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

The diamagnetic nickel mononitrosyl complexes (Tm-R)Ni(NO) (R = Bu-t, p-Tol) and (Bm(R))Ni(PPh3)(NO) (R = Me, Bu-t) have been readily prepared from Ni(PPh3)(2)(NO)Br and the appropriate Na(Tm-R) or Na(Bm(R)) 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 pseudotetrahedral geometry and the presence of a nearly linear nitrosyl ligand. In contrast, (Bm(Me))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 Bm(Me) ligand and the presence of a weak intramolecular Ni center dot center dot center dot H-B interaction opposite to the apical triphenylphosphine ligand. (c) 2007 Elsevier Ltd. All rights reserved.