Diiron Azadithiolates as Models for the Iron-Only Hydrogenase Active Site: Synthesis, Structure, and Stereoelectronics

Most hydrogenase enzymes have organometallic active sites with CO and CN− as ligands and metal–metal bonds. Recent evidence points to a novel 2-aza-1,3-propanedithiolate cofactor that directly participates in the heterolytic processing of dihydrogen. A close analogue of this cofactor and its organometallic subunit has been synthesized (see picture); spectroscopic, structural, and theoretical analysis of this model provides detailed insights into the properties of the proposed enzyme active site.