Nickel nitrosyl complexes in a sulfur-rich environment: The first poly(mercaptoimidazolyl)borate derivatives

The diamagnetic nickel mononitrosyl complexes (TmR)Ni(NO) (R = But, p-Tol) and (BmR)Ni(PPh3)(NO) (R = Me, But) have been readily prepared from Ni(PPh3)2(NO)Br and the appropriate Na(TmR) or Na(BmR) reagents, respectively. These species constitute the first nickel nitrosyl complexes supported by these ligand systems. An X-ray diffraction study of (Tmp-Tol)Ni(NO) confirmed its pseudo-tetrahedral geometry and the presence of a nearly linear nitrosyl ligand. In contrast, (BmMe)Ni(PPh3)(NO) can be best described as having a trigonal pyramidal geometry, a spatial arrangement unprecedented in nickel nitrosyl chemistry, which is facilitated by the disposition of the BmMe ligand and the presence of a weak intramolecular Ni⋯H–B interaction opposite to the apical triphenylphosphine ligand.

The first nickel nitrosyl complexes supported by bis- and tris(mercaptoimidazolyl)borate ligands, (BmR)Ni(PPh3)(NO) (R = Me, But) and (TmR)Ni(NO) (R = But, p-Tol), have been readily prepared and fully characterized using a combination of analytical and spectroscopic techniques. Whereas the TmR compounds are tetrahedral and contain linear nitrosyl ligands, the BmR derivatives are trigonal pyramidal and display bent NO groups.Figure optionsDownload as PowerPoint slide