Alkali metal and ammonium fluoro(trifluoroacetato)metallates M'[M''_3(μ_3-F)(CF_3COO) _6(CF_3COOH)_3], where M' = Li, Na, K, NH_4, Rb, or Cs and M'' = Ni or Co. Synthesis and crystal structures

摘要

A series of fluoro(trifluoroacetato)metallates were synthesized by crystallization from solutions in trifluoroacetic acid containing nickel(II) or cobalt(II) nitrate hydrates and alkali metal or ammonium fluorides: Li[Ni _3(μ_3-F)(CF_3COO)_6(CF _3COOH)_3](CF_3COOH)_3 (I), M'[Ni_3(μ_3-F)(CF_3COO) _6(CF_3COOH)_3] (M' = Na (II), NH _4 (IV), Rb (V), and Cs (VI)), NH_4[Co_3(μ_3-F) (CF_3COO)_6(CF_3COOH)_3] (III), and Cs[Ni_3(μ_3-F)(CF_3COO) _6(CF_3COOH)_3](CF_3COOH)_(0.5) (VII). The crystal structures of these compounds were determined by single-crystal X-ray diffraction. All structures contain triangular trinuclear complex anions [M _3″(μ_3-F)(CF_3COO) _6(CF_3COOH)_3]- (M″ = Ni, Co) structurally similar to trinuclear 3d metal oxo carboxylate complexes. The three-coordinated F atom is located at the center of the triangle formed by Ni(II) or Co(II) atoms. The metal atoms are linked in pairs by six bridging trifluoroacetate groups located above and below the plane of the [M″_3 F] triangle. The oxygen atoms of the axial CF _3COOH molecules complete the coordination environment of M″ atoms to an octahedron.