A new chiral metalladiphosphine for early–late chemistry. Crystal structure of a D-camphor-based zirconium enolato phosphine and rearrangement of heterobimetallic Zr/Pd complexes
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Abstract
The bis(phosphinoenolato) zirconocene 2, prepared from the phosphino camphor derivative 3-exo-PPh2C10H15O 1, represents the first C2-symmetric chiral diphosphine containing an early transition metal centre tethered to the phosphino groups via an enolato linkage. It allows the selective assembly of Lewis-acid early–late bimetallic combinations, as exemplified with the Zr/Cu and Zr/Ag complexes 4 and 5. The monophosphinoenolato titanocene 3 was also prepared. Reactions of 2 or 3 with [Pd(dmba)(μ-Cl)]2 (dmba = o-C6H4CH2NMe2) or [PdCl2(SEt2)2] led to complete transfer of the functional Pd(PPh2C10H14O
)] 6 or cis-[
Pd(PPh2C10H14O
)2] 8 and [Cp2ZrCl2]/[Cp2TiCl2], respectively. A heterobimetallic Zr/Pd intermediate complex 10 of this rearrangement could be detected. Complexes 6 and 8 were prepared independently by reaction of 1 with [Pd(dmba)(μ-Cl)]2 or [Pd(SEt2)2Cl2], respectively, which first afforded complexes 7 and 9 which were then treated with KH. The crystal structures of 2, 6 and 8·THF·H2O have been determined by