Archive for September, 2012

Group 4 tetracarbamato complexes for lactide polymerization

Ever since Ziegler and Natta’s 1950s discovery of TiCl4 as a catalytic precursor for alkene polymerization, interest in similar compounds with potentially superior properties has soared.

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Marchetti et al. have reported a number of group 4 N,N-dialkylcarbamato complexes alongside their catalytic properties with regard to the ring opening polymerization of rac-lactide. They have also studied their polymerization mechanisms in great detail, concluding that the first stage of the polymerization reaction proceeds through different pathways for the Ti, Zr and Hf analogues, explaining the observed differences in activity. All pathways produce a vacant metal site, which is required for further propagation.

Read more about these new group 4 tetracarbamates and their application as catalytic precursors for the polymerization of rac-lactide in this HOT article.

Ring opening polymerization of rac-lactide by group 4 tetracarbamato complexes: activation, propagation and role of the metal
Fabio Marchetti, Guido Pampaloni, Calogero Pinzino, Filippo Renili, Timo Repo and Sirpa Vuorinen

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Ammonium borohydride – a promising hydrogen storage material?

Stabilization and destabilization of ammonium borohydrideHydrogen has been investigated for some time as a possible renewable energy source but its practical application has been limited by storage problems.   In this HOT article, Tom Autrey and co-workers have studied the stabilisation and destabilisation of ammonium borohydride with a view to its use as a promising hydrogen storage material.  The results suggest that ammonium borohydride could be stabilized by high pressure hydrogen or inert gas.

Read more for FREE at:

Methods to stabilize and destabilize ammonium borohydride
Thomas K. Nielsen, Abhi Karkamkar, Mark Bowden, Flemming Besenbacher, Torben R. Jensen and Tom Autrey
Dalton Trans., 2013, Advance Article
DOI: 10.1039/C2DT31591B

Also of interest may be…

3-Methyl-1,2-BN-cyclopentane: a promising H2 storage material?
Wei Luo, Doinita Neiner, Abhi Karkamkar, Kshitij Parab, Edward B. Garner III, David A. Dixon, Dean Matson, Tom Autrey and Shih-Yuan Liu
Dalton Trans., 2013, Advance Article
DOI: 10.1039/C2DT31617J, Communication

The diammoniate of diborane: crystal structure and hydrogen release
Mark Bowden, David J. Heldebrant, Abhi Karkamkar, Thomas Proffen, Gregory K. Schenter and Tom Autrey
Chem. Commun., 2010, 46, 8564-8566
DOI: 10.1039/C0CC03249B, Communication

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Hybrid polyoxometalate

Trapping {BW12}2 tungstoborateKorenev and colleagues present a new hybrid polyoxometalate in this HOT Dalton Transactions Communication. 

The search is on to enhance the structural diversity of POMs and one approach to this is to “hybridise” — a POM structure can be designed to also include a stable polynuclear unit. Several POM structures containing oxothiocations have been synthesised with this in mind, yielding structures with both hard and soft coordination centres.

Korenev and team have used this approach to synthesis a unique architecture that consists of two tungstoborate subunits which are linked with a hexamolybdate “handle” (shown in pink).

To find out more, you can download the Communication now – which is free to access for 4 weeks!

Trapping {BW12}2 tungstoborate: synthesis and crystal structure of hybrid [{(H2BW12O42)2O}{Mo6O6S6(OH)4(H2O)2}]14− anion
V. S. Korenev, P. A. Abramov, C. Vicent, D. A. Mainichev, S. Floquet, E. Cadot, M. N. Sokolov and V. P. Fedin
Dalton Trans., 2012
DOI: 10.1039/C2DT31512B, Communication

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Ligand Effects on the Catalytic Activity of Ruthenium Nanoparticles

When metal nanoparticles are used as catalysts, they can have a tendency to aggregate. Especially when the metal nanoparticles (NPs) are not functionalized as there isn’t anything to oppose the Van der Waals forces. Aggregation or coalescence of the NPs can lead to a decrease in catalytic activity. Two strategies have been developed for stabilisation — addition of a ligand post NP synthesis or inclusion of a coordinating ligand into the cation of an ionic liquid (IL).

In a previous Dalton Transactions article, (Dalton Trans., 2011, 40, 4660–4668) the stability of ruthenium nanoparticles (RuNPs) was improved by the combination of ILs and stabilising ligands to produce a recyclable catalytic system for the hydrogenation of toluene. In this new article, Agilio Padua and colleagues have taken this one step further and  investigated the effect of various ligands on the catalytic activity of RuNPs in an IL.

RuNPs were prepared in an IL, and in the presence and absence of a series of different ligands. Padua and colleagues discover that the activity of RuNPs with respect to the catalytic hydrogenation of cyclohexadiene, styrene and limonene increased with σ-donor ligands (water and octylamine) but decreased with π-acceptor ligands (carbon monoxide,  phenylphosphine and diphenylphosphine). This paper demonstrates how RuNPs as catalysts are remarkably similar to homogenous catalysts in that their activity and selectivity can be controlled by σ-donor and π-acceptor ligands.

Download the full paper to find out more…

Ligand effect on the catalytic activity of ruthenium nanoparticles in ionic liquids
Santini Catherine, Paul S Campbell, Gorka Salas, Karine Philippot, Agilio A.H. Padua and Margarida Costa Gomes
Dalton Trans., 2012

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No stone left unturned at Dalton Discussion 13

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. 

DD13 Poster Prize winners
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

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)2 and 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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Top ten most accessed articles in July

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

Recent progress in the synthesis of inorganic nanoparticles 
C. N. R. Rao ,  H. S. S. Ramakrishna Matte ,  Rakesh Voggu and A. Govindaraj 
Dalton Trans., 2012,41, 5089-5120 DOI: 10.1039/C2DT12266A  

A one-dimensional coordination polymer constructed from planar pentanuclear copper(ii) clusters with a flexible tripodal ligand 
Qilong Zhu ,  Chaojun Shen ,  Chunhong Tan ,  Tianlu Sheng ,  Shengmin Hu and Xintao Wu  
Dalton Trans., 2012,41, 9604-9606 DOI: 10.1039/C2DT30912B 
 
Nothing frustrating about “Frustrated Lewis pairs” 
Douglas W. Stephan  
Dalton Trans., 2012,41, 9015-9015 DOI: 10.1039/C2DT90093A  

Pushing the frontiers in polyoxometalate and metal oxide cluster science 
De-Liang Long and Leroy Cronin  
Dalton Trans., 2012,41, 9815-9816 DOI: 10.1039/C2DT90121H  

Synthesis of facial cyclometalated iridium(iii) complexes triggered by tripodal ligands 
Toshiyuki Moriuchi ,  Lisheng Mao ,  Hsyueh-Liang Wu ,  Satoshi D. Ohmura ,  Masami Watanabe and Toshikazu Hirao  
Dalton Trans., 2012,41, 9519-9525 DOI: 10.1039/C2DT12309F  

Controlled association of single-molecule magnets (SMMs) into coordination networks: towards a new generation of magnetic materials 
Ie-Rang Jeon and Rodolphe Clérac  
Dalton Trans., 2012,41, 9569-9586 DOI: 10.1039/C2DT30906H  

Metal-directed assembly of chiral bis-Zn(ii) Schiff base structures 
Martha V. Escárcega-Bobadilla ,  Daniele Anselmo ,  Sander J. Wezenberg ,  Eduardo C. Escudero-Adán ,  Marta Martínez Belmonte ,  Eddy Martin and Arjan W. Kleij  
Dalton Trans., 2012,41, 9766-9772 DOI: 10.1039/C2DT30642E  

Cyclometalated ruthenium(ii) complexes with a bis-carbene CCC-pincer ligand 
You-Ming Zhang ,  Jiang-Yang Shao ,  Chang-Jiang Yao and Yu-Wu Zhong  
Dalton Trans., 2012,41, 9280-9282 DOI: 10.1039/C2DT31015E  

Enhanced stability and CO2 affinity of a UiO-66 type metal–organic framework decorated with dimethyl groups 
Yuting Huang ,  Weiping Qin ,  Zhong Li and Yingwei Li  
Dalton Trans., 2012,41, 9283-9285 DOI: 10.1039/C2DT30950E  

Post-modification of a MOF through a fluorescent-labeling technology for the selective sensing and adsorption of Ag+ in aqueous solution 
Lejie Zhang ,  Yuan Jian ,  Jian Wang ,  Cheng He ,  Xuezhao Li ,  Tao Liu and Chunying Duan  
Dalton Trans., 2012,41, 10153-10155 DOI: 10.1039/C2DT30689A  

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

Fancy submitting an article to Dalton Transactions ? Then why not submit to us today or alternatively email us your suggestions.

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The first Gold for Gold article has been published!

We are very pleased to announce that the first Gold for Gold open access article has been published in Dalton Transactions. The Gold for Gold initiative was recently launched and rewards UK RSC Gold subscribers with credits to publish their RSC articles via Open Science, the RSC’s Gold Open Access option. The article by Stephen J. Archibald et al. is free to download to all

CXCR4 chemokine receptor antagonists: nickel(II) complexes of configurationally restricted macrocycles
Rachel Smith , Dana Huskens, Dirk Daelemans, Ryan E. Mewis, Courtney D. Garcia, Amy N. Cain, TaRynn N. Carder Freeman, Christophe Pannecouque, Erik De Clercq, Dominique Schols, Timothy J. Hubin and Stephen J. Archibald
Dalton Trans., 2012, 41, 11369-11377
DOI: 10.1039/C2DT31137B 

More information on Gold for Gold is available on our website. If you have any further questions on the procedure, or are an interested customer from outside the UK, please contact us.

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From double-decker to quintuple-decker: single-molecule magnetic behaviour and f-f interactions

This Hot Article from Masahiro Yamashita and Keiichi Katoh investigates the interactions among the 4f electrons of some multiple-decker Tb3+ and Dy3+ complexes, revealing the importance of molecular symmetry and coordination geometry.

Multiple-decker phthalocyaninato dinuclear lanthanoid(III) single-molecule magnets with dual-magnetic relaxation processes

Correlation between the χM′′(T) peak blocking temperature and the distance between the two Tb(III) ions

Single molecule magnets (SMMs) exhibit superparamagnetism at the molecular scale and have potential application in quantum computing, information storage and magnetic refrigeration. Understanding the relationship between the local environment of complexes and their magnetic properties is important to develop new SMMs with desirable magnetic relaxation behaviours.

Download the paper to see the full details of the team’s discoveries

Multiple-decker phthalocyaninato dinuclear lanthanoid(III) single-molecule magnets with dual-magnetic relaxation processes
Keiichi Katoh, Yoji Horii, Nobuhiro Yasuda, Wolfgang Wernsdorfer, Koshiro Toriumi, Brian K. Breedlove and Masahiro Yamashita

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