Bis(1H-imidazole-κN 3){2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolato-κ4 O,N,N′,O′}iron(III) perchlorate

The title compound, [Fe(C17H16N2O2)(C3H4N2)2]ClO4, consists of monomeric [Fe(salmen)(HIm)2]+ cations {salmen is the 2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolate dianion and HIm is 1H-imiazole} and perchlorate anions. In the cation, the Fe3+ ion is octahedrally coordinated by two N atoms and two O atoms from a tetradentate salmen anion and two N atoms from two Him molecules. These ligands are coordinated to the iron ion in a direction perpendicular to the [Fe(salmen)]+ coordination plane. The benzene ring planes in the salmen ligands are oriented nearly parallel to one another intermolecularly [dihedral angle = 6.36 (3)°]. The dihedral angle between the mean planes through the imidazole rings in the cation is 76.9 (2)°. In the crystal, N—H⋯O interactions link the molecules into a one-dimensional double chain running along [101] and C—H⋯O interactions link the double chains into a two-dimensional network, running parallel to the ac plane.

The title compound, [Fe(C 17 H 16 N 2 O 2 )(C 3 H 4 N 2 ) 2 ]ClO 4 , consists of monomeric [Fe(salmen)(HIm) 2 ] + cations {salmen is the 2,2 0 -[propane-1,2-diylbis(nitrilomethylidyne)]diphenolate dianion and HIm is 1H-imiazole} and perchlorate anions. In the cation, the Fe 3+ ion is octahedrally coordinated by two N atoms and two O atoms from a tetradentate salmen anion and two N atoms from two Him molecules. These ligands are coordinated to the iron ion in a direction perpendicular to the [Fe(salmen)] + coordination plane. The benzene ring planes in the salmen ligands are oriented nearly parallel to one another intermolecularly [dihedral angle = 6.36 (3) ]. The dihedral angle between the mean planes through the imidazole rings in the cation is 76.9 (2) . In the crystal, N-HÁ Á ÁO interactions link the molecules into a one-dimensional double chain running along [101] and C-HÁ Á ÁO interactions link the double chains into a two-dimensional network, running parallel to the ac plane.
In addition, many intermolecular interactions are observed in the crystal structure. Intermolecular C-H···O hydrogen bonds link the benzene hydrogens H7 and H16 with the anion oxygens O6 and O5, respectively. N-H···O hydrogen bonds link the imidazole hydrogen H6A to anionic oxygen O4 and link the imidazole H4A in a bifurcated bond to the ring oxygen O2 and the anion oxygen O6. The N-H···O interactions link the molecules into a one-dimensional double chain (step ladder) running in the [1 0 1] direction, with N4-H4A···O2 acting as the rungs in the ladder. The C-H···O interactions link the double chains into a two-dimensional network, running parallel to the ac plane.

S2. Experimental
The salmen ligand was prepared by the reaction of 1, 2-diaminopropane (2 mmol) and salicylaldehyde (4 mmol) in ethanol. The title compound was synthesized in accordance with the procedure reported in the literature (Brendan et al., 1987).

S3. Refinement
All H-atoms were positioned geometrically (N-H = 0.88 Å and C-H = 0.95 -0.99Å ) and refined a riding model with U iso (H) = 1.2 U eq (C, N) or 1.5 U eq (C) for methyl H atoms.  The molecular structure of the title compound drawn with 50% probability displacement ellipsoids.

Bis(1H-imidazole-κN 3 ){2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolato-κ 4 O,N,N′,O′}iron(III)
perchlorate Crystal data [Fe(C 17  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.77 e Å −3 Δρ min = −0.65 e Å −3 Special details 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 > 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.