Air‐Stable, Well‐Soluble AI2[Nb6Cl18] Cluster Compounds (AI = Organic Cation): A New Route for Preparation, Single‐Crystal Structures, Properties, and ESI‐Mass Spectra

Abstract

Abstract Five niobium cluster compounds of the AI2[Nb6Cl18] type (AI = organic cation: [nPr4N]+, [nBu4N]+, [BMIm]+, [Ph4P]+, and [PPN]+) are obtained through treatment of [Nb6Cl14(H2O)4]·4H2O with excess of thionyl chloride in the presence of an organic chloride, AICl. Single‐crystal structure studies show that the compounds consist of discrete cations and cluster [Nb6Cl18]2– anions. The cluster unit of the hydrated cluster starting material is oxidized by two electrons. Powder diffraction studies and NMR spectroscopic measurements show all compounds to crystallize without co‐crystallized solvent molecules. They are air and water stable. The solubility in organic solvents changes to a great extent on changing the type of cation. The ESI‐MS spectra of [nPr4N]2[Nb6Cl18] and [Ph4P]2[Nb6Cl18] show the pseudomolecular peak of the anionic cluster as well as additional signals, which involve simultaneously chloride mass loss and reduction processes.