New Routes to Fluorinated Ligands and Polymers.

Abstract : The first examples of perfluorobenzyl complexes of the transition metals have been prepared. Several complexes were characterized by X-ray crystallography, and the bond from the perfluorobenzyl ligand to cobalt, rhodium, and iridium appears to be unusually weak. While the perfluorobenzyl ligand in several cobalt complexes was shown to be unusually reactive towards coupling with ancillary ligands like pentam ethylcyclopentadienyl, no examples of insertion of fluorinated olefins into the metal-carbon bond were found. Instead, the alpha-CF2 group of the perfluorobenzyl ligand in rhodium and iridium complexes is remarkably sensitive to hydrolysis, undergoing reaction with even the smallest traces of water on the surface of glass to give a carbonyl group. This is a reaction of some significance, as it requires hot concentrated H2SO4 to accomplish in the absence of the transition metal. A key intermediate has been isolated in which a water molecule and a perfluorobenzyl group are both bound to a cationic rhodium center. The hydrolysis mechanisms has been studied in detail.