C 6H 17N 3] 4[Sb 4V 16O 42]⋅2H 2O and [NH 4] 4[Sb 8V 14O 42]⋅2H 2O— the first isolated Sb derivates of the [V 18O 42] family

Abstract

The solvothermal syntheses and the crystal structures of the two new compounds [C 6H 17N 3] 4[Sb 4V 16O 42]⋅2H 2O ( 1) and [NH 4] 4[Sb 8V 14O 42]⋅2H 2O ( 2) are presented. Compound ( 1) crystallises in the triclinic space group P 1 ¯ and ( 2) in the monoclinic space group P2 1/n. The structures can be derived from the [V 18O 42] archetype by replacing two VO 5 square pyramids by two Sb 2O 5 units in ( 1) and four VO 5 square pyramids by four Sb 2O 5 moieties in ( 2). In compound ( 1) the clusters are stacked along the b-axis in an AAA mode with the cations and water molecules occupying the interstitial space. Between the anions and cations strong N H⋯O hydrogen bonds are observed. Neighboured clusters exhibit a relatively short Sb O separation of 2.852 Å indicating a weak inter-cluster interaction. If this Sb O contact is considered the clusters are connected via Sb 2V 2O 4 rings into infinite chains running along the a-axis. In compound ( 2) the anions are stacked along the b-axis in an …ABAB… fashion. Within the (100) plane every anion is surrounded by 6 neighboured clusters. Again, relatively short Sb O contacts (2.831–2.976 Å) are found which join the isolated clusters into layers extending in the ( 10 − 1 ) plane. The cations and water molecules are located between these layers. Several short N O and O O distances indicate strong hydrogen bonding between cations and anions respectively between the water molecules and the anions.