Organic photoredox catalysts enable diverse chemical transformations, but predicting their activity is challenging due to complex properties. Now, a two-step data-driven approach is introduced for targeted organic photoredox catalysts synthesis and reaction optimization. Using Bayesian optimization, promising catalysts can be efficiently identified, yielding competitive results with iridium catalysts.
Computational chemistry has remained largely inaccessible to the experimental chemistry community. Here we report the VIRTUAL CHEMIST, a software suite free for academic use, that enables organic chemists without expertise in computational chemistry to perform virtual screening experiments for asymmetric catalyst discovery and design.
A groundbreaking discovery by researchers at the University of California, Los Angeles (UCLA) has challenged a long-standing rule in organic chemistry known as Bredt’s Rule. Established nearly a century ago, this rule stated that certain types of specific organic molecules could not be synthesized due to their instability. UCLA’s team’s findings open the door to new molecular structures that were previously deemed unattainable, potentially revolutionizing fields such as pharmaceutical research.
To grasp the significance of this breakthrough, it’s helpful to first understand some basics of organic chemistry. Organic chemistry primarily deals with molecules made of carbon, such as those found in living organisms. Among these, certain molecules known as olefins or alkenes feature double bonds between two carbon atoms. These double bonds create a specific geometry: the atoms and atom groups attached to them are generally in the same plane, making these structures fairly rigid.
In 1924, German chemist Julius Bredt formulated a rule regarding certain molecular structures called bridged bicyclic molecules. These molecules have a complex structure with multiple rings sharing common atoms, akin to two intertwined bracelet loops. Bredt’s Rule dictates that these molecules cannot have a double bond at a position known as the bridgehead, where the two rings meet. The rule is based on geometric reasons: a double bond at the bridgehead would create such significant structural strain that the molecule would become unstable or even impossible to synthesize.
The fact that the cold, dry Mars of today had flowing rivers and lakes several billion years ago has puzzled scientists for decades. Now, Harvard researchers think they have a good explanation for a warmer, wetter ancient Mars.
Building on prior theories describing the Mars of yore as a hot again, cold again place, a team led by researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have determined the chemical mechanisms by which ancient Mars was able to sustain enough warmth in its early days to host water, and possibly life.
“It’s been such a puzzle that there was liquid water on Mars, because Mars is further from the sun, and also, the sun was fainter early on,” said Danica Adams, NASA Sagan Postdoctoral Fellow and lead author of the new paper in Nature Geoscience.
Muon spin rotation (µSR) spectroscopy is a powerful technique that helps to study the behavior of materials at the atomic level. It involves using muons—subatomic particles similar to protons but with a lighter mass. When introduced into a material, muons interact with local magnetic fields, providing unique insights into the material’s structure and dynamics, especially for highly reactive species such as radicals.
In a new study, a team of researchers led by Associate Professor Shigekazu Ito, from the School of Materials and Chemical Technology, Institute of Science Tokyo, Japan, utilized µSR spectroscopy to investigate the regioselective muoniation of peri-trifluoromethylated 12-phosphatetraphene 1. This compound is a phosphorus congener (a variant of a common chemical structure).
The process of µSR spectroscopy initially involves the formation of a muonium (Mu), which is formed when a positively charged muon (µ+) captures an electron (e–). This process continues as the reaction of a muonium (Mu = [µ+e–]) with the phosphorus-containing compound, resulting in the formation of a muoniated radical at the phosphorus site.
Posted in chemistry, nanotechnology, particle physics, quantum physics | Leave a Comment on Nanoscale ‘diamond rings’ provide unconventional giant ’magnetoresistance‘ for the development of new quantum devices
In recent years, technological advancements have made it possible to create synthetic diamonds that have similar physical and chemical properties to natural diamonds. While synthetic diamonds are not considered “fake” or “imitation,” they are often more affordable than their natural counterparts, making them a popular choice for those who want the beauty of a diamond without the high cost. Synthetic diamonds are also often more environmentally friendly, as they do not require the same level of mining and extraction as natural diamonds.
In its pristine state, diamond is a non-conductive material, devoid of free electrons or “holes” that can facilitate electrical conduction (Figure 1). However, by introducing boron atoms into the diamond crystal lattice, its optical and electrical properties can be significantly altered. As the concentration of boron is increased, the diamond’s color shifts from its characteristic clear hue to a delicate shade of blue, while its electrical conductivity transforms from an insulator to a semiconductor.
Further increases in the boron content result in a lustrous blue shade that resembles the sheen of metallic surfaces and eventually culminates in a deep, ebony coloration. Such heavily boron-doped diamond (BDD) is also as electrically conducting as some metals, and at low temperatures, exhibits superconductivity, allowing electrical conduction with no resistance.
From being a promising yet underexplored approach in the 1990s, mRNA therapeutics have evolved dramatically. The discovery of chemical modifications to overcome mRNA’s instability and immunotoxicity enabled these therapeutics to reach clinical trials and the forefront of modern medicine. The platform’s scalability, rapid production and relatively straightforward manufacturing process mean that mRNA therapeutics are a powerful alternative to traditional small molecule drugs and DNA technology.
Enzymes are a vital tool that make in vitro transcription possible and refine the reaction products to generate highly pure, homogeneous mRNA. In this ebook, we provide an in-depth review into:
In a major leap toward sustainable energy, a team of Japanese researchers has developed an artificial photosynthesis system that could help generate hydrogen and oxygen from just water and light. The breakthrough is thanks to a new type of hydrogel, which mimics the natural process of photosynthesis and performs these reactions without requiring external energy. This innovation opens up exciting possibilities for clean energy production, potentially transforming the way we think about renewable resources.
Artificial photosynthesis has long been a goal for scientists looking to replicate the natural process plants use to convert light into energy. The concept is simple in theory: use light to drive chemical reactions that produce useful energy, such as hydrogen. However, previous attempts to harness this process have been hampered by the need for external energy to trigger the reactions, making the systems inefficient and difficult to scale.
Enter hydrogels —a promising new solution. These polymer-based materials are capable of responding to external stimuli like temperature, light, and pH. The challenge, however, has been that these materials often suffer from self-aggregation, where the molecules clump together and hinder the energy conversion process. The Japanese researchers, however, have overcome this obstacle by designing a hydrogel that maintains the precise arrangement of its molecules, enabling a more effective energy transfer.
Researchers at Linköping University (LiU), Sweden, have created an artificial organic neuron that closely mimics the characteristics of biological nerve cells. This artificial neuron can stimulate natural nerves, making it a promising technology for various medical treatments in the future.
Work to develop increasingly functional artificial nerve cells continues at the Laboratory for Organic Electronics, LOE. In 2022, a team of scientists led by associate professor Simone Fabiano demonstrated how an artificial organic neuron could be integrated into a living carnivorous plant to control the opening and closing of its maw. This synthetic nerve cell met two of the 20 characteristics that differentiate it from a biological nerve cell.
In their latest study, published in the journal Nature Materials, the same researchers at LiU have developed a new artificial nerve cell called conductance-based organic electrochemical neuron, or c-OECN, which closely mimics 15 out of the 20 neural features that characterize biological nerve cells, making its functioning much more similar to natural nerve cells.
Artificially engineered biological processes, such as perception systems, remain an elusive target for organic electronics experts due to the reliance of human senses on an adaptive network of sensory neurons, which communicate by firing in response to environmental stimuli.
A new collaboration between Northwestern University and Georgia Tech has unlocked new potential for the field by creating a novel high-performance organic electrochemical neuron (OECN) that responds within the frequency range of human neurons. The team also built a complete perception system by designing other organic materials and integrating their engineered neurons with artificial touch receptors and synapses, which enabled real-time tactile signal sensing and processing.
The research, described in a paper in Proceedings of the National Academy of Sciences, could move the needle on intelligent robots and other systems currently stymied by sensing systems that are less powerful than those of a human.