Dibromido{2-[2-(piperidinium-1-yl)ethyliminomethyl]phenolato}zinc(II) monohydrate

The asymmetric unit of the title compound, [ZnBr2(C14H20N2O)]·H2O, consists of a mononuclear Schiff base zinc(II) complex molecule and a solvent water molecule. The ZnII atom is four-coordinated in an approximately tetrahedral geometry, binding to the imine N and phenolate O atoms of the neutral zwitterionic Schiff base ligand and to two terminal Br− anions. In the crystal structure, molecules are linked through intermolecular O—H⋯Br and O—H⋯O hydrogen bonds, forming chains running along the b axis.

The asymmetric unit of the title compound, [ZnBr 2 (C 14 H 20 N 2 O)]ÁH 2 O, consists of a mononuclear Schiff base zinc(II) complex molecule and a solvent water molecule. The Zn II atom is four-coordinated in an approximately tetrahedral geometry, binding to the imine N and phenolate O atoms of the neutral zwitterionic Schiff base ligand and to two terminal Br À anions. In the crystal structure, molecules are linked through intermolecular O-HÁ Á ÁBr and O-HÁ Á ÁO hydrogen bonds, forming chains running along the b axis.
Recently, we have reported two Schiff base zinc(II) complexes with bromide ligands Zhu et al., 2007).
As a continuation of our work on the structures of such complexes, we report herein the crystal structure of the new title complex, (I), which is isostructural with the zinc(II) complex with chloride ligands (Zhang et al., 2008).
The tetrahedral coordination sphere of Zn II atom in (I) is formed by the imine N and phenolate O atoms of the Schiff base ligand and by two terminal Branions ( Fig. 1). The coordinate bond distances (Table 1) are typical and comparable with the values in other similar zinc(II) complexes (Peng & Hou, 2006;. The O1-Zn1-N1 and O1-Zn1-Br1 bond angles deviate most from ideal tetrahedral geometry with values of 93.91 (11) and 116.12 (8)°, respectively. The other angles in the coordination sphere are in the range 108.84 (9)-113.42 (2)° (Table 1).
In the crystal structure of (I), molecules are linked through intermolecular O-H···Br and O-H···O hydrogen bonds (Table 2), forming chains running along the b axis (Fig. 2).

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 Rfactors(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.