Intercalation of substituted pyridine derivatives and bipyridine compounds into gel-V2O5 and VOPO4 interlayer spaces and protonation of the guest molecules

Abstract

Substituted pyridine derivatives (X-py: X=H, 2,4-Me₂ , 2-Me, 3-Cl, 3-Br and 4-CN) and bipyridine compounds (2,2′- and 4,4′-pyYpy: –Y–=none, –C₂H₂ –, –SS– and –C₂H₄ –) reacted with powdered gel-V₂O₅ 1.6H₂O or VOPO₄ 2H₂O suspended in ethanol to afford intercalation compounds. They contained 0.1–0.4 mol of guest molecules per vanadium ion. In the V₂O₅-intercalation compounds, intercalation essentially occurs through the diffusion of the guest molecules accompanied by the protonation on the nitrogen atoms to some extent in the interlayer space, resulting in a net expansion of the spacings of 4.0–5.0 Å. The long-axis direction of the guest molecules is arranged approximately parallel to the V₂O₅-sheet, and hydrogen bonds are formed between the N-components of the protonated guest molecules and the VO sites. The interlayer distances are lengthened with an increase of the amount of the N-protonated pyridyl moieties in the interlayer space. In the VOPO₄-intercalation compounds, the net expansions of the interlayer spaces were 7.0–12.0 Å, the guest molecules being arranged approximately perpendicular to the host layer. There is no appreciable relationship between the interlayer distances and the amounts of N-protonated pyridyl moieties.