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Free ChemComm inorganic and supramolecular content

04 May 2012

The ChemComm–RSC Prizes & Awards Symposium jointly organised with the Dalton Division takes place at the University of Oxford on 23rd May with the theme of inorganic and supramolecular chemistry.

This is ChemComm’s second UK-based symposium and to celebrate we’ve made some of our best content free to access for a limited period.

We hope you enjoy these articles – but don’t delay! Free access only runs until 30th May.

Germanium/phosphorus cage compounds with germanium in three different oxidation states
Stefan Almstätter, Gábor Balázs, Michael Bodensteiner and Manfred Scheer
Chem. Commun., 2011, 47, 9998-10000
DOI: 10.1039/C1CC13937A

Selective gas sorption in a [2+3] ‘propeller’ cage crystal
Shan Jiang, John Bacsa, Xiaofeng Wu, James T. A. Jones, Robert Dawson, Abbie Trewin, Dave J. Adams and Andrew I. Cooper
Chem. Commun., 2011, 47, 8919-8921
DOI: 10.1039/C1CC12460A

Reversible anion-templated self-assembly of [2+2] and [3+3] metallomacrocycles containing a new dicopper(I) motif
Emily F. V. Dry, Jack K. Clegg, Boris Breiner, Daniel E. Whitaker, Roman Stefak and Jonathan R. Nitschke
Chem. Commun., 2011, 47, 6021-6023
DOI: 10.1039/C1CC11206F

Cleavage of dinitrogen to yield a (t-BuPOCOP)molybdenum(IV) nitride
Travis J. Hebden, Richard R. Schrock, Michael K. Takase and Peter Müller
Chem. Commun., 2012, 48, 1851-1853
DOI: 10.1039/C2CC17634C

Metal-free diastereoselective catalytic hydrogenations of imines using B(C₆F₅)₃
Zachariah M. Heiden and Douglas W. Stephan
Chem. Commun., 2011, 47, 5729-5731
DOI: 10.1039/C1CC10438A

Activation of phosphorus by group 14 elements in low oxidation states
Shabana Khan, Sakya S. Sen and Herbert W. Roesky
Chem. Commun., 2012, 48, 2169-2179
DOI: 10.1039/C2CC17449A

Twisted molecular magnets
Ross Inglis, Constantinos J. Milios, Leigh F. Jones, Stergios Piligkos and Euan K. Brechin
Chem. Commun., 2012, 48, 181-190
DOI: 10.1039/C1CC13558A

Luminescent metal complexes of d⁶, d⁸ and d¹⁰ transition metal centres
Vivian Wing-Wah Yam and Keith Man-Chung Wong
Chem. Commun., 2011, 47, 11579-11592
DOI: 10.1039/C1CC13767K

Uranium-mediated activation of small molecules
Polly L. Arnold
Chem. Commun., 2011, 47, 9005-9010
DOI: 10.1039/C1CC10834D

Also of interest: Take at look at our web themes on Supramolecular Chemistry and Frontiers in Molecular Main Group Chemistry.

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Optical chemosensors for sensing explosives

26 Apr 2012

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

16 Apr 2012

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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Tomayto, tomato? Enantiospecific kinking of DNA

04 Apr 2012

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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Magneto-chiral dichroism observed in light-harvesting antenna

30 Mar 2012

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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Sustainable Inorganic Chemistry – free content for a limited period

22 Mar 2012

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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Ambient pressure XPS on the cheap

21 Mar 2012

X-ray photoelectron spectroscopy (XPS) is capable of characterising the surface composition, oxidation state and electron state of materials. Unfortunately, it uses electrons and so common XPS machines must work at vacuum pressures. But how could you use XPS under ambient pressure?

One option would be to use public synchrotron facilities but access is through proposal review and available time is restricted so it is not feasible for day-to-day studies. Another option would be to follow the lead of Franklin Tao and build an inexpensive, ambient pressure XPS machine in-house.

Such a machine is ideal for catalytic studies. Previously scientists investigated catalysts with conventional vacuum XPS before and after experiments. Tao’s machine enables him to investigate catalyst surface changes during reaction conditions, something that required synchrotron facilities until now. The machine’s novel reaction cell allows XPS measurements to be carried out at up to 25-50 Torr using an inexpensive bench top X-ray source.

: external view of the reaction cell

In addition to the ambient pressure XPS functionality, an on-line mass spectrometer allows correlation between catalytic performance and surface chemistry. Tao has demonstrated this novel machine by investigating the oxidation and reduction of ceria under real reaction conditions.

With day-to-day ambient pressure XPS now within reach of every research group, catalytic studies under reaction conditions have received a significant boost.

To find out more, download the ChemComm article today.

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Stopping bugs in their tracks

20 Mar 2012

To prevent the spread of bugs, scientists in Switzerland have starved microbes of phosphate by using lanthanum oxide nanoparticles. The nanoparticles compete against the microbes for available phosphate and so the microbes can’t grow. The team says that the strategy is of particular technical interest as it can bypass toxic material release and provides an antimicrobial solution with small environmental footprint.

Link to journal article
Phosphate starvation as an antimicrobial strategy: the controllable toxicity of lanthanum oxide nanoparticles
L C Gerber et al
Chem. Commun., 2012, DOI: 10.1039/c2cc30903c

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Cheap and non-toxic porphyrins for detecting cells deep within the body

08 Mar 2012

Near-infrared fluorescent imaging can be used for rapid and sensitive detection of cells deep within the body. However, common NIR dyes and quantum dots are expensive and/or toxic.

Porphyrins are economical fluorescent dyes, but their emission and excitation wavelengths are shorter than the NIR region and they can be toxic and poorly water-soluble. Scientists in Japan have made silica–porphyrin hybrid nanotubes that have no acute toxicity and higher water solubility compared to porphyrin. They used them to label macrophages, injected them into mice and tracked their distribution by fluorescence imaging with good results.

Link to journal article
Silica/Porphyrin Hybrid Nanotubes for In Vivo Cell Tracking by Near-Infrared Fluorescence Imaging
K Hayashi, M Nakamura and K Ishimura
Chem. Commun., 2012, DOI: 10.1039/c2cc17444h

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Micro power for micro devices

08 Mar 2012

An easy way to make high-performance micro-supercapacitors based on nanocrystal building blocks has been developed by scientists in the US and China. Micro-power sources have become a key component for micro-electronics but they are expensive and difficult to make. To demonstrate their concept, the team made nanoporous thin-film pseudocapacitor electrodes that showed ultrafast lithium storage kinetics, high capacitance and excellent cycling stability, giving them great promise for high energy and high power micro-device applications.

Link to journal article
Ready Fabrication of Thin-Film Electrodes from Building Nanocrystals for Micro-Supercapacitors
Z Chen et al
Chem. Commun., 2012, DOI: 10.1039/c2cc30406f

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