Organometallic Reactivity Patterns in Fluorocarbons and Implications for Catalysis:  Synthesis, Structure, Solubility, and Oxidative Additions of a Fluorous Analogue of Vaska's Complex,trans-Ir(CO)(Cl)[P(CH₂CH₂(CF₂)₅CF₃)₃]₂

The reaction of [Ir(Cl)(cod)] 2, P(CH 2 CH 2 (CF 2 ) 5 CF 3 ) 3, and CO (1 atm) gives the title compound ( 2, 97%). Tri( n -octyl)phosphine ( 3 ) and rhodium ( 4 ) analogues are similarly prepared. Crystal structures of 2 and 4 show anti CCCC conformations in the six perfluoroalkyl groups (average torsion angle 169°), with four chains (two per phosphorus) in parallel coplanar arrays that define ca. 21 × 6 Å “rafts”. The other two chains extend on a common side of the raft, which pack back-to-back in stacks, maximizing parallel chains in every dimension. DSC shows one phase transition (melting, 2 / 4 75/79 °C) prior to thermal decomposition (>200 °C). The IR ν CO values ( 2 / 3 / 4 1975/1942/1979 cm - 1 ) show that the CH 2 CH 2 spacers do not completely insulate the metals from the perfluoroalkyl groups. Both 2 and 4 are soluble in CF 3 C 6 F 11, CF 3 C 6 H 5, ether, THF, and acetone but insoluble in hexane, toluene, CHCl 3, and CH 2 Cl 2 (CF 3 C 6 F 11 /THF partition coefficient >99.7:<0.3). Reactions of 2 with RI, H 2, and 3 O 2 or 1 O 2 in CF 3 C 6 F 11 give Ir(CO)(Cl)(R)(I)[P(CH 2 CH 2 (CF 2 ) 5 CF 3 ) 3 ] 2 (R = CH 2 CH 2 (CF 2 ) 7 CF 3 ( 5 ), CH 3 ( 6 ), CH(CH 3 )CH 2 CH 3 ( 7 ), 70−84%), Ir(CO)(Cl)(H) 2 [P(CH 2 CH 2 (CF 2 ) 5 CF 3 ) 3 ] 2 (82%), and Ir(CO)(Cl)(O 2 )[P(CH 2 CH 2 (CF 2 ) 5 CF 3 ) 3 ] 2 ( 9, 67%), respectively. Additions of RI occur by free-radical chain mechanisms (inhibition by duroquinone; slower dark reactions; rates 7 > 5 > 6 ) with no evidence for polar pathways. Complex 9 forms more rapidly in THF, indicating that (relative to THF) 2 and 3 O 2 are stabilized by CF 3 C 6 F 11 more than the transition state.