ray spectromicroscopy enables neuromelanin visualization in human brain tissue. This removes dependence on optical evaluation of pigmentation or chemical staining, opening the door to investigating relationships between depigmentation, metal binding, and neurodegeneration in the most vulnerable neurons in Parkinson's disease. (Image of brain adapted, under license CCBY4.0, from Blausen.com staff, WikiJournal of Medicine 2014, 1, ISSN 2002–4436.) Abstract A hallmark of Parkinson's disease...
Thu May 14, 2020 22:38
Lantibiotics are ribosomally synthesized and post‐translationally modified peptides (RiPPs) characterized by the presence of lanthionine or methyllanthionine rings and their antimicrobial activity. Cacaoidin, a novel glycosylated lantibiotic, was isolated from a Streptomyces cacaoi strain and fully characterized by NMR, mass spectrometry, chemical derivatization approaches and genome analysis. The new molecule combines outstanding structural features, such as a high number of D‐amino acids, an...
Thu May 14, 2020 22:19
Killer instinct: A supramolecular polyvalent antibody mimic (PAM) has been synthesized in situ on the surface of natural killer cells by nucleic acid assembly and hybridization under physiological conditions without genetic manipulation. The PAM‐engineered natural killer cells (green) possess a superb ability to bind to and kill cancer cells (red) and thus constitutes a promising technology platform for cancer immunotherapy. Abstract An ability to promote therapeutic immune cells to recognize...
Thu May 14, 2020 22:00
Getting choosy: In a new sterically controlled C−H olefination, heteroarenes serve as the limiting reagent. The method enables the highly C5‐selective olefination of a wide range of heteroarenes and is shown to be useful in the context of late‐stage functionalization. Abstract The regioselective functionalization of heteroarenes is a highly attractive synthetic target due to the prevalence of multiply substituted heteroarenes in nature and bioactive compounds. Some substitution patterns remain...
Thu May 14, 2020 21:42
Tensile strain increases the hydrogen evolution reaction rate and decreases hydrogen absorption at a palladium surface. A custom electrochemical cell is reported that applies tensile strain to a flexible working electrode, thus enabling the effect of tensile strain on hydrogen absorption and HER activity for a thin film palladium electrocatalyst to be resolved. Abstract Strain engineering can increase the activity and selectivity of an electrocatalyst. Tensile strain is known to improve the...
Thu May 14, 2020 21:41
A luminescent cocrystal exhibits reversible luminescent switching, responding to THF‐vapor/thermal stimuli and mechanical grinding. The crystal‐to‐crystal phase transition between two different cocrystal polymorphs under the external stimuli was demonstrated, enabling an in‐depth understanding of the luminescent switching of organic luminescent materials. Abstract A luminescent cocrystal system is reported to undergo crystal‐to‐crystal phase transformation from yellow‐emitting polymorph I to...
Thu May 14, 2020 21:41
Listen to HER tune: Regulating charge transfer by doping with single transition‐metal atoms and making oxygen vacancies on a TiO2 nanosheet is reported. These approaches modulate the activity of the lattice oxygen atom in titania, providing a way to tune and thus optimize catalysis of the hydrogen evolution reaction (HER). Abstract Single‐atom catalysts have attracted much attention. Reported herein is that regulating charge transfer of lattice oxygen atoms in serial single‐atom‐doped titania...
Thu May 14, 2020 21:40
Polycyclic aromatic hydrocarbons (PAHs), comprising multiple aromatic rings and containing only carbon and hydrogen atoms, are key components of organic electronics. The electronic properties of these carbon‐rich materials can be controlled through doping with heteroatoms such as boron and nitrogen. However, only few studies have reported convenient syntheses of BN‐doped PAHs. Herein, we describe the rational design, two‐step synthesis, and characterization of previously unknown ixene and BN‐doped...
Thu May 14, 2020 21:24
Main group analogues of cyclobutane‐1,3‐diyls are fascinating due to their unique reactivity and electronic properties. So far only heteronuclear examples have been isolated. Here we report the isolation and characterization of all‐silicon 1,3‐cyclobutandiyls as stable closed‐shell singlet species from the reversible reactions of cyclotrisilene c‐Si3Tip4 (Tip = 2,4,6‐triisopropylphenyl) with the N‐heterocyclic silylenes c‑[(CR2CH2)(NtBu)2]Si: (R = H or methyl) with saturated backbones. At elevated...
Thu May 14, 2020 21:18
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