Reactions of 1,2,4‐Trithiolanes with Nonacarbonyldiiron: Sulfurdithiolatodiiron and ‐tetrairon Complexes as Mimics for the Active Site of [Fe‐only] Hydrogenase

Abstract

AbstractThe reactions of 1,2,4‐trithiolane (1a), 3,3,5,5‐tetramethyl‐1,2,4‐trithiolane (1b), 3,3,5,5‐tetraethyl‐1,2,4‐trithiolane (1c), 3,3,5,5‐bis(pentamethylene)‐1,2,4‐trithiolane (1d) and di‐spiro{tricyclo[3.3.1.1]decane‐2,3″‐(1,2,4)‐trithiolane‐5′,2′‐tricyclo[3.3.1.1]decane} (1e) with nonacarbonyldiiron (2) have been investigated. The sulfurdithiolatodiiron complexes 3a–e, which can be considered as novel model complexes of the active site of the [Fe‐only] hydrogenase, were isolated as the main products of these reactions. X‐ray structure analyses were performed on compounds 3b–e. The carbon dithiolato (SCR2S)‐bridged diiron side‐products 4a–e and the tetranuclear clusters 6b–d were also obtained and characterised by X‐ray diffraction analysis (4b–e and 6b–d). In contrast, the reaction of 1e with 2 affords the trinuclear complex 7, which contains a side‐on bonded adamantanethione, besides 3e and 4e. Finally, the reaction of 3a with two equivalents of (Et4N)CN gives the monocyanide complex 8 in good yield. Density functional calculations have been performed to evaluate the bonding situation in the di‐ and tetranuclear clusters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)