Formation of Palladium- and Platinum-Substituted Fulvenes by Cyclopentadienyl Activation in a Formal Insertion Reaction
摘要:
Stepwise, low-temperature reaction of {Pd[CH(SiMe(3))(2)](PMe(3))(mu-Cl)}(2) with CNBu-t and NaCp' (Cp' = C5H5, C(5)H(4)Me) affords metal-substituted fulvenes of composition {Pd[C(NHBu-t)=C(C(4)H(3)R)][CH(SiMe(3))(2)](CNBu-t)(PMe(3))}, of which the C(5)H(4)Me-derived complex 2b (R = Me) has been characterized by X-ray crystallography. The formation of related complexes of Pt is also reported.
Formation of Palladium- and Platinum-Substituted Fulvenes by Activation of a Cyclopentadienyl or Indenyl Ligand
作者:Francisco M. Alías、Tomás R. Belderraín、Margarita Paneque、Manuel L. Poveda、Ernesto Carmona、Pedro Valerga
DOI:10.1021/om9806500
日期:1998.12.1
The stepwise, low-temperature reaction of Pd[CH(SiMe3)(2)](mu-Cl)(PMe3)}(2)(1) with CNBu-t and NaCp' (Cp' = C5H5, C5H4Me) or LiInd (Ind = C9H7) affords metal-substituted fulvenes of composition Pd[C(NHBu-t)=C(C4H3R)][CH(SiMe3)(2)](CNBu-t)(PMe3) (R = H, Me) and Pd[C(NHBu-t)=C(C8H6)][CH(SiMe3)(2)](CNBu-t)(PMe3), of which the C5H4Me-derived complex 5a has been characterized by X-ray crystallography. The mononuclear species Pd[CH(SiMe3)(2)]Cl(CNBu-t)(PMe3) (2) has been isolated as an intermediate of this reaction. An alternative synthesis of the palladabenzofulvene complex 6 involves the reaction of the 16 electron indenyl derivative (eta(3)-Ind)Pd[CH(SiMe3)(2)](PMe3) (7) with 2 equiv of CNBu-t. In this case an eta(1)-indenyl intermediate of composition (eta(1)-Ind)Pd[CH(SiMe3)(2)](CNBu-t)(PMe3) (8) can be observed by low-temperature NMR spectroscopy. The complex Pt[CH(SiMe3)(2)]Cl(CNBu-t)(PMe3) (12) has been synthesized by the comproportionation reaction of Pt[CH(SiMe3)(2)]Cl(PMe3)(2) (10) and Pt[CH(SiMe3)(2)]Cl(CNBu-t)(2) (11), in the presence of catalytic amounts of CNBu-t. Complex 12 reacts with CNBu-t and NaCp to give first the cationic species Pt[CH(SiMe3)(2)](CNBu-t)(2)(PMe3)}Cl (13) and then a mixture of platinafulvene isomers related to the above-mentioned Pd complexes. The fluxionality of these metallafulvene derivatives and the mechanism of their formation are discussed.