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Dramatic Conformer-Dependent Reactivity of the Acetaldehyde Oxide Criegee Intermediate with Dimethylamine Via a 1,2-Insertion Mechanism

Acetaldehyde-oxide (CH3CHOO) is an atmospherically pertinent reactive intermediate that exists in syn (right) and anti (left) conformational forms. Experiment and theory reveal that the reaction of anti with dimethylamine is several orders of magnitude faster than that of syn with dimethylamine, despite both reactions being energetically downhill. Read more »

With a Little Help, New Optical Material Assembles Itself

Researchers have demonstrated that tiny concentric nanocircles self-assemble into an optical material with precision and efficiency. Electron microscopy and x-ray scattering revealed the structure and spatial distribution of each ingredient in the resulting materials. The new findings could enable the large-scale manufacturing of multifunctional nanocomposites. Read more »

A {Ni12}-Wheel-Based Metal–Organic Framework for Coordinative Binding of Sulphur Dioxide and Nitrogen Dioxide

SO2 and NO2 are important air pollutants, and understanding the mechanism of capture materials drives the development of new clean-up technologies. In situ synchrotron x-ray crystallographic and spectroscopic experiments were used to establish a detailed molecular mechanism consisting of reversible coordination of SO2 and NO2 at the six open NiII sites on the unprecedented {Ni12}-wheel of a robust metal–organic framework material at crystallographic resolution. Read more »

Hardening Effects in Superhard Transition-Metal Borides

Novel superhard materials with exciting potential for applications in cutting tools and abrasives can be designed by combining incompressible transition metals with boron to create phases like WB4, pictured here. Diamond-cell-based high-pressure radial diffraction enables the direct study of lattice specific mechanisms for hardening. Read more »

ALS in the News (January 2022)

Synergistic Engineering of Side Chains and Backbone Regioregularity of Polymer Acceptors for High-Performance All-Polymer Solar Cells with 15.1% Efficiency

Researchers developed a series of polymer acceptors with controlled backbone regioregularities and side chain structures. All-polymer solar cells based on a RRg-C20 acceptor which has a regioregular backbone and optimal side chain length achieve a high power conversion efficiency of 15.12%, attributed to high electron mobility and optimal blend morphology. Read more »

Synthesis of new two-dimensional titanium carbonitride Ti2C0.5N0.5Tx MXene and its performance as an electrode material for sodium-ion battery

Researchers report on the synthesis and characterization of a new 2D carbonitride MXene, Ti2C0.5N0.5. They explore the performance of this new MXene as electrode materials for sodium-ion batteries (SIBs). It outperformed its carbide counterpart (i.e., Ti2C) and all the other reports for multilayer MXenes in SIBs, and it showed a stable electrochemical performance over 500 cycles. Read more »

Direct Observation of Surface-Bound Intermediates During Methanol Oxidation on Platinum Under Alkaline Conditions

A comprehensive mechanism for the methanol oxidation reaction (MOR) in alkaline media is presented, and it is shown that the MOR proceeds via two different pathways (via COad or H3C–Oad intermediates). The latter dominates the overall MOR current, suggesting that the H3C–Oad oxidation could be a viable pathway to accelerate the MOR in alkaline systems. Read more »