Using DFT calculations, we calculated the binding energy of the thiol in the hypothetical molecule Fe II (acac)2(EtOH)(PhSH) to be 19 kcal/mol. To further investigate the effects of thiol coordination to iron(II), we calculated the BDFE of the S-H bond in this iron(II) complex. Upon binding to Fe II (acac)2(EtOH), the BDFE of the S-H bond in PhSH weakened from 82 to 66 kcal/mol. Therefore, binding to iron(II) would make the S-H bond weaker than the O-H bond in iron(II) ethanol complexes (calcd. 70 kcal/mol). As a result, quenching of the alkyl radical can feasibly proceed via PCET from an iron(II) thiol complex.