New Family of Cerium Halide Based Materials: CeX₃·ROH Compounds Containing Planes, Chains, and Tetradecanuclear Rings

Six members of a new family of cerium-halide-based materials with promising scintillation behavior have been synthesized in single crystal form, and their crystal structures were determined. Specifically, these new compounds are [(CeCl₃)₇(BuOH)₁₆(H₂O)₂]·(BuOH)₂ (1), (CeBr₃)₁₄(BuOH)₃₆ (2), [(CeCl₃)₇(1-PrOH)₁₆(H₂O)₂]·(1-PrOH)₂ (3), [(CeBr₃)₇(1-PrOH)₁₈]·(1-PrOH)₂ (4), [(CeCl₃)₆(iBuOH)₁₅]·(iBuOH)₂ (5), and CeCl₃(sec-BuOH)₂(H₂O) (6). Additionally, the scintillation ability of compound 1 was established. The structures of these cerium-halide-based materials consist of catenated tetradecanuclear rings that arrange themselves into three distinct structural motifs which contain the largest lanthanide-based ring structures reported to date; the different motifs are obtained by involving specific alcohols during synthesis. Specifically, n-butanol and n-propanol lead to 1-D chains of tetradecanuclear rings, and iso-butanol leads to 2-D parquet-patterned sheets of rectangular tetradecanuclear rings, while sec-butanol results in a zigzag 1-D chain structure. One of the compounds, [(CeCl₃)₆(iBuOH)₁₅]·(iBuOH)₂, has been shown to scintillate with a light yield of up to 1920 photons/MeV, and due to the presence of protons, it should be capable of detecting high energy neutrons without the necessity of prior thermalization. Furthermore, it also appears to be the first cerium-based compound that scintillates in spite of the fact that water coordinates to two of the Ce­(III) centers within the structure.