Advances in metal-catalysed polymerisation and related transformations

Welcome to this themed issue of Dalton Transactions in the area of metal-catalysed or -initiated polymerisation and oligomerisation. This collection contains 41 contributions from international leaders in these areas from around the world. It encompasses a range of new developments, as well as five Perspective or Frontier articles reviewing key aspects of the different types of polymerisation processes represented herein.

This themed issue is an update on an earlier one in this area organised by Carmen Claver and Barbara Milani in 2009 (Dalton Trans., 2009, 8769–9076). Looking back at this issue, all four Perspective articles and two thirds of the 31 communications and full papers dealt with olefin polymerisation of one type or another. The remaining contributions reported aspects of epoxide-based and cyclic ester ring-opening polymerisation (ROP). In this 2013 collection the distribution of articles and reviews reflects the continuing interest and activity of the community in olefin polymerisation, but the balance between these contributions and those based on epoxide- and (especially) lactone/lactide-based polymerisation is more even. This is representative of the growth in interest in the design and mechanisms of operation of ROP initiators and catalysts across the periodic table. We have organised this issue as follows: as usual the Perspective and Frontier articles are found at the front of the collection; these are followed by papers dealing broadly with olefin or polar monomer polymerisation; the final group of contributions focuses on CO₂/epoxide polymerisation and the ring-opening polymerisation of cyclic esters.

Two of the Perspective articles describe aspects of olefin polymerisation. Severn and Chadwick provide a timely overview of the factors affecting the activity and stability of supported catalysts, while Redshaw and Sun report on recent progress in the use of iron-based complexes for ethylene polymerisation. Kerton et al.'s Perspective article is an account of the copolymerisation of epoxides with CO₂ using aluminium complexes, while Dagorne, Kol and Okuda provide a review of Group 4 initiators for lactide ROP. The Frontier article by Bourissou and Amgoune also addresses the ROP of lactones, as well as the polymerisation of polar olefins, but from the point of view of dual catalysis.

The next part of this issue contains 21 research articles describing recent advances in a number of areas of ethylene, propylene, hexene, styrene and 1,3-diene polymerisation. Bochmann et al. and Boisson et al. report on new insights from a kinetic perspective while Macchioni and Busico describe the use of diffusion NMR spectroscopy to study catalyst systems. Transition metal catalyst systems feature strongly among the articles, but Group 3, the lanthanides and actinides are also represented (cf. the communication from Hou et al. and the articles from Arnold and Bonnet, Eisen, Cui and Trifonov and their coworkers). The transition metal based polymerisation systems range from the early to the late metals, and include a contribution from Theopold et al. for the selective oligomerisation of ethylene. As well as new catalysts for the polymerisation of ethylene and α-olefins in general, the isospecific polymerisation of propylene is also represented (see the papers by Kol, Makio and Mashima, et al. for example), along with 1,3-diene polymerisation. Most of the catalysts described in these areas are based around the coordination–insertion (Cossee–Arlman) mechanism, but ring-opening metathesis (Hillmyer et al.) and metal-mediated radical (Poli or Shaver et al.) polymerisation systems also feature among the contributions. Articles by de Bruin et al. and Poli et al. report on interesting approaches to functionalised polyethylenes or polystyrenes. This section of the issue finishes with a joint experimental and theoretical investigation by Fang, Maron et al. of the polymerisation of MMA using an yttrium-based catalyst system.

The last part of the collection features 14 full papers in the areas of CO₂/epoxide polymerisation (Kozak and Lee et al.) and the ROP of cyclic esters with a particular focus on ε-caprolactone and lactide. A range of initiator/catalyst types from across the periodic table are reported: Group 1 (e.g. Carpentier and Sarazin et al.), Group 2 (e.g., Roesky and Guillaume; Mountford, Junk and Deacon; Chen, and their coworkers), the rare earths (Pellecchia), the early transition metals (Chen, Liang, Schaper, et al.), and the post-transition metals, focusing on aluminium (Jones and Otero et al.) and bismuth (Chisholm et al.). While most of these systems appear to operate via the more usual coordination–insertion mechanism, other papers include interesting mechanistic studies of the activated monomer mechanism (Carpentier and Sarazin, and Mountford et al.). The prize for the most intriguing title surely must go to Malcolm Chisholm and his coworkers for their paper, “Use of over the counter oral relief aids or dietary supplements for the ring-opening polymerization of lactide”.

Finally, both as Guest Editor and current Chair of the journal's Editorial Board, I would like to thank all of the contributors for submitting their new research and reviews to Dalton Transactions. Obviously, without their high quality hard work and willingness to join in this venture this themed issue would not exist. I would like to extend my thanks also to Jamie Humphrey and especially Fiona McKenzie and all the Dalton Transactions editorial team for their hard work and typical professionalism in handling all the manuscripts.

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