The binuclear iron complex [{Fe("EtN2S2")}(2)] (1b, "EtN2S2" = N,N'-diethyl-3,7-diaZanonane-1,9-dithiolate) was prepared from the free ligand and ferrous bis[bis(trimethylsilyl)amide] in toluene. In dichloromethane 1b reacts with the [Fe4S4I4](2-) cubane cluster to displace two iodo ligands and to form the neutral hexanuclear cluster [{Fe("EtN2S2")}(2)Fe4S4I2] (2), which is isolated as black crystals in 87% yield. As elucidated by an X-ray structure analysis, 2 contains the novel hexanuclear stair-like [Fe-6 (mu(3)-S)(4)(mu(2)-SR)(4)] core, which exhibits crystallographic inversion symmetry. The compound crystallizes as a solvate with two molecules of CH2Cl2 per formula unit in the monoclinic space group P2(1)/n with a = 1570.5(2) pm, b = 1060.2(1) pm, c = 1604.0(2) pm, beta = 114.93(1)degrees, and Z = 2. In the aprotic polar solvents DMF, 1,2-propylenecarbonate, and DMSO, 2 dissolves with decomposition and formation of the cluster [{Fe("EtN2S2")}(2)Fe4S5] (3), which is isolated as black needles from DMF. 3.2DMF crystallizes in the triclinic space group P (1) over bar with a = 950.9(1) pm, b = 1086.0(1) pm, c = 2381.5(2) pm, alpha = 101.81(1)degrees, beta = 91.94(1)degrees, gamma = 97.01(1)degrees, and Z = 2. The neutral compound contains a nest-like [Fe-6(mu(4)-S)(mu(3)-S)(2)(mu(2)-S)(2)(mu(2)-SR)(4)] core of idealized C-2v symmetry that is closely related to that of other well-known clusters, e.g., the cluster anion [Fe6S9(SR)(2)](4-). The zero-field Fe-57 Mossbauer spectrum of 3 is in accordance with four Fe2.5+S4 centers (delta = 0.46 mm/s; Delta E-Q = 1.14 mm/s) and two N2S3-bound high-spin Fe2+ sites (delta = 0.83 mm/s; Delta E-Q = 3.64 mm/s). A total cluster spin of 0 is deduced from the Mossbauer spectrum at 4.2 K and 5.3 T, which yields magnetic splitting from the applied field only. For 2, three subspectra are observed in the Mossbauer spectrum (a, delta = 0.45 mm/s, Delta E-Q = 1.05 mm/s; b, delta = 0.55 mm/s, Delta E-Q = 1.61 mm/s, c, delta = 0.80 mm/s; Delta E-Q = 3.83 mm/s) reflecting different coordination environments of the iron atoms rather than different oxidation states. The electrochemical properties of 1b, 2, and 3 were determined by cyclic voltammetry. 1b can be quasi reversibly oxidized in dichloromethane solution at -75 mV (vs SCE). Whereas 2 shows only an irreversible redox behavior in N,N-dimethylimidazolidin-2-one solution, 3 in the same solvent can be quasi-reversibly reduced in two consecutive steps at -830 and -1630 mV (vs SCE) to the dianion, which consists entirely of Fe(II).