The first systematic study of diferrous dicyano dithiolates is described. Oxidation of [Fe2(S2C2H4)(CN) 2(CO)4]2- in the presence of cyanide and tertiary phosphines and of Fe2(S2C2H 4)-(CO)4(PMe3)2 in the presence of cyanide affords a series of diferrous cyanide derivatives that bear a stoichiometric, structural, and electronic relationship to the H oxair state of the Fe-only hydrogenases. With PPh 3 as the trapping ligand, we obtained an unsymmetrical isomer of Fe2(S2C2H4)(μ-CO)(CN) 2(PPh3)2- (CO)2, as confirmed crystallographically. This diferrous cyanide features the semibridging CO-ligand, with Fe-μC bond lengths of 2.15 and 1.85 Å. Four isomers of Fe2(S2C2H4)(μ-CO)(CN) 2(PMe3)2(CO)2 were observed, the initial product again being unsymmetrical but more stable isomers being symmetrical. DFT calculations confirm that the most stable isomers of Fe 2(S2C2H4)(μ-CO)(CN) 2(PMe3)2(CO)2 have cyanide trans to μ-CO. Oxidative decarbonylation also afforded the new tetracyanide [Fe 2(S2C2H4)(μ-CO)(CN) 4-(CO)2]2-. Insights into the oxidative decarbonylation mechanism of these syntheses come from the spectroscopic characterization of the tetracarbonyl [Fe2(S2C 2H4)(μ-CO)(CN)3(CO)3]. This species reacts with PEt3 to produce the stable adduct [Fe 2(S2C2H4)(μ-CO)(CN) 3(CO)2(PEt3)]-.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of the American Chemical Society|
|State||Published - Aug 10 2005|
ASJC Scopus subject areas
- Colloid and Surface Chemistry