C—Br...S halogen bonds in novel thiourea N‐oxide cocrystals: analysis of energetic and QTAIM parameters.

Cocrystals of thiourea with 4‐nitropyridine N‐oxide, C5H4N2O3·2CH4N2S, (I), and 3‐bromopyridine N‐oxide, C5H4BrNO·CH4N2S, (II), crystallize in the monoclinic space group P21/c. In the crystals, molecules of both components are linked by N—H...O hydrogen bonds, creating R21(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. [ABSTRACT FROM AUTHOR]