Abstract
Azadithiolate, a cofactor found in all [FeFe]-hydrogenases, is shown to undergo acid-catalyzed rearrangement. Fe(2) [(SCH(2) )(2) NH](CO)(6) self-condenses to give Fe(6) [(SCH(2) )(3) N](2) (CO)(17) . The reaction, which is driven by loss of NH(4)(+) , illustrates the exchange of the amine group. X-ray crystallography reveals that three Fe(2) (SR)(2) (CO)(x) butterfly subunits interconnected by the aminotrithiolate [N(CH(2) S)(3) ](3-) . Mechanistic studies reveal that Fe(2) [(SCH(2) )(2) NR](CO)(6) participate in a range of amine exchange reactions, enabling new methodologies for modifying the adt cofactor. Ru(2) [(SCH(2) )(2) NH](CO)(6) also rearranges, but proceeds further to give derivatives with Ru-alkyl bonds Ru(6) [(SCH(2) )(3) N][(SCH(2) )(2) NCH(2) ]S(CO)(17) and [Ru(2) [(SCH(2) )(2) NCH(2) ](CO)(5) ](2) S.