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Turning natural cofactors into new anti-proliferative agents

07 Dec 2012

Vitamin B12 plays an important role in the metabolism of many organisms, particularly mammals. Since efficient delivery of vitamin B12 into cells has potential applications in medical therapies, Zelder et al. are sure to inspire wider interest in the design, chemistry and biology of backbone modified B12 derivatives with this hot Perspective.

Download the Perspective today for free…

Peptide B12: emerging trends at the interface of inorganic chemistry, chemical biology and medicine
Felix Zelder, Kai Zhou and Marjorie Sonnay
Dalton Trans., 2013
DOI: 10.1039/C2DT32005C

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The curious case of plutonium

29 Nov 2012

Plutonium colloids

Even 70 years after its discovery, the behaviour of plutonium still remains something of an enigma. Now Swedish researchers have discovered that plutonium colloids shrink with age becoming very small (3–4 atoms) with a shortening of the average Pu–O bond and Pu⋯Pu distances, consistent with partial oxidation having occurred.

Two types of colloidal materials were studied: high-fired crystalline PuO₂, and freshly prepared Pu(IV) colloids. The structures of both types were determined by EXAFS at the beginning of the experiment and after controlled aging of up to five years. The results show that even freshly prepared Pu(IV) colloids are polynuclear nano clusters with PuO₂ structure, bringing new insight into the evolution of plutonium with time.

Hybrid nanotubes for high performance Li ion batteries

26 Nov 2012

Commercial Lithium ion batteries (LIBs) usually contain graphitic anode materials but their relatively low capacity means that they can’t be used for high capacity storage applications such as electric vehicles and aerospace transport. Alternative anode materials with higher specific capacities have been studied such as metal oxides and metal sulfides. One dimensional structured metal sulfides in particular have received significant research interest but during charge–discharge experiments, the metal sulfides suffer from volume expansion, limiting their cycling performance.

To overcome this issue, researchers have tried combining metal sulfides and conductive carbon based materials. With this in mind, Yaunzhe Piao and team have successfully made a 1D structured carbon nanotube – MoS₂ (CNTs-MoS₂) hybrid nanomaterial using an environmentally friendly synthetic procedure. The synthesis did not require any surfactants or harmful solvents but used a hydrothermal method with the amino acid, L-cysteine which helped the MoS₂ nanosheets to bind to the CNTs.

The hybrid material has a higher specific capacity than just MoS₂ or CNTs and even has a high specific capacity after 30 charge–discharge cycles. The synthetic approach towards MoS₂-CNTs could be applied to other metal sulfides to explore their electrochemical properties.

To find out more about the electrochemical properties of the new CNT-MoS₂,download the Dalton Transactions article now…

A simple L-cysteine-assisted method for the growth of MoS₂ nanosheets on carbon nanotubes for high-performance lithium ion batteries

Seung-Keun Park, Seung-Ho Yu, Seung-Hee Woo, Bo Quan, Dong-Chan Lee, Min Kun Kim, Yung-Eun Sung and Yuanzhe Piao

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Photoluminescent DNA binder

20 Nov 2012

Upon DNA binding, a 15-fold turn-on in emission intensity occurs.

Stephen Lippard and colleagues at Massachusetts Institute of Technology have synthesised and characterised a platinum(II) complex bearing the tetradentate, β-diketiminate ligand ([Pt(BDIQQ)]Cl). Cytotoxic studies showed [Pt(BDIQQ)]Cl to have similar potency to cisplatin on cervical cancer (HeLa) cells, whereas on human lung carcinoma (A549) cells [Pt(BDIQQ)]Cl was four times more potent than cisplatin. The complex elicits a strong photoluminescent turn-on response upon DNA binding and it is hoped this will be useful for further cellular imaging studies.

Read the article now to find out more…

Photoluminescent DNA binding and cytotoxic activity of a platinum(II) complex bearing a tetradentate β-diketiminate ligand
Jennifer M. Hope, Justin J. Wilson and Stephen J. Lippard
Dalton Trans., 2013
DOI: 10.1039/C2DT32462H, Communication

Other Dalton Transactions articles by this author include:

A C2-symmetric, basic Fe(III) carboxylate complex derived from a novel triptycene-based chelating carboxylate ligand
Yang Li, Justin J. Wilson, Loi H. Do, Ulf-Peter Apfel and Stephen J. Lippard
Dalton Trans., 2012,41, 9272-9275
DOI: 10.1039/C2DT31260C, Communication

Non-traditional platinum compounds for improved accumulation, oral bioavailability, and tumor targeting
Katherine S. Lovejoy and Stephen J. Lippard
Dalton Trans., 2009, 10651-10659
DOI: 10.1039/B913896J, Perspective
From themed issue Metal anticancer compounds

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New antibiotic with reduced risk of future bacterial resistance

19 Nov 2012

Biofilm growth of the bacteria, P. aeruginosa, is responsible for many chronic infections in patients and presents a major challenge for the medical industry since these bacteria are largely resistant to antibiotics, disinfectants and patients’ natural immune defences.

UK scientists have developed a new antibiotic based on gallium metal ions complexed with cellulose which effectively displays antibacterial activity against biofilms of P.aeroginosa. Risk of future resistance to these antibiotics is also reduced as they work by an entirely different mechanism to traditional antibiotics.

A disc diffusion assay shows the inhibitory action of the gallium-carboxymethyl cellulose on P.aeroginosa. The white arrow shows the spherical transparent inhibition zone.

This article is particularly topical considering recent UK news headlines on antibiotic resistance. Download the article now…

Effect of Novel Antibacterial Gallium-Carboxymethyl Cellulose on Pseudomonas aeruginosa
Sabeel P Valappil, Humphrey H.P. Yiu, Laurent Bouffier, Christopher Keith Hope, Gary Evans, John B Claridge, Susan M Higham and Matthew J Rosseinsky

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Ruthenium catalyst for cancer treatment

19 Nov 2012

Scientists from Germany have designed a new complex which inhibits enzymes and reduces tumour cell growth.

The drug complex consists of N-heterocyclic carbene ligands coordinated to a ruthenium metal centre. Ruthenium N-heterocyclic carbene compounds are largely popular due to their catalytic properties but very little attention has been paid to the biological activity of these species.

Why not download the article now to find out what the team did…?

Evaluation of arene ruthenium(II) N-heterocyclic carbene complexes as organometallics interacting with thiol and selenol containing biomolecules
Luciano Oehninger, Maria Stefanopoulou, Hamed Alborzinia, Julia Schur, Stephanie Ludewig, Kazuhiko Namikawa, Alvaro Muñoz-Castro, Reinhard W. Köster, Knut Baumann, Stefan Wölfl, William S. Sheldrick and Ingo Ott

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Homo- and heterogeneous photocatalytic water reduction

14 Nov 2012

With TONs up to 9000 H₂/Co this Hot Communication by Peter Hamm and Roger Alberto et al. is worth a read.

The team have developed a stable, water reducing catalyst which operates under acidic conditions and indicates poly-pyridyl ligand frameworks are superior to some of the other commonly used chelators. They also show the cobalt complex retains catalytic activity when resin bound, meaning it is active as both a homogeneous and heterogeneous catalyst. For full details download the article below.

A highly stable polypyridyl-based cobalt catalyst for homo- and heterogeneous photocatalytic water reduction
Miguel Guttentag, Alexander Rodenberg, Cyril Bachmann, Anna Senn, Peter Hamm and Roger Alberto
Dalton Trans., 2012, Advance Article

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International Symposium on Organometallic Chemistry (ISOMC) 2012

09 Nov 2012

The seventh International Symposium on Organometallic Chemistry (ISOMC 2012) was held at Seoul National University in Korea between 1^st and 3^rd November, attended by Dalton Transactions Editorial Board Chairman, Professor Philip Mountford and New Journal of Chemistry associate editor Professor Peter Junk. Eighteen stimulating lectures were given by a range of established and emerging scientists from academia and industry, representing seven different countries. The poster prize was sponsored by Dalton Transactions and was awarded to Keishi Yamamoto from Professor Kazushi Mashima’s laboratory at Osaka University, Japan. The title of the poster was “Synthesis and structures of iminopyrrolyl and amidopyrrolyl complexes of Group 2 metals”.


Philip Mountford and Keishi Yamamoto	Delegates at the International Symposium on Organometallic Chemistry (ISOMC 2012)

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Diphosphine ligand stabilisation of onion-like RuPt nanoparticles

30 Oct 2012

The catalytic potential of metal nanoparticles is widely understood and some are already used for heterogeneous catalysis. In a dedication to Professor Cole-Hamilton, Karine Philippot and Bruno Chaudret et al. report the synthesis and characterisation of uniquely stabilised RuPt nanoparticles.

A diphenylphospine was used to stabilise bimetallic RuPt nanoparticles, both decorating them and affecting their chemical composition. Neither an ordered alloy nor a core-shell structure was produced; instead, as proven by scattering and spectroscopic techniques, very disordered nanoparticles with Ru cores and alloy shells were observed. The mechanism that produces such an “onion” structure is thought to involve the reaction of the diphosphine ligands with Ru at the beginning of the reaction.

The use of reactive ligands in the synthesis of bimetallic nanoparticles can modify their structure, suggesting the possibility of finely tailoring the structure and surface of such nanoparticles in the future. These modifications have already shown promise, with CO poisoning of RuPt nanoparticles having much less of an effect on hydrogenation reactions than with analagous pure Ru examples.

To find out more about these new bimetallic nanoparticles, download this HOT article now.

On the influence of diphosphine ligands on the chemical order in small RuPt nanoparticles: combined structural and surface reactivity studies
Patricia Lara, Tuğçe Ayvalı, Marie-José Casanove, Pierre Lecante, Alvaro Mayoral, Pier-Francesco Fazzini, Karine Philippot and Bruno Chaudret

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Organic radicals in a self-assembled grid

26 Oct 2012

Konstantin Shuvaev, Annie K. Powell and colleagues have designed a ligand containing the nitronyl nitroxide radical. The ligand can self-assemble with copper(II) ions to give a [2 x 2] grid complex.

The nitronyl nitroxide radical coordinated via the oxo-atom of the N+-O- fragment in a chelating fashion and lies in the equatorial plane of the metal ion.

The high reactivity of organic radicals makes them difficult to use but the nitronyl nitroxide radical is one of the most stable and so can be used in the design of paramagnetic polytopic ligands as building blocks for supramolecular grids. Most previous supramolecular grids have been made using diamagnetic ligands but the team found that being able to use a paramagnetic ligand resulted in a grid with interesting spin coupling and magnetic properties.

Dalton Transactions Blog