31P nuclear magnetic resonance study of conformers of trans-[MCl(CO)(PBu2 tR)2](M = Rh or Ir; R = Me, Et, or Prn)

Abstract
The low temperature 31P n.m.r. spectra of the complexes trans-[MCl(CO)(PRBut 2)2](M = Rh or Ir; R = Me, Et, or Prn) show the presence of three rotamers with very different chemical shifts.