Synthesis and Coordination Behavior of a Flexible Bis(phosphinoferrocene) Ligand

Abstract

A symmetrical flexible bis(phosphinoferrocene) derivative, viz. bis[1′-(diphenylphosphino)ferrocenyl]methane (1), was prepared and studied as a ligand in Pd(II) and Au(I) complexes. The reactions of 1 with [PdCl2(cod)] (cod = cycloocta-1,5-diene) and [Pd(μ-Cl)(LNC)]2 (LNC = [2-(dimethylamino-κN)methyl]phenyl-κC1) produced bis(phosphine) complex trans-[PdCl2(1-κ2P,P′)] (4), wherein the ligand spans trans positions in the square-planar coordination sphere of Pd(II) and the tetranuclear, P,P-bridged complex [(μ(P,P′)-1){PdCl(LNC)}2] (5), respectively. In reactions with the Au(I) precursors [AuCl(tht)] and [Au(tht)2][SbF6] (tht = tetrahydrothiophene), ligand 1 gave rise to tetranuclear Au2Fe2 complex [(μ(P,P′)-1)(AuCl)2] (6) and to symmetrical macrocyclic tetramer [Au4(μ(P,P′)-1)4][SbF6]4 (7). All compounds were characterized by spectroscopic methods. In addition, the structures of compound 1, its synthetic precursor bis[1′-(diphenylphosphino)ferrocenyl]methanone (3), and all aforementioned Pd(II) and Au(I) complexes were determined by single-crystal X-ray diffraction analysis (some in solvated form).

Keywords

• ferrocene ligands
• phosphines
• palladium
• gold
• structure elucidation