Archive for February, 2011

Sleeping Trojan horse to transport metal ions into cancer cells

UK researchers have used a cage-like molecule to smuggle metal ions into cells, which could improve medical imaging.

Medical imaging often requires getting unnatural materials such as metal ions into cells. Scientists have therefore had to come up with ways to disguise these compounds to get them past the cell membranes. Michael Coogan and colleagues at Cardiff University have come up with a way to avoid the current difficulties with some of these imaging treatments.

Graphical abstract: A ‘Sleeping Trojan Horse’ which transports metal ions into cells, localises in nucleoli, and has potential for bimodal fluorescence/PET imaging

Find out their solution by reading the news story in Chemistry World and downloading Coogan’s ChemComm communication.

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CASH pictures and poster prize winners

New year, new start and it seems that the Catalysis and sensing for Health (CASH) meeting got the ball rolling. Held last week at the University of Bath, many delegates travelled across the globe to be there. It seems much fun was had by all and below you can see a small glimpse into what went on…

Professors Evans, Maruoka and Ishihara enjoying a coffee break in the CASH meeting

Nothing quite like catching up with friends

ChemComm Editor Robert Eagling grabbing a cuppa with conference organiser Tony James and ex-ChemComm Associate Editor Andy Evans

Sir Professor Fraser Stoddart enjoying the Civic Reception at the Roman Baths

Also, many congratulations to the poster prize winners for the RSC Publishing prizes, who each received an RSC book to help them with their studies:-

Poster prize winner Shaomin Ji

Poster prize winner Suying Xu

The general chemistry team (Chemical Science, ChemComm and Chem Soc Rev) will be attending many conferences this year, so why not take a look at our conference plans and see if our paths will cross during 2011? Alternatively, feel free to contact us for information or help with any other questions or queries.

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Paper spray ionisation of polar analytes using non-polar solvents

US analytical scientists have used non-polar solvents for the paper spray ionisation of polar compounds.

Polar compounds are normally ionised in mass spectrometry using a desorption ionisation method, such as MALDI, or from solution in a polar solvent using electrospray ionisation (ESI). However, ESI does not usually tolerate non-polar solvents and, as many reactions or purifications of compounds occur in non-polar solvents, this can present some difficulties.

Graham Cooks and co-workers from Purdue University have extended the scope of the recently developed paper spray ionisation technique to allow the use of non-polar solvents. When a low voltage is exposed to a triangle of paper wetted with a solvent such as hexane or toluene, droplets of that solvent are produced.  Polar compounds that are deposited on the paper are transported by the non-polar solvent compounds despite being sparingly soluble in them.

This technique can be applied to biological compounds, such as nucleotides, phospholipids and peptides, and avoids a typical problem associated with ESI where there capillary may clog when a non-ideal solvent is used. Furthermore, compounds may be analysed simply by ionising spots separated via TLC.

If you want to find out more then download the ChemComm article today. For wider look at analytical chemistry, why not check out these papers in our sister journal Chemical Science?

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Hot article round up for January

January can seem like an extra long month for many, with post-holiday blues and dark wintery evenings to contend with. However, the winter solstice has past, so the evenings are gradually getting lighter and here at the ChemComm Editorial Office we have published enough hot articles to keep the blues at bay. So why not take a look at the selection of hot articles below, which caught some of our referees attention…

  • Clostridium botulinum produces the most lethal toxins known to man and, as such, they are high-risk terrorist threats. Alarmingly, there is no approved therapeutic. Why not read Kim Janda‘s communication to find out about a small molecule he’s discovered that inhibits the neurotoxin.                                   
  • Matthias Beller and Anahit Pews-Davtyan synthesised a variety of substituted imidazoles from commercially available starting materials, via a hydroamination–cyclization sequence. Take a look at the communication to see the excellent yields obtained, helped by the presence of catalytic zinc triflate.
  • Enhanced white-light emission was achieved by cleverly loading green- and red-light-emitting donor–acceptor pairs in the separate micellar cores, and inserting blue-light-emitting polymers around their periphery. To find out more on how this system works, take a look at Juan Peng‘s communication.
  • Juyoung Yoon and her colleagues from Ewha Womans University, have developed a unique pyrene-based colourimetric sensor that changes colour, from light yellow to pink, in the presence of lysine. More details can be found in the communication.
  • An observation reported by Gerhard Erker in ChemComm has opened up a new way of utilising frustrated Lewis pair chemistry. To see what has been uncovered in more detail, download their communication today!
  • Andreas Herrmann and co-workers have made ultra-high molecular weight DNA/polymer hybrid materials using molecular biology techniques. Take a look at the communication and read more about this fascinating advance.
  • Molly Stevens and her colleagues have shown that peptide-modified gold nanoparticles can be enzymatically phosphorylated and rapidly aggregated onto a surface or in solution by action of phosphospecific antibodies. The simple and rapid colorimetric response of the assays makes them an attractive approach for drug-screening applications – so why not download the communication to find out more about this exciting research?
  • QM/MM mechanistic modelling has been used to help understand the role of carbamate reactivity in fatty acid amide hydrolase inhibition, as reported in Adrian Mulholland‘s latest communication in ChemComm.
  • Paul O’Brien reports slow temperature growth of crystalline PbS films on plastic substrates by Chemical Vapour Deposition using xanthate. Why not read the communication for further details on the method, as well as looking at the mechanism proposed by the team, with the help of density functional theory calculations.
  • Jeremy Sanders and Ulrich Lüning present the efficient synthesis of a new type of a multi-hydrazone based macrocyclic receptor and investigates its complexation properties with alkali and alkaline earth metal ions using a dynamic combinatorial approach. Read more by downloading the communication today!

All communications have been made freely available until the 7th March 2011, so why not download the ones that interest you today and let us know what you think in our blog below.

If you have some of your own exciting, high impact research to publish then consider submitting your communication to ChemComm, via our online submission system.

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Negishi cross-coupling using a bulky Pd-NHC catalyst

The hugely important field of transition metal catalysed C–C cross-coupling has come a long way over the years, but efficient coupling between Csp2 and secondary Csp3 centres remains a challenge. To achieve just that, Michael Organ and his colleague Selcuk Calimsiz (York University, Toronto) have developed and used a bulky Pd-NHC (N-heterocyclic carbene) catalyst called Pd-PEPPSI-IPent.

In the reactions of secondary alkylzincs with a variety aryl or heteroaryl halides, this catalyst provided excellent regioselectivity for the branched product over the isomerised unbranched product, far outperforming the less bulky Pd-PEPPSI-IPr analogue.

To see the impressive scope of the reaction download the ChemComm communication for free up until 7th March 2011 and leave your comments below.

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MOF magnets deliver drugs

German scientists have encapsulated nanomagnets inside metal organic frameworks (MOFs). The MOF magnets can be filled with a drug, which is released when a magnetic field is applied. 

Stefan Kaskel from the Technical University of Dresden and colleagues made the MOF magnets by integrating superparamagnetic iron oxide particles into carboxylate MOFs. ‘Carboxylate molecules stabilise and activate the nanoparticles,’ explains team member Martin Lohe.

The group then loaded their MOF with ibuprofen and found that they were able to trigger and control its release by simply applying an external magnetic field. The magnetic field heats the magnets in the MOF, which causes the load to burst from the framework.

Superparamagnetic functionalisation of MOFs enables magnetic heating to trigger drug delivery

MOFs in which the frameworks themselves are magnetic have been made before, but they are not easy to manipulate. Kaskel’s embedded MOF magnets, however, can easily be manipulated from the outside. Magnetic fields can penetrate human skin, and magnetic triggers that could be used to release the drugs are already available on the market. However, before the MOF magnets can be used in the human body, toxicity tests will need to be done.

‘An enhanced sustainability of industrial and medical processes is crucial for our future,’ says Lohe. ‘Magnetically functionalised MOFs could be a small building block on this path.’

‘The particles will certainly increase the possibility of using nanoMOFs for drug delivery applications in the near future,’ agrees Christian Serre, an expert in porous solids from the University of Versailles  in France, ‘and they’ll add a new tool to the emerging domain of MOFs in biomedicine.’ 

Ruth Doherty

 

Link to ChemComm article

 Heating and separation using nanomagnet-functionalized metal–organic frameworks
Martin R. Lohe, Kristina Gedrich, Thomas Freudenberg, Emanuel Kockrick, Til Dellmann and Stefan Kaskel,

Chem. Commun., 2011, DOI: 10.1039/c0cc05278g

 

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Palladium impurites are not essential for gold catalysis

Spanish scientists have proved that gold alone can catalyse cross-coupling reactions, following a claim made last year that palladium impurities in the gold are essential for the catalysis. 

Avelino Corma from the Polytechnic University of Valencia and colleagues used kinetic and theoretical studies to prove that gold can catalyse the Sonogashira coupling reaction between phenylacetylene and iodobenzene. ‘Gold nanoparticles are active enough to promote the reaction, regardless of the presence or absence of palladium,’ says Corma.

Graphical abstract: Gold catalyzes the Sonogashira coupling reaction without the requirement of palladium impurities

Read the full news story in Chemistry World and download Corma’s ChemComm communication

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