Metal–ligand cooperative activation of nitriles by a ruthenium complex with a de-aromatized PNN pincer ligand. Issue 40 (1st September 2016)

• Record Type: Journal Article
• Authors: Eijsink, Linda E.; Perdriau, Sébastien C. P.; de Vries, Johannes G.; Otten, Edwin
• Is Part Of: Dalton transactions. Volume 45:Issue 40(2016)
• Page Start: 16033
• Page End: 16039
• Publication Date: 2016-09-01
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt02478e
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Metal–ligand cooperative activation of nitriles by a de-aromatized Ru pincer complex leads to equilibrium mixtures (tautomers) as a result of ligand deprotonation by the Brønsted basic Ru-ketimido moiety. Abstract : The pincer complex (PNN)RuH(CO), with a de-aromatized pyridine in the ligand backbone, is shown to react with nitriles in a metal–ligand cooperative manner. This leads to the formation of a series of complexes with new Ru–N(nitrile) and C(ligand)–C(nitrile) bonds. The initial nitrile cycloaddition products, the ketimido complexes3, have a Brønsted basic (nitrile-derived) Ru–N fragment. This is able to deprotonate a CH2 side-arm of the pincer ligand to give ketimine complexes (4 ) with a de-aromatized pyridine backbone. Alternatively, the presence of a CH2 group adjacent to the nitrile functionality can lead to tautomerization to an enamido complex (5 ). Variable-temperature NMR studies and DFT calculations provide insight in the relative stability of these compounds and highlight the importance of their facile interconversion in the context of subsequent nitrile transformations.