The stability of these dihydrides appears to be the main factor that determines
whether the reaction of K+[HFe(CO)4]− with a phosphine leads to
Fe(CO)3(PR3)2 or H2Fe(CO)2(PR3)2 derivatives. Indeed, the final product of these
reactions is dramatically determined by the reaction conditions, as evidenced in the
case of P(n-Bu)3 (Scheme 1).