Abstract：
New cobalt(II)-based complexes with [N2O2] coordination formed by two bis-chelate ligands were synthesized and characterized by a multi-technique approach. The complexes possess an easy-axis anisotropy (D < 0) and magnetic measurements show a field-induced slow relaxation of magnetization. The spin-reversal barriers, i.e., the splitting of the two lowest Kramers doublets (UZFS), have been measured by THz-EPR spectroscopy, which allows to distinguish the two crystallographically independent species present in one of the complexes. Based on these experimental UZFS energies together with those for related complexes reported in literature, it was possible to establish magneto-structural correlations. UZFS linearly depends on the elongation parameter εT of the (pseudo-)tetrahedral coordination, which is given by the ratio between the average obtuse and acute angles at the cobalt(II) ion, while UZFS was found to be virtually independent of the twist angle of the chelate planes. With increasing deviation from the orthogonality of the latter, the rhombicity (|E/D|) increases.
摘要：
合成了由两个双螯合配体形成的具有[N2O2]配位的新型钴（II）基配合物，并通过多技术方法进行了表征。配合物具有易轴各向异性（D<0），磁测量显示磁场引起的磁化缓慢弛豫。自旋反转障碍，即，两个最低的Kramers双峰(UZFS)的分裂，已经通过THz-EPR光谱测量，这允许区分存在于复合物之一中的两个晶体学上独立的物种。基于这些实验UZFS能量以及文献中报道的相关复合物的能量，建立磁结构相关性是可能的。UZFS线性取决于（伪）四面体配位的伸长参数εT，由钴（II）离子处的平均钝角和锐角之间的比率给出，而发现UZFS实际上与螯合物平面的扭转角无关。随着与后者正交性的偏差越来越大，菱形(|E/D|)增加。
