Structural Characterization of Heterodimetallic Zr/Pd and Zr/Rh Catalyst Precursors Containing the C5H4PPh2Ligand

(Cp-PPh2)2ZrCl2 (5) reacts with (PhCN)2PdCl2 to yield the early−late heterodimetallic complex [(Cp-PPh2)2ZrCl2/PdCl2], 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-PPh2)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-PPh2)2Zr(CH3)2 (13) reacts with [H(CO)Rh(PPh3)3] (14) with loss of two PPh3 ligands and instantaneous liberation of methane to form complex 15, [CH3Zr(μ-Cp-PPh2)2Rh(CO)PPh3](Zr−Rh), which probably contains a metal−metal bond between...