1. Aix Marseille Univ, CNRS, ICR, Marseille, France
2. School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales, UK,
3. Aix Marseille Univ, CNRS, Centrale Marseille, FSCM, Marseille, France
4. Institut Universitaire de France, Paris, France
5. Swedish NMR Center, University of Gothenburg, Gothenburg, SE-405 30, Sweden