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
journal contributionposted on 26.01.1999, 00:00 by Claudio Pettinari, Maura Pellei, Giancarlo Cavicchio, Marcello Crucianelli, Walter Panzeri, Marcello Colapietro, Alberto Cassetta
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-dichloro[3,4-bis-(p-tolylsulfinyl)hexane]palladium(II) ((3R,4R,RS,RS)-7), in which the ligand shows a C2 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)ethylamine]palladium(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 (1H and 13C NMR, [α]25D).