36620-06-1Relevant academic research and scientific papers
Versatility of iminophosphoranes and noninnocent behavior of the 1,5-cyclooctadiene ligand in palladium(II) complexes. Synthesis of σ-allyl derivatives
Aguilar, David,Aznarez, Francisco,Bielsa, Raquel,Falvello, Larry R.,Navarro, Rafael,Urriolabeitia, Esteban P.
, p. 6397 - 6402 (2007)
The treatment of PdCl2(NCPh)2 with Ph 3P=NPh (1) gives the expected complex trans-PdCl2[N(Ph)- PPh3]2 (3). However, the reaction of PdCl2(COD) (COD = 1,5-cyclooctadiene) with 1 or Ph3P=N-1-Np (2) (Np = naphthyl) occurs through nucleophilic attack of 1 or 2 on one olefinic bond of the COD ligand followed by proton abstraction on the adjacent methylene group, giving the η1-allyl complexes [Ph3P(R)NH...Cl 2Pd(C8H11)] (R = Ph, 4; Np, 5). The X-ray structure of 4 has been determined and shows two interesting facts: (i) the η1-η2-bonded cyclooctadienyl ligand, containing a η1-allyl fragment, and (ii) the presence of a strong H bond between one of the Cl ligands and the proton of the NH group. This H bond persists in solution, as shown by NMR and molar conductance measurements. The abstraction of a chloride on 4 by reaction with AgClO4 cleaves the H bond and gives a mixture of the salt [Ph3PN-(H)Ph](ClO4) (6) and the neutral η1-η2-cyclooctadienyl complex [Pd(μ-Cl)(C8H11)]2 (7). Complex 7 is an adequate precursor for the synthesis of other stable η1-allyl complexes, and no η1-η2 allyl interconversion has been observed.
