Tetra-kis(μ-3-aza-niumylbenzoato)-κO:O,O';κO,O':O;κO:O'-bis-[tetra-aqua-neodymium(III)] hexa-chloride tetra-hydrate

Acta Crystallogr Sect E Struct Rep Online. 2011 May 1;67(Pt 5):m584-5. doi: 10.1107/S1600536811012700. Epub 2011 Apr 13.

Abstract

The structure of the title compound, [Nd(2)(C(7)H(7)NO(2))(4)(H(2)O)(8)]Cl(6)·4H(2)O, consists of dimeric cationic units related by an inversion centre. The two Nd(III) atoms are linked by two bridging bidentate carboxyl-ate groups and two bidentate chelating bridging carboxyl-ate groups, with an Nd⋯Nd separation of 4.1259 (4) Å. Each Nd(III) atom is nine-coordin-ated by five O atoms from the carboxyl-ate groups of the zwitterionic azaniumylbenzoate ligands and four from water mol-ecules. 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 carboxyl-ate 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 mol-ecular packing is stabilized by O-H(water)⋯Cl, O-H(water)⋯N, N-H⋯Cl, N-H⋯O, and O-H(water)⋯O hydrogen bonds and π-π stacking inter-actions [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.