Chemical Communications Blog

Gold-catalysed cycloisomerisation of alkynyl hydroxyallyl tosylamides has led to the concise synthesis of oxaazatricyclic compounds and revealed an interesting skeleton structure, say scientists in South Korea.

Research groups across the globe have reported cycloisomerisation reactions of alkynyl allyl alcohols (AAAs) with rhodium, iridium, palladium and nickel catalysts. Naturally, research groups have been led into investigating the use of gold catalysts, providing plausible reaction pathways for these reactions. 

Young Keun Chung and colleagues from Seoul National University and Sangmyung University, used subtly different reaction conditions than have been previously reported, resulting in an usual oxaazatricyclic skeleton compound being uncovered for the first time, as shown in the X-ray structure obtained below.

X-ray structure of cycloisomerised oxaazatricyclic compound

To find out more about this unexpected result and the reaction conditions used, why not download the communication today? The results have been published in ChemComm and will be freely available until the 13th May 2011!

Two porous supramolecular isomeric frameworks have shown unique sorption properties, say a collaboration of Chinese and Japanese scientists. 

One framework shows temperature dependent and selective sorption of CO₂, while the other framework shows gas uptake capacity for CO₂, N₂, H₂ and CH₄ at low temperature and selective sorption of CO₂ over N₂ around room temperature. Wei-Yin Sun and colleagues believe that the results provide useful guidance for improving metal organic framework (MOF) designs for gas storage and separation techniques. 

Two porous supramolecular isomeric frameworks show unique sorption properties

Graphene oxide (GO) plays a crucial role in a new, sensitive biosensing platform, acting as an efficient quencher for upconversion nanophosphors, say scientists in China. 

Zhengping Li, Chenghui Liu and colleagues from Hebei University, have constructed a sensitive and practical biosensing platform by combining lanthanide-doped upconversion nanoparticles (UCNPs) with single-stranded DNA (ssDNA). Upon the addition of water soluble GO the upconversion fluorescence is quenched, effectively turning ‘off’ the fluorescence signal. To test the platforms sensing ability and performance, the team introduced adenosine triphosphate (ATP) resulting in the formation of an aptamer-ATP complex, preventing the UCNPs interacting with the GO surface and thus decreasing the quenching efficiency, resulting in the fluorescence staying ‘on’. Other phosphates were tested, like guanosine triphosphate (GTP), cytidine triphosphate (CTP) and uridine triphosphate (UTP) but no dramatic fluorescence enhancement was observed, so this indicates that the aptamer system is specific to ATP alone.

Upconversion FRET between ssDNA-UCNPs and GO for ATP sensing

Interestingly, the team also tested the biosensing platform with mercury ions, which caused the ssDNA to form double-stranded DNA (dsDNA), preventing the UCNPs interacting with the GO surface and again resulted in enhanced fluorescence emission. Other similar cations were tested in comparison, but the biosensor only shows selectivity for mercury ions, providing a good indication into the high specificity that this biosensing platform has, in addition to its future potential for uses in clinical diagnostic and biosensing applications.

Fancy finding out more? Then why not download the communication today – published in ChemComm, the article has been made free to access until the 13th May 2011.

Please also let us know what you think to this research by blogging some comments below.

Contact area lithography has been used for directly patterning and transferring self-assembled monolayers (SAMs) onto silicon-based substrates.

One-step patterning & transfer of SAMs on SiO2/Si substrates

Hyunjung Shin and colleagues from Kookmin University, in South Korea used a patterned (hard) silicon oxide template and placed it on substrates of interest, introducing a small amount of water in the process.
After drying off the water, the non-contacted areas served directly as growth sites of OTS-SAMs by simple solution deposition. The hard template was then detached from the substrate and the patterns of SAMs were obtained.

In principal, the hard template is cleansable by simple chemical etching without causing any damage. It is also 100% recyclable and can be reused up to ~50 times.

Fancy finding out more about this technique? Then why not download the communication today, which has been published in ChemComm and will be free to access until the 13th May 2011.

Scientists in Belgium have designed a microfluidic setup that manufactures thiol and yne beads, which can then undergo several click-type reactions.

Filip Du Prez and his team at Ghent University demonstrated the yne beads reacting with an azide or two thiols, whereas the thiol beads were tested using nine different reaction conditions. The thiol–isocyanate reaction was seen to be the fastest, being closely followed by the thiol–norbornene reaction.

Light Microscopy image of monodisperse thiol beads (left image). Fluorescent yne beads after clicking with coumarin-derivative (right image).

Du Prez believes that this discovery may help to guide researchers, especially in the field of solid phase synthesis, to choose the most suitable ligation reaction according to their needs since many of the conjugations studied are part of the click family. 

Published in ChemComm this communication will be freely available until the 13th May 2011. Why not download the communication today and find out more about the beads and their clicking abilities?