Derivation of Lanthanide Series Crystal Field Parameters From First Principles
Derivation of Lanthanide Series Crystal Field Parameters From First Principles
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DOI：
10.1002/chem.201903141
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发表时间：
2019-10-30
影响因子：
4.3
通讯作者：
Bolvin, Helene
中科院分区：
文献类型：
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作者：
Jung, Julie;Islam, M. Ashraful;Bolvin, Helene
选择两个系列的镧系元素配合物来分析这两个系列的磁性能和晶体场参数（CFP）的趋势：高度对称的LnZn（16）（picHA）（16）系列（Ln = Tb，Dy，Ho，Er，Yb；picHA =吡啶异羟肟酸）和[Ln（dpa）（3）]（C3H5N2）（3）3H（2）O系列（Ln=Ce-Yb；dpa=2,6-吡啶二羧酸）具有近似三重对称性。第一个系列呈现出由八个氧原子组成的压缩配位球，而在第二个系列中，配位球由由六个氧原子形成的细长配位球组成。 CFP 是使用两种方法从头算计算得出的：AILFT（从头算配体场论）方法，其中参数在轨道层面确定，以及 ITO（不可约张量算子）分解，其中问题在多电子层面处理。已经发现，在给定级数内，CFP 可从一个导数转移到另一个导数，作为第一近似值。两个系列的二阶参数B02的符号不同，反映了不同的环境。已经发现，强度参数S的使用允许在复合物之间进行简单的比较。此外，在这两个系列中，我们发现参数的幅度沿着系列减小，并且这种减小归因于共价效应。
Two series of lanthanide complexes have been chosen to analyze trends in the magnetic properties and crystal field parameters (CFPs) along the two series: The highly symmetric LnZn(16)(picHA)(16) series (Ln=Tb, Dy, Ho, Er, Yb; picHA=picolinohydroxamic acid) and the [Ln(dpa)(3)](C3H5N2)(3)3H(2)O series (Ln=Ce-Yb; dpa=2,6-dipicolinic acid) with approximate three-fold symmetry. The first series presents a compressed coordination sphere of eight oxygen atoms whereas in the second series, the coordination sphere consists of an elongated coordination sphere formed of six oxygen atoms. The CFPs have been deduced from ab initio calculations using two methods: The AILFT (ab initio ligand field theory) method, in which the parameters are determined at the orbital level, and the ITO (irreducible tensor operator) decomposition, in which the problems are treated at the many-electron level. It has been found that the CFPs are transferable from one derivative to another, within a given series, as a first approximation. The sign of the second-order parameter B02 differs in the two series, reflecting the different environments. It has been found that the use of the strength parameter S allows for an easy comparison between complexes. Furthermore, in both series, the parameters have been found to decrease in magnitude along the series, and this decrease is attributed to covalent effects.