Scandium Phosphonioketene: Synthesis, Bonding and Reactivity.

Author(s) Mao, W.; Wang, Y.; Xiang, L.; Peng, Q.; Leng, X.; Chen, Y.
Journal Chemistry
Date Published 2019 Jun 14

Reaction of a scandium phosphoniomethylidene with carbon monoxide provides the first scandium phosphonioketene (1). X-ray diffraction shows that the complex has a very short Sc-C bond (2.138(2) Å), and DFT analysis indicates that this unusual short bond length is due to the significant contribution of ionic coulomb interaction between carbon and scandium and the η2-O,C coordination fashion. Complex 1 is rather thermal stable, but shows high reactivity towards a series of unsaturated substrates, including carbon dioxide, ketone, imine, nitrile and isocyanide. In the reaction with tert-butyl isocyanide, not only an insertion of tert-butyl isocyanide into Sc-C bond but also a C-H activation on phenyl ring occur. DFT calculations show the reactivity of 1 operated by nucleophilic property, and therefore the reaction mechanism favors the nucleophilic attacking to isocyanide as a rate-determining step, followed by the stepwise C-H activation through an interesting C-H deprotonation.

DOI 10.1002/chem.201902008
ISSN 1521-3765
Citation Mao W, Wang Y, Xiang L, Peng Q, Leng X, Chen Y. Scandium Phosphonioketene: Synthesis, Bonding and Reactivity. Chemistry. 2019.