Low-Dimensional Sulfoantimonates with Metal Complexes as Counterions. Hydrothermal Synthesis and Properties of [M(en)₃]Sb₂S₄ (M = Co, Ni) and [M(en)₃]Sb₄S₇ (M = Fe, Ni)

[M(en)₃]Sb₂S₄ (M = Co, Ni) and [M(en)₃]Sb₄S₇ (M = Fe, Ni) were prepared from the MX₂/Na₃SbS₃/en system (X = Cl, Br; en = ethylenediamine) under hydrothermal conditions. Orange-yellow [Ni(en)₃]Sb₂S₄ (1) crystallizes in the monoclinic space group P2₁/c (No. 14) with a = 10.538(2) Å, b = 14.460(4) Å, c = 12.434(5) Å, β = 99.93(2)°, and Z = 4. Green-yellow [Co(en)₃]Sb₂S₄ (2) crystallizes as a superstructure of 1 with a = 21.131(4) Å, b = 14.619(2) Å, c = 12.540(2) Å, β = 100.50(1)°, and Z = 8. The antimony sulfide frameworks in 1 and 2 consist of SbS₃ pyramids sharing two corners to form l/∞[SbS₂]^- chains. Orange-yellow [Ni(en)₃]Sb₄S₇ (3) crystallizes in the monoclinic space group P2₁/c (No. 14) with a = 9.930(1) Å, b = 14.212(2) Å, c = 17.242(2) Å, β = 102.55(1)°, and Z = 4. The 1/∞[Sb₄S₇]^2- chains are formed by corner-sharing SbS₃ units. Three of these pyramids are arranged to cyclic Sb₃S₆ trimers which share two of the three exocyclic S-atoms with the fourth SbS₃ units to form infinite chains. [Fe(en)₃]Sb₄S₇ (4) is isostructural to 3. In all four compounds the tris(ethylenediamine)metal(II) complexes act as counterions. The thermal, magnetic and optical properties of compounds 1-4 are reported.