Chemical Communications Blog

Illuminating probes identify amino acids

20 Nov 2013

Matt Smith writes about a HOT ChemComm article for Chemistry World

A new technique for the accurate and fast detection of amino acids has been developed by researchers in the US. The simple method, employing cucurbiturils and the lanthanide europium, could light the way to improvements in nutritional analysis and drug detection.

Amino acids are essential building blocks for all living beings. Abnormal amino acid levels can indicate underlying health problems such as malnutrition, pancreatitis and Alzheimer’s disease. Conventional amino acid sensing techniques involve chromatography or electrochemical methods, which can be costly and must be performed by skilled operators.

The method proposed by Pavel Anzenbacher Jr and coworkers at Bowling Green State University in Ohio analyses fluorescence signals when guest europium ions are displaced from an array of two cucurbituril host probes. One of the probes is cylindrical and prefers to bind smaller molecules in a host–guest fashion, whilst the other is a larger linear molecule that wraps around larger analytes.

Probe fluorescence is quenched when an Eu ion is bound. When the Eu is displaced by an analyte, the fluorescence is "turned-on"

Read the full article in Chemistry World»

Read the original journal article in ChemComm:
“Turn-on” fluorescent sensor array for basic amino acids in water
Tsuyoshi Minami, Nina A. Esipenko, Ben Zhang, Lyle Isaacs and Pavel Anzenbacher
Chem. Commun., 2014, Advance Article, DOI: 10.1039/C3CC47416J

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Hydrogen adopts alkali metal position

13 Nov 2013

By Hannah Porter, Publishing Assistant.

Polly Wilson writes about a HOT ChemComm article for Chemistry World

Hydrogen stands in for a lithium in the cubane core of this alkali metal phenolate

Now, Matthew Davidson and colleagues at the University of Bath in the UK have devised an organometallic synthetic strategy to make pseudocubane motifs of ammonium tris(phenol) ligands and lithium or sodium atoms, where one of the metals has been replaced by a hydrogen atom. The hydrogen forms the rarely reported trifurcated 4-centre hydrogen bond. Such an arrangement is not uncommon for the larger alkali metals, which can accommodate higher coordination numbers, but is not preferred by hydrogen.

Davidson says their interest lies in gaining a better understanding of how ligands like amine tris(phenolate) can be used to control reactive metal centres. A thorough comprehension of the coordination chemistry and the ability to draw conceptual similarities between the reactivity of hydrogen and metals as Lewis acids could help advance areas such as organocatalysis.

Read the full article in Chemistry World»

Read the original journal article in ChemComm:

Unprecedented participation of a four-coordinate hydrogen atom in the cubane core of lithium and sodium phenolates
David M. Cousins, Matthew G. Davidson and Daniel García-Vivó
Chem. Commun., 2014, Advance Article
DOI: 10.1039/C3CC47393G, Communication

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Crystal within a crystal

11 Nov 2013

By Bethany Johnson.

Jennifer Newton writes about a HOT ChemComm article for Chemistry World

Cobalt-based crystal surrounded by nickel-based crystal (top) and cobalt-based crystal surrounded by zinc-based crystal (bottom)

Scientists based in France are behind these peculiar looking crystals. Sylvie Ferlay, Mir Wais Hosseini and colleagues at the University of Strasbourg used a molecular tectonics strategy to prepare the crystals. In molecular tectonics, building blocks, called tectons, are designed to recognise each other so that they self-assemble into molecular networks when placed together.

Combining M²⁺ cations (where M = Co, Ni, Cu or Zn) with 2,4,6-pyridinetricarboxylic acid, bisamidinium dications and sodium hydroxide resulted in metal complexes that interconnected into single crystals of different colours depending on the metal cation. Single crystals based on one metal were then immersed in a solution containing the same ligand (2,4,6-pyridinetricarboxylic acid) and organic tectons (bisamidinium dications) and a different metal cation. The single crystals acted as seeds for the crystallisation of the coordination polymer of the different metal cation since the unit cells fitted almost perfectly to each other. Single crystals of one compound grew around the single crystal of another to give a crystal within a crystal.

This crystal engineering strategy is a powerful tool for preparing crystalline materials with different crystalline domains, the researchers say. It just leaves us to wonder how many coloured stripes could be added on?

You can also read this article in Chemistry World

Read the original journal article in ChemComm:
Molecular tectonics: from crystals to crystals of crystals
Gabriela Marinescu, Sylvie Ferlay, Nathalie Kyritsakas and Mir Wais Hosseini
Chem. Commun., 2013,49, 11209-11211, DOI: 10.1039/C3CC45205K

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HOT ChemComm articles for October

05 Nov 2013

By Jeanne Therese Andres.

Here are our referee-recommended HOT ChemComm articles – download them for FREE for a limited time!

Supramolecular architecture, crystal structure and transport properties of the prototypal oxobenzene-bridged bisdithiazolyl radical conductor
Joanne W. L. Wong, Aaron Mailman, Stephen M. Winter, Craig M. Robertson, Rebecca J. Holmberg, Muralee Murugesu, Paul A. Dube and Richard T. Oakley
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC46686H, Communication

Free to access until 1st December 2013

Synthesis of a metal-free coordinating ring via formation of a cleavable [2]catenane
Frédéric Niess and Jean-Pierre Sauvage
Chem. Commun., 2013,49, 10790-10792
DOI: 10.1039/C3CC46452K, Communication

Free to access until 1st December 2013

Expanding the scope of oxime ligation: facile synthesis of large cyclopeptide-based glycodendrimers
Baptiste Thomas, Nathalie Berthet, Julian Garcia, Pascal Dumy and Olivier Renaudet
Chem. Commun., 2013,49, 10796-10798
DOI: 10.1039/C3CC45368E, Communication

Free to access until 1st December 2013

A FRET-based ratiometric fluorescent and colorimetric probe for the facile detection of organophosphonate nerve agent mimic DCP
Weimin Xuan, Yanting Cao, Jiahong Zhou and Wei Wang
Chem. Commun., 2013,49, 10474-10476
DOI: 10.1039/C3CC46095A, Communication

Free to access until 1st December 2013

Gold plating of silver nanoparticles for superior stability and preserved plasmonic and sensing properties
Nimer Murshid, Ilya Gourevich, Neil Coombs and Vladimir Kitaev
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC46075D, Communication

Free to access until 1st December 2013

In situ atomic imaging of coalescence of Au nanoparticles on graphene: rotation and grain boundary migration
Jong Min Yuk, Myoungho Jeong, Sang Yun Kim, Hyeon Kook Seo, Jihyun Kim and Jeong Yong Lee
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC46545D, Communication
From themed collection Structure and chemistry of materials from in-situ electron microscopy

Free to access until 1st December 2013

Click here for more free HOT ChemComm articles for October!

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Bioluminescence powers photosynthesis

28 Oct 2013

By Bethany Johnson.

Amy Middleton-Gear writes about a HOT ChemComm article for Chemistry World

Chinese chemists report that, in the absence of sunlight, bioluminescence can drive photosynthesis.

Photosynthesis uses energy from light to convert carbon dioxide and water into oxygen and carbohydrates. Although light emitting diodes (LEDs) and fluorescent lamps have been tested as alternative light sources to natural sunlight, bioluminescence has received much less attention. Advantages of bioluminescence include no heat radiation, high energy conversion efficiencies and no electrical requirements.

When luminol is oxidised to its dianion form, by hydrogen peroxide and the enzyme horseradish peroxidase, it produces blue luminescence. In general, plants grown under blue light photosynthesise faster than plants grown under red or green light. Armed with this knowledge, Shu Wang and his team at the Chinese Academy of Sciences in Beijing have shown that blue luminescence generated from luminol can initiate photosynthesis in geranium leaves.

Blue luminescence, emitted when luminol is oxidised by hydrogen peroxide and horseradish peroxidase, can drive photosynthesis

Read the full article in Chemistry World»

Read the original journal article in ChemComm:
Bioluminescence as a light source for photosynthesis
Huanxiang Yuan, Libing Liu, Fengting Lv and Shu Wang
Chem. Commun., 2013,49, 10685-10687, DOI: 10.1039/C3CC45264F

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ChemComm Emerging Investigator Lectureship 2014

18 Oct 2013

By Jane Hordern, Deputy Editor.

We are delighted to invite nominations for ChemComm Emerging Investigator Lectureships 2014. The lectureships, which are awarded annually, will recognise emerging scientists in the early stages of their independent academic career.

2014 marks the 50th volume of ChemComm and in celebration of this very special anniversary we will be awarding three ChemComm Emerging Investigator Lectureships next year. So nominate a colleague today!

To qualify
To be eligible for the ChemComm Emerging Investigator Lectureship, the candidate should have completed their PhD on or after 4th September 2005. The candidate should also have published at least one article in ChemComm during the course of their independent career.

Lectureship details
The recipient of the Lectureship will be invited to present a lecture at three different locations over a 12 month period. It is expected that at least one of the locations will be a conference. The recipient will receive a contribution of £1500 towards travel and accommodation costs. S/he will also be presented with a certificate and be asked to contribute a ChemComm Feature Article.

Nominations
Those wishing to make a nomination should send the following details to the ChemComm Editorial Office by Friday 6th December 2013:

Recommendation letter, including the name, contact details and website URL of the nominee.
A one page CV for the nominee, including their date of birth, summary of education and career, list of up to five independent publications, total numbers of publications and patents and other indicators of esteem and evidence of independence.
A copy of the candidate’s best publication to date (as judged by the nominator).
Two supporting letters of recommendation from two independent referees. These should not be someone from the same institution or the candidate’s post doc or PhD supervisor.

The nominator and independent referees are requested to comment on the candidate’s presenting skills.

Please note that self nomination is not permitted.

Selection procedure
The ChemComm Editorial Board will draw up a short-list of candidates based on the information provided by the referees and nominator. Short-listed candidates will be asked to provide a supporting statement justifying why they deserve the Lectureship. The recipients of the Lectureship will then be selected and endorsed by the ChemComm Editorial Board, and will be announced in Spring 2014.

Previous winners

2013		Professor Louise A. Berben (University of California Davis, USA) for synthetic and physical inorganic chemistry, who will give a plenary lecture at ISACS 13 in Dublin.
2013		Dr Marina Kuimova (Imperial College London, UK) for biophysical chemistry who will give her Lectureship in 2014.
2012		Professor Hiromitsu Maeda (Ritsumeikan University, Japan) – he was presented with his lecture certificate at ICPOC 21.
2011		Dr Scott Dalgarno (Heriot-Watt University, Edinburgh, UK) – Find out about his Emerging Investigator Lecture tour in China.

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Intramolecular enolate arylation: formation of 4° amino-acid–derived hydantoins

03 Oct 2013

By Ruth E. Gilligan.

The synthesis of quaternary amino acids is an important challenge facing researchers in bioorganic and medicinal chemistry. While there are a number of ways to transform tertiary amino acids into their quaternary counterparts, α-arylation of amino acids and their derivatives remains limited.

Now, in this HOT ChemComm article, Professor Jonathan Clayden and co-workers at the University of Manchester have revealed an elegant intramolecular arylation of tertiary amino acid derivates, which exploits the use of a urea linkage to connect the amino acid derivative—a nitrile or acid—and the aryl “electrophile”. During the course of the reaction, this N-aryl substituent migrates to the α-carbon of the amino acid moiety. This is followed by a cyclisation, leading to a heterocyclic hydantoin derivative. The reaction is mediated by strong base, and is thought to proceed via the metallated enolate.

Interestingly, the researchers found that the migration of the aryl ring was not influenced by its electronic properties, and that the transition-metal–free reaction could be applied successfully to a range of natural and unnatural tertiary amino acid substrates. If the tertiary amino acid nitrogen is protected with a PMB (p-methoxybenzyl) group, the resulting hydantoin product can subsequently be hydrolysed, affording the acyclic quaternary amino acid.

The reaction was monitored by in situ infrared spectroscopy (ReactIR) to identify the reaction intermediates and cast light on the mechanism of the arylation. Further details of the ReactIR analysis can be found in the electronic supplementary information. Ultimately, Clayden and his group hope to further develop this useful methodology to allow the enantioselective arylation of amino acids.

For more, check out this HOT ChemComm article in full:

Intramolecular arylation of amino acid enolates

Rachel C. Atkinson, Daniel J. Leonard, Julien Maury, Daniele Castagnolo, Nicole Volz and Jonathan Clayden

Chem. Commun., 2013, 49, 9734–9736

DOI: 10.1039/C3CC46193A

Ruth E. Gilligan is a guest web-writer for ChemComm. She has recently completed her PhD in the group of Prof. Matthew J. Gaunt at the University of Cambridge, focusing on the development and application of C–H functionalisation methodology.

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The chemists’ enzyme

27 Sep 2013

By Ruaraidh McIntosh, Science Writer.

The title of this post was taken from the website of Barry Trost, one of the world’s leading scientists and author of an astonishing 924 papers. Describing his work, he states:

One major activity in designing new reactions and reagents involves the development of “chemists’ enzymes” – non-peptidic transition metal based catalysts that can perform chemo-, regio-, diastereo-, and especially enantioselective reactions.

Chemists have, for a long time, sought to reproduce the incredible feats of nature. Natural biology has evolved over many years to achieve the efficiency and reactivity that most lab-based chemists could only dream of. Nature achieves this by employing incredibly sophisticated enzymes which are, sadly, almost impossible to replicate by a synthetic chemist due to their complexity. An alternative idea is to use these enzymes as inspiration for new catalysts and try to focus on the general reasons why they work rather than trying to create direct copies.

Supramolecular catalysts for decarboxylative hydroformylation and aldehyde reduction.

Dr Bernhard Breit, Lisa Diab and Urs Gellrich at Albert-Ludwigs-Univertat in Germany have shown in a HOT ChemComm article that a highly selective catalyst can be created when combining a metal catalyst with a directing ligand to control the reaction. In this Communication, they report excellent results using rhodium, the classic metal of choice for hydroformylation, and a functional group for recognition of the substrate. The net effect of these features combined is that the substrate is held in a specific way at the catalytic site. As a result, the reaction which follows can only occur in a specific way. This is similar to how enzymes control the chirality.

The concept behind this catalyst is one which could be applied to a great number of different reactions – no doubt we can look forward to reading about these in the near future.

Read this HOT ChemComm article today!

Tandem decarboxylative hydroformylation–hydrogenation reaction of α,β-unsaturated carboxylic acids toward aliphatic alcohols under mild conditions employing a supramolecular catalyst system
Lisa Diab, Urs Gellrich and Bernhard Breit
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC45547E, Communication

Ruaraidh McIntosh is a guest web-writer for ChemComm. His research interests include supramolecular chemistry and catalysis. When not working as a Research Fellow at Heriot-Watt University, Ruaraidh can usually be found in the kitchen where he has found a secondary application for his redoubtable skills in burning and profanity.

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Chemical Communications Blog

Illuminating probes identify amino acids

Hydrogen adopts alkali metal position

Crystal within a crystal

HOT ChemComm articles for October

Bioluminescence powers photosynthesis

ChemComm Emerging Investigator Lectureship 2014

Intramolecular enolate arylation: formation of 4° amino-acid–derived hydantoins

The chemists’ enzyme

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