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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HOT Chemical Science articles for April

We are happy to present a selection of our HOT articles for April. To see all of our HOT referee-recommended articles from 2019, please find the collection here.

As always, Chemical Science articles are free to access.

The full dynamics of energy relaxation in large organic molecules: from photo-excitation to solvent heating

Vytautas Balevičius Jr, Tiejun Wei, Devis Di Tommaso, Darius Abramavicius, Jürgen Hauer, Tomas Polívka and Christopher D. P. Duffy*

Chem. Sci., 2019, 10, 4792-4804

DOI
: 10.1039/C9SC00410F, Edge Article

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Chiral diversification through the assembly of achiral phenylacetylene macrocycles with a two-fold bridge

Ryo Katoono,* Keiichi Kusaka, Yuki Saito, Kazuki Sakamoto and Takanori Suzuki

Chem. Sci., 2019, 10, 4782-4791

DOI
: 10.1039/C9SC00972H, Edge Article

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NosL is a dedicated copper chaperone for assembly of the CuZ center of nitrous oxide reductase

Sophie P. Bennett, Manuel J. Soriano-Laguna, Justin M. Bradley, Dimitri A. Svistunenko, David J. Richardson, Andrew J. Gates* and Nick E. Le Brun

Chem. Sci., 2019, 10, 4985-4993

DOI
: 10.1039/C9SC01053J, Edge Article

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Brønsted acid catalysis – the effect of 3,3′-substituents on the structural space and the stabilization of imine/phosphoric acid complexes

Maxime Melikian, Johannes Gramüller, Johnny Hioe, Julian Greindl and Ruth M. Gschwind*

Chem. Sci., 2019, 10, 5226-5234

DOI
: 10.1039/C9SC01044K, Edge Article

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Theoretical design of a technetium-like alloy and its catalytic properties

Wei Xie* and Michihisa Koyama*

Chem. Sci., 2019, 10, 5461-5469

DOI
: 10.1039/C9SC00912D, Edge Article

 

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Highly regioselective complexation of tungsten with Eu@C82/Eu@C84: interplay between endohedral and exohedral metallic units induced by electron transfer

Lipiao Bao, Pengyuan Yu, Ying Li, Changwang Pan, Wangqiang Shen, Peng Jin,* Shuquan Liang* and Xing Lu*

Chem. Sci., 2019, 10, 4945-4950

DOI
: 10.1039/C9SC01479A, Edge Article

 

 

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One-Pot MOFs

Metal-organic frameworks, commonly known as MOFs, are one to three-dimensional structures composed of metal ions coordinated to organic linkers. They’ve drawn substantial research interest given their highly porous nature, the extreme tunability of their properties, and, in the early days, relative ease of synthesis. As the field has matured, the syntheses of the organic linkers have increased in complexity. New linkers require substantial expertise in synthetic organic chemistry and can be time and cost intensive to produce. One strategy to avoid the linker-induced bottleneck in MOF development is to create one-pot procedures, generating both the linker and the MOF in a single vessel. While the idea is straightforward, in practice it involves carefully balancing conditions to crystalize the MOF without producing unwanted side reactions.

Figure 1. Reaction motifs utilized for in-situ ligand generation. a) nitro-compound reduction, b) diazo coupling of nitro compounds, c) condensation of boronic acids, and d) imidization of an anhydride and an amine.

Researchers in China recently examined several classes of organic reactions to test the viability of in-situ ligand and MOF synthesis. The basic procedure involves complex ligand generation, formation of small metal clusters, and finally crystallization of the final MOF structure. They chose reduction and diazo coupling of nitro compounds, condensation of boronic acids, and imidization between anhydrides and amines (Figure 1). A rigid, nitro-containing dicarboxylic acid proved the most robust for the reduction studies.  When combined with a hydrated metal salt (copper, zinc, and indium nitrates and manganese chloride), exposed to a protic solvent, and heated, a MOF formed in a single vessel without the addition of a purposeful reductant. This specific ligand didn’t have the proper geometry to produce MOFs via diazo couplings, but a similar motif was used to create a new ligand with greater distance separating the carboxylic acid groups. The researchers dissolved the ligand and various metal salts in DMF, then added proton source, and heated the mixture. The reactions with zirconium, zinc, cadmium, and indium all produced MOFs. The reaction conditions varied from metal to metal, producing different forms of the ligand in-situ that resulted in MOFs of a range of morphologies (Figure 2).

Figure 2. Structures of zirconium, zinc, cadmium, and indium-based MOFs synthesized by ligands generated via diazo coupling.

While these MOFs formed via strong, irreversible reactions, the covalent organic framework literature utilizes the plethora of reversible reactions to expand the scope of possible MOFs. This inspired the researchers to use boronic acid derivatives as a proof of concept. When a ligand with both boronic and carboxylic acid motifs reacted with zirconium or hafnium and formic acid, the researchers isolated a MOF with tetrahedral cages. This approach also proved successful when combining two ligands in a Schiff base synthesis to form a zirconium-based MOF. The reversible reactions required meticulous tuning of the acid source to effectively crystalize and assemble the MOFs. However, the ease of reaction set up allows more rapid screening of conditions than full-scale ligand synthesis.

This relatively simple and efficient strategy for producing new MOFs likely has broader applications than the few reactions currently explored. This will hopefully increase the speed of new MOF discovery with increasingly complex ligands.

To find out more please read:

Constructing new metal-organic frameworks with complicated ligands from “One-Pot” in situ reactions

Xiang-Jing Kong, Tao He, Yong-Zheng Zhang, Xue-Quian Wu, Si-Nan Wang, Ming-Ming Xu, Guang-Rui Si, and Jian-Rong Li

Chem. Sci., 2019, 10, 3949 – 3955.

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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A Single Nickel Site Reduces Nitrate Ions to Nitrogen Gas

Surface runoff of agricultural or landscape areas with excessive nitrate fertilizers has resulted in increasing nitrate ion concentrations in freshwater. This issue leads to eutrophication and algae blooms that significantly threaten aquatic lives and ecosystems. Eliminating nitrate ions is thus necessary to address the nitrate-borne water pollution. Nature presents a delicate yet complicated process for turning NO3 into N2 by four metalloenzymes. Is it possible to develop an artificial method with just one catalyst to drive the same process?

Lee, Baik, and coworkers at the Institute for Basic Science (IBS) and Korea Advanced Institute of Science and Technology (KAIST) answered yes. The researchers synthesized a square-planar nickel(II)-based complex, (PNP)Ni(ONO2) (PNP = N[2-P’Pr-4-methyl-C6H3]2), which converted NO3 to N2 in the presence of CO and NO. Ni2+ is the only active site. This breakthrough has been published in Chemical Science (DOI: 10.1039/C9SC00717B).

The reaction mechanism involves four successive redox reactions among (PNP)Ni(ONO2), CO, and NO (Figure 1). The first two steps consecutively transfer two oxygen atoms from (PNP)Ni(ONO2) to CO at room temperature, yielding two molecules of CO2 and a Ni-nitrosyl complex, (PNP)Ni(NO). Afterwards, the (PNP)Ni(NO) undergoes a disproportionation reaction with NO, generating (PNP)Ni(NO2) and N2O. The as-formed N2O interacts with the remaining (PNP)Ni(NO) and is eventually reduced to N2. The yield of N2 is 46% (based on the amount of N2O).

Figure 1. The schematic shows the artificial nitrate reduction with a Ni(II)-based complex, (PNP)Ni(ONO2), as the catalyst. Pr: propyl group.

Besides nitrate reduction, the (PNP)Ni(ONO2) could act as a potential alternative to the platinum-containing catalysts used in the catalytic converters of gasoline cars, because it transforms hazardous CO and NO into less toxic CO2 and N2.

To find out more please read:

One Metal is Enough: A Nickel Complex Reduces Nitrate Anions to Nitrogen Gas

Jinseong Gwak, Seihwan Ahn, Mu-Hyun Baik and Yunho Lee

Chem. Sci., 2019, 10, 4767-4774

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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Chemical biology symposium 2019

The Chemical biology symposium 2019 was recently held at Burlington House in London, UK on 20th May. Chemical Science and Organic & Biomolecular Chemistry were proud to support the meeting, and Chemical Science Senior Editor James Moore attended to meet with delegates and represent the Royal Society of Chemistry.

The symposium showcased the state of the art in chemical biology, bringing together the wider community with leading national and international experts in the field. The programme explored all aspects of chemical biology and highlighted the wider scope and impact of the field.

Chemical Science were proud to present Tiffany Chan from Imperial College London with the poster prize for her poster on ‘Targeted delivery of metal complexes across the blood-brain barrier for the treatment of Alzheimer’s disease’.

Organic & Biomolecular Chemistry were proud to present Sophie Newgas from King’s College London with the runner up poster prize for her poster on ‘Understanding the role of nitric oxide synthase in biosynthetic nitration’.

Congratulations to them both!

Tiffany Chan

Sophie Newgas

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17th Symposium on Host-Guest and Supramolecular Chemistry

The 17th Symposium on Host-Guest and Supramolecular Chemistry was held in Kanazawa, Japan, on 18th and 19th of May, chaired by Professor Shigehisa Akine of Kanazawa University. Professor Tatsuya Nabeshima of the University of Tsukuba and president of the Association of Research for Host-Guest and Supramolecular Chemistry was also in attendance, as was Hiromitsu Urakami on behalf of the Royal Society of Chemistry.

The Chemical Science poster prize was awarded to Mr. Akihiro Kanamori of Kanazawa University for his poster on the ‘Synthesis of Salicylideneimine-Based Cryptophane Derivatives through Chiral Self-sorting and Their Guest Recognition Behavior’.

The Chemical Communications poster prize was awarded to Mr. Lingyun Hu of the University of Tokyo for his poster on the ‘Construction of Metal-responsive DNAzymes by Incorporating CuII-mediated Imidazole-4-carboxylate Base Pairing’.

The Organic & Biomolecular Chemistry poster prize was awarded to Mr. Sota Yonemura of the University of Tsukuba for his poster on the ‘Formation of Chiral Single Isomer by Metal Complexation of a β-Cyclodextrin Derivatives introduced Seven Bipyridyl Groups and Origomer Complex of the Isomer’.

Congratulations to Akihiro, Lingyun & Sota!

(From left) Hiromitsu Urakami, Tatsuya Nabeshima, Akihiro Kanamori (ChemSci poster winner), Shigehisa Akine

Organic & Biomolecular Chemistry poster winner Sota Yonemura

(From left) Hiro Urakami, Tatsuya Nabeshima, Lingyun Hu (ChemComm poster winner), Shigehisa Akine

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Molecular Switching: from Blue Biradicals to Colorless Housanes

As chemists, we typically first encounter molecular switches, the general term for any molecule that exists in at least two stable or meta-stable states, as pH indicators in introductory chemistry classes. The external factor that causes the conversion can vary from a redox event to UV light. This makes molecular switches attractive sensors for a range of chemically relevant applications. The reversible and controllable bond-making and bond-breaking also provides a system within which to interrogate the nature of chemical bonding.

Figure 1. The biradical (left) and housane (right) in solution along with their simplified chemical structures.

Chemists at the University of Rostock in Germany explored light-driven molecular switching behavior in a class of heterocyclic molecules. These can exist as either biradicals or housanes (see Figure 1 for why the name makes sense) with a bond between the two phosphorus atoms. Understanding the mechanism by which the photo-isomerization occurs is important for future applications of the biradical system in small molecule activation. The in-depth studies used the 2,6-dimethylphenyl (2Dmp) derivative, since it was the most stable of the synthesized derivatives. The researchers monitored the conversion between species by examining their dramatically different 31P NMR spectra, with the housane resonances between -50 and -200 ppm and the biradical resonances between 200 and 300 ppm. An additional distinguishing feature between is color: the starting biradical is blue while the housane is colorless. The researchers found that biradical converts to the housane, which has a half-life of about 7 minutes at room temperature in solution, with an almost 25% quantum yield.

Figure 2. A single crystal of the biradical. Upon irradiation, the transition to the colorless housane can be observed, along with extensive cracking of the crystal.

This switching occurs not only in solution, but also in the solid state (Figure 2). The cracking evident in the images of a single crystal is attributed to the stress caused by changes to the crystal lattice by conversion of the biradical to the housane. Despite various efforts by the team, including crystallization attempts under constant irradiation, they were unable to obtain high enough quality crystals to acquire a crystal structure of the housane. The specific isomerization mechanism was computationally modeled and showed that the photoexcitation of the biradical led to a bonding interaction and distortion, allowing for housane formation. The reverse, thermally activated process, occurs due to the intersection of the ground and excited state energies near a transition state.

Given this enhanced understanding of the isomerization mechanism, the researchers manipulated the reactivity of the biradical by adding tert-butyl isocyanide (tBuNC). tBuNC catalyzed the thermal conversion of the housane back to the diradical. While the mechanism of the catalysis is unknown, it’s an exciting proof-of-concept for easily tuning molecular switching behavior.

To find out more please read:

A chemical reaction controlled by light-activatedmolecular switches based on hetero-cyclopentanediyls

Jonas Bresien, Thomas Kröger-Badge, Stefan Lochbrunner, Dirk Michalik, Henrik Müller, Axel Schultz, and Edgar Zander

Chem. Sci., 2019, 10, 3486-3493

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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HOT Chemical Science articles for March

We are happy to present a selection of our HOT articles for March. To see all of our HOT referee-recommended articles from 2019, please find the collection here.

As always, Chemical Science articles are free to access.

The antioxidant activity of polysulfides: it’s radical!

Jean-Philippe R. Chauvin, Markus Griesser and Derek A. Pratt*

Chem. Sci., 2019, 10, 4999-5010

DOI
: 10.1039/C9SC00276F, Edge Article

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Anisotropic strain release in a thermosalient crystal: correlation between the microscopic orientation of molecular rearrangements and the macroscopic mechanical motion

Tomohiro Seki,* Takaki Mashimo and Hajime Ito*

Chem. Sci., 2019, 10, 4185-4191

DOI
: 10.1039/C8SC05563G, Edge Article

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Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence

Thomas J. Feuerstein, Bhupendra Goswami, Pascal Rauthe, Ralf Köppe, Sergei Lebedkin, Manfred M. Kappes and Peter W. Roesky*

Chem. Sci., 2019, 10, 4742-4749

DOI
: 10.1039/C9SC00629J, Edge Article

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Direct observation of prion protein oligomer formation reveals an aggregation mechanism with multiple conformationally distinct species

Jason C. Sang, Ji-Eun Lee, Alexander J. Dear, Suman De, Georg Meisl, Alana M. Thackray, Raymond Bujdoso, Tuomas P. J. Knowles and David Klenerman*

Chem. Sci., 2019, 10, 4588-4597

DOI
: 10.1039/C8SC05627G, Edge Article

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Using coligands to gain mechanistic insight into iridium complexes hyperpolarized with para-hydrogen

Ben. J. Tickner, Richard O. John, Soumya S. Roy, Sam J. Hart, Adrian C. Whitwood and Simon B. Duckett*

Chem. Sci., 2019, 10, Advance Article

DOI
: 10.1039/C9SC00444K, Edge Article

 

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Direct conversion of phenols into primary anilines with hydrazine catalyzed by palladium

Zihang Qiu, Leiyang Lv, Jianbin Li, Chen-Chen Li and Chao-Jun Li*

Chem. Sci., 2019, 10, 4775-4781

DOI
: 10.1039/C9SC00595A, Edge Article

 

 

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Bioorthogonal & Bioresponsive Symposium 2019

The second Bioorthogonal & Bioresponsive symposium will be held at the Institute of Genetics & Molecular Medicine in Edinburgh on the 6th and 7th of June 2019. Chemical Science is proud to sponsor the symposium and our new Assistant Editor Amelia Newman will be attending.

The symposium aims to bring together chemists and biologists interested in the latest advances in bioorthogonal and bioresponsive strategies. Talks will highlight state-of-the-art work from leading UK and international experts, and speakers include Jason Chin, Ben Davis, Karen Faulds, Sarah Heilshorn, Ludovic Jullien and Vincent Rotello.

It’s not too late to join us at this exciting meeting – registration is still open at the RSC Events webpage. The registration deadline is 31st May 2019.

If you cannot attend the symposium next month, you can follow @BBSymposium1 on Twitter to stay updated.

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