(4-Fluoro­phen­yl)thio­urea–1,10-phenanthroline (1/1)

Refluxing a mixture of 1,10-phenanthroline, (4-fluoro­phen­yl)thio­urea and cadmium(II) chloride did not produce the expected mixed-ligand complex but formed a co-crystal of the two ligands, C₁₂H₈N₂·C₇H₇FN₂S. The asymmetric unit consists of two pairs of the co-crystal mol­ecules. In each (4-fluoro­phen­yl)thio­urea mol­ecule, the planes of the N₂CS thio­urea units are almost perpendicular to the corresponding fluoro­benzene rings, subtending angles of 76.53 (7) and 85.25 (7)°. In the crystal, N—H...N and N—H...S hydrogen bonds form inversion dimers from the co-crystal pairs. A weak π–π inter­action between the phenanthroline rings [centroid–centroid distance = 3.7430 (15)Å] is also observed.