Hydrothermal synthesis and characterization of two new arsenic–vanadate compounds with the same cluster anion [As₈V₁₄O₄₂(H₂O)]⁴⁻

Abstract

Two new arsenic–vanadate compounds [Co(C₄H₁₃N₃)₂]₂[As₈V₁₄O₄₂(H₂O)] · 3.5H₂O (1) and (C₂N₂H₉)₂(C₂N₂H₁₀)[As₈V₁₄O₄₂(H₂O)] · 2.33H₂O (2) have been hydrothermally synthesized and characterized by X-ray single crystal diffraction, IR spectra and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/c, a = 24.649(9) Å, b = 13.364(5) Å, c = 22.463(8) Å, β = 104.008(5)°, V = 7180(5) ų, Z = 4, R ₁ = 0.0787, and wR ₂ = 0.1859. Compound 2 crystallizes in rhombohedral system with space group R3c, a = b = c = 22.2405(5) Å, α = β = γ = 110.4030(10)°, V = 8163.4(3) ų, Z = 6, R ₁ = 0.0341 and wR ₂ = 0.0941. The structural analyses show that both compounds have the same discrete cluster anion [As₈V₁₄O₄₂(H₂O)]⁴⁻. Moreover, in 1, the polyanions are connected through van der Waals forces to generate soft channels that are filled by [Co(C₄H₁₃N₃)₂]²⁺ cations and water. In 2, water and organic molecules link cluster anions to create the supramolecular assembly through hydrogen bonding.

Keywords:

• Arsenic–vanadate
• Cluster
• Hydrothermal synthesis
• Crystal structure

Acknowledgement

The authors thank the Nature Science Foundation of Liaoning province (20062139) for financial support.