Electron Spin

Resonance Group

Newsletter

March 2003

RS•C

ROYAL SOCIETY OF CHEMISTRY

SpinDrift from John Walton

In its early years ESR spectroscopy was one of the key reference points for testing QM theory. The classic INDO semi-empirical MO method related experimental data to predictions from quantum mechanics. Modern ab initio DFT theory, with sophisticated basis sets, enables isotropic and anisotropic hyperfine interactions to be computed with an accuracy undreamed of a few years ago. However, a major trend in the last few years has been away from theory and towards the application of ESR techniques to probing natural phenomena and solving problems in biology, chemistry, catalysis and related branches of science. ESR and its sibling techniques are becoming integrated with large projects bringing a whole armoury of analytical instrumentation to the most challenging projects in a holistic fashion.

More than 1500 papers on ESR appeared in 2002-03. Many of these were orthodox studies in well trodden areas such as polymerisation, oxidative stress, spin trapping or TM complex characterisation. Notable growth was registered in the area of spin labelling

(83 papers) with applications to protein dynamics, membrane-peptide interactions, muscle fibers and carbohydrates. ESR has penetrated into areas as diverse as spin mapping in organic conductors, analysis of spectra with large quadrupole couplings, gut fluids of caterpillars, dating of hominid sites in Southern China and dose rates in tooth enamels. This is rather vivid evidence of the robust adaptability of the technique to 21st. century demands.

The 35^th ESR Group Meeting took place last April amidst the baronial splendour of Aberdeen UniversityÕs KingÕs College Conference Centre. ESR depends critically on a combination of electric and magnetic fields. It was most appropriate therefore that ESR should "come home" to the place where James Clerk Maxwell, the father of modern electro-magnetic theory, worked for many years. The global importance of ESR was illustrated by the large range of nationalities and disciplines represented amongst the 110 participants. The quality of the scientific programme matched the senatorial character of the conference lecture facilities. The programme commenced with a fine lecture on Imaging of Free Radicals In Vivo Using Overhauser Techniques by [cont. over]

35^th ESR Group Meeting (cont.)

Aberdeen's David Lurie. Plenary lectures by Jay Sweier (John Hopkins), Karsten MŠder (Hoffmann-LaRoche, Basel), Bernard Goodman (Scottish Crop Research Institute), Ronald Mason (NIEH), David Collison (Manchester), Angelo Alberti (Bologna), Thomas Prisner (JW Goethe University) were balanced by shorter talks covering many new applications and techniques. The keynote Bruker Lecture was given jointly by Gareth and Sandra Eaton (Denver) on the general theme of interaction of electron spins. The Jeol session, where three PG students gave showcase lectures in competition for the Jeol student prize, was another highlight. Congratulations to Anna Ferretti (Milano) the eventual winner. Bernard Goodman's dictum that "the only place for 'spin' in science should be in the context of magnetic resonance" received vigorous endorsement throughout this outstanding conference.

David H Whiffen, pioneer ESR spectroscopist died in December 2002.

His research career began at Oxford in 1943 where he worked on IR and microwave radiation with Sir Harold W. Thompson. Moving to Birmingham in 1949 he continued work with IR but became interested in free radicals. He constructed an early ESR spectrometer and carried out world-leading experimental and theoretical work on glycine and other radicals trapped in crystals. At John Pople's invitation he moved to the National Physical Laboratory in 1958 and over the next few years published many seminal papers on EPR and ENDOR spectra of inorganic ions and organic free radicals at 9 and 35 GHz. He was elected FRS in 1966. Whiffen became Professor of Physical Chemistry at Newcastle in 1968 eventually rising to Pro-Vice-Chancellor. He will be remembered for, among other attributes, his brilliant and insightful mind.

The 9 GHz EPR spectrum shown to the left was obtained on photolysis of a solution of

PhCH=NOC(O)C(O)N(Bn)-(CH₂)₃CH=CH ₂ and p-methoxybenzophenone in

t-butylbenzene at 220 K.

Identify the 3 radicals I, A and C.

(For the answer see: Chem. Commun. 2002, 2086.)

ESR GROUP COMMITTEE.

The ESR Group committee was elected at the AGM held in Aberdeen on 10th April 2002 and has the following members:

Chair

Professor John C. Walton, School of Chemistry, University of St. Andrews

Secretary/Treasurer

Dr Damien M. Murphy, Department of Chemistry, Cardiff University

Conference Organisers

Drs Eric McInnes and David Collinson, Department of Chemistry , University of Manchester

Ordinary Members

Dr Shirley A. Fairhurst, John Innes Centre, Norwich

Dr Simon K. Jackson, Dept. Medical Microbiology , University of Wales College of Medicine, Cardiff

Dr Chris W. M. Kay, Institut fŸr Experimentalphysik, Free University of Berlin, Germany

Dr Paul J. Krusic, DuPont, Wilmington, Delaware, USA

Dr David J. Lowe, John Innes Centre, Norwich

Dr Mark E. Newton, Department of Chemistry, University of Warwick

Dr Graham Smith, School of Physics, University of St. Andrews

Dr Lesley Yellowlees, Department of Chemistry, Edinburgh University

Membership of the ESR Group currently stands at about 100. All scientists who are members of the Royal Society of Chemistry, and have an interest in ESR/EPR spectroscopy, are invited and urged to tick the ESR Group box on their membership renewal forms. The cost is only £2 per annum! Membership carries entitlement to reduced registration fees at ESR Group annual conferences.

Website

http://www.esr-group.org.uk