Oxidative addition of organic halides on palladium(0) complexes stabilized by dimethylfumarate and quinoline-based N–P or N–S spectator ligands

Abstract

a b s t r a c tWe have studied the oxidative addition of some organic halides on palladium(0) dimethylfumarate complexes bearing heteroditopic (N-P or N-S) quinoline-based spectator ligands from the experimental and theoretical point of view. We have measured the half-life of some oxidative addition reactions carried out in two different solvents (CD 2 Cl 2 and CD 3 CN). The reactions were studied under mild conditions by NMR and the reactivities of different oxidants towards the complexes under study were compared. The rates of reaction were influenced by the nature of the spectator ligands and the solvent. The thioquinoline derivatives display a higher reactivity than that of the phosphoquinoline complexes and in general the reaction rates are higher in CD 3 CN than in CD 2 Cl 2 , although such a behavior is not always observed. We propose a plausible mechanism for the oxidative reaction in different solvents based on the experimental results and an adequate computational approach. Finally, the solid state structures of two reaction products were resolved and reported.

Synthesis and characterization of novel olefin complexes of palladium(0) with chelating bis(N-heterocyclic carbenes) as spectator ligands

“…The complexes 1a-c [11], 1d-d 0 [12], 1e [13] and the imidazolium salts [7c] were synthesized according to published procedures. The silver carbene complexes 2, 3 were obtained by adding in the dark Ag 2 O in slight stoichiometric excess to a methanol solution of the corresponding imidazolium salt [14].…”

“…The silver carbene complexes 2, 3 were obtained by adding in the dark Ag 2 O in slight stoichiometric excess to a methanol solution of the corresponding imidazolium salt [14]. The reaction progress was monitored by the progressive disappearance of the solid Ag 2 O, whereas the 1 H and 13 C NMR spectra of the isolated derivatives and in particular the disappearance of the signal ascribable to the imidazolium proton within 9-10 ppm confirm the formation of the expected species (See Fig. S1, Supplementary Material).…”

“…The 13 C NMR spectra exhibit the signals ascribable to carbon of the coordinated carbene, of the nitrile (CN) and of the benzyl (ACH 2 APh) groups at ca. 186, 127, and 55 ppm, respectively.…”

“…The IR, 1 H, 13 C and 31 P NMR spectra were recorded on a Perkin-Elmer Spectrum One spectrophotometer and on a Bruker 300 Avance spectrometer, respectively. The elemental analysis of the synthesized complexes was carried out using an Elementar CHN ''CUBO micro Vario" analyzer.…”

Synthesis of novel olefin complexes of palladium(0) bearing monodentate NHC, phosphine and isocyanide spectator ligands

“…The complexes 1a -d [11], 1e, 5a [12], 3 and 4 [13] were synthesized according to published procedures. The preparation of the imidaziolium salt 1,3-bis(4-methylbenzyl)-2,3-dihydro-1H-imidazole bromide and its derivative 2 will be described in Section 4.…”