NMR Studies of Chiral P,S-Chelate Platinum, Rhodium, and Iridium Complexes and the X-ray Structure of a Palladium(II) Allyl Derivative

Abstract

Several Rh(I), Ir(III), and Pt(II) complexes of the chiral P,S-bidentate ligand 2 have been prepared and characterized. Detailed two-dimensional NMR studies show that (i) the boat-type chelate ring and the stereogenic sulfur center can invert rapidly at ambient temperature and (ii) the sulfur donor may dissociate, essentially destroying the chiral pocket. The solid-state structure of [Pt(η 3 -C 3 H 5 )( 2 )]PF 6 ( 3 ) has been determined and the sulfur substituent shown to have an axial orientation. The six-membered chelate ring takes up a boatlike conformation. As shown by an X-ray diffraction study for 3, and via incoherent inelastic neutron scattering (IINS) measurements for the Pd analog, 4, the OH group is remote from the metal atom.