Crystal structure and hydrogen-bonding patterns in 5-fluoro-cytosinium picrate

Abstract

In the crystal structure of the title compound, 5-fluoro-cytosinium picrate, C₄H₅FN₃O⁺·C₆H₂N₃O₇^-, one N heteroatom of the 5-fluoro-cytosine (5FC) ring is protonated. The 5FC ring forms a dihedral angle of 19.97 (11)° with the ring of the picrate (PA^-) anion. In the crystal, the 5FC⁺ cation inter-acts with the PA^- anion through three-centre N-H⋯O hydrogen bonds, forming two conjoined rings having R₂¹(6) and R₁²(6) motifs, and is extended by N-H⋯O hydrogen bonds and C-H⋯O inter-actions into a two-dimensional sheet structure lying parallel to (001). Also present in the crystal structure are weak C-F⋯π inter-actions.

Keywords: 5-fluoro­cytosine; bifurcated inter­actions; crystal structure; hydrogen bonding; picrate.

Figure 1

The naming scheme for the 5FC⁺ cation and the PA⁻ anion in the title compound, showing 30% probability level displacement ellipsoids. Dashed lines represent hydrogen bonds.

Figure 2

A view of the supra­molecular network formed via N—H⋯O and C—H⋯O inter­actions. Dashed lines represent hydrogen bonds. For symmetry codes, see Table 1 ▸.

Figure 3

A view of the C5—F5⋯π inter­action between 5FC⁺ cations.