Fluorine containing ansolvo super acids and intercalants in graphite—a common link

Abstract

Ansolvo super acids and intercalants in acceptor graphite intercalation compounds (GICs) must both be excellent electron acceptors, a property most frequently encountered in coordinatively seemingly unsaturated fluorine containing compounds. Interestingly AsF 5 and SbF 5 have served in both capacities. There is a crucial difference however: the intercalation process is a red-ox reaction with the exact nature of the intercalate unclear and often subject to controversies. The acceptor ability of ansolvo super acids is directed towards anion abstraction to generate coordinatively saturated super acid anions, capable of generating and stabilizing unusual cations either in solution or in solids. The oxidative intercalation to generate the super acid anion SO 3F − in graphite, the physical properties and bonding will be discussed. Its reaction with AsF 5 and SbF 5 and the protic acids HSO 3F and HSO 3CF 3 will be described. A generally applicable, interacting ion model will be proposed to describe bonding and electron transfer. The development of SO 3X-based super acid systems in HSO 3X, with X = F or CF 3 will be developed and the preparation aimed at M(SO 3X) 4 will be discussed for a wide range of metals. Solution studies on the systems Pt(SO 3F) 4HSO 3F, Sn(SO 3CF 3) 4HSO 3CF 3 and An(SO 3F) 3HSO 3F will be described. Preparative attempts to stabilise a number of unusual cations will illustrate the effectiveness of the ansolvo super acids developed by us.