Alkali metal and ammonium fluoro(trifluoroacetato)metallates M′[M′′3(μ3-F)(CF3COO)6(CF3COOH)3], where M′ = Li, Na, K, NH4, Rb, or Cs and M′′ = Ni or Co. Synthesis and crystal structures

Abstract

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 3 COO) 6 (CF 3 COOH) 3 ](CF 3 COOH) 3 ( I ), M ′[Ni 3 (μ 3 -F)(CF 3 COO) 6 (CF 3 COOH) 3 ] ( M ′ = Na ( II ), NH 4 ( IV ), Rb ( V ), and Cs ( VI )), NH 4 [Co 3 (μ 3 -F) (CF 3 COO) 6 (CF 3 COOH) 3 ] ( III ), and Cs[Ni 3 (μ 3 -F)(CF 3 COO) 6 (CF 3 COOH) 3 ](CF 3 COOH) 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 3 COO) 6 (CF 3 COOH) 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 3 COOH molecules complete the coordination environment of M ″ atoms to an octahedron.