Nearly Monodisperse Insulator Cs4PbX6 (X = Cl, Br, I) Nanocrystals, Their Mixed Halide Compositions, and Their Transformation into CsPbX3 Nanocrystals
Doesn't look like they thought they were pranking him.
Palladium(II)-catalyzed oxidation reactions exhibit broad utility in organic synthesis; however, they often feature high catalyst loading and low turnover numbers relative to non-oxidative cross-coupling reactions. Insights into the fate of the Pd catalyst during turnover could help to address this limitation. Herein, we report the identification and characterization of a dimeric PdI species in two prototypical Pd-catalyzed aerobic oxidation reactions: allylic C−H acetoxylation of terminal alkenes and intramolecular aza-Wacker cyclization. Both reactions employ 4,5-diazafluoren-9-one (DAF) as an ancillary ligand. The dimeric PdI complex, [PdI(μ-DAF)(OAc)]2, which features two bridging DAF ligands and two terminal acetate ligands, has been characterized by several spectroscopic methods, as well as single-crystal X-ray crystallography. The origin of this PdI complex and its implications for catalytic reactivity are discussed.
Catalyst entanglement: Catalyst dimerization is observed in both the aerobic palladium-catalyzed allylic C−H acetoxylation and aza-Wacker cyclization. A novel PdI species is rigorously characterized in catalysis which has implications for palladium catalyst design and presents insights into catalyst deactivation.
Lesbianism seemed like it had a pretty stringent entry fee to me when I was in my twenties.
http://www.girlswithslingshots.com//comic/gws510">Here's the old strip!
Physical Organic Approach to Persistent, Cyclable, Low-Potential Electrolytes for Flow Battery Applications
α-Imino Gold Carbenes from 1,2,4-Oxadiazoles: Atom-Economical Access to Fully Substituted 4-Aminoimidazoles
My friends are dropping like flies…
Every few months, another one sits us down and breaks the news. He or she is leaving New York. They got a new job, their partner got a job, they want to be closer to their parents, they’re sick of the cold winters, they want more space, the rent is just too high (basically this).… Read more
Atomic Modulation of FeCo–Nitrogen–Carbon Bifunctional Oxygen Electrodes for Rechargeable and Flexible All-Solid-State Zinc–Air Battery
Rational design and exploration of robust and low-cost bifunctional oxygen reduction/evolution electrocatalysts are greatly desired for metal–air batteries. Herein, a novel high-performance oxygen electrode catalyst is developed based on bimetal FeCo nanoparticles encapsulated in in situ grown nitrogen-doped graphitic carbon nanotubes with bamboo-like structure. The obtained catalyst exhibits a positive half-wave potential of 0.92 V (vs the reversible hydrogen electrode, RHE) for oxygen reduction reaction, and a low operating potential of 1.73 V to achieve a 10 mA cm−2 current density for oxygen evolution reaction. The reversible oxygen electrode index is 0.81 V, surpassing that of most highly active bifunctional catalysts reported to date. By combining experimental and simulation studies, a strong synergetic coupling between FeCo alloy and N-doped carbon nanotubes is proposed in producing a favorable local coordination environment and electronic structure, which affords the pyridinic N-rich catalyst surface promoting the reversible oxygen reactions. Impressively, the assembled zinc–air batteries using liquid electrolytes and the all-solid-state batteries with the synthesized bifunctional catalyst as the air electrode demonstrate superior charging–discharging performance, long lifetime, and high flexibility, holding great potential in practical implementation of new-generation powerful rechargeable batteries with portable or even wearable characteristic.
Bamboo-like FeCo alloy encapsulated in nitrogen-doped carbon nanotubes exhibits superior catalytic oxygen reduction and oxygen evolution performance than that of noble metal benchmarks, which benefits from the nitrogen-rich and defect-rich catalyst surface. The all-solid-state zinc–air batteries equipped by the synthesized materials show low charging/discharging overpotentials, long lifetime, and high flexibility, suitable for practical application.
Understanding of Strain Effect in Electrochemical Reduction of CO2: Using Pd Nanostructures as an Ideal Platform
Tuning the surface strain of heterogeneous catalysts represents a powerful strategy to engineer their catalytic properties by altering the electronic structures. However, a clear and systematic understanding of strain effect in electrochemical reduction of carbon dioxide is still lacking, which restricts the use of surface strain as a tool to optimize the performance of electrocatalysts. Herein, we demonstrate the strain effect in electrochemical reduction of CO2 by using Pd octahedra and icosahedra with similar sizes as a well-defined platform. The Pd icosahedra/C catalyst shows a maximum Faradaic efficiency for CO production of 91.1 % at −0.8 V versus reversible hydrogen electrode (vs. RHE), 1.7-fold higher than the maximum Faradaic efficiency of Pd octahedra/C catalyst at −0.7 V (vs. RHE). The combination of molecular dynamic simulations and density functional theory calculations reveals that the tensile strain on the surface of icosahedra boosts the catalytic activity by shifting up the d-band center and thus strengthening the adsorption of key intermediate COOH*. This strain effect was further verified directly by the surface valence-band photoemission spectra and electrochemical analysis.
No strain, no gain: Pd octahedra and icosahedra with similar sizes are used as a well-defined platform to study the effect of surface strain in electrochemical reduction of CO2. The results show that tensile strain improves catalytic activity by shifting up the d-band center and thus strengthening the adsorption of key intermediate COOH*.
In the first of a three-part video series, Vox’s Joss Fong looks at how the technology used to film nature documentaries has changed over the past 50 years and how the producers of Planet Earth II used contemporary image stabilization techniques to make the series with a more cinematic style.
In the 1970s and ’80s, it was enough for the NHU to show people a creature they’d never seen before and provide the details in the narration. The films were illustrated zoology lectures. Since then, the producers have become sticklers for capturing specific behaviors, and in Planet Earth II, they showcase the drama of those behaviors. Each scene sets up the characters to perform something - something brave, something brutal, something bizarre. They’ve made room for our emotions; that’s what cinematic storytelling means.
And visually, the cinematic approach means the camera is often moving.
Hollywood filmmakers have kept the camera in motion for decades, but for obvious reasons, it’s much more difficult when your subject is wildlife. As we explain in the video at the top of this post, NHU producers used new stabilization tools throughout the production of Planet Earth II to move the camera alongside the animals.
The program doesn’t make you wait long to showcase this new approach. The tracking shot of a lemur jumping from tree to tree is one of the first things you see in the first episode and it put my jaw right on the floor. It’s so close and fluid, how did they do that? Going into the series, I thought it was going to be more of the same — Planet Earth but with new stories, different animals, etc. — but this is really some next-level shit. The kids were more excited after watching it than any movie they’ve seen in the past 6 months (aside from possibly Rogue One). The Blu-ray will be out at the end of March1 but there’s also a 4K “ultra HD” version that had me researching new ultra HD TVs I don’t really need.
Oh, and remember that thrilling sequence of the snakes chasing the newly hatched iguanas? Here’s a short clip on how they filmed it.
I still have a Blu-ray player than I barely use and only buy 1-2 BR discs a year, but Planet Earth II is one of those increasingly rare programs you want to see in full HD without compression or streaming artifacts.↩