Full Text for Volume 48 Number 4 (October 2004)

 

This issue contains the following:

Ruthenium Vinylidenes Exhibit Remarkable Activity and Selectivity
Ruthenium vinylidene complexes are easily accessible from commercial starting materials. They display moderate to high metathesis activity and stability, and show good tolerance towards an array of functional groups, air and moisture. Valerian Dragutan and Ileana Dragutan (Institute of Organic Chemistry, Romanian Academy, Romania) review these complexes which show great potential for use in organic and polymer synthesis. Their physical-chemical properties and catalytic attributes make them promising candidates for applications in ring-closing metathesis, cross metathesis and ring-opening metathesis polymerisation.

 

Preparation of Palladium-Iron Alloy Particles in a Carbon Matrix
Scientists at AIST, Japan, report their method of forming fine Pd-Fe alloy particles dispersed in a carbon matrix. The synthesis involves the reduction, first of palladium chloride, then of iron chloride, after their intercalation in the graphite layers.

 

Electrochemistry and Catalysis of Iridium Hexacyanometallates
The production and properties of thin films of metal-hexacyanoiridium(III) (MHCI) used as surface modifiers for glassy carbon electrodes are described by Professor Kasem K. Kasem and Leslie Huddleston (Indiana University Kokomo, U.S.A.). The redox behaviour of the counter/central ions of these films in aqueous electrolytes is described. Evidence is presented of the efficient manipulation of Ir hexacyanometallate film structures to desired composition and porosity. The catalytic behaviour of MHCI films towards the reduction of iodate is reported.

 

Carbon Nanontube Particulates Made by Removal of a Support
Small-diameter carbon nanotubes, with one or more walls and an outer wall of diameter 0.5 to 3 nm, can be produced by contacting a catalyst of Ru, Rh, Pd, Os, Ir, Pt, Fe or Mo on a magnesia support with methane at 500-1500°C. This work, by scientists from Carbon Nanotechnologies Inc., U.S.A., has been patented. On removal of the support, the deposited carbon appears as enmeshed nanotubes which retain the approximate 3D shape and size of the removed particulate support. As electron emitters, these nanotubes exhibit very low 'turn on’ emission field.

 

Review of Volume 5 of "Comprehensive Coordination Chemistry II"
Volume 5 of "Comprehensive Coordination Chemistry II. From Biology to Nanotechnology", on “Transition Metal Groups 7 and 8”, edited by E. C. Constable and J. R. Dilworth, is reviewed by Chris Barnard and Steve Bennett (Johnson Matthey Technology Centre, U.K.). They describe the work that has been done on ruthenium and osmium in their low and high oxidation states.

 

Increased Luminescence of Ru(II) Complexes at Room Temperature
Room temperature luminescent Ru(tpy)₂²⁺ (tpy = 2,2':6',2''-terpyridine) species having a substituent of 2-pyrimidyl on one tpy moiety and an organic 9-anthryl chromophore on the other were synthesised by a team from the Université de Montréal, Canada, and Università di Messina, Italy. The separation of the chromophores was > 1 nm. The 9-anthryl subunit is an energy store for the ³MLCT emissive state and is on the ligand that does not act as the acceptor ligand. Prolonged luminescence lifetimes via excited-state equilibration have been obtained for the first time using a simplified procedure.

 

Catalytic Activity of Platinum Group Metal/Gold Systems
Some catalytic processes that have benefited from the synergy between a pgm and gold are described by David T. Thompson, a consultant to the World Gold Council. He considers these findings could well lead to new applications in chemical processing, pollution control and fuel cells.

 

13th International Congress on Catalysis
The 13th ICC, held in Paris in July 2004, covered a number of catalytic topics: preparation and characterisation of catalysts, reaction mechanisms and engineering, fuel and energy for the future, synthesis of chemicals and polymers, and pollution prevention and remediation. Alvaro Amieiro-Fonseca, Janet Fisher and Sonia Garcia (Johnson Matthey Technology Centre, U.K.) review some of the many papers relating to the pgms that were presented.

 

The Discoverers of the Isotopes of Osmium
The discovery of the isotopes of osmium and their discoverers is described by John Arblaster of Coleshill Laboratories, West Midlands, U.K. Between 1931 and 1989, thirty-four isotopes of osmium were discovered. Francis W. Aston, who received the 1922 Nobel Prize for Chemistry for the invention of the mass spectrograph, discovered the first six major isotopes of osmium.

 

"Concepts of Modern Catalysis and Kinetics"
This book, by I. Chorkendorff and J. W. Niemantsverdriet, aimed at students, is reviewed by Tim Watling (Johnson Matthey Technology Centre, U.K.). Important applications of the pgms covered include bifunctional reforming catalysis, fuel cells and, more unusually for a textbook, automotive exhaust catalysis.

 

Discovery of Osmium and Iridium by Tennant
Osmium and iridium were discovered two hundred years ago by Smithson Tennant in London. Historical events surrounding their discovery are described by Professor Bill (W. P.) Griffith of Imperial College, London. Tennant named osmium after the Greek osme, smell, and iridium after the Latin iris, a rainbow.

 

The issue also contains a selection of abstracts based on recently published patent and scientific literature, and ends with the Indexes to Volume 48.

Susan V. Ashton
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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