There is a growing understanding of the large role inorganic nanoparticles and their assemblies for Earth sciences. Complex structures from NPs are found in rocks, soils, and sea sediments but the mechanisms of their formation are poorly understood, which causes controversial conclusions about their genesis. Here we show that graphene quantum dots (GQDs), can assemble into complex structures driven by coordination interactions with metal ions commonly present in environment and serve a special role...
Sun Sep 01, 2019 17:00
Natural livings normally have amazing control over the color, shape or morphology for camouflage, communication or even reproduction in response to interplay between several environmental stimuli. Such interesting phenomenon inspires scientists to develop smart soft actuators/robotics via integrating color‐changing functionality based on polymer films or elastomers. However, there is still no important progress with synergistic color‐changing and shape‐morphing capabilities in life‐like material...
Sun Sep 01, 2019 17:00
Bending the planar trigonal boron atom of triphenylborane by connecting its aryl rings with carbon or phosphorus linkers gave access to a series of 9‐boratriptycene derivatives with unprecedented structures and reactivities. NMR and X‐ray diffraction investigations of the Lewis adducts of these non‐planar boron Lewis acids with weak Lewis bases (OPEt 3 , CH 3 CN, EtOAc, Cl – , Br – , I – ) revealed particularly strong covalent bond formation. The first Lewis adduct of a trivalent boron...
Mon Sep 02, 2019 11:54
Branched selectivity in asymmetric allylic C‐H alkylation has been favorably enabled by using 2‐acylimidazoles as nucleophiles in the presence of chiral phosphoramidite‐palladium catalysis. A wide range of terminal alkenes, including1,4‐dienes and allylarenes, are nicely tolerated to provide chiral 2‐acylimidazoles in moderate to high yields and with high levels of regio‐, E/Z‐ and enantioselectivities. Mechanistic studies by density functional theory (DFT) calculations suggest a nucleophile coordination‐enabled...
Mon Sep 02, 2019 13:30
Herein, we report a two‐step process forming arene C–O bonds in excellent site‐selectivity at a late‐stage. The C–O bond formation is achieved by selective introduction of a thianthrenium group, which is then converted into C–O bonds using photoredox chemistry. Electron‐rich, ‐poor and ‐neutral arenes as well as complex drug‐like small molecules are successfully transformed into both phenols and various ethers. The sequence differs conceptually from all previous arene oxygenation reactions in that...
Mon Sep 02, 2019 14:38
How to maximize the activity of materials towards the alkaline hydrogen evolution reaction while maintaining its structural stability under realistic working conditions, remains elusive and is a research hotspot, where tailoring the electronic structure on active sites is the key to the rational design of efficient electrocatalysts. Herein, we first report the controllable surface N modification on V8C7 and monolayer graphene (G) heterostructures via a simplified pressure‐assisted device at low temperature....
Mon Sep 02, 2019 15:29
Highly dynamic and complex systems of microtubules undergo substrate induced change of conformation which leads to polymerization. Due to the augmented catalytic potential at the polymerized state, rapid hydrolysis of the substrate is observed leading to catastrophe, thus realising the out‐of‐equilibrium state. We report a simple synthetic mimic of these dynamic natural systems, where similar substrate induced conformational change is observed and a transient helical morphology is accessed. Further,...
Mon Sep 02, 2019 15:29
Planar pyridyl N‐oxides are encapsulated in mono‐metallic Pd(II)/Pt(II)‐cages based on a tetra‐pyridyl calix[4]pyrrole ligand. The exchange dynamics of the cage complexes are slow on both the NMR chemical shift and EXSY timescales, but encapsulation of the guests by the cages is fast on the human timescale. A “french doors” mechanism, involving the rotation of the meso‐phenyl walls of the cages, allows the passage of the planar guests. The encapsulation of quinuclidine N‐oxide, a sterically more...
Mon Sep 02, 2019 17:07
Pt‐based materials are the state‐of‐the‐art catalysts for oxygen reduction reaction (ORR), but their high cost and scarcity remain the major obstacles for large‐scale applications in renewable energy industries. To produce efficient ORR catalysts with low Pt content, PtNi porous films (PFs) with sufficiently exposed Pt active sites were rationally designed through a programmable approach combining electrochemical bottom‐up (electrodeposition) and top‐down (anodization) processes. The unique dynamic...
Mon Sep 02, 2019 17:58
Experimental and computational studies provided detailed insights into selectivity‐ and reactivity‐controlling factors in bifurcated ruthenium‐catalyzed direct C–H arylations and dehydrogenative C–H/C–H functionalizations. Thorough investigations revealed the importance of arene‐ligand‐free complexes for the formation of biscyclometalated intermediates within a ruthenium(II/IV/II) mechanistic manifold.
Mon Sep 02, 2019 17:58
Charge‐shift bonds (CSB) constitute a new class of bonds different than covalent/polar‐covalent and ionic‐bonds. Bonding in CSB is not contributed by either the covalent or the ionic structures of the bond, but rather by the resonance interaction between the structures. This essay describes the reasons why the CSB family was overlooked by valence‐bond pioneers (Textbox 1). It then demonstrates that the unique status of CSBs is not theory‐dependent. Thus, Valence‐bond (VB), molecular‐orbital (MO),[21,22]...
Mon Sep 02, 2019 17:58
The production of multicarbon products (C2+) from CO2 electroreduction reaction (CO2RR) is highly desirable for storing renewable energy and reducing carbon emission. Here we report the electrochemical synthesis of CO2RR catalysts that are highly selective for C2+ products via electrolyte‐driven nanostructuring. Nanostructured Cu catalysts synthesized in the presence of specific anions can selectively convert CO2 to ethylene and multicarbon alcohols in aqueous 0.1 M KHCO3 solution, with the iodine‐modified...
Mon Sep 02, 2019 19:44
This paper describes an unprecedented dearomatization protocol that enables the first dearomatization of aryl iodanes via a “rearrangement/addition” sequence. The process consists of two stages. First, a rapid [3,3]‐sigmatropic rearrangement of aryl iodane with α‐stannyl nitrile affords a highly electrophilic dearomatized intermediate at ‐78 °C. The low‐temperature rearrangement allows for the low‐temperature trapping of the in situ generated unstable dearomatized specie with various nucleophiles....
Mon Sep 02, 2019 19:44
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