934199-81-2Relevant academic research and scientific papers
Ruthenated acetonitrile: Unusual bronsted acidity of a polar Aprotic solvent
Derrah, Eric J.,Giesbrecht, Karina E.,McDonald, Robert,Rosenberg, Lisa
, p. 5025 - 5032 (2009/03/11)
Addition of acetonitrile to the complex [Ru(η5-indenyl) (PR2)(PPh3)] (1) gives the unusual metalation product [Ru(η5-indenyl)(CH2CN)(HPR2)(PPh 3)] (2), which has been structurally characterized. This reaction clearly demonstrates high Bronsted basicity at the terminal phosphide ligand in 1. 31P{1H} NMR studies show that less acidic N-donor solvents simply disrupt the Ru-P π-bond in 1 to give adducts [Ru(η5-indenyl)(L)(HPR2)(PPh3)] (L = benzonitrile (6) or pyridine (7)), which are in equilibrium with 1 and free L. The analogous acetonitrile adduct (4) was observed by NMR at 240 K during the formation of 2, but is quickly replaced by 2 at higher temperatures. NMR studies of an alternate route to the metalated complex 2, starting from the cationic N-bound acetonitrile adduct [Ru(η5-indenyl)(NCCH 3-(HPCy2)(PPh3)][PF6] (3a), along with the demonstrated lability of the benzonitrile and pyridine adducts, suggest that the metalation of acetonitrile by 1 proceeds via an intermolecular C-H addition across the Ru=P double bond, rather than the intramolecular C-H activation of N-bound acetonitrile. This is confirmed by the observation, by 31P[1H} NMR, of multiple product isotopomers in the reaction of 1 with a 1:1 mixture of d3- and d0- acetonitrile. O-Donor solvents also deprotonated by 1 include water, alcohols, and acetone, which give the complexes [Ru(η5-indenyi)(X) (HPCy2)(PPh3)], where X = OR (8), CH2(=O) CH3 (10).
