The synthesis of substituted bis [(diarylphosphinomethyl)cyclopentadienyl] zirconocene dichloride complexes for the preparation of heterodimetallic complexes containing early/late transition metal combinations

Article abstract of DOI:10.1016/s0020-1693(97)06002-7

Fulvenes (1a-e) derived from condensation of cyclopentadiene with acetone or a variety of aldehydes were treated with LiPAr₂ (Ar=phenyl, p-tolyl) to yield the respective substituted (diarylphosphinomethyl)cyclopentadienides (2, 3). Subsequent reaction with ZrCl₄ (THF)₂ gave the respective bis [(diarylphosphinomethyl)cyclopentadienyl] zirconium dichlorides (Ar=phenyl (4), p-tolyl (5)). The complex rac-[C₅H₄-CH(CH₃)-PPh₂] ₂ZrCl₂ (rac-4b) was characterized by X-ray diffraction. The reaction of complexes 4a and 5a [(Cp-CMe₂-PAr₂)₂ZrCl₂] with PdCl₂(NCPh)₂ or PtCl₂(NCPh)₂ leads to the formation of the trans-(metallocene-chelate-phosphane)metal complexes 6-9 (e.g. trans-Cl₂Pd(Ph₂P-CMe₂-Cp)₂ZrCl ₂]. Chloride abstraction from the reaction product of [Cp-CH(CMe₃)PPh₂]₂ZrCl₂ with PdCl₂(NCPh)₂ eventually gave the cationic complex [meso,trans-(Cp-CH(CMe₃)PPh₂) ₂(Cl)Zr(μ-Cl)Pd(Cl)]⁺ (10) that was also characterized by X-ray diffraction. It features a dimetallabicyclic framework with two Cp-CHR-PPh₂ ligands and a chloride bridging between the early and the late transition metal center.