On the Synthesis of a T‐Shaped Imido Nickel Complex and Trigonal Amido Nickel Complexes

• Published in: European journal of inorganic chemistry 2022-04, Vol.2022 (10), p.n/a
• Main Authors: Reckziegel, Alexander, Battistella, Beatrice, Werncke, C. Gunnar
• Format: Article
• Language: English
• Subjects: Alkoxides; Amides; Amido ligands; Imido ligands; Inorganic chemistry; Nickel; Organic salts; Redox chemistry; Structure elucidation; Substrates; Synthesis
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202101102

The synthesis of a T‐shaped imido nickel complex is reported, obtained by the reaction of phenyl azide with the linear nickel(I) silylamide complex K{18‐crown‐6}[NiL2] (L=−N(Dipp)SiMe3; Dipp=2,6‐diisopropylphenyl). In addition, an unusual shift of a SiMe3 unit from an ancillary ligand to a putative [Ni=NPh] complex is observed. Examination of the resulting [Ni=NDipp] complex for its electronic properties leads to its description as a low‐spin nickel(III) imide and revealed only limited activity with respect to H‐atom ion from C−H bonds or nitrene. Attempts to obtain information about the general features of trigonal nickel(II) amide products, that would result from such a H‐atom ion reaction, via reaction of linear nickel(II) silylamide [NiL2] with alkali metal salts of primary amides revealed the reduction to the linear nickel(I) complex K{18‐crown‐6}[NiL2]. The same is observed for alkoxides, secondary amides or benzyl. Reaction of the organic salts with the anionic nickel(II) complex NBu4[NiBrL2] under salt elimination also give the linear nickel(I) complex. Partial formation of an otherwise stable T‐shaped nickel(II) can be observed only for the electron‐poor diphenyl amide. This implicates that reduction of the starting nickel(II) complexes by different organic alkali metal salts likely does not occur via a homolytic Ni−R bond cleavage but a direct SET process from the unligated substrate to the nickel(II) ion. We describe the synthesis of a stable T‐shaped low‐spin nickel(III) imide which is subject of intramolecular SiMe3‐shift from an amide to the original imide function. Attempts to obtain anionic trigonal nickel(II) amides lead to reduction of the nickel center with the exception of the electron‐poor diphenylamide.