Crystal structure of diaqua[5,10,15,20-tetrakis(4-bromophenyl)porphyrinato-κ4N]magnesium

Abstract

The title compound, [Mg(C44H24Br4N4)(H2O)2] or [Mg(TBrPP)(H2O)2], where TBrPP is the 5,10,15,20-tetrakis(4-bromophenyl)porphyrinato ligand, was obtained unintentionally as a by-product of the reaction of the [Mg(TBrPP)] complex with an excess of dimethylglyoxime in dichloromethane. The entire molecule 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 MgII 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 molecule are incompatible with the fourfold rotation axis and are disordered over two sites. In the crystal, molecules are packed in rows along [001]. Weak intermolecular C—H...π and C—H...Br interactions, as well as O—H...Br hydrogen bonds, stabilize the crystal packing.

Keywords

• crystal structure
• magnesium porphyrin complex
• O—H...Br hydrogen bonds
• C—H...Br interactions
• C—H...π interactions