Halogen exchange reactions in preparing catalysts and their precursors

摘要: Chloropentafluorobenzene or bromopentafluorobenzene is formed by heating perhalobenzene, C 6 F n X 6-n where 0 to 4, and each is, independently, a chlorine bromine atom, with alkali metal fluoride, an aminophosphonium catalyst (e.g., (Et 2 N) 4 PBr). The resultant chloropentafluorobenzene can be converted into pentafluorophenyl Grignard reagent compound. This in turn tris(pentafluorophenylborane), which single coordination complex comprising labile tetra(pentafluorophenyl)boron anion trialkylammonium tetra(pentafluorophenyl) boron N,N-dimethylanilinium complex). used the preparation of active mixing cyclopentadienyl compound containing Group suitable solvent diluent so that cation reacts irreversibly ligand compound, such forms non-coordinating ion pair resulting produced from Alternatively, tris(pentafluorophenylborane) contacted metallocene formula LMX wherein L derivative delocalized pi-bonded group imparting constrained geometry site contains up 50 non-hydrogen atoms, M metal, hydride, hydrocarbyl, silyl, germyl having 20 carbon, silicon, germanium atoms form limiting charge separated structure ⊕ XA ⊖ A tris(pentafluorophenyl)borane.