Organoamido‐ and Aryloxo‐lanthanoids, 14 . Organometallic Compounds of the Lanthanoids, 106 . Synthesis and Characterisation of Complexes of Lanthanoid Pyrazolates with 1,2‐Dimethoxyethane and the X‐Ray Structures of (1,2‐Dimethoxyethane‐ O 1 : O 2 )(1,2‐dimethoxyethane‐ O 1 )tris(3,5‐diphenylpyrazolato)erbium(III) and catena ‐Poly[tris(3,5‐di‐ tert ‐butylpyrazolato)‐μ‐(1,2‐dimethoxyethane‐ O 1 : O 2 )‐neodymium(III)]

The complexes [Ln(Ph 2 pz) 3 (DME) 2 ] and [Ln( t Bu 2 pz) 3 (DME)] (Ln = La, Nd, Er; Ph 2 pzH = 3,5‐diphenylpyrazole; t Bu 2 pzH = 3,5‐di‐ tert ‐butylpyrazole; DME = 1,2‐dimethoxyethane) have been prepared by reaction of the lanthanoid metal with bis(pentafluorophenyl)mercury and the pyrazole in DME. The molecular structures of [Er(Ph 2 pz) 3 (DME) 2 ] ( 3 ) and [Nd( t Bu 2 pz) 3 (DME)] ∞ ( 5 ) have been determined by X‐ray diffraction. Complex 3 has nine‐coordinate Er with three chelating Ph 2 pz ligands and one chelating and one η 1 ‐bound DME. There is a trigonal prismatic arrangement of the oxygen donors and the centres of the N – N bonds. 5 was found to be a linear polymer with transoid DME ligands bridging Nd( t Bu 2 pz) 3 units in a novel manner. The centres of the N – N bonds (which are essentially coplanar with Nd), and the oxygen donor atoms adopt an arrangement intermediate between trigonal‐bipyramidal and square‐pyramidal [O – Nd – O 153.5(2)°].