We report here the synthesis and a preliminary characterization of the tetranuclear complex of formula [Ga3V(LEt)2(dpm)6], Ga3VEt, in which H3LEt = 2-Ethyl-2-(hydroxymethyl)-propane-1,3-diol and Hdpm = dipivaloylmethane, containing a single paramagnetic vanadium(III) center, from a structural, magnetic, and spectroscopic point of view. Structural characterization by X-ray diffraction evidenced that this derivative is isostructural with the star-shaped Single-Molecule Magnet [Fe3V(LEt)2(dpm)6], Fe3VEt, and can, thus, be considered a model to analyze the magnetic anisotropy of the vanadium(III) ion in that system. The observed results confirm the complexity in obtaining a rationalization of the magnetic behavior of this metal ion, with magnetization data and High Field Electron Paramagnetic Resonance (HF-EPR) spectroscopy providing apparently conflicting results. Indeed, the former were rationalized assuming a rhombic distortion of the ligand field and a dominant easy-axis type anisotropy (equivalent to D ≈ −14.1 cm−1, E ≈ 1.2 cm−1), while a simple axial Spin Hamiltonian approach could explain HF-EPR data (|D| ≈ 6.98 cm−1).

中文翻译：

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准八面体钒 (III) 中磁各向异性的复杂测定：HF-EPR 和磁学研究

我们在此报告了式 [Ga3V(LEt)2(dpm)6]、Ga3VEt 的四核络合物的合成和初步表征，其中 H3LEt = 2-Ethyl-2-(羟甲基)-propane-1,3-diol和 Hdpm = 二戊酰甲烷，从结构、磁性和光谱的角度来看，包含单个顺磁性钒 (III) 中心。X 射线衍射的结构表征证明，该导数与星形单分子磁铁 [Fe3V(LEt)2(dpm)6]、Fe3VEt 是同构的，因此可以被视为分析磁各向异性的模型该系统中钒 (III) 离子的浓度。观察到的结果证实了获得该金属离子磁性行为合理化的复杂性，磁化数据和高场电子顺磁共振 (HF-EPR) 光谱提供了明显相互矛盾的结果。事实上，前者被合理化，假设配体场的菱形畸变和主要的易轴型各向异性（相当于 D ≈ -14.1 cm-1，E ≈ 1.2 cm-1），而简单的轴向自旋哈密顿方法可以解释HF-EPR 数据 (|D| ≈ 6.98 cm-1)。