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ChemComm–RSC Prizes and Awards Symposium in Oxford

06 Mar 2012

We are delighted to announce the forthcoming ChemComm–RSC Prizes & Awards Symposium jointly organised with the RSC Dalton Division.

Date: Wednesday 23rd May 2012
Location: University of Oxford, UK
Time: 11am – 6.45 pm

The purpose of this event is to bring together scientists in a stimulating and friendly environment to recognise the achievements of individuals in advancing the chemical sciences and also to foster collaborations. The symposium will appeal to academic and industrial scientists with an interest in inorganic and supramolecular chemistry. Attendance at the symposium is FREE OF CHARGE and student participation is strongly encouraged.

The following distinguished scientists have agreed to speak:

Professor Manfred Scheer, University of Regensburg, Germany (ChemComm sponsored speaker) – Polyphosphorus Ligands in Supramolecular Chemistry
Professor Kay Severin, EPFL, Switzerland (ChemComm sponsored speaker) – Multicomponent Assembly of Molecular and Polymeric Nanostructures
Professor Andrew Cooper, University of Liverpool, UK (ChemComm sponsored speaker) – Porous Organic Cages: MOFs Minus the Metals?
Professor Lawrence Que, University of Minnesota, USA (Inorganic Mechanisms Award 2011 Winner) – C-H Bond Cleavage by High-Valent Non-haem Iron-Oxo Complexes
Professor Russell Morris, University of St Andrews, UK (Applied Inorganic Chemistry Award 2011 Winner) – Adsorption, storage and delivery of medically important gases in porous solids
Dr Jonathan Nitschke, University of Cambridge, UK (Corday-Morgan Prize 2011 Winner ) – Designing complexity and function within self-assembled chemical systems

To register for the symposium, please complete the online registration form.

For further details, please contact Richard Walker.

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Grinding gathers momentum for coordination polymers

03 Feb 2012

It is a fairly common assumption that the sample you are characterising is the same sample that you made at the lab bench. While it may indeed be the same sample, it may not be the same structure as Peter Stephens and Jagadese Vittal discovered.

By grinding coordination polymers with KBr (as is standard practise in solid state sample preparation for infrared characterisation), they generated coordination polymers with completely new structures – and as a result, completely different optical properties as well.

The team have attributed this to an exchange between the bridging ligands and the bromide ions from KBr. While this is an interesting avenue to explore for the preparation of new coordination polymers, Stephens and Vittal warn researchers working with such materials that observed changes in sample colour or texture during pre-characterisation preparation may not always be a physical phenomenon and to tread with caution…

Read the ChemComm article today.

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100th anniversary of first X-ray diffraction experiment

30 Jan 2012

It’s 2012 and avid readers of our blog will know that the number 100 is very important to ChemComm this year.

This is the first year ChemComm will publish 100 issues but did you know it is also 100 years since Max von Laue’s first X-ray diffraction experiment?

Max von Laue was a Professor of Physics at the University of Munich in Germany and he used copper sulfate as a 3D diffraction grating for X-rays. The field developed rapidly after this pioneering work and today X-ray diffraction is a commonly used technique for revealing information about the structure of materials.

$ChemComm outside front cover highlighting 100 years of Laue diffraction$ The anniversary of Laue diffraction has been highlighted on the cover of ChemComm issue 16 by Oliver Oeckler and colleagues, who report their recent use of Laue diffraction in the issue. More specifically, they used in situ microfocus Laue diffraction to investigate temperature-dependent phase transitions of GeTe-rich compounds. Find out what they discovered by downloading their communication.

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Nitron, the new N-heterocyclic carbene

15 Nov 2011

N-heterocyclic carbenes (NHCs) are extremely useful reagents in synthesis and catalysis, but unfortunately they are expensive with 1 gram costing several hundred US dollars.

However, as Ulrich Siemeling and his colleagues report in their latest ChemComm, it seems that a much cheaper alternative is on the horizon…

The team of scientists based at the University of Kassel have discovered that Nitron, a low cost analytical reagent, exhibits surprising NHC reactivity, more akin to that of its tautomeric form than its conventional Lewis structure. By reacting Nitron with typical carbene trapping reagents such as elemental sulphur, CS₂, and rhodium complexes, they have proven that it is indeed Nitron’s tautomer that it responsible for its NHC-like reactivity in solution, despite being present at concentrations undetectable by NMR spectroscopy.

At a fraction of the price and already commercially available, Nitron may soon become a very popular choice in NHC reactions.

To read more about how Siemeling and co-workers established the cause for Nitron’s unusual reactivity, download the ChemComm article.

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50 days until 100 issues…

11 Nov 2011

….and did you know….?

Graphical abstract: Percent buried volume for phosphine and N-heterocyclic carbene ligands: steric properties in organometallic chemistry Steven Nolan’s Feature article from 2010 has received 50 citations to date according to Web of Science^SM (Thomson Reuters, 2011).

Read it: Percent buried volume for phosphine and N-heterocyclic carbene ligands: steric properties in organometallic chemistry

Are you interested in writing a Feature article? Contact the Editorial Office with your suggestion.

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Further insight into aromatic borylation chemistry

31 Oct 2011

Thorough characterisation of arene–borane Lewis acid contacts is essential for understanding the mechanistic pathway for aromatic borylation chemistry and by extension, electrophilic aromatic substitution. However, until now, structural determination of such arene–borane compounds has been somewhat ambiguous.

Simon Aldridge and his team have set out to fill this knowledge gap by reacting a sterically encumbered pyridine donor with BBr₃ to yield a cationic tri-coordinate borane–arene complex. Employing crystallography and computational studies, the team found that a weak electrostatic interaction is responsible for the short contacts between the positively charged boron centre and the arene π system.

Read the ChemComm article to find out more…

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Supramolecular assembly of polyoxometalate triangles

31 Oct 2011

Polyoxometalates (POMs) are a diverse class of inorganic materials that are of great interest due to their exciting range of redox, conducting, magnetic and catalytic properties. Recent collaborative work from Professor Garry Hanan in Montreal and Professor Bernold Hasenknopf in Paris reports the inclusion of a Lindqvist-type hexavanadate POM as a component of a self-assembling supramolecular framework.

They designed ligand 1 utilising a triol motif to complex the POM in combination with pyridyl groups to serve as binding sites for a transition metal. The reaction of 1 with a suitable decavanadate yielded complex 2, a hexavanadate POM complex that is itself a structurally rigid and spatially well-defined bi-pyridyl ligand. The 60° angle between the coordination vectors of the pyridyl groups led the authors to predict that the coordination of a trans-PdCl₂ unit by 2 would result in a supramolecular triangle.

Initially the reaction of 2 with [PdCl₂(CH₃CN)₂] in DMAc yielded a complex mixture of products; however, heating to 80 °C for 48 hours led to just a single assembly. This was shown by a number of analytical techniques to be the predicted triangular assembly 3.

This work elegantly uses a classical motif for self-assembly to create a multi-component supramolecular architecture. It is a great step towards the goal of creating functional supramolecular arrays, integrating the desirable properties of POMs into a new framework and bridging the gap between solid state oxides and coordination chemistry.

Researcher’s perspective:

The obtention of discrete coordination-driven POM-based arrays had so far eluded the community, with only a few well characterised coordination polymers. We started this challenging project of a molecular triangle by a simple drawing based on geometrical considerations. A range of conditions were explored, but most lead to complex mixtures except one. This identification of optimal conditions was our first satisfaction. However, we needed solid evidence of the triangular nature of the obtained array to validate our approach as a rational design: a combination of techniques confirmed the successful and selective synthesis of the triangle. As a student, I learnt a lot from the complementary competencies provided by the two groups on a project at the interface of inorganic, organic, supramolecular and coordination chemistry. Dealing with the specific difficulties of each domain has been an exciting challenge that has re-confirmed my choice in academic research. Marie-Pierre Santoni, a student in the research collaboration

To read more about Hanan and Hasenknopf’s work, download their ChemComm article.

Posted on behalf of Cally Haynes, ChemComm web writer.

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Ionic Liquids web theme issue – welcoming submissions

03 Oct 2011

ChemComm is delighted to announce a high-profile web themed issue on Ionic Liquids.

Guest editors: Robin D. Rogers (University of Alabama), Doug MacFarlane (Monash University) and Suojiang Zhang (Institute of Process Engineering)

Picture courtesy of Photodisc

This issue will consist of a series of Communications and Feature Articles from prominent scientists working on all aspects of ionic liquid chemistry. The scope will range from new fundamental knowledge about ionic liquids to novel applications of ionic liquids which take advantage of their unique attributes. Follow on studies or those of routine interest will not be considered.

The level of quality of this issue will be extremely high, and all manuscripts will undergo strict peer review. You are therefore encouraged to report work that you consider to be very important and conceptually significant in accord with the ChemComm mandate. Please note that inclusion in the issue is subject to the discretion of the guest editors.

Publication of the peer-reviewed articles will occur without delay to ensure the timely dissemination of the work. The articles will then be assembled on the ChemComm website as a web-based thematic issue.

Submit your work before 29^th February 2012. Please add “ionic liquids” in the comments to the editor section.

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A step forward for photodynamic therapy

20 Jul 2011

Scientists in the US have developed a new photodynamic therapeutic reagent that works in the absence of oxygen_.

Photodynamic therapy (PDT) is an emerging treatment used to eradicate premalignant and early-stage cancer, and also reduces tumour size in end-stage cancers. PDT works by exposing the tissue sample to a light source, which excites the PDT reagent causing singlet oxygen to form due to a reaction with the more common triplet oxygen. The resulting singlet oxygen then invokes cell death in tumour cells.

The PDT reagent has been designed by Karen Brewer and co-workers from Virginia Tech, where they have shown its capabilities for binding and photocleaving DNA under red light irradiation. The anti-cancer complex [(bpy)₂Os(dpp)RhCl)₂(phen)]³⁺has two metal centres; the osmium portion is capable of photocleaving DNA by singlet oxygen generation and the rhodium part is capable of binding to the DNA in the first place.

Crucially, this is the first complex that works in the absence of oxygen. Tumour cells are often oxygen-depleted environments and therefore a treatment that functions in the absence of oxygen is an important step forward. Future investigations will centre on the bioreactivity of this and other related complexes.

Interested in finding out more? Then download the ChemComm article, which will be free to access until 25th July 2011.

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The first hydroamination reaction with a zincocene complex

20 Jul 2011

Peter Roesky, Siegfried Blechert and co-workers at the Karlsruhe Institute of Technology and the Berlin University of Technology have reported the first use of a dizinc complex as the catalyst in a hydroamination reaction.

Hydroamination is the addition of an N–H bond of an amine to an unsaturated C–C bond to give a molecule that contains nitrogen in one step. This is particularly important because many current amine syntheses are multi-step processes. Zinc complexes are advantageous for hydroamination as they are relatively cheap, air and moisture stable and tolerant to a wide variety of functional groups.

With this in mind Roesky and Blechert decided to test the zincocene complex, Zn₂(η⁵-C₅Me₅)₂, for its hydroamination activity. This complex was discovered in 2004 but it is the first time that it has been used as a catalyst. The team found that the catalyst worked well with good yields and conversions and that it tolerates many functional groups.

Want to find out more? Then download the ChemComm article for free today and leave a comment below.

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