Ligand-assisted O-dealkylation of bis(bipyridyl) ruthenium(II) phosphine-ether complexes

Abstract

The preparation and characterization of three [Ru(bpy)₂(POR-P,O)](PF₆)₂ complexes are reported where POR = 2-methoxyphenyldiphenylphosphine in 1, 2-ethoxyphenyldiphenylphosphine in 2 and 2-methoxyethyldiphenylphosphine in 3. Complexes 1 and 2 undergo ligand-assisted O-dealkylation by the same weakly basic phosphines, a reaction typically observed for complexes containing highly basic phosphines with multiple ether substituents. The electron deficiency of the Ru(II) centre in these complexes is likely responsible for how readily they are dealkylated to yield the aryloxide complexes. Complex 3 is not susceptible to ligand-assisted dealkylation, primarily because the lower steric demand of its phosphine-ether ligand permits the thermodynamically favoured direct attack of phosphines at the Ru centre.