Di-μ-bromido-bis­[(diethyl ether-κO)(2,4,6-tri­methyl­phen­yl)magnesium]: the mesityl Grignard reagent

The crystal structure of the title compound, [Mg₂Br₂(C₉H₁₁)₂(C₄H₁₀O)₂], features a centrosymmetric two-centre magnesium complex with half a mol­ecule in the asymmetric unit. The Mg atom is in a considerably distorted Br₂CO coordination. Bond lengths and angles are comparable with already published values. The crystal packing is stabilized by C—H...π inter­actions linking the complexes into sheets parallel to (0-11).

4,4′-Dimethyl-2,2′-{[2,3,3a,4,5,6,7,7a-octa­hydro-1H-benzimidazole-1,3-di­yl]bis­(methyl­ene)}diphenol

The asymmetric unit of the title compound, C₂₃H₃₀N₂O₂, contains one half-mol­ecule, with a twofold axis splitting the mol­ecule in two identical halves. The structure of the racemic mixture has been reported previously [Rivera et al. (2009) J. Chem. Crystallogr. 39, 827–830] but the enanti­omer reported here crystallized in the ortho­rhom­bic space group P2₁2₁2 (Z = 2), whereas the racemate occurs in the triclinic space group P-1 (Z = 2). The observed mol­ecular conformation is stabilized by two intra­molecular O—H...N hydrogen bonds, which generate rings with graph-set motif S(6). In the crystal, mol­ecules are linked via non-classical C—H...O inter­actions, which stack the mol­ecules along the b axis.

4,4′-Di-tert-butyl-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol

In the title compound, C₂₅H₃₆N₂O₂, the two tert-butyl-substituted benzene rings are inclined at an angle of 53.5 (3)° to one another. The imidazolidine ring has an envelope conformation with with one of the C atoms of the ethylene fragment as the flap. The structure displays two intra­molecular O—H...N hydrogen bonds that generate S(6) ring motifs. The crystal studied was a non-merohedral twin with a fractional contribution of 0.281(6) for the minor domain.