Crystal structure of bis(μ-2-benzoylbenzoato-κ2 O:O′)bis[bis(2,2′-bipyridine-κ2 N,N′)manganese(II)] bis(perchlorate)

The title compound, [Mn2(C6H5COC6H4COO)2(C10H8N2)4](ClO4)2, comprises a centrosymmetric binuclear cation and two perchlorate anions. In the complex cation, two MnII atoms are bridged by two O atoms of two different 2-benzoylbenzoate ligands, each MnII atom being further coordinated by two 2,2′-bipyridine (bipy) ligands in a distorted octahedral environment. Within the binuclear molecule, the Mn⋯Mn separation is 4.513 (7) Å. Intermolecular C—H⋯O and C—H⋯ π interactions link the molecules into a three-dimensional network.


S2. Structural commentary
In this paper, we will report the synthesis and structure of a new bimetallic manganese complex, [Mn 2 (C 6 H 5 COC 6 H 4 COO) 2 (C 10 H 8 N 2 ) 4 ](ClO 4 ) 2 ]. The molecular structure of the complex is illustrated in Fig.1. In the centrosymmetric binuclear molecule the Mn(II) ion is coordinated by two O atoms from two different benzoyl benzoate ligands, four N atoms from two chelating bipy ligands, generating a distorted octahedral MnN4O2 coordination geometry. The cisoid bond angles fall in the region 72.8 (7)-101.5 (7)°, and transoid ones are 161.5 (7)°, and 172.9 (7)° exhibiting substantial deviations from an ideal octahedral geometry.

S3. Supramolecular features
In the crystal structure binuclear species are assembled into a three-dimensional supramolecular architecture by O-H···O, C-H···C hydrogen bonds and C-H··· π, and π-π interactions ( Fig. 2, Table 2). The closest centroid-centroid distance of the N1,C1-C5 rings is 4.031 Å. The complex molecules are weakly linked by hydrogen bonds through the perchlorate ions to generate the three-dimensional supramolecular structure.

S4. Synthesis and crystallization
Mn(ClO 4 ) 2 ·6H 2 O in methanol (0.076 mmol) was added slowly to a mixed solution of 2,2?-bipyridine (0.155 mmol) and benzoyl benzoic acid (0.080 mmol) in methanol (7 ml). After refluxing for 3 h, the mixture was filtered off while hot. The green color single crystals suitable for X-ray analysis were obtained by slow evaporation of the above filtrate at room temperature after a week.

S5. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1.

Figure 2
Packing view drawn along the c axis, showing O-H···O, C-H···C hydrogen bonds and C-H··· π, and π-π stacking interactions drawn as dotted lines.

Bis(µ-2-benzoylbenzoato-κ 2 O:O′)bis[bis(2,2′-bipyridine-κ 2 N,N′)manganese(II)] bis(perchlorate)
Crystal data Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.