Neutral Ruthenium Carbene Complexes bearing N,N,O Heteroscorpionate Ligands: Syntheses and Activity in Metathesis Reactions

Neutral Fischer-type ruthenium(II) aminocarbene complexes bearing the bis(3,5-dimethylpyrazol-1-yl)acetato (bdmpza) ligand have been synthesized by addition of ammonia or methylamine to the α-carbon atom of vinylidene and allenylidene complexes. Reaction with dimethylamine was not successful. These differences in the chemical behavior can be explained by the intermediate formation of intramolecular hydrogen bridges that have been indicated by DFT calculations. Furthermore, octahedral ruthenium(II) benzylidene complexes with the bis(pyrazol-1-yl)acetato (bpza) and the bdmpza ligand were obtained by reacting [RuCl2(CHPh)(PR3)2] (R = Cy, Ph) with K[bpza] or K[bdmpza], respectively. The latter complexes have successfully been tested for RCM reactions.