Electrophilicity of aliphatic nitrilium closo-decaborate clusters: Hyperconjugation provides an unexpected inverse reactivity order

Publication date: 1 September 2018Source: Journal of Organometallic Chemistry, Volume 870Author(s): Valeria K. Burianova, Alexander S. Mikherdov, Dmitrii S. Bolotin, Alexander S. Novikov, Pennie Petrus Mokolokolo, Andreas Roodt, Vadim P. Boyarskiy, Vitalii V. Suslonov, Andrey P. Zhdanov, Konstantin Yu Zhizhin, Nikolay T. KuznetsovAbstractThe nucleophilic addition of 2-pyridyl carbamidoxime to the C≡N group of the aliphatic nitrilium closo-decaborate clusters (PhCH2PPh3)[B10H9NCR] (R = Me, Et, and iPr) proceeds to give 2-iminium closo-decaborates (68–88% isolated yields). A systematic kinetic and theoretical study of the nucleophilic addition indicates that the reactivity of the nitrile ligand at the boron cluster unexpectedly increases in the order of R: Me < Et < iPr. It was shown theoretically, that the electrophilicity of the C≡N group is primarily determined by hyperconjugation with the neighboring aliphatic moiety, which induced by substantial (ca. +0.6 e) positive charge at the nitrile C atom.Graphical abstract

Source: Journal of Organometallic Chemistry - July 11, 2018 Category: Chemistry Source Type: research