Complexes of hybrid ligands. The synthesis of a thioanisole-substituted fluoro-alcohol and its complexes with Pd2+ and Pt2+; the structure of a palladium(II) complex containing alkoxide, phosphine, thioether, and chloride donors

Abstract

The compound 2-thioanisole-1,1,1,3,3,3-hexafluoro-2-propanol, CH3S—C6H4—C(CF3)2OH, HL2, has been prepared, and shown to act (in the ionized form) as a hybrid, chelating, ligand. Neutral bis-complexes M(L2)2 are formed with Pd2+ and Pt2+; the former reacts with PdCl42− to give the Cl-bridged dinuclear complex (L2)Pd(μ-Cl)2Pd(L2), which may in turn be cleaved by PPh3 or PPh2Me to give PdCl(L2)(PR3).A complete structural determination has been made for PdCl(L2)(PPh2Me); C23H20ClF6OPPdS. Crystals are monoclinic, space group P21/n, a = 15.526(5), b = 12.966(9), c = 12.900(8) Å, β = 101.84°, V = 2542(2) Å3, Z = 4. Least-squares refinement on F of 198 variables using 2801 observations converged at R1 = 0.0434, R2 = 0.0559. The complex consists of discrete square-planar molecules with phosphine and alkoxide trans-disposed. Bond lengths are Pd—O, 2.053(3); Pd—P, 2.242(1); Pd—Cl, 2.323(2); Pd—S, 2.252(2) Å. In the six-membered chelate ring, all atoms with the exception of Pd are close to coplanarity; there is a dihedral angle of 127.9° between the O—Pd—S plane and that of the aromatic ring.Multinuclear nmr measurements are used to show that both cis- and trans-forms of complexes PdCl(L2)(PR3) are present in solution, with inversion at coordinated sulfur occurring much more rapidly in the latter.