With a chemical “trick”, scientists in Germany have succeeded in isolating a stable gold carbene complex. Experts have been proposing gold carbenes as essential short-lived intermediates in catalytic reactions, but they elude study because of their high reactivity. Chemist Prof. Dr. Bernd F. Straub and his team are the first to have created the basis for directly examining the otherwise unstable gold-carbon double bond.
Iron is present in tiny concentrations in seawater, on the order of a few billionths of a gram in a liter. However, its availability in seawater can have a profound effect on phytoplankton growth and, consequently, the Earth's carbon cycle. In recent research, an assessment was made of the various sources of dissolved iron in the north Atlantic Ocean and surprising discoveries were made about their origins.
Ancient Japanese gold leaf artists were truly masters of their craft. An analysis of six of these Japanese paper screens show that these artifacts are gilded with gold leaf that was hand-beaten to the nanometer scale. The study was able to prove this without any damage to the screens through the use of x-ray fluorescence spectroscopy.
Titanium dioxide nanoparticles show great promise as optical encapsulants or fillers for tunable refractive index coatings. However, they've been largely shunned because they’ve been difficult and expensive to make. Scientists at Sandia National Laboratories have now come up with an inexpensive way to synthesize properly sized titanium dioxide nanoparticles and is seeking partners who can demonstrate the process at industrial scale.
A breakthrough has been made in identifying the origin of superconductivity in high-temperature superconductors, which has puzzled researchers for the past three decades. Researchers in the U.K. have found that ripples of electrons, known as charge density waves or charge order, create twisted ‘pockets’ of electrons in these materials, from which superconductivity emerges.
A new nanoparticle platform developed in California increases the efficiency of drug delivery and allows excess particles to be washed away. A simple etching technique using biocompatible chemicals rapidly disassembles and removes the silver nanoparticles outside living cells. This method leaves only the intact nanoparticles for imaging or quantification, revealing which cells have been targeted and how much each cell internalized.
Surface catalysts are notoriously difficult to study mechanistically, but scientists at two universities have recently shown how to get real-time reaction information from silver nanocatalysts that have long frustrated attempts to describe their kinetic behavior in detail. The key to the team's success was bridging a size gap that had represented a wide chasm to researchers in the past.
Rensselaer Polytechnic Institute scientists have developed a method that can predict how subjecting metals to severe pressure can lower their electrical resistance. The finding which involved theoretical predictions, use of a supercomputer, and equipment capable of exerting pressures up to 40,000 atmospheres, could have applications in computer chips and other materials that could benefit from specific electrical resistance.
Research published in the Proceedings of the National Academy of Sciences makes it possible to predict how subjecting metals to severe pressure can lower their electrical resistance, a finding that could have applications in computer chips and other materials that could benefit from specific electrical resistance.
Thermal systems use heat to produce cold, and vice versa. The human body demonstrates this function when it perspires, but what is lacking for devices that operate on this principle are materials capable of sufficiently discharging the water vapor quickly. Metal organic frameworks (MOFs) are well suited to this task. Researchers have built a new 3-D porous MOF from metals and organic linkers that substantially increases water absorption.
Using a doped-graphene matrix to slow down and then trap atoms of the precious metal osmium, researchers in the U.K. have shown the ability to control and quantify the growth of metal-crystals. When the trapped atoms come into contact with further osmium atoms they bind together, eventually growing into 3-D metal-crystals. They have called this new technique nanocrystallometry.
Researchers in Japan have developed a new nickel catalyst with a “kabuto-like” structure that was found to catalyze the cross-coupling reaction between carbonyl compounds and readily available phenol derivatives, to form arylketones, which are found in many biologically active compounds. A kabuto is a helmet worn by Japanese samurai.
An international team of researchers have figured out a new way of storing and releasing hydrogen by making a unique crystal phase of a material containing lithium, boron and the key ingredient, hydrogen. To check how they could get the hydrogen back out of the material, the scientists heated it and found that it released hydrogen easily, quickly and only traces of unwanted by-products.
Vanadium dioxide is called a "wacky oxide" because it transitions between a conducting metal and an insulating semiconductor and with the addition of heat or electrical current. A device created by Penn State engineers uses a thin film of vanadium oxide on a titanium dioxide substrate to create an oscillating switch that could form the basis of a computational device that uses a fraction of the energy necessary for today’s computers.
While flexible gadgets such as “electronic skin” and roll-up touch screens are moving ever closer to reality, their would-be power sources are either too wimpy or too stiff. But that’s changing fast. Scientists have developed a new device that’s far thinner than paper, can flex and bend, and store enough energy to provide critical back-up power for portable electronics.
Northwestern Univ. researchers are the first to develop a new solar cell with good efficiency that uses tin instead of lead perovskite as the harvester of light. The low-cost, environmentally friendly solar cell can be made easily using "bench" chemistry, with no fancy equipment or hazardous materials.
For the first time, scientists have a clearer understanding of how to control the appearance of a superconducting phase in a material, adding crucial fundamental knowledge and perhaps setting the stage for advances in the field of superconductivity. The paper focuses on a calcium-iron-arsenide single crystal, which has structural, thermodynamic and transport properties that can be varied through carefully controlled synthesis.
Scientists at Ames Laboratory have observed magnetic properties typically associated with those observed in rare-earth elements in iron. These properties are observed in a new iron based compound that does not contain rare earth elements, when the iron atom is positioned between two nitrogen atoms.
Using an ultra-fast laser system, a group in Physical and Life Sciences at Lawrence Livermore National Laboratory have subjected iron to extremely rapid dynamic compression and have shown that the transition from one crystal structure to another can take place in less than 100 trillionths of a second after the compression begins.
Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides. Researchers from Cornell Univ. and Brookhaven National Laboratory have shown how to switch a particular transition metal oxide, a lanthanum nickelate (LaNiO3), from a metal to an insulator by making the material less than a nanometer thick.
Scientists at Yale Univ. have devised a dramatically faster way of identifying and characterizing complex alloys known as bulk metallic glasses (BMGs), a versatile type of pliable glass that's stronger than steel. Using traditional methods, it usually takes a full day to identify a single metal alloy appropriate for making BMGs.
In the fight against “superbugs,” scientists have discovered a class of agents that can make some of the most notorious strains vulnerable to the same antibiotics that they once handily shrugged off. Recently discovered metallopolymers, when paired with the same antibiotics MRSA normally dispatches with ease, helped evade the bacteria’s defensive enzymes and destroyed its protective walls, causing the bacteria to burst.
Recent experiments in Austria have explained the behavior of electrons at tiny step edges on titanium oxide surfaces. The finding, which shows why oxygen atoms attach so well to these edges, is important for solar cell technology and novel, more effective catalysts.
In steel making, two desirable qualities, strength and ductility, tend to be at odds: Stronger steel is less ductile, and more ductile steel is not as strong. Engineers at Brown Univ., three Chinese universities, and the Chinese Academy of Sciences have shown that when cylinders of steel are twisted, their strength is improved without sacrificing ductility.
Researchers are turning some of the basic tenets of chemistry and physics upside down to cut a trail toward the discovery of a new set of materials. They’re called “polar metals” and, according to many scientific principles, they probably shouldn’t exist.