Archive for the ‘News’ Category

What’s left isn’t always right in total synthesis

Using detective skills that would make Hercule Poirot proud, researchers in the US have solved a longstanding mystery around the absolute configuration of natural product (+)-frondosin B.1

Source: Royal Society of Chemistry Summary of the enantioselective frondosin B syntheses reported to date

(+)-Frondosin B is part of a family of marine sesquiterpenes found in underwater sponges that exhibit anti-inflammatory properties and have potential applications in anticancer and HIV therapy. Starting with Samuel Danishefsky’s route in 2001,2 there have been 5 total syntheses of (+)-frondosin B. However, due to a discrepancy in the optical rotation of the final product during Dirk Trauner’s 2002 synthesis,3 which was observed to have S rather than the expected R configuration, there has been a fierce debate in the synthetic community about the true stereochemistry at C8 in the natural product. After more than decade of attempts by synthetic organic chemists to explain this, particularly focused on different inversion processes, no definitive answer had arisen.

Read the full story by Jason Woolford on Chemistry World.

1 L A Joyce et al, Chem. Sci., 2017, DOI: 10.1039/c7sc04249c (This paper is open access.)

2 M Inoue et al, J. Am. Chem. Soc., 2001, 123, 1878 (DOI: 10.1021/ja0021060)

 

 

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Benchmark for molecular machine learning

A team at Stanford University in the US has developed a benchmark for machine learning in chemistry. By providing a consistent way to test different techniques across a range of chemical data, it aims to accelerate the growth of this new type of scientific problem-solving.

Source: Royal Society of Chemistry
MoleculeNet curates multiple public datasets, establishes metrics for evaluation, and offers high quality open-source implementations of multiple previously proposed molecular featurisation and learning algorithms (released as part of the DeepChem open source library)

Machine learning methods train a computer to efficiently get from raw data to already-known answers. Once the expected results are consistently reproduced, the software is ready to perform the same task with entirely new data. To fairly compare different learning approaches, research groups around the globe need to train and test their methods using a shared set of problems. Reference databases already exist for images and text; MoleculeNet, an extension of the DeepChem project, provides such a benchmark for chemistry.

Read the full story by Alexander Whiteside on Chemistry World.

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Protonation enhances water splitting

Researchers in China and Singapore have designed a new platinum electrocatalyst for the hydrogen evolution reaction that outperforms existing catalysts and also performs better than theoretical calculations suggest it should.

Source: Royal Society of Chemistry
Transmission electron microscopy image of the new electrocatalyst showing its branched structure

Hydrogen can serve as a clean fuel, and electrochemical water splitting through the hydrogen evolution reaction is one way to generate this valuable resource. Many current electrocatalysts for the hydrogen evolution reaction are based on platinum, which, although expensive, can be very efficient. Researchers are always looking to improve the efficiency of platinum electrocatalysts to make the hydrogen evolution reaction a suitable replacement for fossil fuels.

Read the full story by Suzanne Howson on Chemistry World.

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Peptide vehicle drives CRISPR delivery of Cas9 into cells

Scientists in Spain have put forward what they describe as the first non-covalent strategy for delivering the CRISPR Cas9 ribonucleoprotein into cells.1

Cas9 is a large RNA-guided DNA endonuclease enzyme that is responsible for accurately recognising and cutting the desired sequence of DNA in a cell’s genome during the gene editing process known as CRISPR. At the moment, CRISPR scientists typically transfect cells with a plasmid containing instructions to make Cas9: however, this isn’t ideal as it might result in permanent DNA recombination and persistent expression, which could have adverse effects. Researchers are therefore exploring methods that deliver Cas9 into cells.

Read the full story by Adrian Robinson on Chemistry World.

Peptide/Cas9 nanostructures for ribonucleoprotein cell membrane transport and gene edition

1 I Lostalé-Seijo et al, Chem. Sci., 2017, DOI: 10.1039/c7sc03918b (This paper is open access.)

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Zirconium MOF buckles under dynamite pressure

Scientists in the US have found that a metal–organic framework (MOF) known for its robustness takes in the same amount of energy as a TNT blast releases when it breaks.

Shock-absorber MOF

Source: Royal Society of Chemistry After compression, the effective number of Zr–carboxylate oxygen bonds (shown in yellow) for each Zr(IV) ion decreased from 4 to ≈2

MOF materials are porous framework solids whose typical applications include gas storage, separation and catalysis. Scientists have studied the zirconium-based MOF, UiO-66, in more detail than most. It’s easily synthesised, has a well-known structure and is strong. Unlike some other MOFs, it doesn’t react with water, and on removing its residual solvent, the framework remains intact with true, empty voids.

Read the full story by Emma Stephen on Chemistry World.

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Quick test on pinprick of blood could help stop Ebola in its tracks

Scientists have developed a quick, cheap, safe and field-deployable method to detect the Ebola virus in unprocessed whole blood.

artist's impression of an ebola virus in the body

Source: Shutterstock The World Health Organization declared an end to the most recent Ebola epidemic in January 2016

The recent Ebola epidemic in West Africa was responsible for 11,310 deaths. Containing this deadly virus relies on rapid, reliable diagnoses, but Ebola is difficult to diagnose because it shares its initial symptoms with other diseases such as malaria and yellow fever. It usually takes weeks before patients develop the bleeding associated with Ebola haemorrhagic fever; by this time, they may have passed the infection on to others.

The standard method of detection is reverse transcription polymerase chain reaction (RT-qPCR), where chemical probes flag nucleic acids in the virus genome. This is reliable but involves deploying whole mobile laboratories and trained personnel. It is also expensive and results can take hours or even days, while the virus continues to spread. Another drawback is that it requires a blood draw, which is risky for both medical personnel and haemorrhagic patients.

Read the full story by Will Bergius on Chemistry World.

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Celebrate Open Access Week with Chemical Science!

Open Access Week is taking place on 23 – 29 October 2017! This global event is entering its 8th year, and is an opportunity for the research community to learn about the benefits of open access.

What is open access? It’s free, immediate, online access to published research and has widespread implications for academia, industry, medicine, and the entire society.

Here at Chemical Science, we are in our third year of being gold open access! This allows our publications, from breakthroughs in organic chemistry to research in energy and environmental chemistry, to be communicated to a worldwide audience without barriers.

Chemical Science articles published from 2015 onwards are freely available to read from our website and, as our publications charges are currently waived, it is also free for authors to publish. To date, we’ve published over 2,500 open access articles! Below is a selection of some of the articles that you can read for free.

Follow us on Twitter where we’ll be highlighting an ‘Article of the Day’ during Open Access Week!

Enrichment and single-cell analysis of circulating tumor cells
Yanling Song,Tian Tian, Yuanzhi Shi, Wenli Liu, Yuan Zou, Tahereh Khajvand, Sili Wang, Zhi Zhu and Chaoyong Yang
Chem. Sci., 2017, 8, 1736-1751
DOI: 10.1039/C6SC04671A

Design of template-stabilized active and earth-abundant oxygen evolution catalysts in acid
Michael Huynh, Tuncay Ozel, Chong Liu, Eric C. Lau and Daniel G. Nocera
Chem. Sci., 2017, 8, 4779-4794
DOI: 10.1039/C7SC01239J

Recent developments in and perspectives on three-coordinate boron materials: a bright future
Lei Ji, Stefanie Griesbeck and Todd B. Marder
Chem. Sci., 2017, 8, 846-863
DOI: 10.1039/C6SC04245G

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Chemists reinvent the wheel

Scientists in the US have made a new molecular wheel. The bimetallic cluster, Nb2Au6, consists of a Nb≡Nb tripled bonded unit surrounded by a Au6 ring.

A molecular wheel with a short Nb≡Nb triple bond coordinated by an Au6 ring and reinforced by σ aromaticity

Lai-Sheng Wang and his team at Brown University made the cluster by striking a gold and niobium solid target with an intense laser beam. Theoretical calculations show that there are two π bonds and one σ bond in the Nb2 dimer. The cluster also has five totally delocalised σ bonds – scientists have not reported σ aromaticity in a metal–ligand system before.

Read the full story by Jennifer Newton on Chemistry World.

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Scientists poke holes in zeolite theory

Theorists in the UK have studied the aluminium distribution in a number of catalytically active zeolite species, finding evidence that –Al–O–Al– linkages could exist in some zeolite species after all.1


Source: Royal Society of Chemistry
Löwenstein’s rule of ‘aluminium avoidance’ says that that –Al–O–Al– bonds are forbidden but new research hints that this motif may not be as elusive as is generally believed

Since Löwenstein first published his study on ‘the distribution of aluminium in the tetrahedra of silicates and aluminates’ in 1954,2 scientists had generally accepted that aluminium clusters cannot exist within zeolite structures. Löwenstein’s rule of ‘aluminium avoidance’ states that whenever two tetrahedra are linked by an oxygen bridge, if the centre of one is occupied by an aluminium atom, the other must be occupied by silicon. As such, Löwenstein’s rule prohibits –Al–O–Al– linkages from occurring within zeolites, and dictates that the ratio of Al:Si in zeolites must be 1:1.

Read the full story by Hannah Dunckley on Chemistry World.

1 R E Fletcher, S Ling and B Slater, Chem. Sci., 2017, DOI: 10.1039/c7sc02531a (This article is open access.)
2 W Löwenstein, Am. Mineral., 1954, 39, 92

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Hydrogen bonded system faces strength test

Scientists in Spain have devised a versatile technique that uses DNA to pull apart host–guest complexes so they can measure the overall strength of hydrogen bonds in that system. The method can distinguish forces as low as 0.1–1pN.

Source: © Royal Society of Chemistry
Using a DNA reporter guarantees that the force measurements refer to a single system

Procedures to measure supramolecular interactions in the bulk, under equilibrium conditions, are well established. But nature operates out of equilibrium, so scientists want a technique to measure hydrogen bonds in conditions realistic to living systems.

Read the full story by Jennifer Newton on Chemistry World.

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