Structure and reactivity of [(L·Pd)n·(1,5-cyclooctadiene)] (n=1–2) complexes bearing biaryl phosphine ligands

The graphical abstract shows the reactivity modes of the [L·Pd(1,5-COD)] species studied in this work. They can react with CDCl3 or aryl halides to produce Pd(II) species, or with electron-deficient alkenes to produce new olefin-bound Pd(0) species. [Display omitted] •Solid state NMR spectra of [(1,5-cyclooctadiene)(1·Pd)2].•Reactivity of [(1,5-cyclooctadiene)(1·Pd)2] with CDCl3.•X-ray structure of Pd(0) species [(N-phenylmaleimide)Pd·1].•Synthesis and reactivity of [(1,5-cyclooctadiene)(L·Pd)2] complexes (L=6–8).•Synthesis and reactivity of [(1,5-cyclooctadiene)(15·Pd)]. The structure of the stable Pd(0) precatalyst [(1,5-cyclooctadiene)(L·Pd)2] (L=AdBrettPhos) for the Pd-catalyzed fluorination of aryl triflates has been further studied by solid state NMR and X-ray cystrallography of the analogous N-phenylmaleimide complex. The reactivity of this complex with CDCl3 to form a dearomatized complex is also presented. In addition, studies suggest that related bulky biaryl phosphine ligands form similar complexes, although the smaller ligand BrettPhos forms a monomeric [(1,5-cyclooctadiene)(L·Pd)] species instead.