CC BY 3.0 UnportedEijsink, Linda E.Perdriau, Sébastien C. P.de Vries, Johannes G.Otten, Edwin2022-05-052022-05-052016https://oa.tib.eu/renate/handle/123456789/8869https://doi.org/10.34657/7907The 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 complexes 3, 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.enghttps://creativecommons.org/licenses/by/3.0/540AromatizationCyanidesLigandsPyridineCycloaddition productsDFT calculationInterconversionsPincer complexesRelative stabilitiesRuthenium complexesTautomerizationsVariable-temperature NMRRuthenium compoundsArticle