Synthesis and stereochemical studies of the chiral ruthenium complexes [Ru(η-C5H5)(S)dpompyr-PP′X] [dpompyr = N-diphenylphosphino-2-(diphenylphosphinoxymethyl)pyrrolidine, X = H or Cl]. Crystal structure of [(S)Ru(η-C5H5)(S)dpompyr-PP′Cl]