A remarkable ring opening observed in the reaction of cyclopropyl ferrocenyl thioketone with triiron dodecacarbonyl Fe3(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 eta(4)-1-thia-1,3-diene-type mononuclear tricarbonyl iron complex 2 and eta(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.