10th National Conference on Inorganic Chemistry of the Chinese Chemical Society

Chemical Science was pleased to support the 10th National Conference on Inorganic Chemistry of the Chinese Chemical Society which took place at Shandong University last month. Poster prizes were given on behalf of Chemical Science as well as Inorganic Chemistry Frontiers, Materials Chemistry Frontiers, Catalysis Science & Technology, Physical Chemistry Chemical Physics, Green Chemistry, Dalton Transactions, RSC Advances, Nanoscale, Nanoscale Advances, Materials Horizons and Journal of Materials Chemistry A, B and C. Energy & Environmental Science and Sustainable Energy & Fuels also provided a joint prize. The winners are:

Poster prize winners of the 10th National Conference on Inorganic Chemistry of the Chinese Chemical Society

Yuan Xiong 熊昱安 东南大学
Southeast University
Lingling Xu 徐令令 西安交通大学
Xi’an Jiaotong University
Fan Guo 郭帆 南京大学
Nanjing University
Wenbin Wang 王文彬 华中科技大学
Huazhong University of Science and Technology
Mengfei Li 李梦菲 中国石油大学(华东)
China University Of Petroleum
Jing Dong 董婧 北京理工大学
Beijing Institute Of Technology
Bingqi Han 韩冰琪 吉林大学
Jilin University
Wenzhu Yu 于文竹 山东大学
Shandong University
Liang Zhou 周亮 北京大学
Peking University
Genfeng Feng 冯根锋 南京大学
Nanjing University
Peipei Cui 崔培培 德州学院
Dezhou University
Xiaoting Liu 刘晓婷 南开大学
Nankai University
Dong Li 李冬 厦门大学
Xiamen University
Zhi Wang 王芝 山东大学
Shandong University
Shuang Liu 刘爽 东北师范大学
Northeast Normal University

Congratulations to all the winners!

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Breaking C-H bonds with water, iron, and electricity

As we transition to an energy future composed primarily of intermittent, renewable technologies, finding ways to store the excess generated charges will be critical. While the general public typically thinks of batteries, another area of massive interest is storing the electrons in a chemical bond. This can be accomplished by creating electrocatalysts that can couple an electric current with chemicals like water and oxygen to generate stable new bonds in molecules for later use as fuels. These renewably generated fuels would then be available whenever needed, like at night. However, finding efficient electrocatalysts composed of earth-abundant materials has proven challenging. Many researchers have turned to nature for inspiration by designing molecules that mimic the active sites of enzymes.

Researchers in the United States used this approach, focusing on creating high-valent iron-oxo species, which others previously identified as the key catalytic intermediates in multiple enzymatic reactions. These types of species have traditionally been synthesized by reacting a reduced iron complex with an oxygen transfer reagent, but the researchers developed a system to generate highly reactive species using electricity as the reaction driving force and water as the oxygen source. The studied catalyst is a commercially available iron(III)-aquo complex with a tetraamido macrocyclic ligand (TAML) as the ancillary ligand (Figure 1B).

Figure 1. A. Cyclic voltammagram of (TAML)Fe in acetonitrile. B. Structure of (TAML)Fe and cyclic voltammagram showing increased current upon the addition of ethylbenzene.

When analyzed by cyclic voltammetry, an electrochemical technique where you cycle the voltage between set points and measure the current output, the (TAML)Fe shows two redox events at around 650 and 1250 mV that the researchers attributed to generating the FeIV-OH and FeV(O) species (Figure 1). Addition of ethylbenzene, which should react with the FeV species, increased the current at voltages of 1250 mV and higher, indicating (TAML)Fe turnover. However, isolating the Fev(O) species proved challenging as it reacts rapidly with the (TAML)Fe to form an FeIV dimer. This also limits the efficiency of the overall system by decreasing the amount of the most reactive species in solution.

Figure 2. A, B. Products generated by oxidation of various substrates screened with (TAML)Fe for electrocatalysis with isolated yield and calculated conversion in parenthesis. C. Substrates that did not react with the (TAML)Fe complex.

Both the FeIV dimer and FeV(O) species proved capable of oxidizing C-H bonds in ethylbenzene, but the FeV(O) is much more reactive and increases the oxidation rate at high electrochemical potentials. The researchers tested the scope of (TAML)Fe reactivity using a series of compounds with benzylic C-H bonds (Figure 2). They found that the (TAML)Fe performed well with electron-rich and electron-neutral derivatives, with an electron-deficient nitro-substituted derivative showing lower reactivity. Several substrates with non-benzylic C-H bonds showed high selectivity for oxidation at the benzylic C-H bond. (TAML)Fe also showed high electrocatalytic activity for oxidizing alcohols and converted substrates as simple as cyclohexanol and as complex as a steroid to ketones in high yields (up to 97%).

This study of an earth-abundant, stable, and commercially available electrocatalyst acts as a baseline for further studies with other similar metal complexes. Despite the efficiency limits attributed to dimerization, the high stability and selectivity of the (TAML)Fe could lead to its use with a broader range of substrates with varied functional groups.

To find out more please read:

Electrochemical C–H oxygenation and alcohol dehydrogenation involving Fe-oxo species using water as the oxygen source

Amit Das, Jordan E. Nutting and Shannon S. Stahl

Chem. Sci., 2019, 10, 7542-7548

About the blogger:

Beth Mundy is a PhD candidate in chemistry in the Cossairt lab at the University of Washington in Seattle, Washington. Her research focuses on developing new and better ways to synthesize nanomaterials for energy applications. She is often spotted knitting in seminars or with her nose in a good book. You can find her on Twitter at @BethMundySci.

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International Conference on Energy Materials and Interfaces

Last month the North East Centre for Energy Materials (NECEM) held the International Conference on Energy Materials and Interfaces in Newcastle, UK, which was sponsored by Chemical Science. The conference covered topics including flexible photovoltaics, thermoelectric devices, computational simulations of interfaces in energy capture devices, applications of 2D materials in energy capture and storage, tailored interfaces in turbines and new conc‌epts in electrical and electrochemical energy storage.

Chemical Science sponsored a poster prize, which was awarded to Stephen Campbell from Northumbria University. RSC journals Energy & Environmental Science and Sustainable Energy & Fuels also awarded poster prizes to David Alejandro Palacios Gomez from Durham Unviersity and Wei-Hsiang Lin from National Tsing Hua University.

Energy & Environmental Science poster prize winner David Alejandro Palacios Gomez, from Durham University

Sustainable Energy & Fuels poster prize winner Wei-Hsiang Lin from National Tsing Hua University

Congratulations to the prize winners from everyone at Chemical Science!

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26th International Symposium: Synthesis in Organic Chemistry

The 26th International Symposium on Synthesis in Organic Chemistry was held in Cambridge last month, showcasing exciting work in this core area of organic chemistry – synthesis. Chemical Science, alongside Organic and Biomolecular Chemistry, was proud to sponsor the event, which included talks covering a variety of aspects of modern synthesis and provided a forum for emerging methodologies and strategies.

The symposium featured talks from researchers working at the cutting-edge of synthesis in organic chemistry, including Chemical Science Associate Editor Vy Dong, Frances Arnold, Shankar Balasubramanian, Tanja Gulder, Robert Knowles, Daniele Leonori, David Nicewicz, Robert Phipps, Tobias Ritter, Tomislav Rovis, Franziska Schoenebeck, Hiroaki Suga, Edward Tate, F Dean Toste, Matthew Tudge, and William Unsworth.

Chemical Science’s Executive Editor, May Copsey, was proud to present the Poster Prizes for the meeting, sponsored by Chemical Science and Organic and Biomolecular Chemistry. Congratulations to Roman Abrams (University of Bristol) and Claire Flitcroft (The University of Sydney) for winning the judge’s choice poster prizes, and to Tobias Wagener (Westfälische Wilhelms-Universität Münster) and Thomas Brouder (University College Cork) for winning the participant’s vote prizes. There was a fantastic array of posters – congratulations to all those who displayed work.

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Microscale Motion and Light

Chemical Science recently sponsored the successful Microscale Motion and Light conference which took place last month in Dresden, Germany. The event ran from the 22nd – 26th July and focussed on the below topics including discussion by invited speakers of the exciting new opportunities for smart materials and applications.:

Professor Tom Mallouk hands Linlin Wang her award for best poster (first prize)

  • Micromotion
  • Photochemistry
  • Catalysis
  • Active matter
  • Non-equilibrium-systems
  • Colloids
  • Water splitting
  • Electrochemistry
  • Light-responsive materials
  • Colloidal assembly

Chemical Science provided two best poster prizes which were handed out by the conference co-organiser, Professor Tom Mallouk (Penn State University, USA).

The prize winners were Linlin Wang who was awarded first prize and Tao Huang who received the second prize for best poster.

Professor Tom Mallouk (left) hands Tao Huang (right) his award for best poster (second prize)

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Bioorthogonal & Bioresponsive 2019

Chemical Science recently sponsored Bioorthogonal & Bioresponsive 2019 in Edinburgh, which brought together chemists and biologists interested in the latest advances in bioorthogonal and bioresponsive strategies.

The meeting featured stunning talks from a variety of international experts, including Jason Chin, Ben Davis, Karen Faulds, Sarah Heilshorn, Ludovic Jullien and Vince Rotello.

We finished the first day with a poster session and drinks reception on the top floor of the Institute of Genetics & Molecular Medicine, with a stunning view across the city. There was a fantastic display of posters, and Chemical Science along with Organic and Biomolecular Chemistry were delighted to sponsor the poster prizes. Congratulations to both of the prize winners!

Sally Vanden-Hehir (left) won the Chemical Science prize for best poster and flash presentation.
Sam Benson (right) won the Organic and Biomolecular Chemistry prize for best poster.

Organisers and hosts Marc Vendrell and Asier Unciti-Broceta, prize winners Sally Vanden-Hehir and Sam Benson, and Chemical Science representative Amelia Newman.

The beautiful view from the top of the Institute of Genetics & Molecular Medicine.

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Making Gyroid Polymer Films to Speed up Proton Conduction

Proton exchange membranes (PEMs) are essential to the functionality of fuel cells. They conduct protons in electrolytes and drive electricity generation by oxidizing fuels. Following the success of Nafion® –– a family of commercial proton-conductive fluoropolymers –– materials researchers around the globe are developing innovative PEMs with high proton conductivities and affordable prices.

A group of Japanese researchers has recently synthesized self-standing polymer films with a gyroid nanostructure. These films possess two unique characteristics that other PEMs rarely have: a high proton conductivity in the order of 10-1 S/cm and retention of the conductivity across a wide temperature range (20-120 °C). This finding has been published in Chem. Sci. (doi: 10.1039/C9SC00131J).

The authors used a tailor-made macromolecule, Diene-GZI (Figure 1a), as the building block. It had an amphipathic structure, with one end being a hydrophilic zwitterionic group and another end of a hydrophobic alkyl chain. When mixed with bis(trifluoromethanesulfonyl)imide and water, multiple Diene-GZI molecules could assemble together into a gyroid network –– an infinitely periodic minimal surface (Figure 1b). After the self-assembly, ultra-violet-irradiation-induced polymerization solidified the morphology of the gyroid nanostructure.

Figure 1. (a) The molecular structure of Diene-GZI. (b) Solidification of the self-assembled gyroid via polymerization.

The high proton conductivity of the polymer film originated from its three-dimensional gyroid structure. Since the gyroid surface was densely coated with the hydrophilic zwitterionic chains, the film could readily uptake as high as 15.6 wt.% of water at a relative humidity of 90%. The adsorbed water layers formed a three-dimensional continuous pathway along the gyroid surface, serving as proton-conduction expressways and resulting in a high conductivity in the order of 10-1 S/cm. Due to the strong binding force between water and the zwitterionic groups, heating the polymer film to 120 °C did not decrease the water content significantly, and thus, the proton conductivity remained high. Additionally, the control films with no gyroid structures were unable to compete with the gyroid film in terms of proton conductivities within the measured temperature range (Figure 2).

Figure 2. The dependence between proton conductivities and temperature. Legends: red solid circles – gyroid film; others – control samples without the gyroid nanostructure.

This work highlights the critical role of rational design of raw materials to augment the proton conductivities of PEMs. The advantage of the gyroid phase in speeding up ion diffusion could also inspire innovative materials in applications demanding ultrafast ion transport, e.g., supercapacitor electrodes.

 

To find out more, please read:

Gyroid Structured Aqua-Sheets with Sub-Nanometer Thickness Enabling 3D Fast Proton Relay Conduction

Tsubasa Kobayashi, Ya-xin Li, Ayaka Ono, Xiang-bing Zeng, and Takahiro Ichikawa

Chem. Sci., 2019, 10, 6245-6253

About the blogger:

Tianyu Liu obtained his Ph.D. (2017) in Chemistry from University of California, Santa Cruz in the United States. He is passionate about scientific communication to introduce cutting-edge research to both the general public and scientists with diverse research expertise. He is a blog writer for Chem. Commun. and Chem. Sci. More information about him can be found at http://liutianyuresearch.weebly.com/.

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Tryptophan, Featuring BN/CC Isosterism

Ever wanted to find a way to replace a carbon-carbon (CC) double bond with another bond that will change the physical and chemical properties of a molecule without significantly altering its sterics? Look no further than a boron-nitrogen bond! BN/CC isosterism involves substituting a CC double bond with a BN bond, which can substantially change the electronic properties of a molecule while keeping it the same size. This isosterism could be a powerful tool in biomedical studies of biologically relevant arene-containing organic molecules, which are plentiful. However, few studies report on the differences in functions cause by substituting a BN bond into an arene. Initial results suggest that the BN compounds can have similar or increased activity and availability when compared to the natural, all carbon molecules.

Figure 1. Image of naturally occuring tryptophan and the BN-tryptophan analogue.

Researchers in the United States synthesized a BN-analogue of tryptophan (Figure 1) for use as an unnatural amino acid (UAA) to study and intentionally alter the properties of proteins. Tryptophan, in addition to making Americans sleepy at Thanksgiving, is relatively rare, but participates in pi system interactions and is the primary source of native protein fluorescence. This makes it an important target for UAA research. The researchers synthesized the sodium salt of BN-tryptophan in a 6-step process, which can be modified to resolve the two enantiomers by chiral HPLC. The BN-tryptophan exhibits noticeably red-shifted absorbance and emission spectra, with the fluorescence maximum shifted by almost 40 nm in the BN compound.

In order to test whether the BN-tryptophan could be incorporated into proteins, researchers incorporated it into media without tryptophan and monitored whether E. coli cells that lacked the ability to produce tryptophan would grow. They found that the cells grew when in the presence of BN-tryptophan, but to a significantly lesser degree than with an equivalent quantity of natural tryptophan. However, cell growth increased when the media contained both BN-tryptophan and natural tryptophan. This suggests that cells will accept BN-tryptophan as a tryptophan analogue, but they don’t tolerate full replacement well.

Figure 2. Representation of the protein sequence, structures of other tryptophan analogues, and fluorescence plot for the studied substrates.

Further studies incorporated BN-tryptophan and three other previously utilized tryptophan analogues into a green fluorescent protein (GFP). For fluorescence to be detected, the analogue must be incorporated into the protein and then accurately read by cells. The BN-tryptophan performs as well or better than the established tryptophan analogues, proving its functionality (Figure 2). The proteins with BN-tryptophan also demonstrate several different properties than those containing natural tryptophan; their fluorescence is red shifted and they are more susceptible to oxidation by hydrogen peroxide. These alterations in activity could prove useful in future studies.

To find out more please read:

Synthesis and characterization of an unnatural boron and nitrogen-containing tryptophan analogue and its incorporation into proteins

Katherine Boknevitz, James S. Italia, Bo Li, Abhishek Chatterjee and Shih-Yuan Liu

Chem. Sci., 2019, 10, 4994–4998.

About the blogger:

Beth Mundy is a PhD candidate in chemistry in the Cossairt lab at the University of Washington in Seattle, Washington. Her research focuses on developing new and better ways to synthesize nanomaterials for energy applications. She is often spotted knitting in seminars or with her nose in a good book. You can find her on Twitter at @BethMundySci.

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2019 Alberta Nanosymposium

The 6th Alberta Nano Research Symposium was held earlier this year in May. The theme this year was NaNoTeCH: Celebrating the periodic table, with keynote speakers Dr Shirley Tang (University of Waterloo) and Dr Robert Carpick (University of Pennsylvania).

Chemical Science sponsored a poster prize, along with RSC journal Nanoscale Horizons. Congratulations to both of the prize winners from everyone at Chemical Science!

Taylor Lynk was awarded the Chemical Science Poster Prize

Nidhika Bhoria was awarded the Nanoscale Horizons Poster Prize

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Charge & Substrate Transport in 3D Electrocatalytic Materials, ACS Fall Meeting

Chemical Science, along with RSC journals RSC AdvancesEnergy & Environmental ScienceSustainable Energy & Fuels and Nanoscale Advances are pleased to be sponsoring the Charge & Substrate Transport in 3D Electrocatalytic Materials symposium at the ACS Fall 2019 National Meeting and Exposition in San Diego this August. It will be held at 8:30 am on Tuesday 27th in the Marina Ballroom Salon G at Marriott Marquis San Diego Marina.

Organized by Anthony Hall, Charles McCrory and V. Sara Thoi as part of the Division of Inorganic Chemistry, this symposia will be presided by Charles McCrory (University of Michigan) and feature presentations from Shelley D Minteer (University of Utah), Daniel Esposito (Columbia University), Yogesh Surendranath (MIT), Joseph Thomas Hupp (Northwestern University), Casey R Wade (Ohio State University), Amanda J Morris (Virginia Tech) as well as Charles McCrory.

 

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