Oxidative assembly of octahedral nickel(II)-tris(3,5-dimethylpyrazol-1-yl)methane (Tpm∗) complexes by reaction of Ni(COD)2 (COD = 1,5-cyclooctadiene) with putative oxene and nitrene precursors

Reactions of [Ni0(COD)2] (COD = 1,5-cyclooctadiene) with meta-chloroperoxybenzoic acid, phenyl-N-tosylimidoiodinane or 2-(tert-butylsulfonyl)iodosylbenzene were performed in THF solution in the presence of one equivalent of tris(3,5-dimethylpyrazol-1-yl)methane (Tpm∗), yielding the product complexes [Tpm∗NiII(OH2)(3-ClC6H4CO2)2] (2), [(Tpm∗)2NiII][NiII(NHTs)4] (3), and [Tpm∗NiII(OH)2(OH2)] (4), respectively. Products 2–4 arise from oxidation of solvated [Ni0(COD)2], with subsequent ligation of Tpm∗ and substrate fragments leading to assembly of disparate octahedral nickel(II) centers. For comparative purposes, the previously reported complex [(Tpm∗)NiII(OH2)Cl2] (1) was also obtained from Tpm∗ and NiCl2. All complexes were characterized spectroscopically, and complexes 1–3 were also structurally characterized by X-ray crystallography.

Graphical abstractOxidation of Ni(COD)2 with a variety of oxene and nitrene precursors in the presence of tris(3,5-dimethylpyrazol-1-yl)methane (Tpm∗) leads to isolation of several octahedral Tpm∗-supported nickel(II) complexes.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Tris(3,5-dimethylpyrazol-1-yl) complexes of nickel. ► Oxidation of Ni(COD)2. ► In situ assembly of octahedral scorpionate nickel(II) complexes. ► Spectroscopic and structural characterizations.