Chemical Communications Blog

Improvements to a selective hydrogenation process using ionic liquids

26 Aug 2014

In this ChemComm communication, Peter Claus and co-workers describe an interesting application of room temperature ionic liquids to the selective hydrogenation of 2-hexyne. Unlike many reports in the literature, where an ionic liquid acting as a solvent may enhance a particular reaction, this report outlines a solid supported catalyst system modified with an ionic liquid layer.

Such materials, known as SCILLS, (solid catalyst with an ionic liquid layer) have been investigated in a variety of hydrogenation reactions. In this work the desired reaction is the reduction of 2-hexyne to cis-2-hexene. The catalyst is 1 wt% palladium on silica, modified with various loadings of 3 common ionic liquids: BMIM hexafluorophosphate, BMIM bis(triflouoromethanesulfonyl)imide and N-butyl-N-methylpyrrolidinium dicyanamide ([BMPL][DCA]). The performance of the unmodified catalyst was compared with the yield and selectivity afforded by the SCILL systems. The best results were reported with the dicyanamide ionic liquid SCILL, ([BMPL][DCA]) at 30 wt% ionic liquid loading.

In such a process, there are several reactions that must be suppressed. As the product is an olefin, isomerisation to the trans product must be controlled, as must further hydrogenation to the fully reduced material, hexane. For a number of reasons, based on the nature and amount of chemisorbed hydrogen, and favourable dicyanamide anion interactions with palladium, the dicyanamide SCILL system is particularly effective.

Notably, this system gives improved performance in terms of selectivity and yield over the two best performing commercial catalysts for this task. For example, Lindlar´s catalyst, palladium on calcium carbonate, deactivated with lead, cannot match its performance. In this work, the authors give an example of how ionic liquids can add value to a commercial process, while also offering considerable process improvements, in terms of toxicity and arguably, simplicity. The group’s focus now turns to SCILL activity and stability in a continuous hydrogenation process.

Read this RSC Chemical Communication today!

Highly cis-selective and lead-free hydrogenation of 2-hexyne by a supported Pd catalyst with an

ionic-liquid layer
Frederick Schwab, Natascha Weidler, Martin Lucas and Peter Claus

DOI: 10.1039/C4CC04183F

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Inducing β-Peptide Structures from the Inside Out

22 Aug 2014

By Anthea Blackburn, Web Science Writer.

Researchers from Japan have shown that fluoridation of β-peptide chains can influence their stability. Anthea Blackburn writes more…

The synthesis of tailor-made peptide chains represents a powerful tool for tuning the structure and properties of peptides, allowing for the development of analogues for medical, technological and synthetic purposes.

For example, the β-peptide is a synthetic peptide, which, in contrast to its naturally-occurring α-peptide analogue, is bonded through the β-carbon rather than the α-carbon. As a result of this seemingly small structural change, alterations in the peptide’s secondary structure and thermodynamic stability are observed.

Adding fluoride groups to peptide chains represents another way to alter and stabilise the folding structure through the presence of stronger hydrogen bonds and the introduction of fluorophilicity. This approach is generally employed for the addition of fluoride groups at ‘remote positions,’ spaced two or more methylene units from the peptide backbone. However, this method has less of an effect on the conformation of the peptide itself, and instead primarily influences the tertiary and quaternary self-aggregation of peptide chains, as a result of the fluorophilic effect of the functionalised peptide chains.

Much less commonly studied is the effect of incorporating fluorine groups in ‘direct proximity’ to the peptide chain, that is, directly attached to the β-carbon, where it is proposed that the intramolecular hydrogen bonding will be directly affected, and consequently, so too will the secondary structure of the peptide chain.

Yasuhiro Ishida and co-workers from the RIKEN Center for Emergent Matter Science have shown that this ‘direct’ fluorination of β-peptides can, in fact, affect the higher order structures of these peptide chains. Specifically, a hexameric β-peptide was designed, which consisted of cyclohexane-based β-amino acids in the 1-,3-,4- and 6-positions and L-alanine derivatives in the 2- and 5-positions, where the L-alanine methyl groups were either native or perfluorinated.

Irrespective of the degree of perfluorination in the β-peptide, it was found that the chains were arranged in the same left-handed 14-helix structure, with the NH-amide of the second and fifth residues participating in stabilising intramolecular H-bonding interactions. Moreover, it was found that although the presence of fluoride groups did not noticeably alter the overall secondary structure of the β-peptide chains, the stability of these structures was dramatically enhanced, showing the significant effect that fluoride groups can have on the hydrogen-bond donating ability of NH-amides.

This new approach of modifying peptide chains offers an interesting method for influencing the secondary, and higher order, structures of the compounds, as well as their kinetic and thermodynamic properties. The effect of these structural modifications offers the possibility of tuning the chemical and biological properties of these peptide chains for use in new types of antibiotics and synthetic systems.

Read this HOT ChemComm article in full!

Stabilization of β-peptide helices by direct attachment of trifluoromethyl groups to peptide backbones
Joonil Cho, Kyohei Sawaki, Shinya Hanashima, Yoshiki Yamaguchi, Motoo Shiro, Kazuhiko Saigo and Yasuhiro Ishida
Chem. Commun., 2014, 50, 9855–9858.

About the Writer

Anthea Blackburn is a guest web writer for Chemical Communications. Anthea is a graduate student hailing from New Zealand, studying at Northwestern University in the US under the tutelage of Prof. Fraser Stoddart (a Scot), where she is exploiting supramolecular chemistry to develop multidimensional systems and study the emergent properties that arise in these superstructures. When time and money allow, she is ambitiously attempting to visit all 50 US states before graduation.

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Hot ChemComm articles for August

20 Aug 2014

By Bethany Johnson.

All of the referee-recommended articles below are free to access until 17th September 2014

Nanoscale insight into C–C coupling on cobalt nanoparticles
E. A. Lewis, C. J. Murphy, A. Pronschinske, M. L. Liriano and E. C. H. Sykes
Chem. Commun., 2014,50, 10035-10037
DOI: 10.1039/C4CC03678F, Communication
From themed collection Scanning Probe Studies of Molecular Systems

A bifunctional curcumin analogue for two-photon imaging and inhibiting crosslinking of amyloid beta in Alzheimer’s disease
Xueli Zhang, Yanli Tian, Peng Yuan, Yuyan Li, Mohammad A. Yaseen, Jaime Grutzendler, Anna Moore and Chongzhao Ran
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC03731F, Communication

Rapid engineering of versatile molecular logic gates using heterologous genetic transcriptional modules
Baojun Wang and Martin Buck
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC05264A, Communication

Geometric and redox flexibility of pyridine as a redox-active ligand that can reversibly accept one or two electrons
Richard A. Lewis, K. Cory MacLeod, Brandon Q. Mercado and Patrick L. Holland
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC05495D, Communication
From themed collection Non-Innocent Ligands

Targeted theranostic prodrugs based on an aggregation-induced emission (AIE) luminogen for real-time dual-drug tracking
Youyong Yuan, Ryan T. K. Kwok, Ruoyu Zhang, Ben Zhong Tang and Bin Liu
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC05255B, Communication

Anion–π interactions and positive electrostatic potentials of N-heterocycles arise from the positions of the nuclei, not changes in the π-electron distribution
Steven E. Wheeler and Jacob W. G. Bloom
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC05304D, Communication

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Radiolabels help evaluate emerging cancer treatment

19 Aug 2014

By Bethany Johnson.

Laura Fisher writes about a hot ChemComm article for Chemistry World

Researchers in Spain have come up with a way to track the biodistribution of a boron cluster complex used to prepare boron-carrier drugs for a prospective cancer treatment called boron neutron capture therapy (BNCT).

Drugs based on the boron cluster complex COSAN (cobaltabisdicarbollide) exploit the over-expression of membrane receptors in cancer cells to deliver therapeutic levels of 10B across the membrane. Although 10B is a stable isotope, when a beam of low-energy neutrons is applied to the cell, 10B captures a neutron and subsequently decays, releasing a high-energy α-particle and destroying the cell.

Read the full article in Chemistry World»

Read the original journal article in ChemComm – it’s free to access until 26th September:
COSAN as a molecular imaging platform: synthesis and “in vivo” imaging
Kiran B. Gona, Adnana Zaulet, Vanessa Gómez-Vallejo, Francesc Teixidor, Jordi Llop and Clara Viñas
Chem. Commun., 2014, Advance Article, DOI: 10.1039/C4CC05058D, Communication

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ChemComm’s Impact Factor reaches another record high – 6.7

31 Jul 2014

By Alessia Millemaggi.

The latest citation data released by Thomson Reuters reveals that ChemComm’s Impact Factor has risen once again this year to 6.718.

Coupled with fast publication times and great author service, these impressive trends underline the continuing success of ChemComm as the largest publisher of high quality communications within the general chemistry arena. You can read some of our most highly cited articles listed below.

Thank you to all who have contributed to the journal’s success so far – our authors, referees, readers and Editorial and Advisory Boards – we are very grateful for your support.

We invite you to submit your next urgent Communication to ChemComm.

Find out how other Royal Society of Chemistry journals are ranked in the latest Impact Factor release

Top cited ChemComm articles:

Feature Articles

Graphene quantum dots: emergent nanolights for bioimaging, sensors, catalysis and photovoltaic devices
Jianhua Shen, Yihua Zhu, Xiaoling Yang and Chunzhong Li

Diketopyrrolopyrrole (DPP)-based materials for organic photovoltaics
Sanyin Qu and He Tian

Enhancing the performances of Li-ion batteries by carbon-coating: present and future Huiqiao Li and Haoshen Zhou

Communications

One-step synthesis of amino-functionalized fluorescent carbon nanoparticles by hydrothermal carbonization of chitosan
Yunhua Yang, Jianghu Cui, Mingtao Zheng, Chaofan Hu, Shaozao Tan, Yong Xiao, Qu Yang and Yingliang Liu

Graphene-enveloped sulfur in a one pot reaction: a cathode with good coulombic efficiency and high practical sulfur content
Scott Evers and Linda F. Nazar

Carbon nanodots as fluorescence probes for rapid, sensitive, and label-free detection of Hg²⁺ and biothiols in complex matrices
Li Zhou, Youhui Lin, Zhenzhen Huang, Jinsong Ren and Xiaogang Qu

Hierarchical porous NiCo₂O₄ nanowires for high-rate supercapacitors
Hao Jiang, Jan Ma and Chunzhong Li

*The Impact Factor provides an indication of the average number of citations per paper. Produced annually, Impact Factors are calculated by dividing the number of citations in a year, by the number of citeable articles published in the preceding two years. Data based on 2013 Journal Citation Reports^®, (Thomson Reuters, 2014).

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Nitrogen-rich Formazanate Ligands: Redox and Coordination Chemistry

30 Jul 2014

By Kevin Murnaghan, web writer.

Kevin Murnaghan is a guest web-writer for Chemical Communications. He is currently a Research Chemist in the Adhesive Technologies Business Sector of Henkel AG & Co. KGaA, based in Düsseldorf, Germany. His research interests focus primarily on enabling chemistries and technologies for next generation adhesives and surface treatments. Any views expressed here are his personal ones and not those of Henkel AG & Co. KGaA.

In this communication, Edwin Otten and Mu-Chieh Chang from the Stratingh Institute for Chemistry at the University of Groningen describe their work with formazanate ligands. They detail here an easier route to boron difluoride chelates with this type of ligand via an exchange transmetallation from a zinc complex with the same ligand in the presence of boron difluoride etherate (BF3.Et2O).

Formazan, or formazanate in its deprotonated form, is an example of a ‘non-innocent ligand’. Just like transition metals, it has an accessible redox chemistry all of its own, and can effectively store electrons by existing in several oxidation states stabilised by its structure. Chemically, formazanates, with a NNCNN backbone are nitrogen rich analogs of diketiminates, which can be represented by NCCCN. In this case, aryl substitution on the terminal nitrogen and central carbon atoms aid the electron stabilisation.

Crystal structure and cyclic voltammagram of formazanate boron difluoride complex

The mono formazanate boron difluoride complex was readily accessible by mixing a bis formazanate zinc complex with BF3 etherate in hot toluene. Zinc fluoride precipitated from solution and the air stable, crystalline material boron chelate was isolated in high yield. X-ray crystal structure determination was possible, showing a tetrahedral environment around the boron atom, and equal bond lengths in the NNCNN core of the ligand, proving its delocalised nature. An important intermediate of the process was also isolated and identified by this technique aiding mechanism elucidation.

Using cobaltocene as reducing agent, a reduced from of the complex was also isolated and characterised, and use of cyclic voltammetry quantified the redox potentials for formation of the further reduced forms of the material. All three redox states were observed. Applications of these materials in catalysis and further investigation in coordination chemistry are ongoing. The potential for application of such ligands in the area of sensors and devices, or even therapeutics poses many possibilities.

Read this RSC Chemical Communication today – access is free* for a limited time only!

Synthesis and ligand-based reduction chemistry of boron-difluoride complexes with redox-active formazanate ligands
M.-C. Chang and E. Otten
DOI: 10.1039/c4cc03244f

*Access is free until 29th August 2014 through a registered RSC account – click here to register

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Hot ChemComm articles for July

23 Jul 2014

By Bethany Johnson.

All of the referee-recommended articles below are free to access until 20th August 2014

Magnetic, superhydrophobic and durable silicone sponges and their applications in removal of organic pollutants from water
Lingxiao Li, Bucheng Li, Lei Wu, Xia Zhao and Junping Zhang
Chem. Commun., 2014,50, 7831-7833
DOI: 10.1039/C4CC03045A, Communication

Electrochemiluminescent swimmers for dynamic enzymatic sensing
Milica Sentic, Stephane Arbault, Bertrand Goudeau, Dragan Manojlovic, Alexander Kuhn, Laurent Bouffier and Neso Sojic
Chem. Commun., 2014, Accepted Manuscript
DOI: 10.1039/C4CC04105D, Communication

Nucleobase-functionalized ABC triblock copolymers: self-assembly of supramolecular architectures
Keren Zhang, Gregory B. Fahs, Motohiro Aiba, Robert B. Moore and Timothy E. Long
Chem. Commun., 2014,50, 9145-9148
DOI: 10.1039/C4CC03363A, Communication
From themed collection Polymer Self-Assembly

Thermo-regulated phase separable catalysis (TPSC)-based atom transfer radical polymerization in a thermo-regulated ionic liquid
Xiangyang Du, Jinlong Pan, Mengting Chen, Lifen Zhang, Zhenping Cheng and Xiulin Zhu
Chem. Commun., 2014,50, 9266-9269
DOI: 10.1039/C4CC03918A, Communication

The photo-thermal plasmonic effect in spin crossover@silica–gold nanocomposites
Iurii Suleimanov, José Sánchez Costa, Gábor Molnár, Lionel Salmon and Azzedine Bousseksou
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC02652G, Communication

An “Off-axis” Mn–Mn bond in Mn2(CO)10 at high pressure
Piero Macchi, Nicola Casati, Shaun R. Evans, Fabia Gozzo, Petra Simoncic and Davide Tiana
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C4CC04152F, Communication

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ChemComm Emerging Investigator Lectureship: Marina Kuimova

23 Jul 2014

By Jane Hordern, Deputy Editor.

Dr Marina Kuimova (Imperial College London) was a recipient of the 2013 ChemComm Emerging Investigator Lectureship.

Marina has just completed her lectureship tour which took place in three locations in Europe from 7 – 13 July:

25th IUPAC Symposium on Photochemistry, Bordeaux, France
Universidad del País Vasco-EHU, Bilbao, Spain
Donostia International Physics Center (DIPC), San Sebastian, Spain

ChemComm Lectureship recipient Marina Kuimova giving her lecture at the IUPAC Symposium on Photochemistry

Our annual lectureship recognises an emerging scientist in the early stages of their independent academic career.

Professor Louise Berben (University of California Davis, USA) was the other recipient of the lectureship last year and we have just announced the 2014 winners – look out for further details of their lectureship tours soon.

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ChemComm introduces Rachel Caruso as Associate Editor

18 Jul 2014

By Liz Bowley.

We would like give Rachel Caruso, from the University of Melbourne a warm welcome into the ChemComm team as a new Associate Editor.

Rachel is a materials chemist with expertise in the fabrication of advanced porous functional materials. She is now accepting submissions to ChemComm in the area of materials chemistry.

Biography

Rachel completed her PhD at the University of Melbourne and then worked as a postdoctoral fellow and group leader at Berlin’s Hahn-Meitner Institute and the Max-Planck Institute of Colloids and Interfaces in Germany. She returned to Australia in 2003 to take up an Australian Research Council Fellowship. Since 2008, Rachel has held a joint appointment between the University of Melbourne and CSIRO as an Associate Professor and Reader in the School of Chemistry and as a CEO Science Leader in the division of Materials Science and Engineering. She currently leads an Advanced Porous Materials research group which consists of postdoctoral fellows and PhD students at both the Univeristy of Melbourne and CSIRO.

With over 60 research papers accepted in international journals with high impact factors, Rachel’s publications are extremely well cited and she has had her research displayed on six journal covers.

Submit your next top-notch, high-impact Communication to Rachel Caruso’s Editorial Office

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Announcing the 24th International Symposium: Synthesis in Organic Chemistry (OS24)

08 Jul 2014

By Bethany Johnson.

The Organic Division of the Royal Society of Chemistry is pleased to announce that the 24th International Symposium: Synthesis in Organic Chemistry (OS24) will take place from 20-23 July 2015. You are invited you to join them at Churchill College, Cambridge for award-winning speakers, evening lectures and extensive opportunities for networking.

The Synthesis in Organic Chemistry conference series is a renowned and long-running flagship event for the international organic chemistry community – a valuable chance to explore the most recent methodologies and strategies in contemporary organic synthesis.

Register your interest to receive updates and deadline alerts for this conference.

The conference will feature 2 poster sessions, and abstract submission is now open – submit your abstract before 14 February 2015.

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Chemical Communications Blog

Improvements to a selective hydrogenation process using ionic liquids

Inducing β-Peptide Structures from the Inside Out

Hot ChemComm articles for August

Radiolabels help evaluate emerging cancer treatment

ChemComm’s Impact Factor reaches another record high – 6.7

Nitrogen-rich Formazanate Ligands: Redox and Coordination Chemistry

Hot ChemComm articles for July

ChemComm Emerging Investigator Lectureship: Marina Kuimova

ChemComm introduces Rachel Caruso as Associate Editor

Announcing the 24th International Symposium: Synthesis in Organic Chemistry (OS24)

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