Ferrocenyl sulfides. Preparation and reactivity as bidentate chelating ligands

Article abstract of DOI:10.1021/om00127a020

A series of ferrocenyl sulfide derivatives, Fe(C₅H₄SR)₂, where R = Me, i-Pr, I-Bu, Ph, and PhCH₂, have been prepared by lithiation of ferrocene followed by reaction with the appropriate disulfide. The complexes were characterized by ¹H and ¹³C NMR, mass spectra, and infrared spectroscopy. The ferrocenyl sulfide derivatives readily chelate palladium and platinum halides to form [3]ferrocenophane complexes Fe-(C₅H₄SR)₂MX₂ (R = Me, i-Pr, i-Bu, Ph, PhCH₂; M = Pd, Pt; X = Cl, Br). ¹H, ¹³C, and ¹⁹⁵Pt NMR spectra were obtained where possible, and infrared, ultraviolet-visible and cyclic voltammetry data of the complexes are presented. The structure of Fe(C₅H₄S-i-Bu)₂PdCl₂ (6) was determined by single-crystal X-ray diffraction measurements. Compound 6 crystallizes in the orthorhombic space group Pbca with lattice parameters a = 22.168 (11) ?, b = 11.855 (7) ?, c = 16.131 (6) ?, M_r = 539.69, ρ(calcd) = 1.691 cm^-3, and Z = 8. Least-squares refinement gave a final R value of 0.046 for 3689 observed reflections. The dihedral angle between the Fe-S₁-S₂ plane and the S₁-Pd-S₂ plane is 104.6°. The molecule 6 is fluxional in solution where the palladium atom flips from one side of the Fe-S₁-S₂ plane to the other.