metal-organic compounds
Open access
The title compound, {[Er2(C4H2O4)2(C2O4)(H2O)4]·4H2O}n, was synthesized by the reaction of erbium nitrate hexahydrate with fumaric acid and oxalic acid under hydrothermal conditions. The Er3+ cation (site symmetry ..2) is eight-coordinated by six O atoms from four fumarate anions (site symmetry ..2) and one bidentate oxalate anion (site symmetry 222), and by two water molecules. The complex exhibits a three-dimensional structure consisting of oxalate pillared Er–fumarate layers with channels occupied by coordinating and lattice water molecules. The three-dimensional structure features by Owater—HO hydrogen bonds involving both the coordinating and lattice water molecules.
organic compounds
Open access
In the title compound, C17H16Br2N2O2, the dihedral angle between the benzene rings is 57.7 (3)°. The conformation of the central N—C—C—C—N chain is gauche-anti [torsion angles = −64.2 (4) and −167.8 (4)°]. Two intramolecular O—HN hydrogen bonds occur. In the crystal, molecules are linked by pairs of C—HO hydrogen bonds, forming inversion dimers.