Electronic Structure and Magnetic Properties of a Low-Spin Cr II Complex: trans -[CrCl 2 (dmpe) 2 ] (dmpe = 1,2-Bis(dimethylphosphino)ethane)
Electronic Structure and Magnetic Properties of a Low-Spin Cr II Complex: trans -[CrCl 2 (dmpe) 2 ] (dmpe = 1,2-Bis(dimethylphosphino)ethane)
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低自旋 Cr II 配合物的电子结构和磁性：反式 -[CrCl 2 (dmpe) 2 ] (dmpe = 1,2-双(二甲基膦基)乙烷)
DOI：
10.1021/acs.inorgchem.1c02471
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发表时间：
2021
影响因子：
4.6
通讯作者：
Telser, Joshua
中科院分区：
文献类型：
--
作者：
Zolnhofer, Eva M.;Opalade, Adedamola A.;Jackson, Timothy A.;Heinemann, Frank W.;Meyer, Karsten;Krzystek, J.;Ozarowski, Andrew;Telser, Joshua
通式[MX2(R2ECH2CH2ER2)2](MII=Ti，V，Cr，Mn；E=N，P；R=烷基，芳基)的八面体配合物是配位化学和有机金属化学的基石，其中许多配合物具有独特的电子结构，但尚未完全研究过。[CrCl2(Dmpe)2]配合物(dmpe=Me2PCH2CH2PMe2)最初由Girolami和他的同事在1985年报道，它是一个罕见的具有ANS=1(自旋三重态)基态的六坐标d4系统，而不是高自旋(S=2，自旋五元组)态。用传统的光谱方法研究OFS=1体系的基态性质具有挑战性，因此，反式[CrCl2(Dmpe)2]的电子结构在很大程度上仍未被探索。在本工作中，我们用高频场电子顺磁共振(HFEPR)谱表征了反式[CrCl2(Dmpe)2]的基态电子结构。这一分析得到了一组完整的自旋哈密顿参数：D=+7.39(1)cm-1，E=+0.093(1)(E/D=0.012)，g=[1.999(5)，2.00(1)，2.00(1)]。为了对反式[CrCl2(Dmpe)2]进行详细的电子结构描述，我们使用了经典的配位场理论和量子化学理论(QCT)计算，其中考虑了所有的五重态、三重态和单重态。虽然高密度的态表明这一“简单的”配位络合物的电子结构出人意料地复杂，但配位场和QCT方法都能够很好地重现实验中的自旋哈密顿参数。QCT计算也被用作指认反式-[CrCl2(Dmpe)2]在甲苯中的电子吸收光谱的基础。
Octahedral coordination complexes of the general formulatrans-[MX2(R2ECH2CH2ER2)2] (MII= Ti, V, Cr, Mn; E = N, P; R = alkyl, aryl) are a cornerstone of both coordination and organometallic chemistry, and many of these complexes are known to have unique electronic structures that have been incompletely examined. Thetrans-[CrCl2(dmpe)2] complex (dmpe = Me2PCH2CH2PMe2), originally reported by Girolami and co-workers in 1985, is a rare example of a six-coordinate d4system with anS= 1 (spin triplet) ground state, as opposed to the high-spin (S= 2, spin quintet) state. The ground-state properties ofS= 1 systems are challenging to study using conventional spectroscopic methods, and consequently, the electronic structure oftrans-[CrCl2(dmpe)2] has remained largely unexplored. In this present work, we have employed high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy to characterize the ground-state electronic structure oftrans-[CrCl2(dmpe)2]. This analysis yielded a complete set of spin Hamiltonian parameters for thisS= 1 complex:D= +7.39(1) cm–1,E= +0.093(1) (E/D= 0.012), andg= [1.999(5), 2.00(1), 2.00(1)]. To develop a detailed electronic structure description fortrans-[CrCl2(dmpe)2], we employed both classical ligand-field theory and quantum chemical theory (QCT) calculations, which considered all quintet, triplet, and singlet ligand-field states. While the high density of states suggests an unexpectedly complex electronic structure for this “simple” coordination complex, both the ligand-field and QCT methods were able to reproduce the experimental spin Hamiltonian parameters quite nicely. The QCT computations were also used as a basis for assigning the electronic absorption spectrum oftrans-[CrCl2(dmpe)2] in toluene.