IFP, 1-4 avenue de Bois Préau 92852 Rueil-Malmaison Cedex, France, and UMR 5180, Université Claude Bernard Lyon I, 43 bvd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France * To whom correspondence ...

Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, and Department of Chemistry, Southwestern University, Georgetown, Texas 79626 * To whom correspondence ...