Dalton Transactions Blog

The presence of C–F bonds in organic compounds has a dramatic influence on their physical, chemical and biological properties.  Metal mediated reactions that result in C–F bond formation or C–F bond activation have attracted considerable attention as the demand for organofluorine compounds has increased. Metal-catalysed decarboxylative cross-coupling reactions using trifluoracetate as a cheap source of  introducing “CF₃” represents an attractive approach.  Until now, little has been known about the fragmentation mechanisms of metal trifluoracetates.   In this Dalton Transactions HOT article,  Rijs and O’Hair use a combination of gas-phase 3D quadrupole ion trap mass spectrometry experiments and density functional theory (DFT) calculations to examine the mechanism of thermal decomposition of fluorinated coinage metal carboxylates.  Synthetic chemists should be able to use these results to design new ways of incorporating CF₃ and F fragments using trifluoroacetate.

Read more for FREE until the 13th March 2012 at:

Forming trifluoromethylmetallates: competition between decarboxylation and C–F bond activation of group 11 trifluoroacetate complexes, [CF₃CO₂ML]^–
Nicole J. Rijs and Richard A. J. O’Hair
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT12117D

Ferrocene is a sandwich complex of two cyclopentadienyl (Cp) units bound to an Fe centre and is probably the most famous organometallic compound containing a Cp ligand. There are a huge variety of organometallic complexes with a range of metal centres and ligands and there is a great deal of interest in their structural, chemical and physical properties.

This Hot Article details the preparation of a series of [(η⁷-C₇H₇)Zr(η⁵-L)] (L = Cp and Ind) complexes and their structural characterisation. The authors use this information to develop a system to measure the steric bulk of Cp ligands………..so how big is a Cp?

To find out, you can download this article now, which is free to access for 4 weeks

How big is a Cp? Cycloheptatrienyl zirconium complexes with bulky cyclopentadienyl and indenyl ligands
Andreas Glöckner, Heiko Bauer, Miyuki Maekawa, Thomas Bannenberg, Constantin G. Daniliuc, Peter G. Jones, Yu Sun, Helmut Sitzmann, Matthias Tamm and Marc D. Walter
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT12132H

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Jie-Sheng Chen and colleagues from Shanghai Jiao Tong University report the synthesis of a Pd/Fe₃O₄ nanocomposite that can be used as a heterogeneous catalyst for the hydrogenation of p-nitrophenol.  Convenient recycling of the catalyst using a magnet is possible – find out more by downloading the article whilst it’s free to access:

Controlled synthesis of magnetic Pd/Fe₃O₄ spheres via an ethylenediamine-assisted route
Hai-Qun Wang, Xiao Wei, Kai-Xue Wang and Jie-Sheng Chen
Dalton Trans., 2012
DOI: 10.1039/C2DT12278B

A team of researchers have determined the structure of metastable compound Bi₂Mn_xAl_7−xO₁₄, an intermediate phase in the decomposition of mullite-Bi₂Mn_xAl_4-xO_9+δ, using a strategy  that included the use of a charge-flipping algorithm and Monte-Carlo based simulations.  The strategy may be particularly useful in situations where it is difficult to get high quality crystals.

The article is currently free so download it today.

Mullite-derivative Bi₂Mn_xAl_7−xO₁₄ (x ~ 1): structure determination by powder X-ray diffraction from a multi-phase sample
Tao Yang,  Vaclav Petricek,  Wei Wan,  Zidong Wei and Junliang Sun
Dalton Trans., 2012
DOI: 10.1039/C2DT11855F

This Hot Article from the University of Western Ontario by Laura C. Pavelka and Kim M. Baines details some interesting cycloaddition reactions of phosphaalkenes with alkynes.

Reactions of this type have not been well studied and typically require electron rich alkynes and quite specialised phosphoalkenes for the reaction to proceed. Here the authors have developed a much simpler approach to the syntheses using readily available reagents and a more direct route, allowing them to produce a variety of 1,2-dihydrophosphinines in good yields.

To find out how, you can download their article which is free to access for the next 4 weeks

Facile synthesis of luminescent benzo-1,2-dihydrophosphinines from a phosphaalkene
Laura C. Pavelka and Kim M. Baines
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT11690A

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A team of researchers have synthesised an iron(II) bispyrazolylpyridine complex in order to elucidate the interplay between spin transition and polymorphism.

Complexes demonstrating high spin–low spin crossover could prove to be very useful materials in technologies which rely on switching mechanisms, however, to use them to their full potential, any properties affecting their performance need to be understood – crystal symmetry being one of them. Mario Ruben and co-workers discovered that crystallisation of the iron(II) bispyrazolylpyridine complex produced two polymorphs which upon heating, yields a third polymorphic form. Interestingly, the different polymorphs each demonstrate different magnetic behaviour.

Whilst one polymorph, exhibits an abrupt, hysteretic high/low spin transition, the other remains low spin. The team have attributed this to varying levels of inter-molecular cooperativity within the crystal structures.

To read more, download the Dalton Transactions article now…

The interplay of iron(II) spin transition and polymorphism
Ivan Šalitroš, Olaf Fuhr, Andreas Eichhöfer, Robert Kruk, Ján Pavlik, Lubor Dlháň, Roman Boča and Mario Ruben