Crystal structure of tetrachloride ferrate (III) complex with methylene blue

The crystal structure of tetrachloride ferrate (III) complex with methylene blue, [MB] + [FeCl4] – (where [MB] + methylthioninium or 3,7-bis(dimethylamino)-phenothiazine-5-ium cation), has been prepared by mechanochemical way and studied by the single crystal X-ray crystallography. The crystal structure of title compound is built from by [FeCl 4 ] 2- tetrahedral ion and planar [MB] + counter ions. The [MB] + cations are linked in the 3D network by the C–H···Cl hydrogen bonds. The [MB] + cations are stacked in an antiparallel fashion with the sulfur atom disposed alternatively on an opposite sides of the stacking. The centroids-centroids distance between the thiazine rings is 3.975 Å and the planar- planar angle is 1.6°. Intermolecular short contacts were analyzed by 3D Hirshfeld surfaces method and 2D fingerprint plots. Intermolecular interaction energy between two neighboring MB + cation pair was calculated by using of CE- B3LYP/6-31G (d, p) theoretical level.