Lanthanide(III) solvation: N,N′-dimethylformamide as a unidentate O-donor

Structure determinations for the lanthanide (Ln) complexes [(CH3)2NH2][Gd(dmf)8](ClO4)4, [Tb(dmf)8](ClO4)3 and [Ho(dmf)7(OH2)](ClO4)3 (dmf=N,N-dimethylformamide) show all three to contain an LnO8 coordination unit of essentially square-antiprismatic geometry. The geometry of the inner coordination sphere appears to be little perturbed by quite major differences in the lattice environment of the cations. Attractive interactions between coordinated dmf molecules may be one contributor to the stability of the primary coordination sphere.