Activation and η 2 -co-ordination of arenes: crystal and molecular structure of an (η 2 -hexafluorobenzene)rhodium complex

The photolytic reaction of (Cp)Rh(PMe3)(C2H4), (1, Cp=η5-C5H5) with benzene yields (Cp)Rh(PMe3)(Ph)H via a transient η2-C6F6 complex detected by laser flash photolysis; the corresponding reaction of (1) with C6F6 yields (C)Rh(PMe3)(η2-C6F6) which contains an almost planar C6F4 unit with the remaining fluorines bent out of the plane by 43 °.