Transfers by Ligand Type

It is also possible to envision a bridging intermediate for transfer of 7t-allyl groups. A model structure comes from the studies of Werner and Kuhn (19,20), who found that the reaction of i 3-allyl- 5-cyclopentadienyl palladium with tertiary phosphines led to dinuclear complexes having the general structure 3. X-Ray analysis verified the structure. The platinum analog could also be prepared. 

Reaction of nickelocene with iron pentacarbonyl was shown to yield 4 as well as the cyclopentadienyl (Cp) compounds Cp2Ni2(CO)2 and 

Cp2Fe2(CO)4, but ferrocene did not react with nickel tetracarbonyl to give Cp-nickel complexes (2/). They proposed that bridging intermediate 4 was involved in the Cp transfer. 

Nesmeyanov s laboratory (22) found that t/3-allyl palladium cyclopentadienyl reacted with iron pentacarbonyl to produce [CpFe(CO)2]2 and Cp2Fe. The fate of the palladium was not revealed. In a similar fashion, Cp(f/3-C3Hj)Pd reacted with FeCl2 in THF to produce [(r/3-C3H5)PdCl]2 and Cp2Fe. No conversions or yields were given. 

Several groups (23-25) have reported that nickelocene reacts with bis-phosphinenickel dihalides to produce CpNiX(PR3) in 70-90 % yield. Since 

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