Reactions of 1,2,4-trithiolane, 1,2,5-trithiepane, 1,2,5-trithiocane and 1,2,6-trithionane with nonacarbonyldiiron: Structural determination and electrochemical investigation

The reactions of 1,2,4-trithiolane (1), 1,2,5-trithiepane (6), 1,2,5-trithiocane (12) and 1,2,6-trithionane (10) with nonacarbonyldiiron (2) have been investigated. A novel diiron model complex, which can serve as a model complex of the active site of [Fe-only]-hydrogenase, was formed from the reaction with 1. In contrast, the reaction of 6 with 2 afforded the trinuclear iron cluster 7. Interestingly, the diiron compound 11 was obtained with 1,2,6-trithionane (10), which can be attributed to the more flexible dithiolato ligand 10. Furthermore, the reaction with 1,2,5-trithiocane (12) yielded the trinuclear cluster 13. X-ray structure analyses were performed on compounds 3, 7, 10, 11 and 13. The reactions of the reduced iron species 3 with pivalic acid (HP) were studied electrochemically. The most significant features of the experimental cyclic voltammograms (CVs) could be reproduced by digital simulation on the basis of a reaction scheme that includes both the coordination of HP as well as the catalytic generation of hydrogen. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007.