A simple approach to synthesis of a polynuclear Bi(III)-oxo cluster bridged by nitrate: Topological structure and thermal stability

Reaction of Bi(NO₃)₃ · 5 H₂O and NaOH with 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetic acid (Haha) in water under heating condition leads to the facile formation of a bismuth-oxo cluster compound with formula [Bi₆O₅(OH)₃(NO₃)₅(H₂O) · 2 H₂O]_n. This simple route affords a convenient synthesis of a polynuclear Bi(III)-oxo cluster with the yield of 71%. It features the centrosymmetric {Bi₁₂O₁₀(OH)₆} central cores, which is composed of tetra- and penta-coordinated Bi(III) centers, μ₃- and μ₄-bridging oxygen atoms, and μ₃-bridging OH^- anions. The central cores are connected by NO₃^- anions by coordination interactions with Bi(III) centers in κ₂μ₂- and κ₂μ₃-bridging modes, forming a ten-connected network with the Schläfli symobl of {3¹²·4²⁸·5⁵}. As the temperature increases, compound <b>1</b> first loses three water molecules, then three OH^- anions, and finally NO₃^- anions.