Tuning Connectivity in Hybrid Organic–Inorganic Antimony Halides through Reactant Concentration Effects

Abstract We report the synthesis and characterization of two hybrid organic–inorganic (HOI) antimony halides by varying the concentration of Sb2O3, CuCl2, and DABCO (DABCO = 1,4-diazabicyclo[2.2.2]octane) in concentrated hydrochloric acid. Different concentrations lead to different antimony oxidation states, resulting in different inorganic substructures ranging from isolated units to layers and a three-dimensional metal halide framework. (DABCOH2)(SbVCl6)Cl (1) contains isolated [SbVCl6]− units separated by the organic cation and chloride. Mixed-valent (DABCOH2)12(SbIII)14(SbV)2Cl79(H3O)3(H2O)33 (2) features a three-dimensional framework of [SbIIICl6]3– units with a previously unknown network topology as well as [SbVCl6]− and an octahedral chloride hydrate cluster with chloride at the center of the water shell. Compound 2 was characterized by single-crystal X-ray diffraction, spectroscopic, and computational methods. A chloride hydrate cluster is also present in the literature-known (DABCOH2)4Sb2IIICu2IICl18(H2O)4, obtained at the highest reactant concentrations and characterized here by solid-state NMR. These compounds show that the chemical space of antimony halides can be systematically expanded by careful reaction control.