Archive for the ‘Hot Articles’ Category

Hot Perspective: Shedding light on the oxygen-evolving-complex

Can we mimic the Photosystem II machinery for light-driven oxidation of water to molecular oxygen?

Can we mimic the Photosystem II machinery for light-driven oxidation of water to molecular oxygen?

In this Dalton Transactions Perspective, Philipp Kurz and colleagues discuss manganese-containing compounds that have been studied as potential analogues of the oxygen-evolving-complex in Photosystem II.  They highlight how the desire to produce solar fuels is inspiring research into artificial photosynthesis.

Read more for free until 29th November at:

Water oxidation catalysed by manganese compounds: from complexes to ‘biomimetic rocks’
Mathias Wiechen, Hans-Martin Berends and Philipp Kurz
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11537E, Perspective

You might also find these Dalton Trans. articles on biomimetic water-oxidation catalysis interesting…

Nano-size amorphous calcium–manganese oxide as an efficient and biomimetic water oxidizing catalyst for artificial photosynthesis: back to manganese
Mohammad Mahdi Najafpour, Sara Nayeri and Babak Pashaei
Dalton Trans., 2011, 40, 9374-9378
DOI: 10.1039/C1DT11048A

High turnover catalysis of water oxidation by Mn(II) complexes of monoanionic pentadentate ligands
Rune Kirk Seidler-Egdal, Anne Nielsen, Andrew D. Bond, Morten J. Bjerrum and Christine J. McKenzie
Dalton Trans., 2011, 40, 3849-3858
DOI: 10.1039/C0DT01340D

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HOT Article: Fine tuning of catalyst performance

Transition metal complexes bearing functional P,N-type ligands attract much attention because they combine hard nitrogen donor(s) and soft phosphorus donor(s) and offer considerable chemical and structural diversity. In this HOT Article,  Braunstein et al. report several palladium/cobalt and nickel complexes with phosphino-oxazoline ligands. Some of the nickel complexes were further checked for their ethylene reactivity, and showed activity for ethylene non-selective oligomerization. Interestingly, a reversible interconversion transform phenomena was observed between a couple of the isomeric Ni-complexes with variation of the solvent between CH2Cl2 and CHCl3.
The role of functional bidentate ligands in catalysis provides a versatile tool for fine tuning the performance of catalysts (Lewis base – Lewis acid interactions).

Read more for FREE until 29th November at:
A phosphino-oxazoline ligand as a P,N-bridge in palladium/cobalt or P,N-chelate in nickel complexes: catalytic ethylene oligomerization
Shuanming Zhang, Roberto Pattacini, Suyun Jie and Pierre Braunstein
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT11352F

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Traffic light signals for biolabelling

Luminescent iridium complex surfactants form spherical aggregates in water, changing from red to green on aggregation, scientists from Germany and Italy have discovered.
The team, led by Luisa De Cola, say that the aggregates have different properties to the single components, and that the change between them could enable this system to be used as a probe for bio-imaging and bio-labelling. Read more in their Hot Article – free to access until the 29th November 2011.

Aggregation induced colour change for phosphorescent iridium(III) complex-based anionic surfactants
Matteo Mauro, Gabriele De Paoli, Matthias Otter, Daniela Donghi, Giuseppe D’Alfonso and Luisa De Cola
Dalton Trans., 2011, DOI: 10.1039/C1DT11251A

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HOT Article: Figures of eight

Braunstein and co-workers have formed a dinuclear Ir(I) complex with a bis-NHC ligand in situ from
1,1′-((4,6-dimethyl-1,3-phenylene)bis(methylene))bis(3-methyl-1H-imidazol-3-ium) in
the presence of Cs2CO3 and [Ir(µ-Cl)(cod)]2. Its solid-state structure, determined by X-ray
diffraction, shows a figure-of-eight loop with both the P and M enantiomers being present. Solution NMR studies were also performed to examine the enantiodiscrimination between them.

Read more for FREE until the 29th November 2011 at:

Chiral anion-based NMR enantiodiscrimination of a dinuclear, cationic Ir(I) NHC complex with a figure-of-eight loop structure
Xianghao Liu, Jérôme Lacour and Pierre Braunstein
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11604E

Also read about the formation of unprecedented eight-membered chelates at:

Contrasting bonding modes of a tridentate bis(oxazoline)phosphine ligand in cobalt and iron vs. palladium complexes: unprecedented N,N-coordination for a N,P,N ligand
Anthony Kermagoret and Pierre Braunstein
Dalton Trans., 2008, 585-587
DOI: 10.1039/B717021C

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HOT Article: Ionic liquids in biphasic catalysis

Oelkers and Sundermeyer, in this HOT Article, present a general approach towards 1,4-diazabutadiene (DADS) ligands with various onium cations via acid–base reactions and towards their noble-metal complexes. The solubility and immobilization of such complexes in ILs is quantitatively shown via photometric measurements using a chromophoric Mo(0) DADS complex in a toluene/[BMIM]OTf biphasic mixture as a model system. It was shown that complexes with ionic liquid (IL) – typical onium salts of sulfonated diazadienes as ligands are strongly retained in an IL phase in contact with a toluene phase, which may make these ligands potentially useful in IL/organic biphasic catalysis.

Read more for FREE until mid-November:

Sulfonate-tagged 1,4-diazabutadiene (DADS) ligands and their noble-metal complexes – synthesis, characterization and immobilization in ionic liquids
Benjamin Oelkers and Jörg Sundermeyer
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10939A

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HOT Article: True gold

In this HOT Article, US researchers have presented an in depth reactivity study of alkynylgold species and phosphonates. As protodeauration is the main terminating step in gold catalysis, the effect of labile P–H bonds will be of interest to those studying gold catalysis, as well as those studying phosphite chemistry.

Read more about these gold complexes for FREE until mid-November at:

P–H activation using alkynylgold substrates: steric and electronic effects

Gerald F. Manbeck, Mark C. Kohler, Meghan R. Porter and Robert A. Stockland Jr.
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT11337B

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Photocrystallography provides isomeric answers

Mike George, Paul Raithby and co-workers using photocrystallography to identify isomers in a nickel complex. Photocrystallography allows the groups to study metastable linkage isomers and they have shown that the technique provides scope for the identification of new species.

Photocrystallography involves the photo-activation of species within a crystalline lattice. It brings a dynamic aspect to X-ray crystallographic experiments, so that reactions within a crystal can be monitored as they occur or the structures of molecules in metastable or short-lived photo-activated states can be determined. Read more about the group’s findings in their Dalton Transactions Hot Article:

Photocrystallographic identification of metastable nitrito linkage isomers in a series of nickel(II) complexes
Simon K. Brayshaw, Timothy L. Easun, Michael W. George, Alexandra M. E. Griffin, Andrew L. Johnson, Paul R. Raithby, Teresa L. Savarese, Stefanie Schiffers, John E. Warren, Mark R. Warren and Simon J. Teat
Dalton Trans., 2011, DOI: 10.1039/C1DT11379H

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Hot Article: Very Vanadium

Phalguni Chaudhuri and colleagues, from the Max-Planck-Institut in Mulheim, Germany, investigate the interactions between a potentially tetradentate tripodal ligand and the biologically important metal, Vanadium. What were the resulting complexes? Find out in  their Hot Article – FREE to read until mid November.

Non-oxo 5-coordinate and 6-coordinate vanadium(IV) complexes with their precursor [LVIII(CH3OH)]0, where L = a trianionic aminetris(phenolate)-[N,O,O,O] donor ligand: a magnetostructural and EPR study
Takashi Kajiwara, Rita Wagner, Eckhard Bill, Thomas Weyhermüller and Phalguni Chaudhuri
Dalton Trans., 2011, DOI: 10.1039/C1DT11277E

 

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Hot Article: Chirality effects on star-burst complexes

In their Dalton Trans. Hot Article, a group of Japanese chemists led by Hisako Sato, used vibrational circular dichroism (VCD) spectroscopy to study the stereochemical properties of a star-burst type tetranuclear Ru(III) complex. By comparing the VCD spectra of eight diastereomeric enantiomers, they were able to see the homo- or hetero-chiral nature of the bridging part of the compound which connected the central core and the peripheral region

Chirality effects on core-periphery connection in a star-burst type tetranuclear Ru(III) complex: application of vibrational circular dichroism spectroscopy
Hisako Sato, Fumi Sato, Masahiro Taniguchi and Akihiko Yamagishi
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11510C

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HOT Article: Forbidden compositions?

This HOT article by Mukherjee et al. reports the synthesis, structure, magnetic properties and DFT studies of four Cu(II)-azide polymers. Cu(II)-azide polymers are presently  being studied by many groups due to their interesting structural variation and magnetic properties. In this paper, three out of the four compounds studied are of new structural topologies.  All four complexes exhibit an overall ferromagnetic behaviour; the magnetic results are corroborated by DFT studies. The structural analysis shows how a simple change in the structure of the blocking ligand can generate entirely different structures and magnetic properties, even though the basic structures seems to be almost identical. It is also shown that another blocking diamine does not produce similar complexes under the same reaction conditions, which leads to the question: are certain compositions forbidden?

Read more about forbidden compositions and magnetic behaviour for FREE until the 2nd November at:
CuII-azide polymers with various molar equivalents of blocking diamine ligands: synthesis, structures, magnetic properties with DFT studies
Sandip Mukherjee, Yogesh P. Patil and Partha Sarathi Mukherjee
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT11312G

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