title: Metal-ligand cooperative activation of nitriles by a ruthenium complex with a de-aromatized PNN pincer ligand.
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 complexes 3, have a Brønsted basic (nitrile-derived) Ru-N fragment. This is able to deprotonate a CH2side-arm of the pincer ligand to give ketimine complexes (4) with a de-aromatized pyridine backbone. Alternatively, the presence of a CH2group 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.
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands. edwin.otten@rug.nl.
authors.forename: Linda E
authors.initials: LE
authors.lastname: Eijsink
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands. edwin.otten@rug.nl.
authors.forename: Sébastien C P
authors.initials: SC
authors.lastname: Perdriau
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands. edwin.otten@rug.nl and Leibniz-Institut für Katalyse an der Universität Rostock, Albert-Einstein-Strasse 29a, 18059 Rostock, Germany.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: de Vries
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands. edwin.otten@rug.nl.
authors.forename: Edwin
authors.initials: E
authors.lastname: Otten