Surprising Condensation Reactions of the Azadithiolate Cofactor

Azadithiolate, a cofactor found in all [FeFe]-hydrogenases, is shown to undergo acid-catalyzed rearrangement.nn Fe2[(SCH2)2NH](CO)6nself-condenses to give Fe6[(SCH2)3N]2(CO)17. The reaction, which is driven by loss of NH4+, illustrates the exchange of the amine group. X-ray crystallography reveals that three Fe2(SR)2(CO)xnbutterfly subunits interconnected by the aminotrithiolate [N(CH2S)3]3-. Mechanistic studies reveal that Fe2[(SCH2)2NR](CO)6nparticipate in a range of amine exchange reactions, enabling new methodologies for modifying the adt cofactor.nn.nnRu2[(SCH2)2NH](CO)6nalso rearranges, but proceeds further to give derivatives with Ru-alkyl bonds Ru6[(SCH2)3N][(SCH2)2NCH2]S(CO)17nandn [Ru2[(SCH2)2NCH2](CO)5]2S , featuring Ru-alkyl bonds. .