Thiophendioxid-Komplexe des Cobalts

Thiophene-1,1-dioxide (TDO) is thermally unstable and can be stabilized by coordination to metals in low oxidation states as hitherto shown in the case of some iron carbonyl compounds. We now present examples of cobalt complexes such as CoCp(η4-TDO) (4) and their derivatives: CoCp(η4-2,5-diphenylthiophenedioxide) (5), CoCp(η4-3,4-diphenylthiophenedioxide) (6), CoCp(η4-tetraphenylthiophenedioxide) (7). CoCp(η4-2,5-di-t-butylthiophenedioxide) (8) and CoCp(η4-di-t-butylthiophenedioxide) (9). Also complexes with the η3-ligand 2-hydrothiophenedioxide (TDO-H), containing a cyclic allyl system have been obtained: Co(CO)3(TDO-H) (11). One or two CO groups may be substituted by a variety of organophosphanes and phosphites including the chelating diphosphanes DPPM and DPPE. All compounds have been characterized by 1H and 13C NMR methods. In addition the crystal structures of 4, 7 and Co(CO)(η2-DPPE)(TDO-H) (11i) have been determined.