Crystal structure of di-aqua-[5,10,15,20-tetra-kis-(4-bromo-phen-yl)porphyrinato-κ(4) N]magnesium.

The title compound, [Mg(C44H24Br4N4)(H2O)2] or [Mg(TBrPP)(H2O)2], where TBrPP is the 5,10,15,20-tetra-kis-(4-bromo-phen-yl)porphyrinato ligand, was obtained unintentionally as a by-product of the reaction of the [Mg(TBrPP)] complex with an excess of di-methyl-glyoxime in di-chloro-methane. The entire mol-ecule exhibits point group symmetry 4/m. In the asymmetric unit, except for two C atoms of the phenyl ring, all other atoms lie on special positions. The Mg(II) atom is situated at a site with symmetry 4/m, while the N and the C atoms of the porphyrin macrocycle, as well as two C atoms of the phenyl ring and the Br atom lie in the mirror plane containing the porphyrin core. The H atoms of the axially bonded water mol-ecule are incompatible with the fourfold rotation axis and are disordered over two sites. In the crystal, mol-ecules are packed in rows along [001]. Weak inter-molecular C-H⋯π and C-H⋯Br inter-actions, as well as O-H⋯Br hydrogen bonds, stabilize the crystal packing.