The possibility of free rotation of m-tolyl and substituted pyridine groups about their bonds to square-planar organonickel(II) species

Abstract

For the purpose of this study 21 new organonickel(II) complexes of types trans-[NiRR′(PR″₃)₂] and trans-[NiR(PR″₃)₂L][ClO₄], where R = C₆Cl₅, mesityl, or Cl₂C = CCl and PR″₃= PMe₂Ph, PMe₃, or PMePh₂, have been prepared. Hydrogen-1 n.m.r. spectral investigations revealed that the m-tolyl group (R′) and 3-substituted pyridine ligands (L) bonded to trans-[NiR(PMe₂Ph)₂] units are oriented perpendicularly to the nickel co-ordination plane, while those bonded to trans-[NiR(PMe₃)₂] units rotate freely about the bond to the nickel at room temperature.