Structural Characterization of Heterodimetallic Zr/Pd and Zr/Rh Catalyst Precursors Containing the C₅H₄PPh₂ Ligand

(Cp-PPh 2 ) 2 ZrCl 2 ( 5 ) reacts with (PhCN) 2 PdCl 2 to yield the early−late heterodimetallic complex [(Cp-PPh 2 ) 2 ZrCl 2 /PdCl 2 ], 7, which was characterized by an X-ray crystal structure analysis. The phosphine-substituted bent metallocene moiety in 7 serves as a conformationally flexible chelate phosphine ligand (angle P−Pd−P: 96.46(3)°). Complex 7 is an active catalyst for the cross-coupling of sec -butylmagnesium bromide with bromobenzene, leading to excellent regioselectivity and moderate reactivity. Complex 5 reacts with dicarbonylrhodium chloride dimer (0.5 equiv) to yield the triply bridged complex 12, [ClZr(μ-Cp-PPh 2 ) 2 (μ-Cl)Rh(CO)Cl], which was also characterized by X-ray diffraction (the angle P−Rh−P is 158° at the distorted square-pyramidal pentacoordinated rhodium center). (Cp-PPh 2 ) 2 Zr(CH 3 ) 2 ( 13 ) reacts with [H(CO)Rh(PPh 3 ) 3 ] ( 14 ) with loss of two PPh 3 ligands and instantaneous liberation of methane to form complex 15, [CH 3 Zr(μ-Cp-PPh 2 ) 2 Rh(CO)PPh 3 ]( Zr − Rh ), which probably contains a metal−metal bond between the early and late transition metal. Complex 15 is a very active 1-hexene hydroformylation catalyst (TOF > 600, n/iso ≈ 3 at 80 °C).