CONVENIENT SYNTHESIS AND CHARACTERIZATION OF THE CHIRAL COMPLEXES CIS-[RU((SS)-PR(I)PYBOX)(PY)(2)CL]PF6 AND TRANS-[RU((SS)-PR(I)PYBOX)(PY)(2)CL]PF6 AND [RU((SS)-PR(I)PYBOX)(BPY)CL]PF6

The chiral oxazoline complexes cis-and trans-[Ru((SS)-Pr(i)pybox)(py)( 2)Cl]PF6 were prepared from the common precursor trans-[Ru((SS)-Pr(i)p ybox)(py)Cl-2], and all three complexes were spectroscopically and str ucturally characterized. The complex cis-[Ru((SS)-Pr(i)pybox)(py)(2)C] ]PF6 crystallized in P2(1)2(1)2(1) With Z = 4, a = 8.396(2) Angstrom, b = 18.396(3) Angstrom, c = 20.954(3) Angstrom, and R = 0.039 for 4131 reflections. The complex trans-[Ru((SS)-Pr-i-pybox)(py)(2)Cl]PF6 crys tallized in P2(1) with Z = 2, a = 10.110(2) Angstrom, b = 13.566(2) An gstrom, c = 12.043(2) Angstrom, beta = 106.10(2)degrees, and R = 0.039 for 3869 reflections. The precursor trans-[Ru((SS)-Pr(i)pybox)(py)Cl- 2] crystallized in P2(1)2(1)2(1) with Z = 8, a = 15.856(2) Angstrom, b = 17.216(1) Angstrom, c = 17.768(1) Angstrom, and R = 0.030 for 5826 reflections. A related reagent, [Ru((SS)-Pr(i)pybox)(bpy)Cl]PF6, was p repared by a more direct route and was also characterized. Aqua comple xes were formed by hydrolysis of the chloride ligand in the bis(pyridi ne) complexes with retention of the stereochemistry. Electrochemical o xidation of the aqua complexes yielded oxo species which are formally ruthenium(IV). Reactions of the oxo complexes with the prochiral reduc tant, methyl p-tolyl sulfide led to stereoselective formation of the s ulfoxide with enantiomeric excess of the R isomer ranging from 7% to 1 3%.