Thermodynamics of hydrogen atom transfer to a high-valent iron imido complex

Thermodynamic investigations relevant to hydrogen atom transfer by the high-valent iron imido complex [L(Mes)Fe NAd]OTf have been undertaken. The complex is found to be weakly oxidizing by cyclic voltammetry (E(1/2) = -0.98 V vs Cp(2)Fe(+)/Cp(2)Fe in MeCN). A combination of experimental and computational studies has been used to determine the acidity of L(Mes)Fe-N(H)Ad(+)(pK(a) = 37 in MeCN), allowing the N-H BDFE (88(5) kcal/mol) to be calculated from a thermodynamic cycle. Consistent with this value. [L(Mes)Fe NAd]OTf reacts with 9,10-dihydroanthracene (C-H BDE = 78(1) kcal/mol) to form anthracene. anthracene.