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 M-1[BY4] salts (M-1 = 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 F-19 and Xe-129 NMR spectra of [C6F5Xe](+) have provided the complete set of aryl F-19-F-19 and Xe-129-F-19 coupling constants and their relative signs. The F-19 NMR parameters of the [C6F5Xe](+) cation in the present series of salts are shown to reflect the relative degrees of cation-solvent interactions.