Metallo‐Ligand Based 3d/4f Coordination Polymers: Synthesis, Structure and Magnetic Properties

Employment of N,N′‐bis(2‐hydroxy‐4‐carboxyphenyl)oxalamide (H6L) in Cu2+ chemistry afforded the mononuclear complex (Et4N)4[CuL] ⋅ 13H2O (A) which comprises a square planar [CuL]4− complex with several O donor atoms in its periphery. The 1 : 1 reaction between complex A and Ln(NO3)3 ⋅ xH2O (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb, x=6 or 9) in 1 : 4 mixture of ethanol/water in the presence of excess of KCl yielded two families of isomorphous 3d/4f coordination polymers, namely (Et4N)0.5[K0.5(H2O)Ln(H2O)4(CuL)] ⋅ 3H2O [Ln=La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6) and Gd(7)] and [K(H2O)Ln(H2O)4(CuL)] ⋅ ⋅6H2O [Ln=Tb(8), Dy(9), Ho(10), Er(11) and Yb(12)]. The crystal structures of 2–4 revealed the presence of 3D coordination polymers while the crystal structure of 9 the presence of a 2D coordination polymer. In both 3d/4f families, complex A retains its original structure and serves as a “metallo‐ligand”. The magnetic properties of 2–4, 7–9, 11 and 12 are discussed. The utilization of the newly synthesized N,N′‐bis(2‐hydroxy‐4‐carboxyphenyl)oxalamide (H6L) in the Cu2+ chemistry afforded the mononuclear metallo‐ligand (Et4N)4[CuL] ⋅ 13H2O (A). Exploitation of A in the lanthanide series afforded two families of isomorphous 3d/4f coordination polymers with unique structural characteristics. The magnetic properties of the Dy3+ polymer revealed SMM behavior and a strong quantum tunnelling of the magnetization.