Understanding the near-infrared fluorescence and field-induced single-molecule-magnetic properties of dinuclear and one-dimensional-chain ytterbium complexes based on 2-hydroxy-3-methoxybenzoic acid

Abstract

The electronic [Xe]4f¹³ configurations of Yb(III) ions generate a variety of electronic energy levels, resulting in the fantastic optical and magnetic multifunctional properties of Yb(III) complexes. Here, 2-hydroxy-3-methoxy benzoic acid (H₂MBA) was used to construct two dinuclear and one-dimensional Yb(III) complexes namely [Yb₂(HMBA)₂(MBA)₂(DMF)₂(H₂O)₂]·6H₂O (1, DMF = N,N-dimethylformamide) and [NH₄][Yb(HMBA)₄] (2). Fluorescence measurements reveal that H₂MBA can sensitize the characteristic near-infrared luminescence of Yb(III). Magnetic susceptibility measurements show that the two Yb(III) complexes are field-induced single-molecule magnets (SMMs) with anisotropy barriers of 18(1) cm⁻¹ and 20(1) cm⁻¹ for 1 and 2, respectively. The magnetism–luminescence–structure correlations as well as relaxation pathways are investigated by ab initio calculations and fluorescence spectrometry.