Four Dinuclear and One-Dimensional-Chain Dysprosium and Terbium Complexes Based on 2-Hydroxy-3-methoxybenzoic Acid: Structures, Fluorescence, Single-Molecule-Magnet, and Ab Initio Investigation

摘要

The unique electronic configurations of lanthanide(III) ions generate abundant electronic energy levels, resulting in the fantastic magnetic and optical multifunctional properties of lanthanide complexes. Here, 2-hydroxy-3-methoxybenzoic acid (H(2)MBA) was used to construct four Dy(III) and Tb(III) complexes containing two isostructural dinuclear complexes of [Ln(2)(HMBA)(2)(MBA)(2)(DMF)(2)(H2O)(2)]center dot 6H(2)O [Ln = Dy (1), Tb (2); DMF = N,N-dimethylformamide] and two other isostructural beltlike one-dimensional-chain complexes of [NH4][Ln(HMBA)(4)] [Ln = Dy (3), Tb (4)]. Fluorescence measurements reveal that H(2)MBA can sensitize Dy(III) and Tb(III) characteristic luminescence. Furthermore, complex 3 can emit white light under UV-light irradiation originating from a dichromatic mixture of a blue emission of H(2)MBA and a dominating yellow emission of Dy3+ ions. Magnetic susceptibility measurements show that two Dy(III) complexes are single-molecule magnets with anisotropy barriers of 90(2) and 31(5) cm(-1) for 1 and 3, respectively. The magnet-luminescence-structure correlations as well as relaxation pathways are investigated by ab initio calculations and fluorescent spectrometry.

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