Poly[(μ-1,3-thiocyanato-κN,S)(isonicotinato-κN,O)(ethanol-κO)cadmium(II)]

In the crystal structure of the title compound, [Cd(NCS)(C6H4NO2)(C2H5OH)]n, the Cd2+ cation is coordinated by one N and two O atoms of two symmetry-related isonicotinate anions, one ethanol molecule and two μ-1,3-bridging thiocyanate anions in a distorted octahedral N2O3S geometry. The metal cations are μ-1,3-bridged via thiocyanate anions into chains that are further connected into layers parallel to the ab plane by bridging isonicotinate anions. The layers are stacked along the c axis. The crystal structure is stabilized by O—H⋯O hydrogen bonds.

In the crystal structure of the title compound, [Cd(NCS)-(C 6 H 4 NO 2 )(C 2 H 5 OH)] n , the Cd 2+ cation is coordinated by one N and two O atoms of two symmetry-related isonicotinate anions, one ethanol molecule and two -1,3-bridging thiocyanate anions in a distorted octahedral N 2 O 3 S geometry. The metal cations are -1,3-bridged via thiocyanate anions into chains that are further connected into layers parallel to the ab plane by bridging isonicotinate anions. The layers are stacked along the c axis. The crystal structure is stabilized by O-HÁ Á ÁO hydrogen bonds.
Data collection: X-AREA (Stoe, 2008); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2011); software used to prepare material for publication: publCIF (Westrip, 2010). The structure of the title compound was prepared within a project on the synthesis of transition metal thiocyanato coordination polymers in which the metal cations are µ-1,3 bridged by the anionic ligands (Näther & Greve, 2003;Boeckmann & Näther, 2010Wöhlert et al., 2011). In the course of our investigations crystals of the title compound were obtained and characterized by single-crystal X-ray diffraction.
In the crystal structure the cadmium(II) cations are coordinated by one N and two O atoms of two µ-1,3,6 bridging isonicotinato anions which are related by symmetry, one N and one S atom of two symmetry-related µ-1,3 bridging thiocyanato anions and one O atom of an ethanol molecule (Fig. 1). The coordination polyhedron of the cadmium cations can be described as a slightly distorted octahedron (Table 1).
The Cd 2+ cations are µ-1,3 bridged by thiocyanato anions into chains, which elongate in the direction of the crystallographic a axis. These chains are bridged by µ-1,3,6 bridging isonicotinato anions into layers in the direction of the crystallographic b axis and the layers are stacked along the crystallographic c axis (Fig. 2).
The shortest Cd···Cd distances within the layers amounts to 5.7778 (3) Å and to 9.2393 (4) Å. It must be noted that according to research in the CCDC database (ConQuest Ver.1.14; Allen, 2002) one coordination compound based on Cd(NCS) 2 , isonicotinato anions and thiocyanato anions is known, in which ethanol is exchanged by water. The overall coordination topology is similar but this compound is not isotypic to the title compound (Yang et al., 2001).
The crystal structure is stabilized by an O-H···O hydrogen bond.

Experimental
Potassium thiocyanate and isonicotinic acid were purchased from Alfa Aesar, Cd(SO 4 ) 2 .4H 2 O was obtained from Merck.
The final product was dried at 80°C. The homogeneity of the product was investigated by X-ray powder diffraction. The title compound was prepared by the reaction of 34.3 mg Cd(NCS) 2 (0.15 mmol) and 36.9 mg isonicotinic acid (0.30 mmol) in 2 ml ethanol at 80°C in a closed 10 ml glass culture tube. After several days colourless needles of the title compound were obtained.

Refinement
The C-H H atoms were positioned with idealized geometry (methyl H atoms allowed to rotate but not to tip) and were refined isotropically with U iso (H) = 1.

Figure 1
Crystal structure of the title compound with labelling and displacement ellipsoids drawn at the 50% probability level.
Symmetry code: i = -x + 1, y + 1/2, -z + 3/2.  Crystal structure of the title compound with view in the direction of the crystallographic c axis.

Poly[(µ-1,3-thiocyanato-κN,S)(isonicotinato-κN,O)(ethanol-κO)cadmium(II)]
Crystal data 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 > 2sigma(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.