Determination of ligand-field parameters and f-electronic structures of double-decker bis(phthalocyaninato)lanthanide complexes
Determination of ligand-field parameters and f-electronic structures of double-decker bis(phthalocyaninato)lanthanide complexes
复制标题
DOI：
10.1021/ic026295u
复制
发表时间：
2003-04-07
影响因子：
4.6
通讯作者：
Kaizu, Y
中科院分区：
文献类型：
--
作者：
Ishikawa, N;Sugita, M;Kaizu, Y
测定了阴离子双(酞菁)稀土离子[Pc(2)Ln](-)(Pc=二阴离子，Ln=Tb3+，Dy3+，Ho3+，Er3+，Tm3+，Yb3+)的基态f电子结构。在1.8-300K温度范围内，[Pc(2)Ln]TBA(TBA=四丁基铵阳离子)粉末样品的磁化率表现出明显的温度依赖性，这是基态多重态分裂的结果。室温下Pc环上两种质子的核磁共振信号在Ln=Tb、Dy和Ho情况下相对于抗磁性Y络合物向较低频率移动，在Er、Tm和Yb情况下向较高频率移动。在这6例中，这两个位置的顺磁移位的比率接近恒定。这表明这些位移主要是由磁偶极项引起的，而磁偶极项是由稀土离子磁化率的各向异性决定的。使用多维非线性最小化算法，我们确定了一组同时再现六个配合物的核磁共振和磁化率数据的配位场参数。假设每个配位场参数都是稀土原子序数的线性函数。给出了多重态子能级的能量和波函数。从理论上预测了六种络合物的磁化率各向异性随温度的变化关系。
The f-electronic structures of the ground states of anionic bis(phthalocyaninato)lanthanides,[Pc(2)Ln](-) (Pc = dianion of phthalocyanine, Ln = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, or Yb3+), are determined. Magnetic susceptibilities of the powder samples Of [Pc(2)Ln]TBA (TBA = tetra-n-butylammonium cation) in the range 1.8-300 K showed characteristic temperature dependences which resulted from splittings of the ground-state multiplets. NMR signals for the two kinds of protons on the Pc rings at room temperature were shifted to lower frequency with respect to the diamagnetic Y complex in Ln = Tb, Dy, and Ho cases, and to higher frequency in Er, Tm, and Yb cases. The ratios of the paramagnetic shifts of the two positions were near constant in the six cases. This indicates that the shifts are predominantly caused by the magnetic dipolar term, which is determined by the anisotropy of the magnetic susceptibility of the lanthanide ion. Using a multidimensional nonlinear minimization algorithm, we determined a set of ligand-field parameters that reproduces both the NMR and the magnetic susceptibility data of the six complexes simultaneously. Each ligand-field parameter was assumed to be a linear function of atomic number of the lanthanide. The energies and wave functions of the sublevels of the multiplets are presented. Temperature dependences of anisotropies in the magnetic susceptibilities are theoretically predicted for the six complexes.