Two lanthanum(III) complexes containing η²-pyrazolate and η²-1,2,4-triazolate ligands: intra­molecular C—H...N/O inter­actions and coordination geometries

The lanthanum(III) complexes tris­(3,5-diphenyl­pyrazolato-κ²N,N′)tris­(tetra­hydro­furan-κO)lanthanum(III) tetra­hydro­furan monosolvate, [La(C₁₅H₁₁N₂)₃(C₄H₈O)₃]·C₄H₈O, (I), and tris­(3,5-diphenyl-1,2,4-triazolato-κ²N¹,N²)tris­(tetra­hydrofuran-κO)lanthanum(III), [La(C₁₄H₁₀N₃)₃(C₄H₈O)₃], (II), both contain La^III atoms coordinated by three heterocyclic ligands and three tetra­hydro­furan ligands, but their coordination geometries differ. Complex (I) has a mer-distorted octa­hedral geometry, while complex (II) has a fac-distorted configuration. The difference in the coordination geometries and the existence of asymmetric La—N bonding in the two complexes is associated with intra­molecular C—H...N/O inter­actions between the ligands.