Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States.
J Org Chem. 2011 Oct 21;76(20):8447-57. doi: 10.1021/jo2017923. Epub 2011 Sep 21.
Oxidation of diaryldiamine 2, a tetrahydrodiazapentacene derivative, provides diarylnitroxide diradical 1 accompanied by an intermediate nitroxide monoradical and a multitude of isolable diamagnetic products. DFT-computed tensors for EPR spectra and paramagnetic (1)H NMR isotropic shifts for nitroxide diradical 1 show good agreement with the experimental EPR spectra in rigid matrices and paramagnetic (1)H NMR spectra in solution, respectively. Examination of the diamagnetic products elucidates their formation via distinct pathways involving C-O bond-forming reactions, including Baeyer-Villiger-type oxidations. An unusual diiminoketone structure and two spirocyclic structures of the predominant diamagnetic products are confirmed by either X-ray crystallography or correlations between DFT-computed and experimental spectroscopic data such as (1)H, (13)C, and (15)N NMR chemical shifts and electronic absorption spectra.
二芳基二胺 2 的氧化提供了二芳基氮氧自由基 1，同时伴随着一个中间体氮氧单自由基和许多可分离的抗磁性产物。DFT 计算的 EPR 光谱张量和氮氧自由基 1 的顺磁（1）H NMR 各向同性位移与刚性基质中的实验 EPR 光谱和溶液中的顺磁（1）H NMR 光谱分别吻合较好。对抗磁性产物的研究阐明了它们通过不同的途径形成，包括 C-O 键形成反应，包括 Baeyer-Villiger 型氧化。通过 X 射线晶体学或 DFT 计算和实验光谱数据（如（1）H、（13）C 和（15）N NMR 化学位移和电子吸收光谱）之间的相关性，证实了主要抗磁性产物的不寻常的二亚氨基酮结构和两个螺环结构。
