Reaction of FeCl 3 · 4 H 2 O with dttd 2- , the dianion of 2,3,8,9-dibenzo-1.4,7,10-tetru-thiadecane, leads to the solvated [Fe(dttd)], which coordinates CO, PMe 3 and N 3 H 4 yielding [Fe(CO) 2 dttd], [Fe(PMe 3 ) 2 dttd], [Fe(CO)PMe 3 (dttd)], [Fe(N 2 H 4 ) 2 dttd] and [Fe(N 2 H 4 )CO(dttd), respectively. With H 2 S and [Fe(dttd)] the Fe(III) complex (PPN) 2 [F e 2(S) 2 (dttd) 2 ] is obtained. PPh 3 cannot be coordinated to [Fe(dttd)], whereas the reaction between [Fe(PPh 3 )(CO) 3 I 2 ] and LiSC 6 H 4 SCH 3 yields [Fe(PPh 3 )CO(CH 3 SCeH 4 S) 2 ] besides the major product [Fe(CO) 2 (CH 3 SCeH 4 S) 2 ]. A PPh 3 complex can be obtained also with o-benzenedithiolate, C 6 H 4 S 2 2- : Reacting [Fe(PPh 3 )(CO) 3 I 3 ] with Li 2 S 2 C 6 H 4 yields the binuclear [Fe(PPh 3 )(CO) 2 C 6 H 4 S 2 ] 2 . Oxidation of [Fe(N 3 H 4 )CO(dttd)] by various agents leads to [Fo(CO)dttd] 2 without evidence of formation of a N 2 complex intermediate. Nucleophilic attack of [Fe(CO) 2 (CH 3 SC 6 H 4 S) 2 ] by lithium organyls as e.g. LiPh leads to the benzoylato complex [Li(THF) 3 ][Fe(CO)(PhCO)(CH 3 SC 6 H 4 S) 2 ]; the structures of the starting complex as well as of the adduct have been elucidated by X-ray structure determination. Nucleophilic attack of the corresponding [Fe(CO) 2 dttd] by LiPh occurs reversibly at the Fe center; by cleavage of a Fe-S bond [Fe(Ph)(CO) 2 dttd′] - is formed, where dttd′ is acting as a tridentate ligand. This result shows how the reactions of formally equivalent complexes like [Fe(CO) 2 (CH 3 SC 6 H 4 S) 2 ] and [Fe(CO) 2 dttd] depend strongly upon the denticity of the sulfur ligands. The dependence upon the character of the nucleophilic agent is shown by the reaction of [Fe(CO) 2 dttd] with Li[BEt 3 H]; in this case again a CO ligand is attacked reversibly yielding the formyl complex [LiBEt 3 ][Fe(HCO)CO(dttd)], the structure of which could be elucidated so far only spectroscopically as well as by elemental analysis. [Fe(Ph)(CO)gdttd′] - forms salts like e.g. (AsPh 4 )[Fe(Ph)(CO) 2 dttd]; in solution they slowly loose CO yielding e.g. binuclear (AsPh 4 ) 2 [Fe(Ph)dttd] 3 . Attempts to isolate the anion as [Li(TMED) 3 ] + salt load to the loss of CO as well as of phenyl ligands yielding the paramagnetic [Fe(TMED)dttd], which is also obtained directly from [Fe(dttd)] and TMED. The phenyl complex [Fe(Ph)dttd] 2 2- is also formed by reaction of [Fe(dttd)] with LiPh; on reaction with dimethyl-formamide it yields [Fe(DMF)dttd] 2 . A series of the above described compounds has been investigated by Mößbauer spectroscopy.