Samuvel Michael David, Schreckenbach Georg
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2.
Inorg Chem. 2024 May 27;63(21):9711-9714. doi: 10.1021/acs.inorgchem.4c00940. Epub 2024 May 15.
The recently reported tris(bis(2,4,6-triisopropylbenzoyl)-phosphide)uranium (U(BAP), ) complex (. , (32), 12508-12517) demonstrated a silent P NMR spectrum. This complex was described as a U(III) complex with an organic radical ligand fragment. Moreover, the EPR spectrum of was indicative of an organic radical in the ligand framework complexed to uranium, in contrast to that of U(BAP), . Herein, with the help of relativistic density functional theory (DFT) calculations, the electronic structures of , , and U(BAP) () are examined in an effort to understand the unusual P NMR spectrum of . Results indicate the reduction of the carbonyl bonds and delocalization of the electrons over the ligands, indicative of U → L backbonding. Additionally, the reduced acyl carbons are found to exist as ketyl radicals [O═C] that are responsible for the silent P NMR spectra of . These findings demonstrate the redox noninnocent nature of BAP in and , causing uranium to exist in a formal oxidation state of +4.
最近报道的三（双（2,4,6-三异丙基苯甲酰基）磷化物）铀（U(BAP)， ）配合物（.， （32），12508 - 12517）显示出沉默的³¹P NMR光谱。该配合物被描述为具有有机自由基配体片段的U(III)配合物。此外， 的电子顺磁共振（EPR）光谱表明配体框架中的有机自由基与铀络合，这与U(BAP)， 的情况相反。在此，借助相对论密度泛函理论（DFT）计算，研究了 、 和U(BAP)（ ）的电子结构，以试图理解 异常的³¹P NMR光谱。结果表明羰基键的还原以及电子在配体上的离域，这表明存在U→L反馈键合。此外，发现还原的酰基碳以酮基自由基[O═C]的形式存在，这是 沉默的³¹P NMR光谱的原因。这些发现证明了BAP在 和 中的氧化还原非无辜性质，导致铀以 +4的形式氧化态存在。
