ORGANOAMIDO-LANTHANOIDS AND ARYLOXO-LANTHANOIDS .9. PREPARATIONS AND STRUCTURES OF TRIS(ETA(2)-3,5-DIPHENYL-PYRAZOLATO)LANTHANOID(III) COMPLEXES WITH TRIPHENYLPHOSPHINE OXIDE AND TETRAHYDROFURAN

From reaction of lanthanoid metals with bis(pentafluorophenyl)mercury and 3,5-diphenylpyrazole (HPh2PZ) in 1,2-dimethoxyethane (dme) and treatment of the products with triphenylphosphine oxide, the complexes [Ln(eta2-Ph2pz)3(OPPh3)2].(dme)n (Ln = Er or Nd, n = 1; Ln = La, n = 0.6) have been isolated. An X-ray crystal structure shows that the erbium complex [monoclinic, space group C2, a 22.08(3), b 14.30(1), c 13.37(1) angstrom, beta 124.09(7)-degrees, Z 2, 2730 'observed' data refined to R 0.046] is monomeric, with eight coordination of the metal. There is a trigonal bipyramidal arrangement of the centres (Cen) of the N-N bonds of three eta2-3,5-diphenylpyrazolate groups (SIGMACen-Er-Cen 360-degrees; [Er-N] 2.344 angstrom) and the oxygens of two equivalent trans triphenylphosphine oxide ligands [O-Er-O 176(1)-degrees; Er-O 2.207(9) angstrom]. Unit cell data indicate that the neodymium analogue [monoclinic, space group C2, a 23.01(3), b 14.94(2), c 13.82(2) angstrom, beta 123.65(8)-degrees] is isostructural with the erbium complex. An analogous reaction of lanthanum or neodymium metal, Hg(C6F5)2, and HPh2PZ in tetrahydrofuran (thf) gives [Ln(eta2-Ph2PZ)3(thf)3].thf (Ln = La or Nd). The X-ray crystal structure of the neodymium complex [orthorhombic, space group P2(1)2(1)2(1), a 14.009(9), b 16.280(8), c 22.640(16) angstrom, Z 4, 2967 'observed' data refined to R 0.046) reveals a nine-coordinate monomer with three eta2-Ph2pz ligands [Nd-N 2.420(10)-2.524(8) angstrom] and three thf ligands [Nd-O 2.497(8)-2.587(8) angstrom]. There is a trigonal prismatic arrangement of the centres of the N-N bonds and the oxygen donor atoms.