Chemical Communications Blog

Ionic liquid drugs hit the spot

18 Apr 2012

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

16 Apr 2012

By Joanne Thomson.

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

10 Apr 2012

By Rachel Blakeburn.

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.

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

04 Apr 2012

By Sarah Brown.

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

04 Apr 2012

By Rachel Blakeburn.

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.

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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Magneto-chiral dichroism observed in light-harvesting antenna

30 Mar 2012

By Joanne Thomson.

Artificial light-harvesting antennas absorb light travelling parallel to a magnetic field differently from light travelling anti-parallel to the field, according to Japanese researchers.

This effect – known as magneto-chiral dichroism (MChD) – is proposed to have played a role in the origin of homochirality in life and is important for the development of new magneto-optical devices.

This is only the second example of MChD reported in organic compounds. It indicates that MChD may occur during the light-harvesting process, says the team, which is important not only for learning more about photosynthesis but also for clarifying the origin of asymmetry in biological systems.

Read the communication:
Magneto-chiral dichroism of artificial light-harvesting antenna
Yuichi Kitagawa, Tomohiro Miyatake and Kazuyuki Ishii
Chem. Commun., 2012, DOI: 10.1039/C2CC30996C

Also of interest:
Nanoscale spectroscopy with optical antennas
Palash Bharadwaj, Ryan Beams and Lukas Novotny, Chem. Sci., 2011, 2, 136-140

Artificial Photosynthesis – a ChemComm web theme

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Abstracts invited for International Conference on Physical Organic Chemistry

29 Mar 2012

By Ross McLaren, Development Editor.

Good news!

There’s still a chance to submit your oral abstract to ICPOC 21: 21st IUPAC International Conference on Physical Organic Chemistry organised by the Organic Division of the RSC on behalf of IUPAC, to be held 9 – 13 September 2012 at Durham University.

The Scientific Committee is currently reviewing all submissions, and has agreed to accept contributions up to Friday 13 April to allow for the Easter holiday break.

Why join ICPOC 21?

Professor Hiromitsu Maeda, Ritsumeikan University, Japan has won the 2012 ChemComm Emerging Investigator Lectureship and will deliver his lecture at ICPOC 21.

This annual award recognises an emerging scientist in the early stages of their independent academic career. Professor Maeda’s has been particularly commended for his contributions to the fields of organic chemistry, supramolecular chemistry and materials science.

In addition to the outstanding plenary sessions, there will be three parallel sessions over the five days comprising invited lectures and contributed talks, as well as poster sessions.

A broad range of scientists from across the whole community who share a quantitative perspective on chemistry will be there, providing an opportunity to discuss and celebrate the current status, development, and the future of physical organic chemistry.

Make sure you are one of them! Don’t miss the oral abstract submission deadline – 13 April.

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Announcing the ChemComm Emerging Investigators issue 2013

28 Mar 2012

By Ross McLaren, Development Editor.

Profiling the very best research from scientists in the early stages of their independent careers

Following the amazing successes of the 2011 and 2012 ChemComm Emerging Investigators issues, we are delighted to announce the forthcoming 2013 Emerging Investigators issue. All interested parties should contact the ChemComm Editorial Office in the first instance.

This issue is dedicated to profiling the very best research from scientists in the early stages of their independent careers from across the chemical sciences. We hope to feature principal investigators whose work has the potential to influence future directions in science or result in new and exciting developments.

Also of interest:
ChemComm Emerging Investigators Issue 2012

ChemComm Emerging Investigator Lectureship 2012: The winner is….

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Sustainable Inorganic Chemistry – free content for a limited period

22 Mar 2012

By Joanne Thomson.

ChemComm is delighted to be sponsoring the forthcoming Symposium on Sustainable Inorganic Chemistry along with the ACS Division of Inorganic Chemistry. The symposium will take place at the ACS Spring 2012 National Meeting & Exposition in San Diego starting on 25th March.

To celebrate we’ve made some articles published by the symposium speakers free to access for a limited period.

We hope you enjoy these articles – but don’t delay! Free access only runs until 1st April.

Selective liquid phase oxidation with supported metal nanoparticles
Nikolaos Dimitratos, Jose A. Lopez-Sanchez and Graham J. Hutchings
Chem. Sci., 2012, 3, 20-44

Mesoscopic organic nanosheets peeled from stacked 2D covalent frameworks
Yugen Zhang, Meixuan Tan, Hai Li, Yuangang Zheng, Shujun Gao, Hua Zhang and Jackie Y. Ying
Chem. Commun., 2011, 47, 7365-7367

Self-assembly in the electrical double layer of ionic liquids
Susan Perkin, Lorna Crowhurst, Heiko Niedermeyer, Tom Welton, Alexander M. Smith and Nitya Nand Gosvami
Chem. Commun., 2011, 47, 6572-6574

Continuous flow organometallic catalysis: new wind in old sails
Ulrich Hintermair, Giancarlo Franciò and Walter Leitner
Chem. Commun., 2011, 47, 3691-3701

CO₂ selectivity of a 1D microporous adenine-based metal–organic framework synthesised in water
Kyriakos C. Stylianou, John E. Warren, Samantha Y. Chong, Jeremy Rabone, John Bacsa, Darren Bradshaw and Matthew J. Rosseinsky
Chem. Commun., 2011, 47, 3389-3391

Room temperature oxidation of methyl orange and methanol over Pt–HCa₂Nb₃O₁₀ and Pt–WO₃ catalysts without light
Emiliana Dvininov, Upendra A. Joshi, James R. Darwent, John B. Claridge, Zhongling Xu and Matthew J. Rosseinsky
Chem. Commun., 2011, 47, 881-883

Tunable, light-assisted co-generation of CO and H₂ from CO₂ and H₂O by Re(bipy-tbu)(CO)₃Cl and p-Si in non-aqueous medium
Bhupendra Kumar, Jonathan M. Smieja, Alissa F. Sasayama and Clifford P. Kubiak
Chem. Commun., 2012, 48, 272-274

Photocatalytic H₂ evolution from neutral water with a molecular cobalt catalyst on a dye-sensitised TiO₂ nanoparticle
Fezile Lakadamyali and Erwin Reisner
Chem. Commun., 2011, 47, 1695-1697

Transition metal catalysed ammonia-borane dehydrogenation in ionic liquids
William R. H. Wright, Emily R. Berkeley, L. R. Alden, R. Tom Baker and Larry G. Sneddon
Chem. Commun., 2011, 47, 3177-3179

Co and Mn polysiloxanes as unique initiator–catalyst-systems for the selective liquid phase oxidation of o-xylene
Tobias Förster, Stephan A. Schunk, Andreas Jentys and Johannes A. Lercher
Chem. Commun., 2011, 47, 3254-3256

@ChemCommun Follow the symposium at #CCsymp

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New drug delivery agents

22 Mar 2012

By Rachel Blakeburn.

Platinum complexes have been employed as anti-cancer drugs for years despite significant side effects. Second generation metal-complex anti-cancer drugs in contrast are still in their infancy, and suffer from low solubility and high reactivity, leading to deactivation before the drug can reach its target.

To overcome these problems, scientists in Australia have developed a gold-based drug chemically incorporated in a polymeric micelle as a drug delivery agent. The resulting molecules showed potent in vitro antitumour activity in human ovarian carcinoma cells.

Link to journal article
Micelles based on Gold-Glycopolymer Complexes as New Chemotherapy Drug Delivery Agents
S Pearson, W Scarano and M H Stenzel
Chem. Commun., 2012, DOI: 10.1039/c2cc30510k

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Chemical Communications Blog

Ionic liquid drugs hit the spot

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

Shining a light on fingerprint detection

Tomayto, tomato? Enantiospecific kinking of DNA

Mass spectrometry imaging: the new tool in counterfeit security

Magneto-chiral dichroism observed in light-harvesting antenna

Abstracts invited for International Conference on Physical Organic Chemistry

Announcing the ChemComm Emerging Investigators issue 2013

Sustainable Inorganic Chemistry – free content for a limited period

New drug delivery agents

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