A new bismuth coordination polymer with proton conductivity and orange-red photoluminescence

A new highly water stable bismuth-containing coordination polymer is reported along with its structural characterizations as determined by single crystal and powder X-ray diffraction, elemental, and thermal analysis, featuring an orange-red photoluminescence, and proton conductivity. The compound, (Imi)₂[Bi₂(pzdc)₄]·2H₂O (1, pzdc^2- = pyrazine-2,3-dicarboxylate; Imi = imidazolium cation), crystallizes in the monoclinic space group, P2₁/c (a = 14.3725(7) Å, b = 22.4499(10) Å, c = 11.5204(6) Å, and β = 91.1183(16)°), which contains 2D layers of Bi that are connected into a 3D supramolecular structure via extended hydrogen bond network. The interlayered voids are occupied by lattice water and imidazolium ions. Compound 1 is synthesized using an optimized, facile slow evaporation method leading to a water stable compound with a well-defined 1D hydrogen-bonded water feature along the crystallographic a-direction that lead to a proton conductivity of 8.41 × 10⁻⁶ S·cm⁻¹ at 85 °C and 95% RH.