Tetrakis(μ-3-azaniumylbenzoato)-κ3O:O,O′;κ3O,O′:O;κ4O:O′-bis[tetraaquaneodymium(III)] hexachloride tetrahydrate

Abstract

The structure of the title compound, [Nd2(C7H7NO2)4(H2O)8]Cl6·4H2O, consists of dimeric cationic units related by an inversion centre. The two NdIII atoms are linked by two bridging bidentate carboxyl­ate groups and two bidentate chelating bridging carboxyl­ate groups, with an Nd⋯Nd separation of 4.1259 (4) Å. Each NdIII atom is nine-coordin­ated by five O atoms from the carboxyl­ate groups of the zwitterionic azaniumylbenzoate ligands and four from water mol­ecules. They adopt a distorted tricapped trigonal–prismatic arrangement. The dihedral angle between the mean planes of the benzene ring and the carboxlate groups are 7.7 (6) and 24.4 (5)°. The two carboxyl­ate groups are almost perpendicular to one another with a dihedral angle of 84.0 (7)°, while the two benzene rings are inclined to one another by 81.8 (2)°. The mol­ecular packing is stabilized by O—Hwater⋯Cl, O—Hwater⋯N, N—H⋯Cl, N—H⋯O, and O—Hwater⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distance = 3.500 (3) Å] between symmetry-related benzene rings. All of the Cl− anions and the uncoordinated water molecules are disordered over two sets of sites with different occupancy ratios.