The Ferrocene−Lithium Cation Complex in the Gas Phase

Abstract

The stable isomers of the ferrocene−lithium cation gas-phase ion complex have been studied with the hybrid density functional theory. The method of calculation chosen has been tested checking its performance for the more studied protonated ferrocene species. Our calculations demonstrate that the procedure used is reliable. We have found two isomers of the ferrocene−lithium cation complex separated by a barrier of 25.6 kcal/mol. The most stable isomer of this complex has Li⁺ on-top of one of the cyclopentadienyls, while in the least stable isomer Li⁺ binds the central iron metal. The latter isomer has been characterized as a planetary system in the sense that Li⁺ has one thermally accessible planar orbit around the central ferrocene moiety. Our calculations lead to a value of ferrocene's gas-phase lithium cation basicity of 37.4 kcal/mol for the on-top complex and 29.4 kcal/mol for the metal-bound complex.