Self-Assembly of 3d-4f ZnII-LnIII (Ln = Ho and Er) Bis(salamo)-Based Complexes: Controlled Syntheses, Structures and Fluorescence Properties

Abstract

Two new hetero-trinuclear 3d-4f complexes [Zn2(L)Ho(μ2-OAc)2(OAc)(MeOH)]·CH2Cl2 (1) and [Zn2(L)Er(μ2-OAc)2]OAc (2), derived from a bis(salamo)-based ligand H4L, were synthesized and characterized via elemental analyses, IR, UV–Vis, fluorescence spectra and X-ray crystallography. The X-ray crystal structure analyses demonstrated that two μ2-acetateanions bridge the ZnII and LnIII (Ln = Ho (1) and Er (2)) atoms in a μ2-fashion forming similar hetero-trinuclear structures, respectively. In complex 1, one methanol molecule as coordinating solvent participates in the coordination, the two ZnII atoms are six- and five-coordinated and have geometries of slightly distorted tetragonal pyramid and octahedron, and the HoIII atom is nine-coordinated and has the geometry of a mono-capped square antiprism. In complex 2, the two ZnII atoms both possess five-coordinated tetragonal pyramid geometries, and the ErIII atom is eight-coordinated with a square antiprism geometry. Furthermore, the fluorescence properties of complexes 1 and 2 were determined.