Synthesis and Structural Characterization of [bpyr]₄[V₄O₄Cl₁₂] and [bpyr]₄[Bi₄Cl₁₆] grown in Ionic Liquid [bpyr][AlCl₄] (bpyr = 1-Butylpyridinium)

Ionic solids with large inorganic cluster anions have been synthesized from the reaction of oxides with a chloroaluminate ionic liquid, [bpyr][AlCl4] (bpyr = 1-butylpyridinium cation). The reaction of the AlCl4− anion with vanadium and bismuth oxides in the presence of metal reducing agents has resulted in two new salts with anionic cluster complexes of vanadium(IV) ([bpyr]4[V4O4Cl12]) and bismuth(III) ([bpyr]4[Bi4Cl16]). The compound [bpyr]4[V4O4Cl12] crystallizes in the monoclinic space group C2/c (a = 32.771(2) Å, b = 9.4505(6) Å, c = 17.5068(11) Å, β = 106.474(1)°) and compound [bpyr]4[Bi4Cl16] crystallizes in the triclinic space group P1̅ (a = 10.9179(1) Å, b = 11.2495(2) Å, c = 13.3045(2) Å, α = 109.460(3)°, β = 94.883(3)°, γ = 101.055(3)°). These materials consist of inorganic clusters of [VOCl3]44−and [BiCl4]44−, respectively, which are separated by discrete butylpyridinium cations. The crystal structure of the neat frozen ionic liquid has also been determined, confirming the presence of AlCl4− tetrahedral units in the compound.