Two tautomers in the same crystal: 3-(4-fluoro­phen­yl)-1H-pyrazole and 5-(4-fluoro­phen­yl)-1H-pyrazole

摘要

The title co-crystal, 3-(4-fluoro­phen­yl)-1H-pyrazole–5-(4-fluoro­phen­yl)-1H-pyrazole (1/1), C9H7FN2, crystallizes with four independent mol­ecules (A, B, C and D) in the asymmetric unit exhibiting two tautomeric forms (A and D; B and C) due to N—H proton exchange between the two N atoms of the pyrazole ring. The dihedral angles between the mean planes of the pyrazole and benzene rings are 15.6 (1), 19.8 (9), 14.0 (1) and 10.7 (7)° in mol­ecules A, B, C and D, respectively. In the crystal, N—H⋯N hydrogen bonds link the four mol­ecules in the asymmetric unit into a ring with an R 4 ⁴(12) motif. Furthermore, weak C—H⋯F inter­actions link the mol­ecules into a three-dimensional network.