Synthesis, structures and luminescent properties of new heterobimetallic Zn-4f Schiff base complexes

Abstract

A series of new 3d–4f heterobimetallic Schiff base complexes of the general formula [Zn(μ-L 2)Ln(NO 3) 3(H 2O) n ] (Ln = La 1, Nd 2, Gd 3, Er 4 and Yb 5; n = 1 or 2; H 2L 2 = N, N′-bis(3-methoxy-5- p-tolylsalicylidene)ethylene-1,2-diamine) are synthesized and characterized. Complexes 1, 2, 4 and 5 are structurally characterized by X-ray crystallography. The photophysical properties of these complexes are also investigated. At room temperature, complexes 1– 5 exhibit similar solution absorption and emission spectra in the UV–Vis region. Furthermore, compounds 2, 4 and 5 exhibit solution emission corresponding to the lanthanide(III) ion in the near-infrared region at room temperature. The triplet state emission of the 3d–4f bimetallic complexes without energy transfer is also determined through the photophysical study of complex 3.