Tetrakis(pentafluorophenyl)borate[(C6F5)4B-] is a weak nucleophilic and an inert non-coordinative anion. Therefore it is employed as a counter anion to unstable cation chemical species, thereby generating the "free" cation that may be used for studies related to reactivity and structure1,2).
Minoura, et al. have succeeded in synthesizing the first nonclassical onium compound, pentaphenyltelluronium 2, using the agent 12). X-ray crystallographic analysis provided evidence for the compound 2 to be free hypervalent tellurium cation without any interaction with the counter anion, (C6F5)4B-, in the crystalline state.
Furthermore, in catalyzed olefin polymerization, a number of catalysts have been reported where the catalytic activity is due to the "free" cation when the anion used was (C6F5)4B- in place of Ph4B- 3).
Published TCIMAIL newest issue No.196
