Synthesis and near-infrared luminescence of 3d-4f bi-metallic Schiff base complexes

The reaction of the zinc(II) Schiff base complex ZnL [H2L = N,N'-bis(3-methoxysalicylidene)ethylene-1,2-diamine] with one equivalent of Ln(NO3)(3')xH(2)O (Ln = Nd, Ho, Er or Yb) gives the neutral 3d-4f bi-metallic Schiff base complexes [Zn(NO3)(mu-L)Ln(NO3)(2)(H2O)], which in solution exhibit emission corresponding to the Ln(III) ions (Ln = Nd, Er and Yb) in the near-infrared region.