Prescription nanoreactors

Scientists in Switzerland have developed a nanoreactor that can synthesise and release the antibiotic cephalexin, which is used to treat bacterial infections.

Lowering the drug dose required to effectively treat a patient would save money and reduce side effects. To achieve this, one area of research is focusing on using a ‘prodrug’ approach in which less toxic substrates, or prodrugs, are given to a patient and are converted to the active drug form by an enzyme only at a specific site.

To maintain its catalytic activity, the enzyme needs to be protected from the surrounding environment, but also be accessible to the prodrug and able to release the final active drug.

Wolfgang Meier and colleagues at the University of Basel have designed a biocompatible nanoreactor that can effectively protect an enzyme. The nanoreactor comprises a copolymer, an outer membrane protein from bacteria cells (OmpF) and the catalyst penicillin acylase. When mixed together, the copolymer self assembles into vesicles forming, along with the membrane protein, a membrane around the catalyst that allows passage of molecules such as a drug and substrates.

Read the whole Chemistry World story or download the full ChemComm article:

Communication Polymer nanoreactors shown to produce and release antibiotics locally
Karolina Langowska , Cornelia G. Palivan and Wolfgang Meier
Chem. Commun., 2012, DOI: 10.1039/C2CC36345C

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Ramakrishnan joins as ChemComm Associate Editor

ChemComm is delighted to announce Professor S. Ramakrishnan (Indian Institute of Science, Bangalore) as a new Associate Editor.

Ramakrishnan is now accepting submissions to ChemComm in the areas of organic materials and polymers. Ramakrishnan will also act as an ambassador for the journal within India, helping to raise the profile of ChemComm and attract the high-quality scientific research being produced from Indian institutes.

Submit your next high-quality communication to Ramakrishnan’s Editorial Office.

Biography
Ramakrishnan completed his BSc from the University of Bombay, MSc from the Indian Institute of Technology, Bombay and received his PhD from the University of Massachusetts, Amherst, in 1988.

After a two-year postdoctoral stint at the Corporate Research Laboratory of Exxon Research and Engineering Company at Annandale, New Jersey, he took up a faculty position in the Department of Inorganic and Physical Chemistry at the Indian Institute of Science, Bangalore, where he is currently a full professor.

His research interests are in the areas of design and development of novel polymerization methods, hyperbranched polymers, polymerizable surfactants, understanding and regulating conformation of synthetic macromolecules in solution and conjugated polymers.

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The Cram Lehn Pedersen Prize in Supramolecular Chemistry – Nominations Open

Sponsored by Chemical Communications

 2013 ISMSC-8 Crystal City, Virginia 7 July – 11 July, 2013 

The International Committee of the International Symposium on Macrocyclic and Supramolecular Chemistry is pleased to invite nominations for the Cram Lehn Pedersen Prize for young supramolecular chemists. 

The Cram Lehn Pedersen Prize, named in honour of the winners of the 1987 Nobel Prize in Chemistry, will recognise signicant original and independent work in supramolecular chemistry.

Those who are within 10 years of receiving their PhD on 31st December 2012 are eligible for the 2013 award. The winner will receive a prize of £2000 and free registration for the ISMSC meeting in Crystal City, Virginia. In addition to giving a lecture at ISMSC, a short lecture tour will be organised after the meeting in consultation with the Editor of Chemical Communications, the sponsor of the award. 
 
 
Nomination Details:

Please send your CV, list of publications (divided into publications from your PhD and post-doc and those form your independent work), and if desired, letter of support, or these materials for someone you wish to nominate to Prof. Roger Harrison (ISMSC Secretary) at rgharris@chem.byu.ed by 31st January 2013.

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Selective formation of (Z)-enynes via Zirconium catalysed alkyne dimerisation

Researchers from the University of British Columbia have developed a ‘head to head’ dimerisation of alkynes to provide (Z)-enynes in high yields.

The conjugated enyne products are important, both as intermediates for organic synthesis and in optoelectronics – a type of electronics that detect, source and control light. Therefore, new methods for the selective synthesis of these compounds are in demand.

Platel and Schafer have overcome regioselectivity problems often associated with alkene dimerisation.  The researchers used a readily accessible Zirconium catalyst (2) in conjunction with aniline as co-catalytic proton source.

A number of alkynes (1) were successfully dimerised to provide (Z)-enynes (3) in mostly high yields. The reaction is tolerant of a number of differentially substituted aryl compounds and also some alkyl rings.

The exclusive formation of (Z)-enynes was at odds with previously established mechanistic pathways for metal-catalysed alkyne dimerisation and led the researchers to further probe the mechanism. Complex 4 was isolated when a stoichiometric amount of aniline and complex 2 were mixed, leading the researchers to consider the validity of 4 as a catalytic intermediate. When 4 was mixed with alkyne (1) under the reaction conditions, complete conversion to (Z)-enyne (3) was observed. This result suggests that the unusual dimeric imido-bridged species is a viable intermediate in the reaction pathway.

This method represents an interesting development in catalytic and regioselective C­–C bond formation.

Read the ‘HOT’ Chem Comm article today:

Zirconium catalyzed alkyne dimerization for selective Z-enyne synthesis
Rachel H. Platel and Laurel L. Schafer
Chem. Commun., 2012, 48, 10609-10611
DOI: 10.1039/C2CC35913H

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Medicinal hope for injectable hydrogels

Injectable hydrogels with dual ionic properties, biodegradability and low cytotoxicity have been developed by South Korean scientists to deliver proteins therapeutically.

Doo Sung Lee and colleagues from Sungkyunkwan University developed an amphoteric copolymer to form dually cationic and anionic hydrogels, in response to pH and temperature changes. The amphoteric nature of the polymer means it should bind to both cationic and anionic biomolecules, and helps sustained co-delivery of them.

The copolymer changing from sol to gel

Read more in Chemistry World or download Lee’s communication in ChemComm.

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Metal-free resins can drive down cost of solar energy

Solar farmCostly metals in some solar cells could be replaced by cheap resins, according to Korean research.

Dye-sensitised solar cells (DSSCs) are an important class of solar cells, which demonstrate a number of important attributes, such as low cost, flexibility and good efficiency. It is perhaps the most actively researched solar cell technology. However, it is still hindered by expensive components.

Currently, a third of the cost of DSSCs could go towards the noble metal-based dyes used to sensitise the titania photocatalyst, allowing it to harvest the more useful visible part of the spectrum. However, Wonyong Choi and his group at Pohang University of Science and Technology have replaced these dyes with a simple and cheap phenolic resin.

Read more in Chemistry World or read Choi’s communication in ChemComm.

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ChemComm celebrates its first Gold for Gold communication

A groundbreaking £1 million initiative to support British researchers

Eugen Stulz (University of Southampton) and colleagues are the first ChemComm authors to publish a communication as part of our Gold for Gold initiative.Gold Image

Their communication, entitled ‘A DNA based five-state switch with programmed reversibility’ is now free to access for all.

‘I’m delighted that Eugen’s communication is the first open access communication to be published in ChemComm using the RSC’s Gold for Gold programme,’  says Phil Gale, Head of Chemistry at the University of Southampton. ‘This open access programme will allow us to showcase our research to a much wider audience.’

Gold for Gold is an innovative initiative rewarding UK RSC Gold customers with credits to publish a select number of papers in RSC journals via Open Science, the RSC’s Gold Open Access option.

More information on Gold for Gold is available on our website. If you have any questions on the procedure, or are an interested customer from outside the UK, please contact goldforgold@rsc.org.

Also of interest:
Gold for Gold – First Open Access credit used by University of Hull

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Biocatalysis: an article collection

A collection of high impact articles focusing on biocatalysis, from the RSC’s Catalysis Science & Technology, Green Chemistry, RSC Advances, Organic & Biomolecular Chemistry (OBC) and ChemComm

Beers, wines and cheeses are enjoyed around the world today and have been for millennia. In fact the practices of brewing and cheese-making pre-date recorded history so it is difficult to accurately determine when we first started using naturally occurring enzymes and microorganisms to create valuable (and in this case, tastier!) products.

Biocatalysts are of course used in far more diverse applications than the creation of food-stuffs, including in many organic syntheses and in the generation of fine chemicals. Due to their natural design, they can offer superior selectivity for particular products and have a far lower environmental impact than many traditional catalysts. Our knowledge and understanding of biocatalysts has increased dramatically in the last few decades, which has allowed us to develop biologically modified and biomimetic catalysts for a range of applications. 

To keep you up to date with the latest advances in this rapidly expanding field we have collected together these high impact articles and made them free to access until the 31st October!

Click here for the full list of free articles

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Lewis acidity of metal ions investigated in the gas phase

In aqueous solutions metal ions can promote acidity via the hydrolysis reaction. This is measured by a hydrolysis constant, which has previously been correlated to the ratio of the ion’s charge to size. Unfortunately lead and tin stubbornly refuse to fit this correlation; additional factors must be at work.

Anthony Stace and team investigated further by studying the minimum number of water molecules needed to stabilise a dication complex in the gas phase against spontaneous hydrolysis (called Coulomb fission in the gas phase). They found an extraordinarily good correlation between the number of water molecules required and the metal ion’s hydrolysis constant in aqueous solution.

What about those stubborn dications, lead and tin? They fit within the trend, requiring a surprising 11 and 26 water molecules to stabilise them respectively. This work suggests that Lewis acidity of metal ions is determined, in part, by the requirement that the ions remain fully solvated.

Plot of acidity constant against minimum number of water molecules required to stabilise the complex against Coulomb fission.

To find out more, download the ChemComm article today.

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A look at Gregynog 2012

Gregynog secretary, Dr Dave Carbery, reflects on this year’s annual synthesis meeting

The annual Gregynog Synthesis Meeting was recently held at Gregynog Hall  (Thursday 13th to Saturday 15th September), amidst the stunning beauty of mid-Wales and accompanied by fair weather. A group of 55 chemists came together to discuss recent progress in organic synthesis. As befits such a broad remit, the range of stakeholders present was pronounced with academic, industrial and scientific publishing attendees all present. As synthesis is an enabling and under-pinning scientific discipline, it was perhaps not surprising to see the range of contexts in which speakers discussed their synthesis. Catalysis, methodology and natural product chemistry were not-surprisingly representative; however, the audience was also treated to medicinal, process and supramolecular chemistries.

The relaxed and residential character of this event helps to encourage a collegiate ethos, helping to welcome younger chemists into the wider synthesis community. Such an ethos facilitates the discussion of initial results on new and adventurous projects in a supportive environment. In this regard, the fresh-faced Dr David France (University of Glasgow) struck a chord with the audience through his imaginative Pd-catalysis work.

The meeting is structured around the complementary formats of a number of short “chalk+talk” presentations (15 minutes with lively discussion and questions) supporting the two main keynote speakers in the evening, one of which has travelled beyond these shores. These keynote speakers have the opportunity to convey what exactly has made them the international names they are. What does the genesis of an idea require? How do the independent research strands in a research group interact with each other? And, importantly for the younger colleagues, how are difficult scientific challenges conquered? The Thursday evening saw Prof Jonathan Clayden (University of Manchester)A slide from Prof Dirk Trauner's keynote talk present the Chemical Communications keynote talk and embraced the meeting’s ethos with a career spanning discussion of the intertwining chemistry problems his group have tackled. The Friday evening session had Prof Dirk Trauner (LMU, Münich) present the Nature keynote talk. Earlier in the meeting, a member of the organising committee had suggested that his talk would be all the better, fitting the meeting’s remit, if he presented lots of “failed reactions” as a vehicle to conveying how he tackled organic synthesis problems. In this respect, it was a delight to later find, in my opinion, the most visually striking slide in a chemistry presentation I have yet seen. Prof Trauner went the extra mile in passing on his undoubted experience in synthesis problem-solving with some exquisite answers and suggestions. These keynote talks, as indeed were the short presentations, were interspersed with comments, suggestions and questions from the floor, indicative of the discerning yet approachable audience.

Finally, the Dave Kelly cup is awarded annually to a chemist who has engaged the audience with difficult concepts in a concise manner, with clarity at the chalk board. This prize is awarded in memory of our colleague Dr Dave Kelly, who was, for many years, synonymous with this important pillar in the synthesis calendar. Without doubt, Dr Steve Goldup (QMUL) was the chemist who hit the spot in this regard. The cup is on the way to the East End as I type.

Posted on behalf of Dr David Carbery, University of Bath

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