Fiona McKenzie, Executive Editor – Page 2

Author Archive

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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CNC pincer ligand catalyst

18 Oct 2012

Scientists in Mexico and Spain have synthesised a ruthenium complex using a N-heterocyclic CNC pincer ligand.

Lutidine-derived pincer complexes are well established amongst organometallic chemists. More traditionally, the pincer ligand motif, PNX has been utilised (where P is a phosphine and X is either a phosphine or N donor ligand) but substitution of phosphines with stronger electron-donating N-heterocyclic carbenes has meant that more active catalytic species have been made for promoting hydrogenation of non-active esters. Mostly speaking, these ligands follow a CNN coordination pattern. According to the researchers, the only CNC pincer complex reported coordinates to the ruthenium centre in a mer geometry.

In their latest Dalton Transactions Communication, the team report on the synthesis of a CNC ligand which coordinates to ruthenium in an usual fac mode. They proved that the resultant complex can be used to catalyse the hydrogenation of imines by firstly deprotonating one of the ligand methylene bridges.

To read more about this development, read the full article now…

Hydrogenation of imines catalysed by ruthenium(II) complexes based on lutidine-derived CNC pincer ligands
Martín Hernández-Juárez, Mónica Vaquero, Eleuterio Álvarez, Verónica Salazar and Andrés Suárez
Dalton Trans., 2012, Advance Article

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Mononuclear Pacmans

09 Oct 2012

As Jason Love described in his 2009 ChemComm Feature Article, pyrrole-based macrocycles are ideal ligands for creating pre-organised metal binding sites to enable the multielectron redox chemistry so required for transforming small molecules such as O₂, carbon dioxide and water.

Here in their latest Dalton Transactions article, Love and colleagues take this a step further.

The team note how their previous attempts to make mononuclear transition metal complexes with the donor ligands were unsuccessful. Despite significant efforts, they could only make bimetallic complexes – well, until now that is…

The newest set of ligands now incorporate N₄^¬with either O₅ or ONO donors which are separated through aryl spacers. Upon binding of a singular metal atom, the complexes fold to form a Pacman-like cleft structure. Love and colleagues expect the structure to play host to guest molecules which can benefit from metal coordination as well as hydrogen bonding interactions to the oxygen and nitrogen atom acceptors.

To read more, download the article now…

Synthesis and structures of transition metal pacman complexes of heteroditopic Schiff-base pyrrole macrocycles
James W. Leeland, Colin Finn, Bérengère Escuyer, Hiroyuki Kawaguchi, Gary S. Nichol, Alexandra M. Z. Slawin and Jason B. Love

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Studying hydrogen activation of FLPs

04 Oct 2012

Scientists from Pacific Northwest National Laboratory have investigated the mechanism of heterolytic H₂ activation by frustrated lewis pairs (FLPs). To do this, they employed an unique approach of solution calorimetry and were able to obtain the enthalpies and relative rates of H₂ activation.

With the exception of previous studies that partly relied on theoretical calculations, there has not been a great deal of work devoted to understanding how molecular hydrogen is activated by FLPs. Autrey and colleagues have found that H₂ activation rates using such species are relatively fast considering no metals are involved. They discovered that the rate was dependent on the structure of the Lewis basic amine involved, and that diffusion of hydrogen across the gas-liquid interface is not rate limiting.

Further work is needed to extract fundamental rate constants, kinetic orders, and activation barriers, say the researchers.

Read the article now to find out more…
A thermodynamic and kinetic study of the heterolytic activation of hydrogen by frustrated borane–amine Lewis pairs
Abhi Karkamkar, Kshitij Parab, Donald M. Camaioni, Doinita Neiner, Herman Cho, Thomas K. Nielsen and Tom Autrey

This article is part of an upcoming themed issue on Boranes and Borohydrides, guest edited by Simon Aldridge. Other articles by this author include:

Methods to stabilize and destabilize ammonium borohydride
Thomas K. Nielsen, Abhi Karkamkar, Mark Bowden, Flemming Besenbacher, Torben R. Jensen and Tom Autrey

Also of interest… Take a look at our recent themed issue in Frustrated Lewis Pairs

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No stone left unturned at Dalton Discussion 13

20 Sep 2012

This year’s Dalton Discussion meeting was based at the University of Sheffield and focused on the topic of Inorganic Photophysics and Photochemistry – Fundamentals and Applications.

The 3 day programme was rich with contributions from Keynote speakers, Richard Eisenberg, Majed Chergui, Peter Ford and Luisa De Cola; Invited speakers, Craig Hill, David Parker, and Chantal Daniel; amongst numerous other excellent presenations from researchers across the international community.


Majed Chergui and Andrea Barbieri	Richard Eisenberg	Craig Hill

The Dalton Discussion format differs slightly from other conferences in that speakers are alloted short 5-10 minute slots to deliver a snappy overview of their latest research based on the contents of their article which will shortly be published in a themed issue of Dalton Transactions.

For every 3 presentations, there follows an hour long discussion amongst the delegates – an excellent opportunity for researchers to get down to the gritty detail of the experiments, understand any tricky concepts, and offer alternative ideas to take the research forward. It was great to see even the graduate students asking questions – something that is sadly, rarely seen at conferences.

The poster sessions were also of great success. Many congratulations to Sven Hansen, Elizabeth Bagaley and Lucy Jones who won the Dalton Transactions, ChemComm and RSC Books poster prizes, respectively.


Otto Horvath in conversation with Peter Burks, student of Peter Ford at UCSB	From left to right: Lucy Jones (University of Manchester), Sven Hansen (Rostock University), Elizabeth Baggaley (University of Sheffield).	No conference is complete without networking at the welcome reception

I am already very much looking forward to what next year’s Dalton Discussion meeting has to offer – which will be adopting a new and improved format for article submission. Watch this space…

Many thanks go to Mike Ward for providing photographs and also for organising such an excellent meeting!

Also of interest…
See here for the RSC’s report on Solar Fuels and Artificial Photosynthesis: Science and innovation to change our future energy options

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New Routes to Versatile Thorium(IV) Precursors

20 Sep 2012

Anhydrous metal halides and their soluble Lewis base-adduct relatives are ubiquitous starting materials in inorganic and organometallic chemistry, serving as extremely versatile precursors to myriad derivatives. As a result, reliable and straight-forward protocols for accessing such species allow researchers to deploy their carefully crafted ligands and explore unexpected reactivity, as well as fully unveil the richness of previously reported systems.

Indeed, only a handful of thorium(IV) halide starting materials are commonly utilized, and as thorium turnings are becoming increasingly hard to come by, new routes to anhydrous thorium(IV) halides from available thorium(IV) salts are crucial. Jaqueline Kiplinger and co-workers have recently reported a facile synthesis of ThI₄(dme)₂and have demonstrated its keen ability to be derivatized. As molecular actinide iodide complexes have been shown to offer markedly differing reactivities from their chloride counterparts, this contribution may allow for yet unseen reactivity at Th(IV) centres, and maybe even provide less tumultuous access to the exceptionally rare Th(III) oxidation state.

Check out the full article to read more about this new precursor and related complexes:

Thorium-mediated ring-opening of tetrahydrofuran and the development of a new thorium starting material: preparation and chemistry of ThI₄(DME)₂
Nicholas Travia, Marisa Monreal, Brian Scott and Jaqueline Kiplinger,
Dalton Transactions, 2012

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Ball milling oxides

09 Aug 2012

Mechanochemistry has been used for centuries – according to some, as early as 371 B.C. The pestle and mortar still has a place in many chemistry labs but nowadays mechanically-induced chemistry is performed with the help of a high-energy ball mill.

In their latest Dalton Transactions Perspective, Vladimir Šepelák, Sylvie Bégin-Colin and Gérard Le Caër describe how ball milling is used to effect transformations in oxides. Whilst understanding of the mechanochemical processes involved in ball-milling metalllic compounds is growing, for the more-complex oxide materials, the field is still relatively immature.

The authors explain the various uses of ball milling oxides which can be grouped into either homogeneous or heterogeneous processes (determined by whether there is a net exchange of atoms across boundaries or not). Homogeneous processes encompass polymorphic transformations and titania phase transformations; heterogeneous processes involve compound formations, decompositions and redox reactions.

To read more about the interesting nanocrystalline characteristics that ball milling offers, read the Perspective article now.

Transformations in oxides induced by high-energy ball-milling
Vladimir Šepelák, Sylvie Bégin-Colin and Gérard Le Caër

Interested in other mechanochemistry articles? Read the growing number of articles being added to the ChemComm web theme in mechanochemistry – guest edited by Stuart James and Tomislav Friščić.

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Frustrated Lewis pairs themed issue now published

20 Jul 2012

We strongly recommend you have a browse of Dalton Transactions’ latest themed issue in Frustrated Lewis Pairs.

As Guest Editor, Doug Stephan says in his Editorial: there’s nothing frustrating about frustrated Lewis pairs! Particularly as these highly reactive compounds are gaining increasing attention from researchers wishing to activate dihydrogen, olefins, disulfides, CO₂… the list continues…

The issue contains 18 articles dedicated to the topic – a small selection is below:

Hydrogen activation by 2-boryl-N,N-dialkylanilines: a revision of Piers’ ansa-aminoborane
Konstantin Chernichenko, Martin Nieger, Markku Leskelä and Timo Repo

Frustrated Lewis pair addition to conjugated diynes: Formation of zwitterionic 1,2,3-butatriene derivatives
Philipp Feldhaus, Birgitta Schirmer, Birgit Wibbeling, Constantin G. Daniliuc, Roland Fröhlich, Stefan Grimme, Gerald Kehr and Gerhard Erker

Fixation of carbon dioxide and related small molecules by a bifunctional frustrated pyrazolylborane Lewis pair
Eileen Theuergarten, Janin Schlösser, Danny Schlüns, Matthias Freytag, Constantin G. Daniliuc, Peter G. Jones and Matthias Tamm

Access the issue here

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Articles from around the world: Korea

06 Jul 2012

This month we are highlighting some of the excellent articles published in Dalton Transactions from South Korea.

Click on the links below to download the articles…

A double-walled triangular metal-organic macrocycle based on a [Cu₂(COO)₄] square paddle-wheel secondary building unit
Xiaokai Song, Xinfang Liu, Minhak Oh and Myoung Soo Lah
Dalton. Trans., 2010, 39, 6178–6180

Preparation and characterisation of divalent hard and soft metal (M = Ca, Co, Cu, Zn, Cd, Hg and Pb) complexes of 1,10-dithia-18-crown-6: structural versatility
In-Hyeok Park, Ki-Min Park and Shim Sung Lee
Dalton Trans., 2010, 39, 9696–9704

Self-assembled molecular squares containing metal-based donor: synthesis and application in the sensing of nitro-aromatics
Vaishali Vajpayee, Hyunuk Kim, Anurag Mishra, Partha Sarathi Mukherjee, Peter J. Stang, Min Hyung Lee, Hwan Kyu Kim and Ki-Whan Chi
Dalton Trans., 2011,40, 3112–3115

Two-dimensional metal–organic frameworks with blue luminescence
Seong Huh, Suhyun Jung, Youngmee Kim, Sung-Jin Kim and Seongsoon Park
Dalton Trans., 2010, 39, 1261–1265

Canted antiferromagnetism and spin reorientation transition in layered inorganic–organic perovskite (C₆H₅CH₂CH₂NH₃)₂MnCl₄Seong-Hun Park, In-Hwan Oh, Sungil Park, Younbong Park, Ji Hyun Kim and Young-Duk Huh
Dalton Trans., 2012, 41, 1237–1242

Self-assembled metalla-bowls for selective sensing of multi-carboxylate anions
Anurag Mishra, Vaishali Vajpayee, Hyunuk Kim, Min Hyung Lee, Hyunji Jung, Ming Wang, Peter J. Stang and Ki-Whan Chi
Dalton Trans., 2012, 41, 1195–1201

Anion variation on a cobalt(III) complex of salen-type ligand tethered by four quaternary ammonium salts for CO₂/epoxide copolymerization
Jina Yoo, Sung Jae Na, Hyeong Cheol Park, Anish Cyriac and Bun Yeoul Lee
Dalton Trans., 2010, 39, 2622–2630

Why not check out last year’s New Talent: Asia themed issue for more articles from Korea and beyond?

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