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Archive for the ‘Hot Articles’ Category

Lewis Pair polymerization

18 Jun 2012

In this HOT article, Chen et al. extend their previous work to present a combined experimental and computational investigation of Lewis Pair polymerization incorporating 11 Lewis acids and 10 achiral and chiral Lewis bases, for the polymerization of 12 different types of monomers.

Read more about the polymerization mechanism for FREE for 4 weeks at:

Lewis pair polymerization by classical and frustrated Lewis pairs: acid, base and monomer scope and polymerization mechanism
Yuetao Zhang, Garret M. Miyake, Mallory G. John, Laura Falivene, Lucia Caporaso, Luigi Cavallo and Eugene Y.-X. Chen
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT30427A

This article will form part of a themed issue on Frustrated Lewis Pairs guest edited by Douglas W. Stephan. Other papers in this issue include:

Exchange chemistry of ^tBu₃P(CO₂)B(C₆F₅)₂Cl
Rebecca C. Neu, Gabriel Ménard and Douglas W. Stephan

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

[2.2]Paracyclophane derived bisphosphines for the activation of hydrogen by FLPs: application in domino hydrosilylation/hydrogenation of enones
Lutz Greb, Pascual Oña-Burgos, Adam Kubas, Florian C. Falk, Frank Breher, Karin Fink and Jan Paradies

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Theoretical study on proton relay at active site of nitogenase

31 May 2012

This HOT paper by Ian Dance, from the University of New South Wales, reports on the mechanism of proton relay in nitrogenase enzymes. The proton relay from the protein surface to a key sulfur atom of the FeMo-cofactor plays a core role in many of nitrogenase’s chemical mechanisms.

The water chain in nitrogenase is comparable with the purported proton pumping pathway of cytochrome c oxidase.

To read more about the detailed analysis of this mechanism you can download the full paper below…

The controlled relay of multiple protons required at the active site of nitrogenase
Ian Dance
Dalton Trans., 2012
DOI: 10.1039/C2DT30518F

Here are some of Ian Dance’s other recent Dalton Transactions publications:

Ramifications of C-centering rather than N-centering of the active site FeMo-co of the enzyme nitrogenase
Ian Dance
Dalton Trans., 2012,41, 4859-4865
DOI: 10.1039/C2DT00049K, Paper

Calculated vibrational frequencies for FeMo-co, the active site of nitrogenase, bearing hydrogen atoms and carbon monoxide
Ian Dance
Dalton Trans., 2011,40, 6480-6489
DOI: 10.1039/C1DT10505A, Paper

How does vanadium nitrogenase reduce CO to hydrocarbons?
Ian Dance
Dalton Trans., 2011,40, 5516-5527
DOI: 10.1039/C1DT10240K, Paper

Mimicking nitrogenase
Ian Dance
Dalton Trans., 2010,39, 2972-2983
DOI: 10.1039/B922606K, Perspective
From themed issue Bioinspired catalysis

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Hydrogenase Hydrogel

24 May 2012

The ability of hydrogenase enzymes to reversibly catalyse the reduction of protons to form molecular hydrogen (H₂) has attracted a great deal of research interest. Synthetic mimics of the hydrogenase active site could potentially replace expensive platinum catalysts in hydrogen fuel cells. Currently these mimics are significantly less efficient than the natural enzyme and they are oxygen sensitive. It is thought that by creating a stable peptide based enviroment around the mimic, the stability and efficiency could be improved.

Encapsulating a hydrogenase mimic into a hydrogel causes a restriction in isomerisation after photolysis

Researchers from the Hunt and Ulijn groups at the University of Strathclyde and the Pickett group from the University of East Anglia have successfully encapsulated a [FeFe]-hydrogenase active site mimic into a dipeptide based hydrogelator. Their research has shown that there is a stark difference in the behaviour of the active site mimic in the gel phase compared to the solution phase. Experiments show that the mimic is significantly more stable in the gel phase and is less senstive to water and UV light which could potentially help to improve catalytic activity.

To find out more, read the full Daltons Transactions article…

Encapsulating [FeFe]-hydrogenase model compounds in peptide hydrogels dramatically modifies stability and photochemistry
Pim Wilhelmus, Johannes Maria Frederix, Rafal Kania, Joseph A Wright , Dimitrios A Lamprou, Rein Ulijn, C J Pickett and Neil T Hunt.

This article is part of the upcoming Dalton Discussion themed issue on Inorganic Photophysics and Photochemistry – Fundamentals and Applications

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Helicate or catenate?

22 May 2012

The team expected the assembly to form a helicate rather than catenate structure

Predicting the structure of large self-assembled units can become very complicated very quickly. Yet it is important for the rational design of new structures to understand how they assemble so new arrangements can be designed, with functional and valuable properties.

This Hot Article from the Piguet group investigates whether a pyridyl-benzimidazole ligand forms a double stranded helicate or a catenated architecture. The thermodynamic approach used to investigate the structures throws up some interesting results.

Looking for the origin of the switch between coordination-captured helicates and catenates
Lilit Aboshyan-Sorgho, Martine Cantuel, Gérald Bernardinelli and Claude Piguet
DOI: 10.1039/C2DT30414G

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Thorium nanochemistry

15 May 2012

Although it has been known for some time that highly charged cations such as Th(IV) are susceptible to hydrolysis and subsequent polymerization, very little has been know about the exact nature of such polymeric species until now. Rothe et al. shed new light on this using a combination of X-ray absorption fine structure (XAFS) spectroscopy, high energy X-ray scattering (HEXS) measurements, and quantum chemical calculations to yield the most favourable structure as two Th(IV) dimers linked by a central Th(IV) cation through hydroxide bridges. This should have important implications in geology and waste reprocessing amongst others.

The solution structure of the Th(IV)-hydroxo pentamer

Read more for FREE for 4 weeks at:
Thorium nanochemistry: the solution structure of the Th(IV)–hydroxo pentamer
Clemens Walther, Jörg Rothe, Bernd Schimmelpfennig and Markus Fuss
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT30243H

Also of interest may be:
Infrared spectra and structures of the Th(OH)₂ and Th(OH)₄ molecules
Xuefeng Wang and Lester Andrews
Phys. Chem. Chem. Phys., 2005,7, 3834-3838
DOI: 10.1039/B509401A

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New hard/soft donor ligand and its effect on the structure and redox behaviour of uranium complexes

15 May 2012

David Emslie and colleagues from McMaster University describe the synthesis of a new rigid NSN-donor ligand as well as the preparation of uranium(IV) and uranium(III) complexes using this ligand and a previously prepared NON-donor ligand. A combination of cyclic voltammetry, DFT calculations and Atoms In Molecules calculations were used to compare U–SAR₂ and U–OAr₂ bonding and the results indicated increased covalency in U-SAR₂ bonds that is probably due to the short U-S distances and tight C-S-U angles in the complexes. This work will aid the advancement of approaches for lanthanide/actinide separation in nuclear fuel reprocessing as well as analytical actinide detection.

Rigid NON- and NSN-ligand complexes of tetravalent and trivalent uranium.

Download the full paper below which is being published as part of an upcoming Dalton Transactions special issue, New Talent: the Americas…

Rigid NON- and NSN-ligand complexes of tetravalent and trivalent uranium: comparison of U–OAr₂ and U–SAr₂ bonding
Balamurugan Vidjayacoumar, Sougandi Ilango, Matthew J. Ray, Terry Chu, Kristopher B. Kolpin, Nicholas R. Andreychuk, Carlos A. Cruz, David J. H. Emslie, Hilary A. Jenkins and James F. Britten
Dalton Trans., 2012
DOI: 10.1039/C2DT30247K

You may also find this 2010 Dalton Transactions themed issue on New horizons in organo-f-block chemistry interesting.

Remember you can keep up to date with all the latest news in inorganic chemistry by following us on twitter and signing up to our e-alert service.

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When 3nm is huge

10 May 2012

The packing structures of ionic crystals is an interesting field of study and this Hot Communication by Masaki Saito and Tomoji Ozeki is certainly no exception!

A Sr2+ salt of [MoVI72MoV60O372(CH3COO)30(H2O)72]42− exhibits a superposed kagome-lattice with huge channels whose diameters measure approximately 3.0 nm

Huge channels in a superposed kagome-lattice

The pair from the Ozeki Research Group have determined the crystal structures of a couple of interesting structures, one of which “exhibits a superposed kagome-lattice with huge channels whose diameters measure approximately 3.0 nm”.

To read more about these new compounds you can download the full paper below

Crystallization of a Keplerate-type polyoxometalate into a superposed kagome-lattice with huge channels
Masaki Saito and Tomoji Ozeki

You might also be interested in a few other papers on polyoxometalates, which along with this article will be published in our upcoming themed issue focusing on the topic.

Orientations of polyoxometalate anions on gold nanoparticles
Shelly Sharet, Ella Sandars, Yifeng Wang, Offer Zeiri, Alevtina Neyman, Louisa Meshi and Ira A. Weinstock

A co-crystal of polyoxometalates exhibiting single-molecule magnet behavior: the structural origin of a large magnetic anisotropy
Xikui Fang, Kendall McCallum, Harry D. Pratt III, Travis M. Anderson, Kevin Dennis and Marshall Luban

Want to keep up with inorganic chemistry? follow us @DaltonTrans

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Cryo-TEM reaveals POM-nanoparticle interactions

27 Apr 2012

Ira Weinstock and colleagues from Ben Gurion University of the Negev have used cryogenic transmission electron microscopy to evaluate the interactions of polyoxometallates of different dimensions and shapes with gold nanoparticles. The study revealed a “face-down” orientation of the Pressyler ion [NaP₅W₃₀O₁₁₀]^14–, and a “tilted” orientation for the Finke-Droege ion [P₄W₃₀Zn₄(H₂O)₂O₁₁₂]^16–, contributing to important ongoing studies on the design of functional-POM protected metal nanoparticles.

"Face-down" orientation of Pressyler ion maximises interactions between cluster anion and Au surface.

To read more, download the communication now – it’s free to access.

Orientations of polyoxometalate anions on gold nanoparticles
Shelly Sharet, Ella Sandars, Yifeng Wang, Offer Zeiri, Alevtina Neyman, Louisa Meshi and Ira A. Weinstock
Dalton Trans., 2012
DOI: 10.1039/C2DT30592E

The findings in the above HOT communication are due to be included in an upcoming themed issue on Polyoxometalates, guest edited by Leroy Cronin and Deliang Long.

Yifeng Wang and Ira Weinstock’s previous Dalton Transactions perspective might also be of interest….

Cation mediated self-assembly of inorganic cluster anion building blocks
Yifeng Wang and Ira A Weinstock
Dalton Trans., 2010, 39, 6143-6152
DOI: 10.1039/C0DT00166J

Are you following us on Twitter? @DaltonTrans

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Delivering cancer-combatting compounds

27 Apr 2012

Scientists from Switzerland have developed a cage-encapsulated ruthenium complex for killing cancer cells.

The multifunctional drug has several features providing it with it’s fantastic anti-cancer properties… 1) it’s ruthenium based instead of platinum (less toxic and has been shown to overcome certain resistance mechanisms induced by Pt); 2) the pyrenyl ligands can easily intercalate with the DNA base pairs; and 3) the metalla-cage bestows water-solubility on the drug therefore enabling it to be internalised within the cancerous cells.

Not only that, the pyrene moiety is fluorescent so the uptake of the drug into the cell can be recorded in action.

Read the HOT article by Bruno Therrien and team now…
Cellular delivery of pyrenyl-arene ruthenium complexes by a water-soluble arene ruthenium metalla-cage
Mona Anca Furrer, Frédéric Schmitt, Michaël Wiederkehr, Lucienne Juillerat-Jeanneret and Bruno Therrien

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Inducing hysteretic spin crossover in solution

23 Apr 2012

Devices that store information magnetically are widespread, from the old floppy disks to credit cards and hard disks. The evolution of computer technologies requires us to continually develop new materials to allow new devices to out-perform their predecessors, for some time molecular spin cross-over complexes have been excellent candidates for new magnetic storage media.

Could mononuclear complexes be the future of magnetic storgae media? Fe3+ organometallic magnetism magnetic storage media

Could mononuclear complexes in solution be the future of magnetic storage media?

This Hot Communication from Grace Morgan and colleagues details their developments in creating an Fe(III) complex which possesses magnetic hysteresis in solution. The authors note that spin cross over in some solid state materials is affected by polymorphism, counter ions and crystallisation solvents in the material. Find out more about the teams discoveries in solution by downloading their article while it is free…

Inducing hysteretic spin crossover in solution
Paulo N. Martinho, Yannick Ortin, Brendan Gildea, Claudio Gandolfi, George McKerr, Barry O’Hagan, Martin Albrecht and Grace G. Morgan
DOI: 10.1039/C2DT12036D

Remeber you can keep up to date with all the latest news in inorganic chemistry by following us on twitter and signing up to our e-alert service.

The following articles might also be of interest;

A magnetic iron(III) switch with controlled and adjustable thermal response for solution processing
Claudio Gandolfi, Grace G. Morgan and Martin Albrecht
DOI: 10.1039/C2DT12037B

Synthesis and self-assembly of spin-labile and redox-active manganese(III) complexes
Claudio Gandolfi, Tatiana Cotting, Paulo N. Martinho, Olha Sereda, Antonia Neels, Grace G. Morgan and Martin Albrecht
DOI: 10.1039/C0DT01222J

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