catena-Poly[bis[(1,10-phenanthroline)iron(II)]-bis(μ-5-carboxybenzene-1,3-dicarboxylato)]

The asymmetric unit of the title compound, [Fe(C9H4O6)(C12H8N2)(H2O)]n, contains one FeII cation, one 5-carboxybenzene-1,3-dicarboxylate dianion (Hbtc), one 1,10-phenanthroline (phen) ligand and one water molecule. The FeII centre displays a distorted octahedral geometry, being surrounded by one phen ligand, two μ2-O atoms of two carboxylate groups from two Hbtc ligands, one O atom from one carboxylate of another Hbtc ligand and one terminal water molecule. One carboxylate group ligates two FeII cations in a μ1,1 mode, while the other carboxylate groups bonds to only one Fe atom. The crystal structure is stabilized by O—H⋯O hydrogen bonds.

The asymmetric unit of the title compound, [Fe(C 9 H 4 O 6 )-(C 12 H 8 N 2 )(H 2 O)] n , contains one Fe II cation, one 5-carboxybenzene-1,3-dicarboxylate dianion (Hbtc), one 1,10-phenanthroline (phen) ligand and one water molecule. The Fe II centre displays a distorted octahedral geometry, being surrounded by one phen ligand, two 2 -O atoms of two carboxylate groups from two Hbtc ligands, one O atom from one carboxylate of another Hbtc ligand and one terminal water molecule. One carboxylate group ligates two Fe II cations in a 1,1 mode, while the other carboxylate groups bonds to only one Fe atom. The crystal structure is stabilized by O-HÁ Á ÁO hydrogen bonds.
The asymmetric unit of the title compound, contains a Fe II cation, a dianion of Hbtc and a chelating phen. In the compound, each Fe II displays a distorted octahedral geometry, being surrounded by one phen ligand, two µ 2 -O atoms of two carboxylates coming from two Hbtc ligands, one O atom from one carboxylate of another Hbtc and one terminal water molecule. The Hbtc ligand coming from the deprotonation of two carboxylates of H3btc acts as a dianion, in which one carboxylate ligates two Fe II cations in the µ 1,1 mode with the Fe-O-Fe angle at 102.75 (7)° and Fe···Fe distance of 3.38 (3) Å, to form a Fe 2 unit; while the other carboxylate adopts a monodentate mode. Thus, the adjacent Fe 2 units are linked each other by a pair of tridentate Hbtc ligands in head-to-tail into a one-dimensional chain. The shortest Fe···Fe distance separated by Hbtc ligands is 10.90 (3) Å. Further, the one-dimensional chains are stabled by intrachain hydrogen bonding between coordinated water molecules and adjacent uncoordinated O atoms of monodentate carboxylates with the O···O distance of 2.602 (3) Å. Finally, the one-dimensional chains are further linked together by the interchain hydrogen bonding between uncoordinated carboxylates and uncoordinated O atoms of coordinated µ 2 -carboxylates as well as coordinated water molecules into a two-dimensional supramolecular network.

S3. Refinement
The H atoms bonded to O atom were located in a difference map and freely refined. Other H atoms were positioned geometrically and refined using a riding model with C-H = 0.93 Å and with U iso (H) = 1.2U eq (C).  The Fe 2 structure of the title compound with 30% thermal ellipsoids. All the H atoms on the C atoms are omitted for clarity. Symmetry codes: a: 1 -x, 2 -y, 1 -z; b: 1 -x, 1 -y, 1 -z; c: x, 1 + y, z.

Figure 2
The one-dimensional chain of the title compound. All the H atoms have been omitted for clarity.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq