New ruthenium metathesis catalysts with chelating indenylidene ligands: synthesis, characterization and reactivity

Six new ruthenium complexes bearing a bidentate (kappa O-2,C)-isopropoxy-indenylidene and PPh3 or PCy3 ligands have been synthesized and characterized by H-1, C-13 NMR spectroscopy and X-ray crystallography. Some of these complexes were synthesized in dimethyl carbonate, a green solvent that was recently shown to be suitable for several catalytic transformations including olefin metathesis. The thermal stability and catalytic efficiency of the PCy3-containing complexes have been evaluated in a series of test reactions.