Solid-state NMR spectroscopic study of coordination compounds of XeF(2) with metal cations and the crystal structure of [Ba(XeF(2))(5)][AsF(6)](2).

The coordination compounds [Mg(XeF(2))(2)]AsF(6), [Mg(XeF(2))(4)]AsF(6), [Ca(XeF(2))(2.5)]AsF(6), [Ba(XeF(2))(3)]AsF(6), and [Ba(XeF(2))(5)]AsF(60 were characterized by solid-state (19)F and (129)Xe magic-angle spinning NMR spectroscopy. The (19)F and (129)Xe NMR data of [Mg(XeF(2))(2)]AsF(6), [Mg(XeF(2)(4)]AsF(6), and [Ca(XeF(2))(2.5)]AsF(6) were correlated with the previously determined crystal structures. The isotropic (19)F chemical shifts and (1)J((129)Xe-(19)F) coupling constants were used to distinguish the terminal and bridging coordination modes of XeF(2). Chemical-shift and coupling-constant calculations for [Mg(XeF(2))(4)]AsF(6) confirmed the assignment of terminal and bridging chemical-shift and coupling-constant ranges. The NMR spectroscopic data of [Ba(XeF(2))(3)]AsF(6) and [Ba(XeF(2))(5)]AsF(6) indicate the absence of any terminal XeF(2) ligands, which was verified for [Ba(XeF(2))(5)]AsF(6) by its X-ray crystal structure. The adduct [Ba(XeF(2))(5)]AsF(6) crystallizes in the space group Fmmm, with a = 11.6604(14) Angstrom, b = 13.658(2) Angstrom, c = 13.7802(17) Angstrom, V = 2194.5(5) Angstrom(3) at -73 degrees C, Z = 4, and R = 0.0350 and contains two crystallographically independent bridging XeF(2) molecules and one nonligating XeF(2) molecule. The AsF(6-) anions in [Mg(XeF(2))(4)]AsF(6), [Ca(XeF(2))(2.5)]AsF(6), [Ba(XeF(2))(3)]AsF(6), and [Ba(XeF(2))(5)]AsF(6) were shown to be fluxional with the fluorines-on-arsenic being equivalent on the NMR time scale, emulating perfectly octahedral anion symmetry.