Dichlorido[1-(8-quinolyliminomethyl)-2-naphtholato]iron(III)

The FeIII ion in the title complex, [FeCl2(C20H13N2O)], has a distorted square-pyramidal coordination formed by one O atom and two N atoms from a tridentate 1-(8-quinolyliminomethyl)-2-naphtholate ligand and two Cl atoms. In the crystal structure, molecules form a column structure along the a axis through π–π stacking interactions, with centroid–centroid distances of 3.657 (1) and 3.818 (2) Å. Weak C—H⋯Cl interactions are observed between the columns.

The Fe III ion in the title complex, [FeCl 2 (C 20 H 13 N 2 O)], has a distorted square-pyramidal coordination formed by one O atom and two N atoms from a tridentate 1-(8-quinolyliminomethyl)-2-naphtholate ligand and two Cl atoms. In the crystal structure, molecules form a column structure along the a axis throughstacking interactions, with centroid-centroid distances of 3.657 (1) and 3.818 (2) Å . Weak C-HÁ Á ÁCl interactions are observed between the columns.

S1. Comment
Self-assembly has been recognized as a most efficient process that organizes individual molecular components into highly ordered supramolecular species (Crivillers et al., 2009). The designed construction of supramolecules from molecular building blocks is noted as one of most challenging issues facing synthetic chemistry today. The method by using self-assembly is very important in developing novel molecular compounds with multi-functions. The cooperativity can be achieved by using π-π interactions as well as by using bridging ligands. We focused on a iron(III) complex with a qnal ligand [qnal = 1-(quinolin-8-yliminomethyl)-naphthalen-2-ol] having large π electron system. Here we report the synthesis and crystal structure of the title complex.
The Fe III ion in the title complex, [Fe(qnal)Cl 2 ], has a distorted five coordination environment formed by one O atom and two N atoms from a qnal ligand, and two Cl atoms. The Fe-O bond length is shortest and the Fe-Cl bond length is longest. The π-π contacts between the benzene and pyridine rings, Cg1···Cg3 i and Cg2···Cg3 ii [symmetry codes: (i) -x, -y, respectively] may stabilize the structure, with centroid-centroid distances of 3.657 (1) and 3.818 (2) Å, respectively. The molecules form a column structure by π-π stacking along the a axis. Three dimensional network is formed through C-H···Cl interactions between columns.

S2. Experimental
The ligand molecule, qnal, was prepared from 8-aminoquinoline (4.2 mg, 0.03 mmol) and 2-hydroxy-1-naphthaldehyde (5.1 mg, 0.03 mmol), which were mixed in 10 ml methanol and heating on a oil bath for about 2 h under reflux. The title complex was prepared by slow diffusion of qnal (9.0 mg, 0.03 mmol) and FeCl 3 (4.9 mg, 0.03 mmol) in methanol by using a H-form tube. After about one week, single crystals were obtained as black needles.

S3. Refinement
All H atoms were positioned geometrically (C-H = 0.93 Å) and were refined as riding, with U iso (H) = 1.2U eq (C).    Part of the crystal structure, showing C-H···Cl interactions as dashed lines.

Dichlorido[1-(8-quinolyliminomethyl)-2-naphtholato]iron(III)
Crystal data [FeCl 2 (C 20  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