title: Oxidation of annelated diarylamines: analysis of reaction pathways to nitroxide diradical and spirocyclic products.
abstract: 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.
authors: Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States. arajca1@unl.edu
authors: Andrzej
authors: A
authors: Rajca
authors: Kouichi
authors: K
authors: Shiraishi
authors: Przemysław J
authors: PJ
authors: Boratyński
authors: Maren
authors: M
authors: Pink
authors: Makoto
authors: M
authors: Miyasaka
authors: Suchada
authors: S
authors: Rajca
mesh_terms: D000588:Amines / Q000737:chemistry*; D002625:Chemistry, Organic / Q000379:methods*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry*; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D012996:Solutions
chemical_list: D000588:Amines; D008024:Ligands; D009589:Nitrogen Oxides; D011084:Polycyclic Aromatic Hydrocarbons; D012996:Solutions; C039900:nitroxyl