Computational Insights into Uranium Complexes Supported by Redox-Active α-Diimine Ligands

The electronic structures of two uranium compounds supported
by
redox-active α-diimine ligands, (MesDABMe)2U­(THF) (1) and Cp2U­(MesDABMe) (2) (MesDABMe = [ArNC­(Me)­C­(Me)NAr]; Ar = 2,4,6-trimethylphenyl
(Mes)), have been investigated using both density functional theory
and multiconfigurational self-consistent field methods. Results from
these studies have established that both uranium centers are tetravalent,
that the ligands are reduced by two electrons, and that the ground
states of these molecules are triplets. Energetically low-lying singlet
states are accessible, and some transitions to these states are visible
in the electronic absorption spectrum.

本研究采用密度泛函理论（density functional theory）与多组态自洽场方法，对两类由氧化还原活性α-二亚胺配体配位支撑的铀化合物——(MesDABMe)₂U(四氢呋喃（THF）)（1）与Cp₂U(MesDABMe)（2）的电子结构展开了系统探究。其中MesDABMe的定义为[ArN=C(Me)C(Me)=NAr]，Ar为2,4,6-三甲基苯基（Mes）。研究结果证实，两种铀中心均为四价态，配体被还原两个电子，且两种分子的基态均为三重态。此外，能量较低的单重态具有可及性，部分向该类单重态的跃迁可在电子吸收光谱中被观测到。