Reactive Dimerization of an N-Heterocyclic Plumbylene: C−H Activation with PbII

Abstract

The N-heterocyclic plumbylene [Fe{(η5-C5H4)NSiMe3}2Pb:] is in equilibrium with an unprecedented dimer in solution, whose formation involves the cleavage of a strong C−H bond and concomitant formation of a Pb−C and an N−H bond. According to a mechanistic DFT assessment, dimer formation does not involve direct PbII insertion into a cyclopentadienyl C−H bond, but is best described as an electrophilic substitution. The bulkier plumbylene [Fe{(η5-C5H4)NSitBuMe2}2Pb:] shows no dimerization, but compensates its electrophilicity by the formation of an intramolecular Fe−Pb bond. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim