The vials shown here contain a molecule that researchers can activate with light to affect biological processes in mammals. It’s part of a class of potential smart drugs that are under development to treat ailments including diabetes, blindness, and the side effects of chemotherapy. Because the molecules turn on only when hit with a certain wavelength of light, researchers can control when and where the compounds are active in the body. This photo was taken by Dusan Kolarski, a graduate student at the University of Groningen in the lab of Ben Feringa, who won the 2016 Nobel Prize in Chemistry for his work on molecular machines. Feringa’s group is working to create antibiotics that can be activated with light and thus may pose a lower risk of bacterial resistance. The team also wants to make water-soluble motors for applications in photopharmacology.—ALEXANDRA TAYLOR
Brian Wagner, a chemistry professor at the University of Prince Edward Island, often works with fluorescent detector molecules in his lab. But instead of showing off his research, he decided to show off the fluorescent objects people interact with all the time by putting them under a 350-nm-wavelength ultraviolet lamp. From left to right, the substances shown are as follows: *Olive oil (contains various fluorescent compounds)
*Vitamin B-2, a.k.a. riboflavin, dissolved in water
*Turmeric dissolved in water (contains the fluorescent molecule curcumin)
*A bar of Irish Spring Original soap (contains the fluorescent molecule pyranine)
*Canola oil (contains various fluorescent compounds)
*Tonic water (contains the fluorescent molecule quinine)
It is an understatement to say that chemical reactions take place everywhere, constantly. In both nature and the lab, chemistry is ubiquitous. But despite advances, it remains a fundamental challenge to gain a complete understanding and control over all aspects of a chemical reaction, such as temperature and the orientation of reacting molecules and atoms.
This requires sophisticated experiments where all the variables that define how two reactants approach, and ultimately react with, each other can be freely chosen. By controlling things like the speed and the orientation of the reactants, chemists can study the finest details of a particular reaction mechanism.
In a new study, a team led by Andreas Osterwalder at EPFL’s Institute of Chemical Sciences and Engineering, working with theorists from the University of Toronto, have built an apparatus that allows them to control the orientation and energies of reacting atoms, down to nearly absolute zero. “It’s the coldest formation of a chemical bond ever observed in molecular beams,” says Osterwalder. A molecular beam is a jet of gas inside a vacuum chamber, frequently used in spectroscopy and studies in fundamental chemistry.
Scientists at the University of Basel have found a way to change the spatial arrangement of bipyridine molecules on a surface. These potential components of dye-sensitized solar cells form complexes with metals and thereby alter their chemical conformation. The results of this interdisciplinary collaboration between chemists and physicists from Basel were recently published in the scientific journal ACS Omega.
Dye-sensitized solar cells have been considered a sustainable alternative to conventional solar cells for many years, even if their energy yield is not yet fully satisfactory. The efficiency can be increased with the use of tandem solar cells, where the dye-sensitized solar cells are stacked on top of each other.
The way in which the dye, which absorbs sunlight, is anchored to the semiconductor plays a crucial role in the effectiveness of these solar cells. However, the anchoring of the dyes on nickel oxide surfaces – which are particularly suitable for tandem dye-sensitized cells – is not yet sufficiently understood.
Scientists at Pacific Northwest National Laboratory (PNNL) have uncovered a molecular game of musical chairs that hurts battery performance.
In an article published in Nature Nanotechnology, the researchers demonstrate how the excitation of oxygen atoms that contributes to better performance of a lithium-ion battery also triggers a process that leads to damage, explaining a phenomenon that has been a mystery to scientists.
The research pinpoints the science behind one barrier on the road to creating longer-lived, higher-capacity rechargeable lithium-ion batteries. It’s an unexpected finding about a process that takes place every day in the batteries that power cell phones, laptop computers, and electric cars.
For physicist Percy Zahl, optimizing and preparing a noncontact atomic force microscope (nc-AFM) to directly visualize the chemical structure of a single molecule is a bit like playing a virtual reality video game. The process requires navigating and manipulating the tip of the instrument over the world of atoms and molecules, eventually picking some up at the right location and in the right way. If these challenges are completed successfully, you advance to the highest level, obtaining images that precisely show where individual atoms are located and how they are chemically bonded to other atoms. But take one wrong move, and it is game over. Time to start again.
“The nc-AFM has a very sensitive single-molecule tip that scans over a carefully prepared clean single-crystal surface at a constant height and "feels” the forces between the tip molecule and single atomsand bonds of molecules placed on this clean surface,“ explained Zahl, who is part of the Interface Science and Catalysis Group at the Center for Functional Nanomaterials (CFN), a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory. "It can take an hour or days to get this sensor working properly. You can’t simply press a button; fine tuning is required. But all of this effort is definitely worthwhile once you see the images appearing like molecules in a chemistry textbook.”
An international research team has used the X-ray laser European XFEL to gain new insights into how radiation damage occurs in biological tissue. The study reveals in detail how water molecules are broken apart by high-energy radiation, creating potentially hazardous radicals and electrically charged ions, which can go on to trigger harmful reactions in the organism. The team led by Maria Novella Piancastelli and Renaud Guillemin from the Sorbonne in Paris, Ludger Inhester from DESY and Till Jahnke from European XFEL is presenting its observations and analyses in the scientific journal Physical Review X.
Sincewater is present in every known living organism, the splitting of the water molecule H2O by radiation, called the photolysis of water, is often the starting point for radiation damage. “However, the chain of reactions that can be triggered in the body by high-energy radiation is still not fully understood,” explains Inhester. “For example, even just observing the formation of individual charged ions and reactive radicals in water when high-energy radiation is absorbed is already very difficult.”
To study this sequence of events, the researchers shot the intense pulses from the X-ray laser at the water vapor. Water molecules normally disintegrate on absorbing a single such high-energy X-ray photon. “Due to the particularly intense pulses from the X-ray laser, it was even possible to observe water molecules absorbing not just one, but two or even more X-ray photons before their debris flew apart,” Inhester reports. This gives the researchers a glimpse of what goes on inside the molecule after the first absorption of an X-ray photon.
A team of researchers at the Institute of Synthetic Polymer Materials of the Russian Academy of Sciences, MIPT and elsewhere has determined how the regularity of polypropylene molecules and thermal treatment affect the mechanical properties of the end product. Their new insights make it possible to synthesize a material with predetermined properties such as elasticity or hardness. The paper detailing the study was published in Polymer.
In terms of production volume, polypropylene it is second only to polyethylene. By tweaking its molecular structure, polypropylene can be used to manufacture materials with a wide range of features, from elastic bands to high-impact plastic. However, the relationship between the polymer’s chemical structure and its mechanical properties is not fully understood.
What makes the properties of polymer materials so variable is their makeup. A polymer molecule is a long chain of repeating units of unequal length. If these molecules are jumbled up more or less at random in a material, it is said to be amorphous. Such polymers are soft. In other materials, the polymer chains form interconnections called crosslinks. This gives rise to regions of highly regular atomic structure (fig. 1), similar to that of crystals, hence the name crystallites. They hold the whole molecular network together, and the more crystallites there are in a material, the harder it is. To form crosslinks, molecular chains need to possess a certain structural regularity called isotacticity.
Blink your eyes and it’s long gone. Carbonic acid exists for only a tiny fraction of a second when carbon dioxide gas dissolves in water before changing into a mix of protons and bicarbonate anions. Despite its short life, however, carbonic acid imparts a lasting impact on Earth’s atmosphere and …
A technique that combines the ultrasensitivity of surface-enhanced Raman scattering (SERS) with a slippery surface invented by Penn State researchers will make it feasible to detect single molecules of a number of chemical and biological species from gaseous, liquid or solid samples. This…
A research team from the Georgia Institute of Technology and ExxonMobil has demonstrated a new carbon-based molecular sieve membrane that could dramatically reduce the energy required to separate a class of hydrocarbon molecules known as alkyl aromatics. The new material is based on polymer…
The machine that unboiled an egg is now being used to develop molecules up to 15 times faster than conventional methods.
Researchers from Flinders University in South Australia in collaboration with the University of California Irvine have used the Vortex Fluidic Device (VFD) to increase the rate of chemical reactions using enzymes.
Lead researcher Joshua Britton said the research was a potential “game-changer” and could be used to speed up production of chemical molecules for use in fuel and medicines.
“Enzymes make life possible by catalysing diverse and challenging chemical transformations with exquisite precision – and no nasty by-products,” Britton said.
“Their use has been limited in some areas, however, because of modest reaction rates, requiring long reaction times and careful optimized conditions. DERA (Deoxyribose-5-phospate), for example, which previously required hours to days, now catalyses 15 times faster using the VFD.”
Researchers from UNIGE have developed a new type of chemical sensor capable of detecting the presence of metals in the environment
An international team, led by researchers from the University of Geneva (UNIGE), Switzerland, has designed a family of molecules capable of binding to metal ions present in its environment and providing an easily detectable light signal during binding. This new type of sensor forms a 3D structure whose molecules are chiral, that is to say structurally identical but not superimposable, like an image and its reflection in a mirror, or like the left and right hands. These molecules consist of a ring and two luminescent arms that emit a particular type of light in a process called Circular Polarized Luminescence (CPL), and selectively detect ions, such as sodium. This research can be read about in Chemical Science.
“The luminescent arms of our molecules function like light bulbs that light up or turn off depending on the presence of a positively charged ion, a metal cation,” explains Jérôme Lacour, Dean of the Faculty of Science at UNIGE and Ordinary Professor in the Department of Organic Chemistry. These molecules can be compared to small locks: when they are ready to operate and detect the presence of metals, they emit a particular type of light (circularly polarized). When a metal ion is inserted, it acts on them like a key, the lock geometry changes and the light disappears.
Consumer demand continually pushes the electronics industry to design smaller devices. Now researchers at A*STAR have used a theoretical model to assess the potential of electric wires made from polymer chains that could help with miniaturization.
As conventional silicon-integrated circuits reach their lower size limit, new concepts are required such as molecular electronics—the use of electronic components comprised of molecular building blocks. Shuo-Wang Yang at A*STAR Institute of High Performance Computing together with his colleagues and collaborators, are using computer modeling to design electric wires made of polymer chains.
“It has been a long-standing goal to make conductive molecular wires on traditional semiconductor or insulator substrates to satisfy the ongoing demand miniaturization in electronic devices,” explains Yang.
Progress has been delayed in identifying molecules that both conduct electricity and bind to substrates. “Structures with functional groups that facilitate strong surface adsorption typically exhibit poor electrical conductivity, because charge carriers tend to localize at these groups,” he adds.
After drying the liquid in his flask under high vacuum, Priya Ranjan Sahoo saw this foam start to bubble up and fill the vessel. Oddly, this netlike foam glowed under ultraviolet light because his product was a silicon rhodamine molecule. Sahoo, a postdoc at Tohoku University’s Institute of Multidisciplinary Research for Advanced Materials, aims to use silicon rhodamines as switchable fluorescent probes in imaging experiments. The key to switchability is controlling which form the molecule takes: when its five-membered lactone ring is intact, the molecule shows very little fluorescence, but when the lactone pops open (transformation shown in scheme), it exhibits an eerie blue glow under a variety of ultraviolet wavelengths (center and left photo; visible light shown in right photo). — Manny Morone
Surface tension of water as revealed by a paperclip.
The paperclip has been placed over a surface marked with parallel lines. The water in contact with the paperclip forms a meniscus, as the water molecules are attracted to the molecules of the metal clip. This makes the water around the paperclip slightly thicker, which refracts the light passing through it, distorting the appearance of the parallel lines.
The cohesive forces between molecules in a liquid are shared with all neighboring molecules. Those on the surface have no neighboring molecules above and, thus, exhibit stronger attractive forces upon their nearest neighbors on and below the surface.
Water molecules want to cling to each other. At the surface, however, there are fewer water molecules to cling to since there is only air above. This results in a stronger bond between those molecules that actually do come in contact with one another, and a layer of strongly bonded water.
This surface layer (held together by surface tension) creates a considerable barrier between the atmosphere and the water. In fact, other than mercury, water has the greatest surface tension of any liquid. -USGS-
Closed-eye fantasies in this world seem sometimes to be revelations of the secret workings of the brain, of the associative and patterning processes, the ordering systems which carry out all our sensing and thinking. Unlike the one I have just described, they are for the most part ever more complex variations upon a theme-ferns sprouting ferns sprouting ferns in multidimensional spaces, vast kaleidoscopic domes of stained glass or mosaic, or patterns like the models of highly intricate molecules-systems of colored balls, each one of which turns out to be a multitude of smaller balls, forever and ever. Is this, perhaps, an inner view of the organizing process which, when the eyes are open, makes sense of the world even at points where it appears to be supremely messy? - quote by Alan Watts
