Crystal Structures of Ln(III) (Ln = La, Pr, Nd, Sm, Eu, and Gd) Complexes with N,N,N′,N′-Tetraethyldiglycolamide Associated with Homoleptic [Ln(NO3)6)]3-

Novel lanthanoid(III) (Ln(III)) complexes with N,N,N',N'-tetraethyldiglycolamide (TEDGA), [Ln(TEDGA)(3)][Ln(NO3)(6)] (Ln = La, Ce, Pr, Nd, Sm, Eu, and Gd), have been synthesized and characterized crystallographically. The crystal structures of these complexes are constructed by the packing of [Ln(TEDGA)(3)](3+) cations and [Ln(NO3)(6)](3-) anions. The [Ln(TEDGA)(3)](3+) cations exhibit distorted tricapped trigonal prismatic geometry, in which Ln(III) ions are coordinated by nine oxygen atoms from three tridentate TEDGA ligands. The [Ln(NO3)(6)](3-) anions have distorted icosahedral geometry, where Ln(III) ions are coordinated by twelve oxygen atoms from the six bidentate nitrate ligands. The Ln-O bond lengths tend to increase in the following order, Ln-O-nitrate > Ln-O-ether > Ln-O-carbo. Each Ln-O bond length becomes gradually short according to the lanthanoid contraction.