Synthesis and Characterisation of Iodobismuthates Containing N-substituted 1,4-Diazabicyclo[2.2.2]octane

Abstract

Two new hybrid iodobismuthates, [C₈H₁₇N₂][C₁₀H₂₂N₂][BiI₆] (1) and [C₆H₁₂N₂]_0.5[C₁₀H₂₂N₂]_3.5[Bi₂I₁₀][Bi₂I₉] (2), have been prepared by solvothermal synthesis in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) and ethanol. Both compounds have been characterized by single-crystal and powder X-ray diffraction, infrared and UV–Vis spectroscopies and thermogravimetric analysis. Structure determination reveals that the crystal structure of 1 contains mononuclear [BiI₆]³⁻ anions, whilst 2 contains an unusual combination of dinuclear anions, [Bi₂I₉]³⁻ and [Bi₂I₁₀]⁴⁻, consisting of two edge- and two face-sharing [BiI₆]³⁻ octahedra, respectively. Mono- and diethylated derivatives of DABCO, which are formed in situ under solvothermal conditions, act as countercations and are located between the discrete anions. The optical band gaps of 1 and 2, which are 2.29(1) and 2.03(2) eV respectively, are consistent with the red color of these compounds, and are comparable to the band gaps measured for other iodobismuthates containing discrete anions.

Two new iodobismuthates, [C₈H₁₇N₂][C₁₀H₂₂N₂][BiI₆] (1) and [C₆H₁₂N₂]_0.5[C₁₀H₂₂N₂]_3.5[Bi₂I₁₀][Bi₂I₉] (2), have been synthesized under solvothermal conditions, and their crystal structures determined by single-crystal X-ray diffraction.