Hydrogen-bonded chains in 3,5-bis(4-fluorophenyl)-1-phenyl-1H-pyrazole and complex hydrogen-bonded sheets in (5RS,6SR)-6-(4-fluorobenzoyl)-5-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5,6-dihydro-4H-1,3,4-oxadiazine N,N-dimethylformamide monosolvate

Two different heterocycles, a pyrazole and an oxadiazine, are formed by the reactions of a common precursor, (2RS,3SR)-2,3-di­bromo-1,3-bis­(4-fluoro­phenyl)propan-1-one, with dif­ferent simple hydrazines. In 3,5-bis­(4-fluoro­phenyl)-1-phenyl-1H-pyrazole, C₂₁H₁₄F₂N₂, (I), formed using phenyl­hydrazine, there is some aromatic-type delocalization in the pyrazole ring, and the mol­ecules are linked into simple chains by a single C-H...π(arene) hydrogen bond. The reaction with 4-hy­droxy­benzo­hydrazide gives (5RS,6SR)-6-(4-fluorobenzoyl)-5-(4-fluoro­phenyl)-2-(4-hy­droxy­phenyl)-5,6-dihydro-4H-1,3,4-oxadiazine, which was crystallized from N,N-di­methyl­formamide to give the mono­solvate, C₂₂H₁₆F₂N₂O₃·C₃H₇NO, (II), in which the solvent mol­ecule is disordered over two sets of atomic sites having occupancies of 0.557 (10) and 0.443 (10). The oxa­diazine mol­ecules in (II) are linked by a combination of N-H...N and C-H...O hydrogen bonds to form complex sheets, having the hydrogen bonds in the central layer and with the solvent mol­ecules attached at the outer faces by O-H...O hydrogen bonds.