K(VO)(SeO₃)₂H:  A New One-Dimensional Compound with Strong Hydrogen Bonding

The hydrothermal synthesis, X-ray single crystal structure, magnetic properties, and solid state NMR and infrared spectroscopic data of a new compound, K(VO)(SeO₃)₂H, are described. K(VO)(SeO₃)₂H crystallizes in the monoclinic space group P2₁/m (No. 11), with a = 7.8659(7) Å, b = 10.4298(7) Å, c = 4.0872(7) Å, β = 96.45(1)°, and Z = 4. The structure is described as parallel linear strands made of repeating [(VO)(SeO₃)₂]^2- units. The chains are held together through hydrogen bondings between selenite oxygens, weak VO···VO bonds, and ionic bonds to the interchain K⁺ ions. The hydrogen bonding in this compound shows many characteristics of the strong hydrogen bonding with a short O−O distance of 2.459(6) Å, a large down field shift of the proton NMR signal of 19 ± 1 ppm, and a low O−H absorption frequency. However, the exact position of the hydrogen atom and, thus, the nature of the hydrogen bonding in this compound is unclear. Possible models for the hydrogen atom positions are discussed based on experimental and literature data. The magnetic susceptibility data show an antiferromagnetic coupling below 19 K. The curve can be explained with a 1-D Heisenberg model for S = ¹/₂ with J/k = 13.8 K and g = 1.97.