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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Measuring the Strength of Hydrogen Bonds

For the first time, a group of scientists from University of California, San Diego in United States has quantitatively measured the strength of hydrogen bonds between two complex molecules. They also observed an abnormal trend regarding the bond strength in the absence and presence of electron transfer. This work contributes to the understanding of how the hydrogen bond strength changes, an important point that reveals the way biological systems function.

Hydrogen bonds are a type of electrostatic attraction between hydrogen atoms and certain highly electronegative atoms including N, O and F. These bonds help to bind individual water molecules together and keep water as liquid at room temperature, a critical condition for the origin of life.

The researchers, led by Prof. Kubiak, picked two ruthenium-based complexes joined by hydrogen bonds as their studying platform. As shown in Figure 1, the two-molecule system has three states depending on whether the ends are charged or not: the neutral state when both ends are not charged (left), the singly reduced state when only one end is negatively charged (middle), and the doubly reduced state when both ends are negatively charged (right). The group utilized infrared spectroscopy, UV-vis spectroscopy and electrochemical measurements to experimentally determine the strength of hydrogen bonds in these different redox states.

The results from the study found that the hydrogen bond energy of the neutral state and the doubly reduced state was in the range of 2.56-2.88 kcal/mol and 4.50-4.63 kcal/mol, respectively. Surprisingly, the hydrogen bond energy of the singly charged state did not lie between that of the neutral state and the doubly reduced state. It ranged from 7.78 kcal/mol to 8.31 kcal/mol, indicating the hydrogen bond is much stronger than for both the neutral and doubly-reduced states. The authors ascribed such an abnormality to the reinforcement brought by electron transfer i.e., the movement of the negative charge between the two ends.

This work is the first demonstration that hydrogen bond strength can be significantly enhanced by electron delocalization.

Figure 1. A schematic diagram showing the hydrogen bond strength of the singly reduced state (middle), the neutral state (left) and the doubly reduced states (right). [Note: In this figure, the lower the state lies, the stronger its hydrogen bond is. ET: electron transfer.]

To find out more please read:

Effects of Electron Transfer on the Stability of Hydrogen Bonds

Tyler M. Porter, Gavin P. Heim and Clifford P. Kubiak

Chem. Sci. DOI: 10.1039/c7sc03361c

About the blogger:

Tianyu Liu is a Ph.D. in chemistry graduated from University of California, Santa Cruz in United States. He is passionate about scientific communication to introduce cutting-edge researches to both the general public and the scientists with diverse research expertise. He is a web blogger for the Chem. Commun. and Chem. Sci. blog websites. More information about him can be found at http://liutianyuresearch.weebly.com/.

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Celebrate Open Access Week with Chemical Science!

Chemical Science is free to access and free to publish, with our publication charges currently waived.

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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Meet Mircea Dincă: Chemical Science Associate Editor

We are delighted to welcome Professor Mircea Dincă as Chemical Science Associate Editor, handling submissions in the area of materials.

Mircea Dincă grew up in Romania and moved to the US to study for a Bachelor’s degree at Princeton University. From here, he graduated with a BA in Chemistry in 2003. Following graduate studies in Inorganic Chemistry at UC Berkeley, Mircea moved to MIT for a postdoctoral appointment in 2008, and was offered an Assistant Professor position in the Department of Chemistry at MIT starting in 2010. Mircea was then promoted to Associate Professor in 2015 and offered tenure in 2017.

Mircea’s research interests lie in the synthesis of new multifunctional materials for applications in electrical and electronic devices, heterogeneous catalysis, and various uses in clean and renewable energy. In recognition of Mircea’s group’s research, he has been awarded the Alan T. Waterman Award from the NSF in 2016 and the ACS Award in Pure Chemistry in 2018, among several others.

Mircea is keen to receive submissions in his area of expertise, particularly MOF-related and multi-functional material research. Below is a list of recent Chemical Science articles published within the MOF-related field – all free to read. We hope you enjoy them!

Functional metal–organic framework boosting lithium metal anode performance via chemical interactions
Wen Liu, Yingying Mi, Zhe Weng, Yiren Zhong, Zishan Wua and Hailiang Wang
Chem. Sci., 2017, 8, 4285-4291
DOI: 10.1039/C7SC00668C

Hollowing out MOFs: hierarchical micro- and mesoporous MOFs with tailorable porosity viaselective acid etching
Jaehyoung Koo, In-Chul Hwang, Xiujun Yu, Subhadeep Saha, Yonghwi Kim and Kimoon Kim
Chem. Sci., 2017, 8, 6799-6803
DOI: 10.1039/C7SC02886E

Is iron unique in promoting electrical conductivity in MOFs?
Lei Sun, Christopher H. Hendon, Sarah S. Park, Yuri Tulchinsky, Ruomeng Wan, Fang Wang, Aron Walsh and Mircea Dinca
Chem. Sci., 2017, 8, 4450-4457
DOI: 10.1039/C7SC00647K

Bond breakage under pressure in a metal organic framework
Zhi Su, Yu-Run Miao, Guanghui Zhang, Jeffrey T. Miller and Kenneth S. Suslick
Chem. Sci., 2017, Advance Article
DOI: 10.1039/C7SC03786D

You can submit your high quality research in the area of materials to Mircea Dincă’s Editorial Office.

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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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Reductive power of hydrated electrons unleashed with green lasers


Source: © Royal Society of Chemistry
Laboratory-scale photoredox catalysis using hydrated electrons sustainably generated with a single green laser. Asc = ascorbate dianion, OER = one-electron reduced form, GS = ground state, MLCT = metal-to-ligand charge-transfer excited state

Solvated electrons are highly reductive so can force stubborn compounds to react where other reagents might fail. Now a team in Germany is generating them sustainably, using only a green laser and vitamin C. The group has used the technique to perform reactions previously impossible with a visible-light responsive catalyst.

Photons from the laser transform a ruthenium-based photocatalyst into an excited state, with a central oxidised ruthenium atom and a radical anion ligand. Vitamin C’s ascorbate dianion then quenches the excited species, producing a one-electron reduced form of the complex – where the ruthenium atom is no longer oxidised, but the ligand remains as a radical anion. Another photon can then eject the additional electron – generating the hydrated electron species that can induce reduction reactions of organic compounds, and simultaneously returns the catalyst to its ground state.

Read the full story by Jamie Durrani on Chemistry World.

 

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HOT Chemical Science articles for September

All of the referee-recommended articles below are free to access.

Chemoenzymatic synthesis of heparan sulfate and heparin oligosaccharides and NMR analysis: paving the way to a diverse library for glycobiologists
Xing Zhang, Vijayakanth Pagadala, Hannah M. Jester, Andrew M. Lim, Truong Quang Pham, Anna Marie P. Goulas, Jian Liu and  Robert J. Linhardt
Chem. Sci., 2017, Advance Article
DOI: 10.1039/C7SC03541A, Edge Article

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Displacement and hybridization reactions in aptamer-functionalized hydrogels for biomimetic protein release and signal transduction
Jinping Lai, Shihui Li, Xuechen Shi, James Coyne, Nan Zhao, Fengping Dong, Yingwei Mao and  Yong Wang
Chem. Sci., 2017, Advance Article
DOI: 10.1039/C7SC03023A, Edge Article

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Effects of electron transfer on the stability of hydrogen bonds
Tyler M. Porter, Gavin P. Heim and Clifford P. Kubiak
Chem. Sci., 2017, Advance Article
DOI: 10.1039/C7SC03361C, Edge Article

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