Synthesis and structure of tetraaquabis(dimethyl ether)magnesium(II) dibromide dimethyl ether disolvate

Unlike typical hexahydrates, the title compound, Mg(C 2 H 6 O) 2 (H 2 O) 4 Br 2 ·2C 2 H 6 O or Mg(H 2 O) 4 (DME) 2 Br 2 ·DME 2 (DME = dimethyl ether, C 2 H 6 O), is a water-poor magnesium(II) complex. The central magnesium cation (site symmetry 1 ) is coordinated by four water molecules and two molecules of dimethyl ether and adopts a slightly elongated trans -octahedral coordination geometry. The water molecules are linked to outer-sphere bromide anions and additional dimethyl ether molecules via O—H...Br and O—H...O hydrogen bonds. Due to the volatility of dimethyl ether, the presence of coordinating and non-coordinating molecules of this ether makes this solid state structure presented here particularly interesting. To investigate the intermolecular interactions leading to this special coordination, a Hirshfeld surface analysis was performed. It showed that the H...H interactions (70.4%) make the largest contribution to the crystal packing, followed by H...Br interactions (19.4%), H...O interactions (10.1%) and Br...O interactions (0.1%).