Chemical Communications Blog

A gel that can move backwards and forwards in a tube in response to changes in light intensity has been developed by an international team of chemists. As it can change its direction of travel, the gel could one day be used as a material to allow tiny intelligent robots to approach more favourable environments or flee advere stimuli.                                      

The gel’s ability to move is thanks to the Belousov–Zhabotinsky (BZ) reaction. BZ reactions are known for their unusual oscillatory properties caused by the non-equilibrium thermodynamics of the reaction. By including the BZ reaction in specific gels, it is possible to obtain soft materials which can show repeated swelling and shrinking on a scale that can even push objects through a tube.

When one end of a BZ gel is made to oscillate faster than the other…

Gel moving away from the light (left) and gel moving towards the light (right)

Read the full article in Chemistry World

Read the original journal article in ChemComm:
Photophobic and phototropic movement of a self-oscillating gel
Xingjie Lu, Lin Ren, Qingyu Gao, Yuemin Zhao, Shaorong Wang, Jiaping Yang and Irving R. Epstein  
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC44480E, Communication

The cuboctahedron consists of copper paddle-wheel nodes and carborane–isophthalic acids

Scientists in the US have made a molecular species containing the highest number of boron atoms ever recorded in a crystallographically characterised molecular species. The unique supramolecular cuboctahedron contains 240 boron atoms and was synthesised by Chad Mirkin and colleagues at Northwestern University in Evanston, Illinois, via coordination-driven assembly.

The previous record for the most boron atoms in a single molecular species was a heptanuclear silver aggregate reported by Lars Wesemann in 2010, but this species only contained 88 boron atoms.

Boron-rich nanostructures form the basis of high-energy materials, nanoelectronic materials and boron neutron capture therapy agents. It is therefore surprising that, in comparison to the myriad of methods for making carbon-rich nanostrucutres, there are relatively few strategies for making boron-rich ones. Mirkin’s team are now pursuing the synthesis of other boron-rich supramolecular assemblies.

This article was originally published in Chemistry World

You can also read the original journal article in ChemComm:
An exceptionally high boron content supramolecular cuboctahedron
Daniel J. Clingerman, Robert D. Kennedy, Joseph E. Mondloch, Amy A. Sarjeant, Joseph T. Hupp, Omar K. Farha and Chad A. Mirkin  
Chem. Commun., 2013, Advance Article
DOI: 10.1039/C3CC44173C, Communication

A chemosensor has been developed by scientists in the US to speed up the quantitative stereochemical analysis of chiral amino alcohols and diamines. Faster stereochemical analysis will help progress the identification of new asymmetric catalysts.  

Different enantiomers of chiral compounds can have similar physicochemical properties but their biological properties may bear no resemblance to each other. Drugs are often chiral molecules but there can be significant differences between the toxicities of enantiomers.

The administration of just the active enantiomer eliminates the toxic effects of other enantiomers and could make administering lower drug doses possible. Asymmetric catalysts that favour the production of one enantiomer over the other provide a way to produce an excess of desired enantiomers and can lower costs by avoiding the labour-intensive and time-consuming separation of enantiomers.

Driven by industrial demand for efficiency, researchers are producing many potential asymmetric catalysts for drugs and other compounds…

Read the full article in Chemistry World»

Read the original journal article in ChemComm:
Sensing of the concentration and enantiomeric excess of chiral compounds with tropos ligand derived metal complexes
Peng Zhang and Christian Wolf  
Chem. Commun., 2013, 49, 7010-7012
DOI: 10.1039/C3CC43653E, Communication

The force of transporting single amino-acid into the living cell measured by atomic force microscopy
Xin Shang, Yuping Shan, Yangang Pan, Mingjun Cai, Junguang Jiang and Hongda Wang
Chem. Commun., 2013, Accepted Manuscript
DOI: 10.1039/C3CC43779E, Communication

Free to access until 25th August 2013

Two homochiral organocatalytic metal organic materials with nanoscopic channels
Michael Zaworotko , Zhuxiu Zhang, Youngran Ji, Lukasz Wojtas, Wen-Yang Gao, Shengqian Ma and Jon Antilla
Chem. Commun., 2013, Accepted Manuscript
DOI: 10.1039/C3CC43801E, Communication

Free to access until 25th August 2013

An n→π* interaction reduces the electrophilicity of the acceptor carbonyl group
Amit Choudhary, Charles G. Fry, Kimberli J. Kamer and Ronald T. Raines
Chem. Commun., 2013, Accepted Manuscript
DOI: 10.1039/C3CC44573A, Communication

Free to access until 25th August 2013

Click here for more free HOT Chem Comm articles for July!

Scientists in Japan have shown that a dye can present more than five different colours according to the acidity of the solution it is in and can be used to visualise acid–base equilibria in non-polar solvents. It is extremely unusual for a single dye to demonstrate so many different colours.

Hydrogen bonding, deprotonation and different degrees of protonation all turn the dye, oxoporphyrinogen, a different colour. Hydrogen bonding of an anion to oxoporphyrinogen gives an increasingly blue colour depending on the strength of the interaction. Strongly basic substances cause oxoporphyrinogen to deprotonate and turn a pale brown hue. In the opposing direction, acids of certain strength can doubly protonate the dye. This induces tautomerisation of the dye’s structure, which varies its conjugated electronic form, leading to another significant colour change, in this case to red. Stronger acids quadruply protonate the dye, so all available electronegative atoms are protonated, turning it bright green.

Jonathan Hill, from the National Institute for Materials Science, Ibaraki, who led the work, says there are two main reasons to want to see acid–base equilibria in non-polar solvents…

Read the full article in Chemistry World

Read the original journal article in ChemComm:
Colorimetric visualization of acid–base equilibria in non-polar solvent
Atsuomi Shundo, Shinsuke Ishihara, Jan Labuta, Yosuke Onuma, Hideki Sakai, Masahiko Abe, Katsuhiko Ariga and Jonathan P. Hill  
Chem. Commun., 2013, 49, 6870-6872
DOI: 10.1039/C3CC42859A