1134644-50-0Relevant articles and documents
Palladium Alkyl complexes containing β-Phosphonato - Phosphine P,O Ligands and their reactivity toward CO-Ethylene or -Acrylate insertion
Hamada, Adel,Braunstein, Pierre
, p. 1688 - 1696 (2009/08/14)
Neutral and cationic square-planar Pd(II) complexes containing the β-phosphonato-phosphine ligand rac-Ph2PCH(Ph)P(O)(OEt) 2 (1) or the new α-silyl-phosphonato-phosphine ligand Ph 2PCH(SiMe3)-P(O)(OMe)2 (4) have been prepared. Reaction of 4 with [Pd(μ-Cl)(dmba)]2 (dmba = o-C6H 4CH2NMe2) afforded an equilibrium mixture of [Pd(dmba){Ph2PCH(SiMe3)P(O)(OMe)2}]Cl (5) and [PdCl(dmba){Ph2PCH(SiMe3)P(O)(OMe)2}] (5 ), which illustrates the hemilabile behavior of the ligand in this system. From the stepwise insertion reaction of CO and ethylene into the Pd - C bond of [PdCKMe) {Ph2PCH(Ph)P(O)(OEt)2 }] (2a), the metallacyclic complex [Pd{CH2CH2C(O)Me{Ph2PCH(Ph)P(O)-(OEt) 2][BF4] (10) was obtained which features the first acetyl - ethylene coupling product containing a phosphine - phosphonate ligand. Chloride abstraction from 2a led to the cationic complex [PdMe(NCMe) {Ph 2PCH(Ph)P(O)(OEt)2 }][BF4] (8), which reacted sequentially with CO and methyl acrylate to afford [Pd{CH[C(O)OMe][CH 2C(O)Me]} {Ph2PCH(Ph)P(O)(OEt)2}][BF 4] (11). The reaction between 8 and the P,O-ligand Ph 2PNHC(O)Me resulted in an equilibrated ligand exchange where the heteroleptic system is preferred over the mixture of the two homoleptic complexes. The complexes 2a and 10 · 1/2CHC13 have been characterized by X-ray diffraction and represent rare examples of crystal structures showing a (diethyl)methylphosphonate ligand coordinated to a metal center.
