Cobalt(I) and cobalt(III) cyclopentadienyl complexes with new silicon-branched fluorous tags

Two new fluorous tags based on omega-[tris(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)silyl]alkyl substituents (alkyl = ethyl, propyl) were synthesized from 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl iodide as the fluorine-containing component. Cyclopentadienes (the mixtures of 1- and 2-substituted isomers) which bore the tags were prepared, cyclopentadienyl cobalt(I) dicarbonyl complexes were subsequently obtained from the reactions of the cyclopentadienes with dicobalt octacarbonyl. Oxidative additions of 1-iodoperfluoroalkanes on the cobalt(I) complexes provided cobalt(III) complexes with one of their four ponytails bonded directly to the metal and with a stereocenter at the metal.