Generation and characterization of the tris(pentafluorophenyl)borane radical anion

The anion derived from B(C6F5)(3) has been detected by EPR, and the boron a nd fluorine hyperfine splitting constants have been determined. Treatment o f B(C6F5)(3) with the reductant Cp*Co-2 in THF at -50 degreesC rapidly resu lts in a dark blue (lambda (max) = 603 nm) paramagnetic solution containing the anion radical. The half-life for disappearance of lambda (max), about 10 min at room temperature, is consistent with that of the EPR signal.