Macrocyclic Amines as Structure-Directing Agents for the Synthesis of Three-Dimensional Antimony-Sulfide Frameworks

A new family of antimony sulfides, incorporating the macrocyclic tetramine 1,4,8,11-tetraazacyclotetradecane (cyclam), has been prepared by a hydrothermal method. [C10N4H26][Sb4S7] (1), [Ni(C10N4H24)][Sb4S7] (2), and [Co(C10N4H24)]x[C10N4H26]1-x[Sb4S7] (0.08 ≤ x ≤ 0.74) (3) have been characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetry, and analytical electron microscopy. All three materials possess the same novel three-dimensional Sb4S72- framework, constructed from layers of parallel arrays of Sb4S84- chains stacked at 90° to one another. In 1, doubly protonated macrocyclic cations reside in the channel structure of the antimony-sulfide framework. In 2 and 3, the cyclam acts as a ligand, chelating the divalent transition-metal cation. Analytical and X-ray diffraction data indicate that the level of metal incorporation in 2 is effectively complete, whereas in 3, both metalated and nonmetalated forms of the macrocycle coexist within the structure.