Polyfluorinated boron clusters
This project investigates fluorinated and other halogenated carba-closo-borate anions and other closo-boron clusters with functionalized groups. The aim of the project is to make polyfluorinated, functionalized boron clusters available as building blocks for different applications. For this purpose (selective) synthetic routes have to be developed and the influence of the fluorine substituents on the properties of the clusters and the functional groups has to be examined.
For the production of the fluorinated clusters, the non-fluorinated starting materials are reacted with elemental fluorine in anhydrous hydrogen fluoride. The polyfluorinated, functionalized boron clusters are characterized by an unexpectedly high chemical reactivity, which differs significantly from the chemically extremely inert, weakly coordinating anions [1-R-closo-1-CB11F11] - (R = H, alkyl, F). An example is the carbon extrusion / cluster contraction reaction of the [1-H2N-closo-CB11F11] - anion to the closo-undecaborate dianion [3-NC-closo-B11F10] 2– shown in the following scheme:
These new anionic highly fluorinated boron clusters are intended to serve as novel synthesis building blocks and ligands with a Teflon-like surface, resulting in applications in the fields of medicine, catalysis and new materials (polymers, ionomers, ionic liquids).