Dibromido{(E)-2-ethoxy-6-[3-(methylammonio)propyliminomethyl]phenolato}zinc(II)

The title complex, [ZnBr2(C13H20N2O2)], is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base (E)-2-ethoxy-6-((3-(methylamino)propylimino)methyl)phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand, and by two bromide ions, in a tetrahedral coordination geometry. Adjacent molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains running along the b axis.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ2525).
The Zn II atom in (I) is four-coordinated by the imine N and phenolate O atoms of the zwitterionic form of the Schiff base ligand and by two Brions in a tetrahedral coordination geometry. The coordinate bond lengths (Table 1) are typical and comparable to the corresponding values observed in other similar zinc(II) Schiff base complexes (Zhu et al., 2007;Wei et al., 2007;Qiu, 2006).
In the crystal structure, adjacent molecules are linked through intermolecular N-H···O hydrogen bonds (Table 2), forming chains running along the b axis (Fig. 2).

Experimental
The Schiff base compound was prepared by the condensation of equimolar amounts of 3-ethoxysalicylaldehyde with Nmethylpropane-1,3-diamine in a methanol solution. The complex was prepared by the following method. To an anhydrous methanol solution (5 ml) of ZnBr 2 (22.5 mg, 0.1 mmol) was added a methanol solution (10 ml) of the Schiff base compound (23.6 mg, 0.1 mmol) with stirring. The mixture was stirred for 30 min at room temperature and filtered. Upon keeping the filtrate in air for a few days, colorless block-shaped crystals were formed at the bottom of the vessel on slow evaporation of the solvent.

Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C-H distances in the range 0.93-0.97 Å, N-H distances of 0.90 Å, and with U iso (H) = 1.2U eq (C,N) and 1.5U eq (methyl C). The structure contains a solvent accessible void of 58 Å 3 , which might accommodate a disordered methanol solvent molecule. Fig. 1. The molecular structure of (I) with ellipsoids drawn at the 30% probability level.