ON CORRELATING THE FREQUENCY OF THE F-7(0)-]D-5(0) TRANSITION IN EU(3+) COMPLEXES WITH THE SUM OF NEPHELAUXETIC PARAMETERS FOR ALL OF THE COORDINATING ATOMS
ON CORRELATING THE FREQUENCY OF THE F-7(0)-]D-5(0) TRANSITION IN EU(3+) COMPLEXES WITH THE SUM OF NEPHELAUXETIC PARAMETERS FOR ALL OF THE COORDINATING ATOMS
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DOI：
10.1016/0020-1693(94)04269-2
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发表时间：
1995-02-01
影响因子：
2.8
通讯作者：
HORROCKS, WD
中科院分区：
文献类型：
--
作者：
FREY, ST;HORROCKS, WD
Eu ~（3+）的F-7（0）→ D-5（0）跃迁频率与Eu ~（3+）配合物中配位原子的电子云拉胀参数之和有关。通过对27个已知配体组成的9配位Eu ~（3+）配合物的F-7（0）--> D-5（0）跃迁频率进行多元线性回归，得到了9种不同配位原子类型的参数。线性相关系数为0.99。从7-，8-，10-，和11-坐标配合物的数据相加，并使用乘法常数，每个配位数的特性，产生第二个线性相关性覆盖37个系统的相关系数为0.98。本方法试图了解影响F-7（0）--> D-5（0）跃迁频率的因素，并对特定配体环境下的这一数量进行预测。它在本质上完全是经验的;然而，其结果可以根据一个潜在的理论原因来理解。在这里获得的参数大致相关的nephelauxetic h-值的约根森的几种情况下，适当的配体匹配。F-7（0）-> D-5（0）项的分离度随着配体共价性的增加而从其自由离子值17 374 cm（-1）下降，目前推导的参数与这一观点一致。这里给出的相关性明显上级我们先前试图确定的F-7（0）--> D-5（0）跃迁频率与络合物中配体上的总形式电荷之间的关系。
The frequency of the F-7(0) --> D-5(0) transition of EU(3+) is found to correlate with the sum of derived nephelauxetic parameters of the ligating atoms in Eu3+ complexes. Parameters for nine distinct coordinating atom types are obtained via a multiple linear regression method applied to experimental F-7(0) --> D-5(0) transition frequencies of twenty-seven 9-coordinate Eu3+ complexes with known ligand constituents. The linear correlation coefficient is 0.99. Addition of data from 7-, 8-, 10-, and 11-coordinate complexes and use of a multiplicative constant, characteristic of each coordination number, produces a second linear correlation covering thirty-seven systems with a correlation coefficient of 0.98. The present approach seeks to understand the factors which influence the F-7(0) --> D-5(0) transition frequency and to make predictions of this quantity for particular ligand environments. It is completely empirical in nature; however, the results may be understood in terms of an underlying theoretical cause. The parameters obtained here correlate roughly with the nephelauxetic h-values of Jorgensen for the few cases where appropriate ligand matches are available. The F-7(0) --> D-5(0) term separation will decrease from its free-ion value of 17 374 cm(-1) with increasing Eu3+-ligand covalency, and the presently derived parameters are consistent with this idea. The correlation presented here is clearly superior to our earlier attempt to identify a relationship between the F-7(0) --> D-5(0) transition frequency and the total formal charge on the ligands in a complex.