The imidazo{[4,5-f][1,10]-phenanthrolin}l-2-ylidene and its palladium complexes: Synthesis, characterization, and application in C-C cross-coupling reactions

Abstract

1,3-dibutyl-1H-imidazo[4,5-f][1,10]phenanthrolinium iodide, L5.2HI ligand and their mono-, di-, tri-, tetra-nuclear palladium(II) complexes (5.HPF6, 6–8) were synthesized and characterized by elemental analysis, FTIR, UV–visible and NMR spectroscopy. In addition, the complexes (5.HPF6, 6–8) were determined by mass spectrometry (MALDI). The ligand L5.2HI was determined by X-ray diffraction. The complexes (5.HPF6, 6–8) were tested in Suzuki-Miyaura and Mizoroki-Heck reactions at elevated temperatures. The activities of the catalysts were monitored by NMR and GC analysis. We found that the poly-nuclear complexes display better activities compared to the mono-nuclear derivatives, thus proposing that an increase in metal moieties which leads to an increase in activity in cross-coupling reaction.