Poly[[μ3-2-(benzotriazol-1-yl)acetato-κ3O:O′:N3]chlorido(ethanol-κO)cobalt(II)]

The reaction of 2-(benzotriazol-1-yl) acetic acid with CoCl2 at room temperature in ethanol generates the title three-dimensional cobalt-based coordination polymer.


Structure description
As a ligand with multiple coordination sites, benzotriazole is a good linker in the generation of metal-organic frameworks (MOFs) as it can bridge different metal cations to afford coordination polymers that exhibit structural diversity and facile accessibility of functionalized new magnetic materials (Bai et al., 2008;Shao et al., 2008;Mu ¨ller-Buschbaum & Mokaddem, 2006).Functional groups such as carboxylate, hydroxy and pyridyl can be added to the benzotriazole core, increasing its coordination possibilities (Stoumpos et al., 2008;Zhang et al., 2007;Hu et al., 2008;Hang & Ye, 2008).1H-Benzotriazole-1-acetic acid (Hbtaa), a flexible ligand, containing a carboxylate group (when deprotonated) and a triazole unit has been used to construct MOFs (Zheng et al., 2010;Zeng, 2013).As part of our work in this area, we now report the synthesis and crystal structure of the title coordination polymer, [Co(C 8 H 6 N 3 O 2 )Cl(C 2 H 5 OH)] n , where C 8 H 6 N 3 O 2 À (L À ) is the 2-benzotriazol-1-yl)acetate anion.Single-crystal structural analysis reveals that the asymmetric unit consists of two Co II cations (one with site symmetry m and one with site symmetry 1), one L À ligand, two chloride ions (both site symmetry m) and one disordered ethanol molecule (Fig. 1).Co1 is four-coordinated by two L À ligands in O-monodentate mode and two � 1 -chloride ions in a tetrahedral coordination geometry, whereas Co2 is six-coordinated by four L À ligands (two in N-monodentate mode and two in O-monodentate mode) and two ethanol molecules.In the extended structure, the � 3 -O,O,N bridging L À ligand links the Co2 nodes into (010) sheets (Fig. 2) and the Co1Cl 2 fragments link the sheets into a tri-periodic network (Fig. 3).An O-H� � �O hydrogen bond (Table 1) occurs.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å
In the title compound, [Co(C 8 H 6 N 3 O 2 )Cl(C 2 H 5 OH)] n , the Co II atoms adopt octahedral trans-CoN 2 O 4 and tetrahedral CoCl 2 O 2 coordination geometries (site symmetries 1 and m, respectively).The bridging � 3 -O:O:N 2-(benzotriazol-1-yl)acetato ligands connect the octahedral cobalt nodes into (010) sheets and the CoCl 2 fragments link the sheets into a tri-periodic network.The structure displays O-H� � �O hydrogen bonding and the ethanol molecule is disordered over two orientations.
treatment H atoms treated by a mixture of independent and constrained refinement �� max , �� min (e A ˚À 3 ) 0.71, À 0.38

Figure 1
Figure 1The asymmetric unit of the title compound showing 50% displacement ellipsoids.Only one orientation of the disordered ethanol molecule is shown.

Table 2
Experimental details.