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

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.