Cluster Salts [Nb6 Cl12 (HIm)6 ]An (with HIm=1H-imidazole and A=Mineral Acid Anion, n=1 or 2) Made in and with Brønsted-basic Ionic Liquids and Liquid Mixtures

Niobium and Tantalum Halocyanide Clusters: The Complete Family

Synthetic procedures providing straightforward access to the whole family of Nb and Ta halide clusters with terminal cyanide ligands have been developed. Corresponding [M₆X₁₂(CN)₁₂]^4- (M = Nb, Ta; X = Cl, Br) can be accessed by ligand-exchange procedures from K₄Nb₆X₁₈ (X = Cl, Br) and Bu₄NCN, (Et₄N)₂[Ta₆Cl₁₈] and Bu₄NCN and from [Ta₆Br₁₂(H₂O)₄Br₂]·4H₂O and KCN in moderate to high yields (50-80%). The products were isolated as Bu₄N salts. The compounds were investigated both experimentally and by quantum chemistry, revealing correlations between structural, electrochemical, electrostatic, electronic, and topological features as a function of type of metal, halide, and charge.