Syntheses, solution multi-NMR characterization, and reactivities of [C6F5Xe]+ salts of weakly coordinating borate anions, [BY4]- (Y = CF3, C6F5, CN, or OTeF5)

New examples of C6F5Xe]+ salts of the weakly coordinating anions B(CF3)4]-, B(C6F5)4]-, B(CN)4]-, and B(OTeF5)4]- have been synthesized by metathesis reactions of C6F5Xe]BF4] with the corresponding MIBY4] salts (MI = K or Cs; Y = CF3, C6F5, CN, or OTeF5). The salts were characterized in solution by multi-NMR spectroscopy. Their stabilities in prototypic solvents (CH3CN and CH2Cl2) and decomposition products are reported. The influence of the coordinating nature of BY4]- on the decomposition rate of C6F5Xe]+ as well as the presence of the weakly nucleophilic BF4]- ion has been studied. The electrophilic pentafluorophenylation of C6H5F by C6F5Xe]BY4] in solvents of different coordinating abilities (CH3CN and CH2Cl2) and the effects of stronger nucleophiles (fluoride and water) on the pentafluorophenylation process have been investigated. Simulations of the 19F and 129Xe NMR spectra of C6F5Xe]+ have provided the complete set of aryl 19F-19F and 129Xe-19F coupling constants and their relative signs. The 19F NMR parameters of the C6F5Xe]+ cation in the present series of salts are shown to reflect the relative degrees of cation-solvent interactions.