Study of the Luminescent and Magnetic Properties of a Series of Heterodinuclear [ZnIILnIII] Complexes

Herein, we report the synthesis, structural investigation, and magnetic and photophysical properties of a series of 13 [ZnIILnIII] heterodinuclear complexes, which have been obtained employing a Schiff-base compartmental ligand derived from o-vanillin [H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]. The complexes have been synthesized starting from the [Zn(valpn)(H2O)] mononuclear compound and the corresponding lanthanide nitrates. The crystallographic investigation indicated two structural types: the first one, [Zn(H2O)(valpn)LnIII(O2NO)3], contains 10-coordinated LnIII ions, while in the second one, [Zn(ONO2)(valpn)LnIII(H2O)(O2NO)2]·2H2O, the rare earth ions are nine-coordinated. The ZnII ions always display a square-pyramidal geometry. The first structural type encompasses the larger Ln ions (4f0–4f9), while the second is found for the smaller ions (4f8–4f11). The dysprosium derivative crystallizes in both forms. Luminescence studies for the heterodinuclear compounds containing NdIII, SmIII, TbIII, DyIII, and YbIII revealed that the [Zn(valpn)(H2O)] moiety acts as an antenna. The magnetic properties for the paramagnetic [ZnIILnIII] complexes have been investigated.