[1] Univ Leeds, Sch Chem, Leeds LS2 9JT, W Yorkshire, England
[2] Aarhus Univ, Dept Chem, DK-8000 Aarhus C, Denmark
[3] Univ Manchester, Dept Chem, Manchester M13 9PL, Lancs, England
[4] Dow Chem Co USA, Texas Operat, Res & Dev, Freeport, TX 77541 USA