Characterization of a monocyanide model of FeFe hydrogenases - highlighting the importance of the bridgehead nitrogen for catalysisElectronic supplementary information (ESI) available: Additional data concerning the crystal structure, catalytic assays and electrochemistry experiments. CCDC 1437643 for 2[Et4N]. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6dt02061e

An azadithiolate bridged monocyanide derivative [Fe 2 (adt)(CO) 5 (CN)] − of [Fe 2 (adt)(CO) 4 (CN) 2 ] 2− has been prepared and extensively characterized as a model of the [FeFe]-hydrogenase active site, using a combination of FTIR spectroscopy, electrochemical methods and catalytic assays with chemical reductants. The presence of two basic nitrogen sites opens up multiple protonation pathways, enabling catalytic proton reduction. To our knowledge [Fe 2 (adt)(CO) 5 (CN)] − represents the first example of a cyanide containing [FeFe]-hydrogenase active site mimic capable of catalytic H 2 formation in aqueous media. A cyanide containing mimic of the [FeFe]-hydrogenase cofactor has been characterized, highlighting the importance of the bridgehead nitrogen for proton reduction catalysis.