Cluster Salts [Nb6Cl12(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. Issue 2 (3rd February 2021)

• Record Type: Journal Article
• Authors: Sperlich, Eric; Köckerling, Martin
• Is Part Of: ChemistryOpen. Volume 10:Issue 2(2021)
• Page Start: 248
• Page End: 254
• Publication Date: 2021-02-03
• Subjects: cluster -- ionic liquid -- structure elucidation -- heterocyclic ligand -- Niobium; Chemistry -- Periodicals; 540; 540.5
• DOI: 10.1002/open.202000266
• Languages: English
• ISSNs: 2191-1363

Abstract

Abstract: Four new hexanuclear niobium cluster compounds of the general formula [Nb6 Cl12 (HIm)6 ]( A )n ⋅ x (solvent molecule) (HIm=1 H ‐imidazole, A =mineral acid anion, Cl − ( n =2) (1 ), (SO4 ) 2− ( n =1) (2 ), (CrO4 ) 2− ( n =1) (3 ), and (HAsO4 ) 2− ( n =1) (4 )) were prepared. Their synthesis can be done in basic ionic liquids, which form on the addition of a mineral acid, which also delivers the counter anion for the final cluster compound, to an excess of the 1 H ‐imidazole. Some addition of an auxiliary solvent, like methanol, improves the speed of crystallisation. The cluster unit comprises a hexanuclear Nb6 unit of octahedral shape with the edges bridged by Cl atoms and the exo sites being occupied by N‐bonded 1 H ‐imidazole ligands. The cluster cation carries sixteen cluster‐based electrons. Between the NH groups of the ligands of the cluster unit, the anions and the co‐crystallised water (1 ), or 1 H ‐imidazole and methanol molecules (2, 3, and 4 ) a network of hydrogen bonds exists. Abstract : Ionic liquids and ionic liquid mixtures allow for the preparation of highly crystalline samples of cluster compounds with cationic cluster units. These consist of hexanuclear, octahedral Nb6 cluster cores, edge‐bridged by Cl atoms. Each Nb atom carries one 1 H ‐imidazole ligand. Mineral acid anions function as counter anions. In crystals of the title compounds an extensive network of hydrogen bonds exists between the cluster cations, the anions and the co‐crystallised solvent molecules.