Four 3d-4f heteromultinuclear zinc(II)-lanthanide(III) complexes constructed from a distinct hexadentate N2O2-type ligand: syntheses, structures and luminescence properties

Four 3d-4f heteronuclear complexes, [(ZnL)(2)La(OAc)(2)]center dot ClO4 center dot 2CHCl(3) (1), [(ZnL)(2)La(OAc)(2)]center dot CF3SO3H2O (2), [ZnNd(L)(Py)(NO3)(3)] (3), and [ZnGd(L)(OAc)(NO3)(2)] (4) (Py=pyridine; H2L=6,6'-dimethoxy-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol), have been prepared by one-pot reaction of H2L with zinc(II) acetate, lanthanide(III) ions and Py. Although the heterobinuclear complexes 1-4 are prepared in the same reaction condition, the Py does not coordinate to Zn(II) of 1, 2, and 4. Instead, the bridging -acetato ligand is present. The coordination of the Py in 3 leads to smaller distortion of square pyramidal coordination site of Zn(II), the higher coplanarity between the planes of ZnO(phenoxo)(2) and LnO(phenoxo)(2), and the longer Zn center dot center dot center dot Ln distance compared with 4. The luminescence properties of 1-4 have been discussed. The ligand (L2-) can sensitize NIR luminescence of Nd(III) ions.