Syntheses and crystallographic studies of [Ir(eta(5)-C5Me5)(L)( RF)I] (L = CO, PMe3; R-F = CF2CF3, CF2CF2CF3, CF2C6F5, CF(CF3)(2)) complexes. Cone and solid angle steric parameters for perfluoroalkyl ligands

摘要

Oxidative addition of RFI (R-F = CF2CF3, CF2CF2CF3, CF2C6F5, CF(CF3)(2)) to [Ir(eta(5)-C5Me5)(CO)(2)] gave the iridium(III) complexes, [Ir(eta(5)-C5Me5)(CO)(R-F)I] 2a-d in good yield. Carbonyl substitution by PMe3 to give [Ir(eta(5)-C5Me5)(PMe3)(R-F)I] 3a-d was achieved by heating in refluxing toluene. Complexes 2a, c, d and 3a, b, d were studied by X-ray crystallography. The perfluoroalkyl Ir-C bonds were found to be shorter than alkyl Ir-C bonds, while the alpha-C-F bonds were longer than the C-F bonds in non-coordinated perfluorocarbons. The steric sizes of the perfluoroalkyl ligands were determined as Tolman cone angles, theta, and solid angles, Omega. The sizes of the ligands followed the expected trend, CF(CF3)(2) > CF2C6F5 > CF2CF2CF3 approximate to CF2CF3, and were substantially larger than corresponding hydrocarbons. [References: 48]