Trivalent rare earth complexes of the unsymmetrical 3-(2 '-Thienyl)-5-(trifluoromethyl)pyrazolate ligand

Trivalent rare earth complexes of the unsymmetrical 3-(2'-thienyl)-5-(trifluoromethyl)pyrazolate (ttfpz) ligand, namely [RE(ttfpz)(3)(thf)(3)]center dot nsolv, where thf = tetrahydrofuran [RE = La, solv = PhMe, n = 0.5 (1); RE = Sm, n = 0 (2); RE = Tb, solv = thf, n = 1 (3)], [RE(ttfpz)(3)(thf)(2)] [RE = Y (4), Ho (5), Lu (6), Sc (7)] and [RE(ttfpz)(3)(dme)(2)]center dot nsolv, where dme = 1,2-dimethoxyethane [RE = La, n = 0 (8a); RE = La, solv = Et2O, n = 0.5 (8b); RE = Eu, solv = dme, n = 1 (9)], were prepared, mainly by redox transmetallation/protolysis from the free metal, Hg(C6F5)(2) and ttfpzH, and structurally characterised. In the nine-coordinate, pseudo-octahedral complexes 1 and 2, eta(2)-pyrazolate and thf ligands are in a facial arrangement, whereas they are arranged meridionally in 3. In the eight-coordinate complexes 4-7 the arrangement of the eta(2)-pyrazolate and thf ligands can be described as in between pseudo-trigonal bipyramidal and -square pyramidal. Ten-coordinate complexes 8a, 8b and 9 exhibit eta(2)-bonded pyrazolates and two chelating dme ligands as opposed to the nine-coordinate 3,5-diphenylpyrazolate (Ph(2)pz) complexes [RE(Ph(2)pz)(3)(dme)(2)], which possess one unidentate and one chelating dme ligand, suggesting that the ttfpz ligand is less bulky than Ph(2)pz.

European Journal of Inorganic Chemistry

European Journal of Inorganic Chemistry

2011

1099-0682

N/A

24

9