A Remarkable Ring Opening Observed in the Reaction of Cyclopropyl Ferrocenyl Thioketone with Triiron Dodecacarbonyl Fe 3 (CO) 12

In continuation of the study focused on synthesis and structure of mimics of the active site of the [FeFe] hydrogenase enzyme, reaction of Fe 3 (CO) 12 with cyclopropyl ferrocenyl thioketone 1 was carried out. Two different complexes with ring‐opened cyclopropyl fragments were isolated and identified as η 4 ‐1‐thia‐1,3‐diene‐type mononuclear tricarbonyl iron complex 2 and η 2 ‐acyl‐type hexacarbonyl diiron complex 3 , respectively. Structures of crystalline products were unambiguously confirmed by single crystal X‐ray analysis. For the ring opening reaction of the cyclopropane moiety, leading to the formation of 2 and 3 , a multistep radical mechanism was postulated. Electrochemical investigations of 3 , being reminiscent of a [FeFe] hydrogenase mimic, were carried out at different scan rates.