catena-Poly[[[pentaaquaeuropium(III)]-μ-5-sulfonatoisophthalato-κ4 O 1,O 1′:O 3,O 3′] 4,4’-bipyridine N,N′-dioxide hemisolvate trihydrate]

In the crystal structure of the title compound, {[Eu(C8H3O7S)(H2O)5]·0.5C10H8N2O2·3H2O}n, the EuIII coordination polymer displays a ribbon motif as the 5-sulfoisopthalate anion uses one of carboxyl –CO2 units to chelate to a Eu atom and the other to bind to other two Eu atoms; the sulfonyl –SO3 unit is not involved in coordination. Adjacent ribbons are linked by O—H⋯O hydrogen bonds, generating a three-dimensional network. The 4,4′-bipyridine-N,N′-dioxide molecule lies on an inversion centre and is hydrogen-bonded to the complex network. The coordination geometry of the Eu atom is a monocapped square antiprism.

In the crystal structure of the title compound, {[Eu(C 8 H 3 O 7 S)-(H 2 O) 5 ]Á0.5C 10 H 8 N 2 O 2 Á3H 2 O} n , the Eu III coordination polymer displays a ribbon motif as the 5-sulfoisopthalate anion uses one of carboxyl -CO 2 units to chelate to a Eu atom and the other to bind to other two Eu atoms; the sulfonyl -SO 3 unit is not involved in coordination. Adjacent ribbons are linked by O-HÁ Á ÁO hydrogen bonds, generating a threedimensional network. The 4,4 0 -bipyridine-N,N 0 -dioxide molecule lies on an inversion centre and is hydrogen-bonded to the complex network. The coordination geometry of the Eu atom is a monocapped square antiprism.

Related literature
For a related structure, see: Hu et al. (2005).

Comment
In the crystal structure of pentaqua(5-sulfoisophthalato)europium monohydrate sesqui-4,4'-bipyridine, the 5-sulfoisophthalate trianion O,O'-chelates to two metal atoms to furnish a polymeric chain structure. The chains are linked by hydrogen bonds into a three-dimensional network, and the N-heterocycles occupy the cavities of the network. The geometry of the metal atom is a monocapped square-antiprism (Hu et al., 2005). A similar hydrothermal synthesis with 4,4'-bipyridine Noxide in place of 4,4'-bipyridine affords the corresponding co-crystal, but the co-crystal is a trihydrated1:0.5 co-crystal. In Eu(H 2 O) 5 (C 8 H 3 O 7 S) . 3H 2 O . 0.5C 10 H 8 N 2 O 2 (Scheme I), the 5-sulfoisopthalate group uses one of carboxyl -CO 2 units to chelate to a Eu(III) atom and uses the other to bind to two other metal atoms; the sulfonyl -SO 3 unit is not involved in coordination ( Fig. 1). The geometry of the europium atom is a monocapped square-antiprism (Fig. 2). Adjacent ribbons (Fig. 3) are linked by O-H···O hydrogen bonds to generate a three-dimensional network ( Table 3). The 4,4'-bipyridine N-oxide molecule, which lies on a center-of-inversion, is hydrogen-bonded to the network.
The bomb was heated to 433 K for 72 h. It was then cooled down to room temperature at a rate of 5 K an hour. Colorless crystals were collected and washed with water (0.195 g, yield 55% based on Eu). The product is stable in air and and is insoluble in water and common organic solvents. CH&N elemental analysis. Calc. for C 18 H 25 N 2 EuO 16 S (709.42): C 34.45, H 3.55, N 3.97%. Found: C 34.24, H 3.50, N 4.08%.

Refinement
Carbon-bound hydrogen atoms were placed in calculated positions (C-H 0.93 Å, U iso (H) 1.2 times U eq (C), and were included in the refinement in the riding model approximation. The water H-atoms were placed placed in calculated positions (O-H 0.84 Å and H···H 1.37 Å) on the basis of hydrogen bonding; their temperature factors were tied by a factor of 1.5.
The final difference Fourier map had a peak and a hole in the vicinity of Eu1, but was otherwise featureless. Attempts to decrease their magnitudes by lowering the 2-theta limit did not lower these values, and the structure did not exhibit any signs of twinning.