Tetra-μ-benzoato-κ4 O:O′;κ3 O:O,O′;κ3 O,O′:O′-bis[(benzoato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N′)terbium(III)] benzoic acid disolvate

The asymmetric unit of the title complex, [Tb2(C7H5O2)6(C12H8N2)2]·2C7H6O2, consists of one-half of the complex molecule, which lies on a crystallographic inversion centre, and one benzoic acid solvent molecule. The two TbIII ions are linked by four bridging benzoate ions, with a Tb⋯Tb distance of 3.9280 (6) Å. Additionally, each TbIII ion is coordinated by one phenanthroline heterocycle and a bidentate benzoate ion. The irregular nine-coordinated geometry of the TbIII ion is composed of seven O and two N atoms. The molecular structure is stabilized by intramolecular C—H⋯O hydrogen bonds. In the crystal structure, molecules are linked into chains along the a axis by intermolecular C—H⋯O hydrogen bonds. The crystal structure is further stabilized by intermolecular C—H⋯O and C—H⋯π interactions. Weak π–π interactions are also observed [centroid–centroid distances = 3.6275 (14)–3.6604 (14) Å].

The asymmetric unit of the title complex, [Tb 2 (C 7 H 5 O 2 ) 6 -(C 12 H 8 N 2 ) 2 ]Á2C 7 H 6 O 2 , consists of one-half of the complex molecule, which lies on a crystallographic inversion centre, and one benzoic acid solvent molecule. The two Tb III ions are linked by four bridging benzoate ions, with a TbÁ Á ÁTb distance of 3.9280 (6) Å . Additionally, each Tb III ion is coordinated by one phenanthroline heterocycle and a bidentate benzoate ion. The irregular nine-coordinated geometry of the Tb III ion is composed of seven O and two N atoms. The molecular structure is stabilized by intramolecular C-HÁ Á ÁO hydrogen bonds. In the crystal structure, molecules are linked into chains along the a axis by intermolecular C-HÁ Á ÁO hydrogen bonds. The crystal structure is further stabilized by intermolecular C-HÁ Á ÁO and C-HÁ Á Á interactions. Weakinteractions are also observed [centroid-centroid distances = 3.6275 (14)-3.6604 (14) Å ].
Experimental 0.5 mmol of TbCl 3 .6H 2 O was dissolved in methanol and then was added into a solution (methanol-H 2 O, 1.5:1) of 1,10phenanthroline (0.5 mmol) and benzoic acid (1.5 mmol). The mixture was sealed in a tube, and heated directly to 403 K.
After keeping at 403 K for 2 days, it was cooled to room temperature. Colourless block crystals of the title compound were obtained by filtration, and were washed with water and ethanol.

Refinement
All hydrogen atoms were placed in their calculated positions, with C-H = 0.93 Å, O-H = 0.82 Å, and refined using a riding model with U iso = 1.2 U eq (C) or 1.5 U eq (O). Fig. 1. The molecular structure of the title complex, showing 20% probability displacement ellipsoids for non-H atoms and the atom-numbering scheme. The suffix A corresponds to the symmetry code [-x+2, -y, -z+2].    Glazer, 1986) operating at 100.0 (1) K.

sup-2 Figures
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.