Full Text for April 2008, Volume 52, Number 2

 

This issue contains the following:

Encapsulated Palladium, Platinum and Osmium Catalysts for Microwave Reactions
The combination of focused microwave heating and encapsulated metal promoters (EnCat^TM) offers a safer, cleaner and more cost-effective solution to a wide range of catalyst-mediated reactions. Mike Pitts (Reaxa Ltd., Manchester, U.K.; currently with the Chemistry Innovation Knowledge Transfer Network, U.K.) describes their use in the palladium-catalysed Sonogashira cross-coupling, palladium-catalysed transfer hydrogenation, platinum-mediated hydrogenation and osmium tetroxide-catalysed dihydroxylation.

 

Olefin Metathesis Using Immobilised Ruthenium Complexes
Ileana Dragutan and Valerian Dragutan (Institute of Organic Chemistry “Costin D. Nenitescu”, Romanian Academy, Romania) present Part I of a two part series describing various routes for immobilising ruthenium alkylidene complexes through their ligands. They highlight particularly advantageous applications in olefin metathesis reactions. This strategy enhances the catalysts’ potential as clean, recyclable and highly efficient 'green' catalysts, and paves the way for scaling up to industrial applications. The concluding paper of this series, Part II, will be published in a future issue of Platinum Metals Review.

 

The Role of PGM Catalysts in 'Green' Chemistry
The book “Green Chemistry and Catalysis”, by Roger A. Sheldon, Isabel Arends and Ulf Hanefeld, focuses on the consequences of uncertainties over crude oil supply. In his review, Duncan Macquarrie (Department of Chemistry, University of York, U.K.) discusses the conversion of renewables, for example biopolymers such as starch and cellulose, into more sophisticated molecules. The outlook for Pd, Pt and related reduction catalysts is very interesting for these applications. Additionally, the role of chemistry in ‘greening’ existing processes will drive the development of more efficient and selective catalysts.

 

A Copper-Palladium Cathode for Electrochemical Reactions
Philippe Poizot and Lydia Laffont-Dantras (LRCS, Université de Picardie Jules Verne, Amiens, France) and Emeritus Professor Jacques Simonet (Laboratoire MaSCE, Université de Rennes 1, Rennes, France) describe a novel method of forming a palladised copper (Cu/Pd) interface of well defined structure. They use the surface as an efficient promoter of the cleavage of carbon–iodide and carbon–bromide bonds in alkyl halides, enabling the heterogeneous generation of free alkyl radicals as transients in electrochemical reactions. These novel cathodic materials could also be of interest for the disposal of halogenated waste.

 

Platinum and Ruthenium Complexes as Anticancer and Anti-HIV Agents
"Dalton Discussion 10: Applications of Metals in Medicine and Healthcare" took place at the University of Durham, U.K., from 3rd to 5th September 2007. Christian G. Hartinger (Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland; and University of Vienna, Institute of Inorganic Chemistry, Austria) reviews the Discussion. He covers the development of new Pt and Ru complexes as anticancer and anti-HIV agents, including compounds such as picoplatin, iproplatin and satraplatin. Pt, Ru and other metal-based drugs may become major treatments for some common diseases.

 

Platinum Useful as an Electrochemical Reference Electrode
Kasem K. Kasem and Stephanie Jones (Department of Natural, Information, and Mathematical Science, Indiana University Kokomo, U.S.A.) investigated the usefulness of Pt as an electrochemical reference electrode. They used well known redox systems as test regimes, and studied the effects of variables such as solvent, physical state and temperature of the electrolyte on electrode performance. They conclude that Pt can be used as a reference electrode under conditions in which traditional reference electrodes cannot be used.

 
 
Bimetallic PGM Nanoalloys
Professor Geoffrey C. Bond (Emeritus Professor, Brunel University, U.K.) attended the Royal Society of Chemistry's "Faraday Discussion 138: Nanoalloys – From Theory to Applications", sponsored by Johnson Matthey and the Collaborative Research Network for Nanotechnology (CRNNT) of the University of Birmingham. It took place at the University of Birmingham, U.K., on 3rd to 5th September 2007. The properties of nanoalloys often differ significantly from those of the corresponding bulk materials. The Discussion clearly demonstrated the potential for practical applications of small bimetallic particles containing pgms.

 

Improved Pharmaceutical and Fine Chemicals Synthesis through PGM Catalysis
The symposium "Challenges in Catalysis for Pharmaceuticals and Fine Chemicals" was held in London on 6th November 2007. Chris Barnard (Johnson Matthey Technology Centre, Sonning Common, U.K.) discusses the increased focus on environmental issues and sustainability. Catalytic processes can reduce waste, energy demand and safety hazards. Examples highlighted include the potential for use of rhodium-catalysed hydroformylation for the preparation of linear aldehydes, and the synthesis of amides with minimal waste via Pd-catalysed reaction of aryl chlorides.

 

The PGMs in the Periodic Table
The year 2007 marked the centenary of the death of Dmitri Mendeleev (1834–1907). Professor Bill Griffith's (Department of Chemistry, Imperial College, London, U.K.) article describes how Mendeleev and some of his predecessors accommodated the pgms in the Periodic Table, and considers the placing of their three transuranic congeners: hassium (Hs), meitnerium (Mt) and darmstadtium (Ds). The placement of the pgms was clearly a challenge, but Mendeleev finally resolved the problem some 140 years ago. Their man-made congeners, Hs, Mt and Ds, are likely to have chemistries similar to those of osmium, iridium and platinum.

 

An Appreciation of Frederick A. Lewis
Frederick Alastair Lewis died in Belfast, Northern Ireland, on 22nd May 2007 after a long illness. Professor Ted B. Flanagan (Department of Chemistry, University of Vermont, Burlington, U.S.A.) reflects on Fred's career at Queen’s University, Belfast. Fred carried out research on metal-hydrogen systems and specifically on palladium and its alloys. He made 33 contributions to Platinum Metals Review between 1960 and 2003. The phenomenon of uphill diffusion of H in Pd is known as the ‘Lewis Effect’ because it was first observed and characterised by Fred Lewis and his coworkers, in 1983.

 

Commercialisation of Fuel Cells
The commercialisation of fuel cells started in 2007, according to Fuel Cell Today in its 2008 Industry Review, released on 30th January 2008. The Review, titled “Fuel Cells: Commercialisation”, reports that in the last year the fuel cell industry has seen a growth of 75% in new units delivered, with some 12,000 new fuel cell units shipped during 2007. Fuel Cell Today believes that current commercial opportunities favour the low-temperature electrolytes, direct methanol fuel cells (DMFCs) and proton exchange membranes (PEMs).

 

The Characterisation of Supported Platinum Catalysts
Tim Hyde's (Johnson Matthey Technology Centre, Sonning Common, U.K.) Final Analysis discusses the use of X-ray diffraction (XRD), in combination with transmission electron microscopy (TEM) and electrochemical methods such as cyclic voltammetry, for the characterisation of supported Pt catalysts. Crystal/particle size information from fresh or aged samples generally correlates with catalytic activity, and average Pt crystallite size can be calculated from XRD peak broadening.

 

Abstracts and New Patents
A selection of abstracts from the scientific and patent literature is presented.

Barry W. Copping
Editor

Contact
The Editor, Platinum Metals Review, Johnson Matthey PLC, Orchard Road, Royston, Hertfordshire SG8 5HE, United Kingdom; Fax +44 (0) 1763 256359; Email jmpmr@matthey.com

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