Archive for April, 2012

Optical chemosensors for sensing explosives

Peroxide-based explosives, such as triacetone triperoxide (TATP), have been increasingly used in criminal activities as they can be easily obtained and are highly sensitive (TATP has 88% the explosive equivalence of TNT). However, detecting TATP is not easy, despite its considerable vapour pressure at room temperature (7.87Pa), This is mainly because of its lack of nitro- or aromatic-groups, which could be revealed in UV absorbance or fluorescence spectra.

Here, researchers in China have demonstrated a new strategy to detect explosive peroxide vapor via deboronation reaction induced fluorescence quenching with good sensitivity (the detection limit of TATP vapour was estimated to be ~0.5ppm), selectivity and fast response.


 

Link to journal article
Highly Efficient Fluorescent Sensor of Explosive Peroxide Vapor via ZnO Nanorod Array Catalyzed Deboronation of Pyrenyl borate

C He et al
Chem. Commun.,
2012, DOI: 10.1039/c2cc31386c

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An interview with Richard Schrock

Richard Schrock, Hon FRSC

Richard Schrock, Hon FRSC

What’s your earliest memory of chemistry?

When I was eight, my older brother Ted gave me a chemistry set. He was attracted to chemistry and thought I might be too. He was right.

Why did you decide to become an academic?

I wanted to change the world on the basis of what I thought was important to do, and I felt that I could only do that in an academic environment. I also wanted to mentor students, teach, lecture, and travel. The life of an academic is simply a more satisfying and broader life, in my opinion.

What are you currently working on in the lab?

A few years ago we discovered new olefin metathesis catalysts – they’re letting us do reactions that couldn’t have been done before, and that are virtually unique to molybdenum and tungsten catalysts, as opposed to ruthenium.

We’re also still trying to improve the catalytic reduction of dinitrogen to ammonia by molybdenum catalysts that we discovered about ten years ago.

Why did you accept the role as Chair of ChemComm?

I think it’s important for me to give back to chemistry some of what chemistry has given me – in the form of service. I’d like to see ChemComm become a journal that is uniformly excellent, and that attracts some of the best papers in competition with other premier journals today.

Even though ChemComm is largely devoted to communications, each article will require all the experimental details that one would expect to have access to, as supporting information, so people can verify and reproduce the work.

In which area in chemistry do you think the next world-shaking advances will be?

Well, predictions of the future are always difficult, and the answer will depend upon what your definition of chemistry is. I often point out that everything in which matter is transformed is chemistry, so that takes care of the latter problem.

If I had to specify the broad areas in which advances will be made, they would include catalysis with metals, and the roles of metals in biology. I hope these will help with what all scientific advances have allowed society to achieve: better health, productivity, comfort, and happiness for all those fortunate enough to take advantage of such progress.

Why do you find chemistry inspiring?

I can make discoveries that potentially change how we view chemistry, at least in some small way. That might be a larger way, though, if I am lucky enough to be in the right place at the right time. Everyone wants to have a shot at changing the world – and, of course, get credit for doing so.

Professor Richard R. Schrock is the Frederick G. Keyes Professor of Chemistry at the Massachusetts Institute of Technology (MIT). In 2005 he was awarded the Nobel Prize in Chemistry (jointly with Yves Chauvin and Robert H. Grubbs) “for the development of the metathesis method in organic synthesis.” He also received the RSC’s Frankland Award in 2004. In January 2012, he began his four-year term as Chair of the Chemical Communications (ChemComm) editorial board.
(This interview is reproduced from RSC News, April 2012)
 
You can read more from Professor Schrock in a recent ChemComm Editorial and article.
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Top ten most accessed articles in March

This month sees the following articles in ChemComm that are in the top ten most accessed:-

Graphene quantum dots: emergent nanolights for bioimaging, sensors, catalysis and photovoltaic devices
Jianhua Shen, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Chem. Commun., 2012, 48, 3686-3699, DOI: 10.1039/C2CC00110A

Carbon-gold core-shell structures: Formation of shells consisting of gold nanoparticles
Jerzy Choma, Dominik Jamioła, Katarzyna Augustynek, Michal Marszewski and Mietek Jaroniec
Chem. Commun., 2012, 48, 3972-3974, DOI: 10.1039/C2CC30372H

N-Heterocyclic carbene chemistry of iron: fundamentals and applications
Michael J. Ingleson and Richard A. Layfield
Chem. Commun., 2012, 48, 3579-3589, DOI: 10.1039/C2CC18021A

Self-assembling porphyrins and phthalocyanines for photoinduced charge separation and charge transport
Hiroshi Imahori, Tomokazu Umeyama, Kei Kurotobi and Yuta Takano
Chem. Commun., 2012, 48, 4032-4045, DOI: 10.1039/C2CC30621B

6-Substituted quinoline-based ratiometric two-photon fluorescent probes for biological Zn2+ detection
Xiangming Meng, Shuxin Wang, Yiming Li, Manzhou Zhu and Qingxiang Guo
Chem. Commun., 2012, 48, 4196-4198, DOI: 10.1039/C2CC30471F

Metal-free TEMPO-catalyzed oxidative C-C bond formation from Csp3-H bonds using molecular oxygen as the oxidant
Bo Zhang, Yuxin Cui and Ning Jiao
Chem. Commun., 2012, 48, 4498-4500, DOI: 10.1039/C2CC30684K

Enhanced isosteric heat of H2 adsorption by inclusion of crown ethers in a porous metal-organic framework
Hye Jeong Park and Myunghyun Paik Suh
Chem. Commun., 2012, 48, 3400-3402, DOI: 10.1039/C2CC17005A

Cobalt-catalyzed arylation of aldimines via directed C-H bond functionalization: addition of 2-arylpyridines and self-coupling of aromatic aldimines
Ke Gao and Naohiko Yoshikai
Chem. Commun., 2012, 48, 4305-4307, DOI: 10.1039/C2CC31114C

Gold-catalyzed amide synthesis from aldehydes and amines in aqueous medium
Gai-Li Li, Karen Ka-Yan Kung and Man-Kin Wong
Chem. Commun., 2012, 48, 4112-4114, DOI: 10.1039/C2CC17689K

Extending the family of Zn-based MOFs: synthetic approaches to chiral framework structures and MOFs with large pores and channels
Nianyong Zhu, Gerard Tobin and Wolfgang Schmitt
Chem. Commun., 2012, 48, 3638-3640, DOI: 10.1039/C2CC17357C

Why not take a look at the articles today and blog your thoughts and comments below.

Fancy submitting an article to ChemComm? Then why not submit to us today or alternatively contact us with your suggestions

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Ionic liquid drugs hit the spot

Robin-Rogers_ionic-liquid-research_250_tcm18-216842

Biologically active ionic liquids supported on mesoporous silica provide solid handling with fast and complete release in an aqueous environment © Andreea Cojocaru and Gabriela Gurau/The University of Alabama

Pharmaceutically active ionic liquids have been immobilised onto solid supports to enable liquid drugs to be administered in solid form. Scientists from the US and Europe hope that their work will make the pharmaceutical industry consider ionic liquids as a viable alternative to solid drugs.

Pharmaceutically active ionic liquids are more soluble and stable than solid drugs and they are better at getting across cell membranes. But they are difficult to prepare and are not easy to handle. Robin Rogers from the University of Alabama in the US and colleagues immobilised the liquids onto mesoporous silica to improve preparation and handling.

The team combined known active pharmaceutical ingredients (APIs) into new dual functioning liquid salts in two ways. ‘In the first, we combined an acidic API with a basic API simply by grinding or mixing them together,’ explains Rogers. ‘This produces a salt in which the proton has transferred from the acid to the base.’ In the second, they started with a cationic API and an anionic API and exchanged the inert counterions to produce a new salt of API1+ and API2-.

Read the full article in Chemistry World

Link to journal article
Pharmaceutically Active Ionic Liquids with Solids Handling, Enhanced Thermal Stability, and Fast Release

Katharina Bica ,  Hector Rodriguez ,  Gabriela Gurau ,  O. Andreea Cojocaru ,  Anders Riisager ,  R Fehrmann and Robin D. Rogers
Chem. Commun.,
2012, Accepted Manuscript, DOI: 10.1039/C2CC30959A

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Novel synthesis of iron catalyst complexes via C-H activation of imidazolium salts

Researchers from Lisbon have developed a mild and efficient catalytic system for reducing sulfoxides. They made the iron-N-heterocyclic carbene (NHC) catalysts (2) via C–H activation of an imidazolium pro-ligand (1) with commercially available Fe3(CO)12. This advance precludes the requirement for the strong bases traditionally employed in the synthesis of similar complexes. Additionally, iron is an economically attractive metal for use in catalysis owing to its abundance and is also non-toxic and therefore more environmentally friendly than other transition metals.

The combination of iron(ll) complex (2) with a silver salt and a silane reducing agent led to the conversion of a range of sulfoxides into the corresponding sulfides in good to excellent yields. Initial mechanistic probes suggest the existence of a free-radical based reaction pathway, although further studies are ongoing.

In this publication, Beatriz Royo’s group have demonstrated an interesting advance for the synthesis of iron-NHC complexes, which may find further utility in other catalytic processes.

Download the communication >

Posted on behalf of Alice Williamson, ChemComm web writer.

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Shining a light on fingerprint detection

Scientists in China have discovered a method for visualising latent fingerprints found at the scene of a crime, which they say is very simple, rapid, does not require professional forensic treatment and does not destroy the print.

Bin Su and co-workers from Zhejiang University, Hangzhou, noticed that the conjugated compound tetraphenylethene (TPE) adhered to the greasy ridges of fingerprints via a hydrophobic interaction. TPE is non-fluorescent in acetonitrile solution, but when light with a 365nm wavelength is shone onto the solution, the compound can lose the extra energy by rotating. However, when TPE sticks to the fingerprint, its molecules clump together (or aggregate). The aggregated molecules can no longer rotate, so instead, they release the energy as light. This phenomenon is known as aggregation induced emission (AIE) and has been used in sensors, but never as a means of detecting fingerprints.

Shining a light on fingerprint detection
The fingerprints were enhanced by aggregation induced emission of tetraphenylethene
© iStockphoto

Read the full story in Chemistry World

Link to journal article
Aggregation induced emission for the recognition of latent fingerprints
Yan Li ,  Linru Xu and Bin Su
Chem. Commun., 2012, 48, 4109-4111, DOI: 10.1039/C2CC30553D

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Tomayto, tomato? Enantiospecific kinking of DNA

A few years ago, when I discovered what an intercalator was, I thought it would be a great name for a burger bar (probably best situated near a chemistry department). In scientific terms (and not catering as sadly the idea didn’t take off), intercalators have attracted a great deal of attention and are best known for their use in anticancer treatments.

Chelate compounds of polycyclic heteroaromatics with transition metals can bind to DNA. The polycyclic moeities intercalate between the base pairs of the DNA, a little like the burger in a bun.  This can have a profound effect on the DNA’s structure, separating the base pairs and causing the helix to kink. However, the extent of this effect is dependent on parameters such as the ligand and which enantiomer of the instrinsically chiral compounds is involved.

A study by Anna Reymer and Bengt Nordén into the ruthenium compound, [Ru(phenanthroline)3]2+,  investigates its two enantiomers (Δ and Λ) and the effect each one has on binding specificity with DNA. Using molecular dynamics simulations, they demonstrated that the Δ-form induced a kink of 53° whilst the Λ-form produced a more typical bend of only 16°. They also reveal information about binding affinities of the compounds and how ‘deeply’ they can insert themselves into the base stack.

This interesting simulation is significant in the context of chiral recognition and evolutionary selection. It also gives further insight into the behaviour of DNA-protein interactions; an analogous kink as produced by Δ- [Ru(phenanthroline)3]2+ have been observed for several classes of operatory proteins.

To find out more download Reymer and Nordén’s communication.

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Mass spectrometry imaging: the new tool in counterfeit security

The ever-increasing sophistication of the counterfeit trade is a growing economic problem, and when applied to pharmaceuticals, dangerous to human health. More covert strategies are required to combat the trade and US researchers have developed a potentially vital tool in the battle against counterfeiting.

A group at the University of Massachusetts, Amherst, led by Vincent Rotello, incorporated gold nanoparticles into ink by straightforward inkjet printing. This ‘barcode’ can be detected in an ambient and non-destructive manner by laser desorption ionisation mass spectrometry imaging – a method to determine the spatial distribution of particles based on their mass. More conventional methods, such as chromatography, require sample destruction for analysis, and non-destructive analytical techniques usually do not give specific chemical information.

Mass-spec-money_c2cc30499f_180_tcm18-216317
Nanoparticle barcode: a mass spectrometry image of different printed gold nanoparticles, overlapping. When scanned, the blue letters of one nanoparticle were detected at m/z = 548; the green letters of another nanoparticle were detected at m/z = 422; and the red pattern from Au+ was detected at m/z = 197

Read the full article in Chemistry World

Link to journal article
Laser desorption ionization mass spectrometric imaging of mass barcoded gold nanoparticles for security applications
B Creran et al
Chem. Commun., 2012, DOI: 10.1039/c2cc30499f

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