Preparation and NMR Studies of Palladium Complexes with a Silsesquioxanate Ligand

Reaction of an incompletely condensed silsesquioxane trisilanol, (c-C5H9)7Si7O9(OH)3, with trans-[Pd(I)(Ar)(PMe3)2] in the presence of Ag2O yielded arylpalladium complexes with a monodentate O-coordinated silsesquioxanate ligand, trans-[Pd{O10Si7(c-C5H9)7(OH)2}(Ar)(PMe3)2] (4a: Ar = Ph, 4b: Ar = C6F5). X-ray crystallographic results of 4b showed trans coordination of the pentafluorophenyl ligand and the O-coordinated silsesquioxanate ligand to the square-planar Pd(II) center. Variable-temperature 1H, 19F{1H}, and 29Si{1H} NMR spectra of 4a and 4b revealed dynamic behavior of the molecules in solution.