Ionic Cocrystals of Pharmaceutical Compounds: Sodium Complexes of Carbamazepine

Three
inorganic cocrystal (ICC) forms of carbamazepine (CBZ) have
been synthesized, and their crystal structures are described. [Na­(CBZ)4(MeOH)]­[I]·H2O, [Na­(CBZ)5]­[I3], and [Na­(CBZ)5]­[C13H10N]­[IBr2]2 are the first CBZ structures that contain metal
cations, and the latter example also contains acridinium, which is
a known metabolite of CBZ. All three Na complexes have distorted square
pyramidal NaO5 coordination geometries but different conformations
of the four basal ligands and different hydrogen bonding interactions
for the apical ligand. The hydrogen bonded synthons that have been
identified for other species that contain neutral CBZ molecules are
absent in all these Na containing ICC phases and are replaced by Na–O
dative bonds. However, previously identified nonpolar supramolecular
constructs in the form of stacks and dimers are shared with other
CBZ containing structures.