Tris(1,10-phenanthroline)iron(II) μ-oxido-bis[trichloridoferrate(III)]

In the title salt, [Fe(C12H8N2)3][Fe2Cl6O], the ionic components are linked into a two-dimensional supramolecular layer by two pairs of C—H⋯Cl hydrogen bonds and π–π stacking interactions [centroid–centroid distances = 3.655 (4) and 3.498 (3) Å]. The salt is characterized as a mixed-valent FeII–FeIII compound, in which an FeII atom is coordinated by three phen ligands, forming a six-coordinated cationic entity and the anionic part is formed by two FeIII atoms in tetrahedral coordination environments constructed by three chloride ions and one bridging oxide ligand. Intramolecular C—H⋯N hydrogen bonds are observed.

In the title salt, [Fe(C 12 H 8 N 2 ) 3 ][Fe 2 Cl 6 O], the ionic components are linked into a two-dimensional supramolecular layer by two pairs of C-HÁ Á ÁCl hydrogen bonds andstacking interactions [centroid-centroid distances = 3.655 (4) and 3.498 (3) Å ]. The salt is characterized as a mixed-valent Fe II -Fe III compound, in which an Fe II atom is coordinated by three phen ligands, forming a six-coordinated cationic entity and the anionic part is formed by two Fe III atoms in tetrahedral coordination environments constructed by three chloride ions and one bridging oxide ligand. Intramolecular C-HÁ Á ÁN hydrogen bonds are observed.
We are grateful for financial support from the Natural Science Foundation of Zhejiang Province (project Y4100610).
In the crystal structure offset face-to face aromatic π-π stacking interactions and hydrogen bonds lead to the formation of a two-dimensional supramolecular layer. Firstly, along the [1 -1 1] direction, all adjacent cation of [Fe(phen) 3 ] 2+ are joined to each other by virtue of π-π stacking interactions between two phen ligands to form a one-dimensional supramolecular chain (Chandrasekhar et al., 2006). Two pairs of phen skeletons are arranged in a parallel fashion, ring 1 (C4-C9) of one cation stacks with ring 2 (C4-C9) i [(i): 2 -x, -y, 1 -z] of a neighbouring cation with an interplanar distance of 3.487 (9) Å, and ring 3 (N4/C20-C24) of one cation stacks with ring 4 (N4/C20-C24) ii [(ii) 1 -x, 1 -y, -z] of a neighbouring cation with an interplanar distance of 3.250 (6) Å. Adjacent chains, in turn, are fused together by the [Cl 3 FeOFeCl 3 ] 2inorganic anion through two pairs of (C-H···Cl) hydrogen bonding interactions between cations and anions ( Table 1). As a result, the supramolecular chains interconnect to form a two-dimensional supramolecular layer.
Crystals of (I) suitable for single-crystal X-ray diffraction were selected directly from the sample as prepared.

Refinement
All hydrogen atoms were added at calculated positions and refined using a riding model (C-H: 0.93Å, U(H): 1.2 × U eq (C). Fig. 1. Structure and labeling of the title compound, with displacement ellipsoids drawn at the 30% probability level and H atoms shown as small spheres of arbitrary radii.