C—Br...S halogen bonds in novel thioureaN-oxide cocrystals: analysis of energetic and QTAIM parameters

Cocrystals of thiourea with 4-nitropyridine N -oxide, C 5 H 4 N 2 O 3 ·2CH 4 N 2 S, ( I ), and 3-bromopyridine N -oxide, C 5 H 4 BrNO·CH 4 N 2 S, ( II ), crystallize in the monoclinic space group P 2 1 / c . In the crystals, molecules of both components are linked by N—H...O hydrogen bonds, creating R 2 1 (6) synthons. The bromine substituent of the N -oxide component in ( II ) is a centre for C—Br...S halogen bonding to the thiourea molecule. Computations based on quantum chemistry methods (quantum theory of atoms in molecules, QTAIM) and atoms in molecules (AIM) theory were performed for a more detailed description of the observed type of halogen-bonding interaction.