Archive for the ‘Supramolecular’ Category

Cram Lehn Pedersen Prize 2017 – call for nominations

ISMSC-ISACS 2017, 2-6 July 2017, Cambridge, UK

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, recognises significant original and independent work in supramolecular chemistry.

Previous winners include Ivan Aprahamian, Feihe Huang, Oren Schermann, Tomoki Ogoshi, Jonathan Nitschke, and Amar Flood.

Those who are within 10 years of receiving their PhD on 31st December 2016 are eligible for the 2017 award. The winner will receive a prize of £2000 and free registration for the ISMSC-ISACS meeting in Cambridge, UK. In addition to giving a lecture at ISMSC-ISACS, 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:

You may nominate yourself or someone else. Please send your CV, list of publications (divided into publications from your PhD and post-doc, and those from your independent work), and if desired, a letter of support, or these materials for someone you wish to nominate, to Prof. Roger Harrison (ISMSC Secretary) at rgharris@chem.byu.edu by 31st December 2016.

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Ivan Aprahamian wins Cram Lehn Pedersen Prize

Photograph of Professor Ivan AprahamianThe International Committee of the International Symposium on Macrocyclic and Supramolecular Chemistry is delighted to announce that the 2016 Cram Lehn Pedersen Prize, given annually to an outstanding early-career supramolecular chemist, has been awarded to Professor Ivan Aprahamian, Dartmouth College, USA for his exciting research on molecular switches – congratulations!

As part of the Prize, Prof. Aprahamian will give a lecture at the 11th International Symposium on Macrocyclic and Supramolecular Chemistry meeting in Seoul, Korea which takes place from 10–14 July 2016.

Photograph of Dr Jeanne AndresDr Jeanne Andres (Deputy Editor of ChemComm) will be attending the event and will present the award in person. She would love to hear about your research and meet with our readers, authors and referees. Please do get in touch with Jeanne if you would like to arrange a meeting in advance.

We are also delighted to announce that the International Symposium on Macrocyclic and Supramolecular Chemistry in 2017 will be held in conjuction with ISACS: Challenges in Organic Materials & Supramolecular Chemistry.

Our keynote speakers will be:

  • François Diederich (ETH Zurich, Switzerland)
  • David Leigh (The University of Manchester, UK)
  • Jeffrey Long (University of California, Berkeley, USA)
  • Vivian Yam (University of Hong Kong, Hong Kong)
  • Xi Zhang (Tsinghua University, China)

Full details of all the confirmed speakers may be found on the event website.

We hope you can join us in Cambridge, UK – save the dates 2–6 July 2017!

While you are waiting you might like to check out some of our recent themed collections of articles in the area of supramolecular chemistry – Enjoy!

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Nominate now for the 2016 Cram Lehn Pedersen Prize in Supramolecular Chemistry

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, recognises significant original and independent work in supramolecular chemistry.

Previous winners include Feihe Huang, Oren Schermann, Tomoki Ogoshi, Jonathan Nitschke, and Amar Flood.

Those who are within 10 years of receiving their PhD on 31st December 2015 are eligible for the 2016 award. The winner will receive a prize of £2000 and free registration for the ISMSC meeting in Seoul, Korea. 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:

You may nominate yourself or someone else. Please send your CV, list of publications (divided into publications from your PhD and post-doc, and those from your independent work), and if desired, a letter of support, or these materials for someone you wish to nominate, to Prof. Roger Harrison (ISMSC Secretary) at rgharris@chem.byu.edu by 31st January 2016.

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Feihe Huang wins Cram Lehn Pedersen Prize 2015

Congratulations to Prof Feihe Huang from the State Key Laboratory of Chemical Engineering at Zhejiang University, China, winner of the 2014 Cram Lehn Pedersen Prize in Supramolecular Chemistry.

The prize, sponsored by ChemComm, is organised by the committee of the International Symposium on Macrocyclic and Supramolecular Chemistry and is awarded each year to a young supramolecular chemist.

The Cram Lehn Pedersen Prize is named in honour of the winners of the 1987 Nobel Prize in Chemistry and recognises significant original and independent work in supramolecular chemistry. Previous winners include Oren Schermann, Tomoki Ogoshi, and Jonathan Nitschke.

Feihe will receive £2000, free registration for the ISMSC meeting in Strasbourg, France, and the opportunity to give a lecture at the ISMSC. He is also giving two additional lectures as part of his prize in Germany, at the Max Planck Institute of Colloids and Interfaces and the Free University of Berlin.

Dr May Copsey, Executive Editor of the journal, will be also attending this conference to personally award Feihe with the lectureship. She hopes to meet many ChemComm readers and authors there. Please do let her know if you will be there too!

“Professor Feihe Huang follows in the tradition of other winners and is an excellent supramolecular scientist. He has published over 100 articles as an independent researcher, in top tear journals such as ChemComm,” says Professor Roger Harrison, Associate Professor at Brigham Young University and Secretary of the ISMSC International Scientific Committee.  He adds, “He has set himself apart from other chemists by investigating supramolecular polymers and learning how to control their properties.”


Find out more about Feihe Huang by reading his recent research in ChemComm:

Prof Feihe Huang, Winner of the Cram Lehn Pedersen Prize 2015

A water-soluble biphen[3]arene: synthesis, host–guest complexation, and application in controllable self-assembly and controlled release
Jiong Zhou, Guocan Yu, Li Shao, Bin Hua and Feihe Huang
Chem. Commun., 2015, 51, 4188-4191
DOI: 10.1039/C5CC00225G, Communication

Reversible formation of a poly[3]rotaxane based on photo dimerization of an anthracene-capped [3]rotaxane
Peifa Wei, Xuzhou Yan and Feihe Huang
Chem. Commun., 2014, 50, 14105-14108
DOI: 10.1039/C4CC07044E, Communication

A CO2-responsive pillar[5]arene: synthesis and self-assembly in water
Kecheng Jie, Yong Yao, Xiaodong Chi and Feihe Huang
Chem. Commun., 2014, 50, 5503-5505
DOI: 10.1039/C4CC01704H, Communication

Host–guest complexation induced emission: a pillar[6]arene-based complex with intense fluorescence in dilute solution
Pi Wang, Xuzhou Yan and Feihe Huang
Chem. Commun., 2014, 50, 5017-5019
DOI: 10.1039/C4CC01560F, Communication

We invite you to submit your next communication article to ChemComm!

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Capturing C60 in a Crystalline Copolymer Chain

Since its structural realisation in 1985, C60 has garnered much attention in the chemical world for not only its spherical shape, but also its stability, electronic properties and the ability to do chemistry on its surface.

One such avenue that has proven popular in recent times is the incorporation of C60 into one-, two- and three-dimensional arrays, either covalently or non-covalently, in attempts to control the distribution of the molecules in the solid- or solution-phase.  One problem that arises in the synthesis of these extended frameworks, however, is that there often a large amount of disorder and void space in the structure, so it can be difficult to ascertain with much degree of certainty how these C60 molecules are oriented. This uncertainty can consequentially result in the properties and behaviours of the new materials remaining unidentified.

Now, researchers from the University of California, DavisMarilyn Olmstead and Alan Balch – have shown that coordination chemistry can be used to not only generate polymers that covalently link molecules of functionalised C60 in such a manner that can they can be studied crystallographically, but also that these polymers can be used to capture free C60 and C70.

Initially, polymers of C60 were synthesised through the mono-functionalisation of C60 with a piperazyl group, which, on account of its two tertiary amines, can coordinate in a linear fashion with transition metal ions, in this case rhodium(II) acetate. Upon the combination of these two components, a linear one-dimensional polymer was formed, in which it could be seen crystallographically that the C60 moieties were positioned on alternating sides of the polymer chain. These polymer chains were further found to extend into two dimensions through the interdigitation of neighbouring chains in a zipper-like fashion. C60-Rh(II) polymers can capture free C60

Perhaps more interestingly is that when these polymer chains were synthesised in the presence of either C60 or C70, free molecules of C60 or C70 were seen to occupy the void spaces between the C60 molecules of the polymer. Additionally, if a mixture of C60 and C70 was present in the polymer synthesis, it was observed that only C60 was captured by the polymer, most likely as a result of a better geometric match between the polymer and the spherical C60 in preference to the more elongated shape of C70.

This work elegantly demonstrates the generation of not only a self-assembling C60-containing polymer that can be characterised structurally in the solid state, but of one  that can entrap free molecules of C60 selectively over molecules of C70. Based on the properties of free C60 and transition metal complexes, the electronic and chromophoric properties of such a crystalline system could also be expected to offer some noteworthy results.

Read this HOT ChemComm article in full!

Zipping up fullerenes into polymers using rhodium(II) acetate dimer and N(CH2CH2)2NC60 as building blocks
Amineh Aghabali, Marilyn M. Olmstead and Alan L. Balch
Chem. Commun., 2014, Advance Article.
DOI: 10.1039/C4CC06995A

Biography

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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Inducing β-Peptide Structures from the Inside Out

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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2014 Cram Lehn Pedersen Prize in supramolecular chemistry – nominations open

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, recognises significant original and independent work in supramolecular chemistry.

Previous winners include:

photo-ogoshi-300x300.jpgc0sc00329h-p3.gifAmar-Flood.jpg

2013 – Tomoki Ogoshi from Kanazawa University in Japan

2012 – Jonathan Nitschke from the University of Cambridge in the UK

2011 – Amar Flood from Indiana University in the US

Those who are within 10 years of receiving their PhD on 31st December 2013 are eligible for the 2014 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 from your independent work), and if desired, a 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 December 2013.


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The chemists’ enzyme

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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Azobenzene switching controls movement of oleate assemblies

The study of controlled motion on the molecular scale is leading to the development of materials in which molecular motions can be used to control a macroscopic effect.  In particular, the isomerisation of azobenzene from the stable trans- form to the cis- isomer on irradiation with UV light has been widely used in supramolecular and soft matter chemistry as a simple, controllable molecular switch for this purpose.

In this HOT ChemComm article, scientists from Hokkaido and Kanagawa universities in Japan have investigated the macroscopic motion of some simple oleate assemblies containing azobenzene derivatives.

Simple oleates form a range of supramolecular assemblies under certain pH conditions.  The authors found that mixtures of simple oleates with their new azobenzene containing analogues could also form these assemblies, and investigated the effect of irradiating the structures with UV light.  They found that vesicles containing azobenzene derivatives could be seen to reversibly expand and contract on irradiation.  Additionally, helical multilayer assemblies containing azobenzene derivatives could be forced to reversibly straighten and re-coil using UV light (shown below).

azobenzen oleatesazobenzene helices

This Communication describes an intriguing demonstration that designing controllable, switchable molecular components can create highly organised macroscopic motions, and is a great step towards functional supramolecular machinery.

Read this HOT ChemComm article today:

Macroscopic motion of supramolecular assemblies actuated by photoisomerization of azobenzene derivatives
Yoshiyuki Kageyama,  Naruho Tanigake,  Yuta Kurokome,  Sachiko Iwaki, Sadamu Takeda,  Kentaro Suzukib  and Tadashi Sugawara
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC43488E

Cally Haynes is a guest web-writer for ChemComm.  She is currently a post doctoral researcher at the University of Southampton, and her research interests include the supramolecular chemistry of anions.  When not in the laboratory, she enjoys travelling and watching football.

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ChemComm-RSC Prizes and Awards Symposium: Supramolecular Chemistry

Last month we were delighted to hold a ChemComm-RSC Prizes and Awards Symposium on supramolecular chemistry at Trinity College Dublin, Ireland. The free one-day event was a great success, with over 160 delegates and a fantastic programme featuring RSC Award winners and leaders in the field.

CC supramolecular symposium

Speakers from the ChemComm-RSC Prizes and Awards Symposium on Supramolecular Chemistry, 24 May 2013, Dublin, Ireland

Speakers included:

  • Jerry Atwood, University of Missouri-Columbia – Winner of the 2012 RSC Supramolecular Award
  • John Callan, University of Ulster
  • Chris Chang, University of California, Berkeley – Winner of the 2012 RSC Chemistry of Transition Metals Award
  • Sylvia Draper, Trinity College Dublin
  • Phil Gale, University of Southampton – ChemComm sponsored lecture
  • David Leigh, University of Manchester – ChemComm sponsored lecture
  • Donal O’Shea, University College Dublin
  • Susan Quinn, University College Dublin
  • Eoin Scanlon, Trinity College Dublin
  • Jonathan Steed, Durham University – ChemComm sponsored lecture

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