Synthesis and Structural Investigations of Novel Palladium(II) and Rhodium(I) Complexes Containing Chiral Ligands with a Stereogenic Sulfur Donor, Such As β-Amino Sulfoxides and C2-Symmetric Bis-Sulfoxides1

Two kinds of new optically active chelating ligands bearing a chiral sulfinyl functionality, namely the 3,4-bis-( p -tolylsulfinyl)hexanes 4 and the N-mono- and N,N-disubstituted β- p -tolylsulfinyl ethylamines 5 and 2, have been synthesized and their coordination chemistry with Pd(II) and Rh(I) metals has been studied in detail. Complexes formed with ligands 4 featured a homocoordination between the two sulfur donors and the metal atom, in solution as well as in the solid state, as demonstrated by X-ray diffraction of cis -dichloro3,4-bis-( p -tolylsulfinyl)hexanepalladium(II) ( (3 R,4 R, R S, R S )- 7 ), in which the ligand shows a C 2 symmetry. Complexes formed with ligands 2 and 5 showed a heterocoordination of the metal by the sulfur and the nitrogen donors, as confirmed by X-ray diffraction of cis -dichloro N, N -dimethyl-2-( p -tolylsulfinyl)ethylaminepalladium(II) (( R )- 6 ). All nine complexes 6 − 11, displaying a monomeric structure, have been synthesized and completely characterized in the solid state (IR, MS-FAB) as well as in solution ( 1 H and 13 C NMR, α 25 D ).