 the reaction of a manganese(v)oxo 
 porphyrinoid complex with the lewis acid b(c6f5)3 leads to reversible stabilization of the valence tautomer 
 mniv(o)(-radical cation ) . 
 the latter complex , in 
 combination with b(c6f5)3 , reacts 
 with aro  
 h substrates via formal hydrogen - atom transfer and 
 exhibits dramatically increased reaction rates over the mnv(o ) starting material . 
Supplementary Material