Interligand Interactions in Half-Sandwich Nickelacarboranes with Phosphine Ligands: Away from Skeletal Rearrangements

Reactions of nickel(II) phosphine complexes [(dppe)NiCl2], [(MePh2P)2NiCl2] and [(Ph3P)2NiCl2] with C-substituted nido-carboranes [7-R-nido-7,8-C2B9H11]- (R = Me, Ph, C(NHCy)2+) were studied. The reactions with [(dppe)NiCl2] lead to the corresponding nickelacarboranes 3,3-(dppe)-1-R-closo-3,1,2-NiC2B9H10 with absent or negligible steric interactions between the ligands. The reactions of [(MePh2P)2NiCl2] with [7-R-nido-7,8-C2B9H11]- (R = H, Me, Ph) result in nickelacarboranes 3,3(MePh2P)2-1-R-closo-3,1,2-NiC2B9H10 with noticeable steric loading, while the reaction with [7-(CyNH)2C-nido-7,8-C2B9H11] proceeds with the displacement of one phosphine ligand with the formation of a mixed-ligand phosphine-chloride half-sandwich complex 3-MePh2P-3-Cl-1-(CyNH)2C-closo-3,1,2-NiC2B9H10.