d⁰ organometallics in catalysis

Researching the organometallic chemistry of d⁰ metals (principally groups 1–5) presents some technical challenges, but it is a very satisfying area in which to work and the opportunities are quite unique, as demonstrated by this excellent collection of papers from leading laboratories around the world.

There are few homogeneous catalytic reactions that are said to be more efficient than Ziegler-type olefin polymerisation, with tiny amounts of inexpensive catalysts producing vast quantities of useful, high-tech, products at diffusion-controlled rates. Despite the age of this particular area the search for new catalysts and new products still goes on in academic and industrial labs worldwide. In this themed issue of Dalton Transactions, Nomura and Liu describe a substantial body of work on half-sandwich titanium catalysis (DOI: 10.1039/c1dt10086f), Cui and Liu demonstrate butadiene/isoprene copolymerization (DOI: 10.1039/c1dt10100e) and other new catalysts are described by the groups of Jin et al. (DOI: 10.1039/c0dt01800g) and Bai et al. (DOI: 10.1039/c1dt10365b). Generations of this kind of imaginative research has also provided useful catalysts and reagents for other catalytic processes.

One such related hot area is alkene hydroamination which has recently been transported from the world of group 3 and lanthanide compounds to group 4 where it is more accessible to organic chemists and users in the pharmaceutical and fine chemicals industries. Here another fundamental challenge asserts itself – how to control product stereochemistry while maintaining high activity. Ward and Wixey (DOI: 10.1039/c1dt10732a) and Livinghouse et al. (DOI: 10.1039/c1dt10222b) describe some new alkaline earth metal and group 3/lanthanide catalysts for the enantioselective hydroamination reaction and Schafer and Ayinla demonstrate that catalytic intermolecular allene hydroamination can be achieved by group 4 metals even in the presence of heteroatoms (DOI: 10.1039/c1dt10448a), an important consideration in the use of these oxophilic metals.

The relatively low cost of these metals also makes stoichiometric reactions such as Negishi-type diene cyclisation a viable process, and Chirik et al. provides new isolable reagents for this process here (DOI: 10.1039/c1dt10149h). These areas of work are backed up by fundamental studies of structure, bonding and reactivity by Kawaguchi et al. (DOI: 10.1039/c1dt10040h), Parkin et al. (DOI: 10.1039/c1dt10806a), Waterman et al. (DOI: 10.1039/c1dt10105f) and Arnold et al. (DOI: 10.1039/c1dt10202h).

It is exciting to see that the chemistry of d⁰ metals also extends into what might be called “Global Challenge” areas – the discovery of H₂ storage systems (the work of Rosenthal et al. (DOI: 10.1039/c1dt10366k) and Hill et al. (DOI: 10.1039/c1dt10171d) on dihydrogen production from boranes), elucidation of biological pathways (insights into the vanadium-catalysed oxidation of thiols to disulfides by Zampella et al. (DOI: 10.1039/c1dt10103j)), the creation of sustainable polymeric products (from Okuda and Buffet's scandium catalysts (DOI: 10.1039/c1dt10075k)) and the study of advanced electronic materials (including the synthetic and structural contributions of relevance to rare earth OLEDs by Katkova et al. (DOI: 10.1039/c1dt10318k)).

The papers in this themed issue exemplify all these areas of study, from fundamental chemistry to application, and come from a range of young and established researchers. It has been a pleasure to help gather these articles together and we thank the authors again for their excellent contributions.

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