ORGANOAMIDO-LANTHANOIDS AND ARYLOXO-LANTHANOIDS .13. ORGANOMETALLIC COMPOUNDS OF THE LANTHANOIDS .105. NEW LANTHANOID(III) COMPLEXES WITH PYRAZOLATE LIGANDS

The complexes Er(Me(2)pz)(3)(thf) and Ln(Ph(2)pz)(3)(thf)(n) (Ln = Sc, Y, Gd, Er, n = 2; Ln = Lu, n = 3) (Me(2)pz(-) = 3,5-dimethylpyrazolat e, thf = tetrahydrofuran, Ph(2)pz(-) = 3,5-diphenylpyrazolate) have be en prepared by reaction of the lanthanoid metal with bis(pentafluoroph enyl)mercury and the pyrazole in thf. The Ln(Ph(2)pz)(3)(thf)(2) compl exes are considered to be eight coordinate with three eta(2)-Ph(2)pz l igands. Other lanthanoid pyrazolate complexes, Y(pz)(3)(thf)(2), La(Me (2)pz)(3)(thf), Cp(2)Ln(Me(2)pz)(thf)(n) (Ln = Y, Lu, n = 0; Ln = Lu, n = 1), (C(5)Me(5))(2)Y(pz)(thf), (C(5)Me(5))(2)Y(Mepz)(thf), (C(5)Me( 5))(2)Y(Me(2)pz)(thf)(2) (pz(-) = pyrazolate, Mepz(-) = 3-methylpyrazo late, Cp = cyclopentadienyl) have been synthesized by reaction of LnCl (3), Cp(2)LnCl, or (C(5)Me(5))(2)LnCl with the appropriate sodium pyra zolate in thf. The structure of Ln(Me(2)pz)(3)(thf) (Ln = La or Er) is considered to be a symmetrical dimer with four chelating and two brid ging Me(2)pz groups, and two bridging thf ligands, whereas the cyclope ntadienyl complexes are most likely dimers with bridging pyrazolate gr oups, and lattice thf of solvation.