128389-55-9Relevant articles and documents
Novel Basic Ligands for the Homogeneous Catalytic Carbonylation of Methanol, XXVIII. - Synthesis, Properties and Fluxional Behavior of (Ether-Phosphine)palladium Complexes
Lindner, Ekkehard,Speidel, Robert,Fawzi, Riad,Hiller, Wolfgang
, p. 2255 - 2260 (2007/10/02)
Cl2Pd(COD) (1) (COD = 1,5-cyclooctadiene) reacts with 1 equiv. of the (ether-phosphine) ligand Ph2P-D (2a-c) to give the dimeric complexes 2 (3a-c) (P-D = η1-P-coordinated).According to the field-desorption mass spectra which show only one peak for the monomeric moieties ClPd(Ph2P-D), 3a-c have a very weak Pd2Cl2 bridge. trans-Cl2Pd(Ph2P-D)2 (4a-c) is obtained either from 3a-c and 2a-c by cleaving the Pd2Cl2 bridge or from 1 and 2 equiv. of the ligands 2a-c. 4c crystallizes in the monoclinic spacegroup P21/c with Z = 2.AgClO4 selectively abstracts one Cl- ligand from 4a-c which results in the formation of the cationic complexes D)(Ph2P-D)PdCl>+ (5a-c) (PD = η2-D,P-coordinated) containing one chelated and one η1-P-bonded (ether-phosphine) ligand. 5a-c show fluxional behavior which is demonstrated by temperature-dependent 31P-NMR investigations.The coalescence points have been determined and are at 253 (5a), 303 (5b), and 283 K (5c).The activation enthalpies ΔGexcit. are estimated at 48, 58, and 54 kJ/mol.The abstraction of the second Cl- ligand from 5a-c succeeds only in the presence of AgSbF6 yielding the dicationic bis(chelate) complexes D)2Pd>2+ (6a-c).The latter are also obtained from 4a-c and AgSbF6.The hydrogenating properties of 3a-c and 4a-c toward 1-hexyne are investigated in comparison with trans-Cl2Pd(Ph2PCH2CH2CH3)2.